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View Full Version : junkyard belt grinder build (2" x 72")



dian
01-13-2016, 02:44 PM
we dont have any of those fancy kits over here, so i decided to build one myself. the purpose of this thread is to get advise but also to make me actually do it. i intend to put one hour into it every day and will document how long it took me.

it will be "junkyard" in the sence, that i will try and use only the stuff i already have or can find around the shop. any purchase will be a failure. it will also be a very crude build, i will not derust the metal, break any edges, ream anything for fit nor will i paint it. its suppsed to be a grinder with the least effort and investment possible. will it be ugly? for sure. will it work? we will see.

this is the pile of stuff the grinder is supposed to emerge from:

http://i973.photobucket.com/albums/ae218/romandian/3%20002_zps6p6cosae.jpg (http://s973.photobucket.com/user/romandian/media/3%20002_zps6p6cosae.jpg.html)

these are the requirements the grinder has to satisfy:

- fit into the space on the bench (600 mm)
- the wheels or platten are not to portrude more than 50 - 100 mm beyond the edge
- be semi portabe, so two guys can carry it (motor is around 40 pounds)

for the "grinding point" not to portrude into the walk through space, the tracking wheel has to compensate for all conceivable cofigurations, so it has to move up and down by around 150 mm (300 total). therefore it will get a rotating tracking contraption, to make the adjustment be always rectangular to belt tension.

http://i973.photobucket.com/albums/ae218/romandian/3%20003_zpsh3gpoiay.jpg (http://s973.photobucket.com/user/romandian/media/3%20003_zpsh3gpoiay.jpg.html)

what i have in mind looks like this.

http://i973.photobucket.com/albums/ae218/romandian/3%20223_zpssrngynl7.jpg (http://s973.photobucket.com/user/romandian/media/3%20223_zpssrngynl7.jpg.html)

i have never worked on a grinder with a soft wheel. (we dont have these type of machines, i have never seen one, they would probably be considered as unsafe.) if i find out that i still need a slack belt, i might do it in the way shown in the lower drawing.

the platten will go between the soft wheel and the idler at 45° or so and be at least 400 mm or longer. it might be strange in the beginning, but im sure i will get used to it. i might make a vertical platten with small radius attachments in the future, but dont see any need for it at this point.

the motor is a 2.2 kw 2900 rpm 3 phase and has been living in this box for ages connected to its vfd:

http://i973.photobucket.com/albums/ae218/romandian/3%20004_zpsw4ixt9nq.jpg (http://s973.photobucket.com/user/romandian/media/3%20004_zpsw4ixt9nq.jpg.html)

i invite any comments or critique about details or the whole concept, as mentioned i have never worked on this type of grinder.

this must be the larges compilation of belt grinders, btw. i have never seen it mentioned on here:

http://gonza-rytec.rajce.idnes.cz/belt_grinders2/

DICKEYBIRD
01-13-2016, 02:59 PM
Don't know much about the subject but your junkyard sure looks better than mine!;) Your plan looks to be sound & well thought-out....but that's to be expected coming from you.

mattthemuppet
01-13-2016, 03:54 PM
this'll be neat, looking forward to the build! I have plans for a belt/disk sander rattling around my head, so I'm really interested to see what you come up with.

Guido
01-13-2016, 04:08 PM
-------------No chore for a 'stepper', go for it------------------

gellfex
01-13-2016, 07:56 PM
Seems overpowered to me, compared to my classic Rockwell or Taiwanese Delta 1x42's. My 6" belt has 2 hp. But whatever, seems like fun. Will you be making crowned pulleys? And which type of center adjuster will you use? I hate the one on the Delta.

If I were doing it I would just scale up the 1" Rockwell.

http://industrial-library.com/catalog/images/189_RDSanderS_Cover.gif

ironmonger
01-13-2016, 09:46 PM
https://dl.dropboxusercontent.com/u/37105624/PICT0184-1.JPG

It's a KMG clone.

I use to stall my 2 HP 2X72, now running a 3 HP with a VFD as does yours. 3 HP is definitely not overkill. The motor is an under drive to save space. I'm adding a water mist system for heavy hogging next spring.

I don't have the figures, but I'm going to guess my contact wheel is around 40 Durometer. Never had an issue with the 'soft' contact wheel, which is now 7 years old. The contact wheel is flat and both the idler and drive wheel are crowned. The actual tracking wheel deflection is quite small. +/- maybe 3° or so.

I use to have a pdf of the plans in my dropbox folder, but I may have deleted them. I can make them available if you would like to see them.

The KMG (http://www.beaumontmetalworks.com/shop/category.aspx?catid=12) uses accessory bars to hold the various wheels. In the photo you can see the adapter for the small contact wheels. The small contact wheels is a 1" but they range from 5/8" to 1-3/4" diameter.

The slack belt is an accessory bar as well and has an adjustable platen and work table shown attached to the slack belt bar.

https://dl.dropboxusercontent.com/u/37105624/PICT0188-1.JPG

this bit was just fun

https://dl.dropboxusercontent.com/u/37105624/PICT0185-1.JPG

I used an air cylinder as a tensioning spring. A builder had this idea on another board and some guy was flaming him cause it needed shop air to work... so what, it needs electricity too. ITS IN YOUR SHOP... probably never find an air line there. :~)

That is a impressive collection of grinders in your link...

lakeside53
01-14-2016, 02:26 AM
Another "junk" belt grinder build, actually 2 of them... Did buy a real contact wheels and 3hp vfd's though. Even the vfd control heads were from parts scrounged from old sonar displays. 3 hp isn't overkill at all.



http://i238.photobucket.com/albums/ff150/lakeside53/x72%20Belt%20grinder/DSCN2416Medium.jpg (http://s238.photobucket.com/user/lakeside53/media/x72%20Belt%20grinder/DSCN2416Medium.jpg.html)

Lots of details/pics here : http://s238.photobucket.com/user/lakeside53/library/x72%20Belt%20grinder?sort=4&page=1

dian
01-14-2016, 04:42 AM
lakeside, that is a "nasa build", i will try and keep it simple. im planning to only crown the drive pulley.

http://s238.photobucket.com/user/lakeside53/media/x72%20Belt%20grinder/DSC_8675Medium.jpg.html?sort=4&o=26

so you are adjusting tracking with the horizontal knob, tilting the whole assembly? does that work? im thinking the belt has to run parallel to the rotation of the wheel. but maybe not?

lakeside53
01-14-2016, 12:42 PM
The horizontal knob (front) rotates the arm and wheel assembly in the horizontal plane. The top knob locks it in place (not really needed to "lock" - just some friction). Works well. Tilting the wheel in the vertical plane also works; I just choose the former method.

Black Forest
01-14-2016, 01:22 PM
Lakeside those grinders are really well made. How long did it take you to figure out everything? I bet you hated to put paint on all those really cool machined parts. Paint covers up all the great work that went in to build those grinders. Next time spray them with clear polyurethane.

I am really impressed with the work you did.

cijuanni
01-14-2016, 01:23 PM
it will be "junkyard" in the sence, that i will try and use only the stuff i already have or can find around the shop. any purchase will be a failure. it will also be a very crude build, i will not derust the metal, break any edges, ream anything for fit nor will i paint it. its suppsed to be a grinder with the least effort and investment possible. will it be ugly? for sure. will it work? we will see.



Why?

I have built 3 grinders, the cost/time is in the motor, vfd, bearings, wheels and contact wheel.
Don't think making an intentionally ugly, rusty framework with finger cutting sharp edges to hold 3 or 4 wheels in proper alignment is going to save you much money or effort.

dian
01-14-2016, 01:27 PM
lakeside, doesnt the belt then not run true to the wheel? so maybe it doesnt mater to have a slight angle difference? im asking because it would spare me fabricating a swiveling tracking contaption.

dian
01-14-2016, 01:36 PM
cij, in my experience it will. it usually takes three times the effort, money and time to make my stuff look good. and then priming/painting is annother effort im going to avoid. i just want to grind.

ironmonger
01-14-2016, 01:58 PM
doesnt the belt then not run true to the wheel? so maybe it doesnt mater to have a slight angle difference? im asking because it would spare me fabricating a swiveling tracking contaption.

In the KMG grinder the the idler swings in an arc perpendicular to the plane of the belt, observing from the end of the motor shaft it has freedom in the pitch plane with no yaw.

https://dl.dropboxusercontent.com/u/37105624/PICT0185-1.JPG

you can make out the small blocks that the pivot pin goes through just to the left of the idler wheel. The idler is bolted through the block opposite the adjustment screw that are between the two .5"X2"X2.5" blocks bolter to the winging tensioner frame. It's a .75"X2"X2.5" block pivoting near the top and the 2"X2.5" face is drilled for a 1/2-13 bolt that carries the idler.

See page 5 of 7 at the first part of this file (https://dl.dropboxusercontent.com/u/37105624/Grinder%20Plans.pdf)

This entire grinder is made from flat stock. And while I am perfectly capable of welding, the mounting tunnel that carries the tool bars was fabricated from flat stock. The fit is quite close and I didn’t want to take a chance on a very slight warpage in the 10" long tunnel that would impede the insertion of the tool support bars, which are 1.25" square stock.

gellfex
01-14-2016, 02:00 PM
Damn Lakeside, have a little mercy? You set the bar really high, those things are PURTY! I don't need a 2" grinder for the AL & Delrin I use, but now I want one.....

Paul Alciatore
01-14-2016, 02:58 PM
Good luck with your build.

Extra points are awarded if you incorporate that section of rail in it.

And I would really encourage you to at least take some extra time to break the sharp edges. Your hands will thank you many times over. Personally, I would work on any rust too, but that's me.

Black Forest
01-14-2016, 03:13 PM
Don't worry you guys about Dian breaking edges and cleaning it up some. He is Swiss. He will do it. It is a genetic thing. He won't be able to not do it.

lakeside53
01-15-2016, 01:16 AM
lakeside, doesnt the belt then not run true to the wheel? so maybe it doesnt mater to have a slight angle difference? im asking because it would spare me fabricating a swiveling tracking contaption.

The tracking wheel (the one that moves around ) is crowned 1 degee. You are just biasing the belt across the crown. If you tilt vertically (easy, and most designs to do) you change the tension on the belt more on one side verse the other. It doesn't seem to matter.

outlawspeeder
01-15-2016, 01:30 AM
I built mine a year ago and use it any day I am in the shop.

Mine was built from leftover parts. I did have to play with alinement but once that was done it is my got to tool for quick work.

+1 on using the rail!

Glug
01-15-2016, 07:07 PM
It takes a certain amount of courage to post an in-progress build here, warts and all, with the tremendous skill and experience of the audience. I don't think there is anything wrong with banging out a quick belt grinder with parts on hand, and not getting caught up in perfection, or analysis paralysis. And when you start looking at those really well thought out and constructed grinders, it sure could bog you down, pun not intended. Plus, you can use this first one to help build the second one, or rebuild the first.


http://gonza-rytec.rajce.idnes.cz/belt_grinders2/

There are some great belt grinders in that collection. I like wayy too many of those designs. There is one about 3/4 the way down that caught my eye. It uses an apparently undersized motor to drive two belt grinders, in a very interesting arrangement. It looks like yould could stick a blade between the two belts and rapidly form an edge or rough sharpen. Thoughts on that? I also like how the shafts serve double duty, with the buffing wheel (or deburring?) and disc at the far ends. Though I wonder whether it is sufficiently rigid, since the two vertical columns are not connected. The wheels touching probably helps. The I-beam base is also a nice touch.

http://img99.rajce.idnes.cz/d9902/8/8662/8662419_b95110d2ed90dc46750baef03d293214/images/bruska639.jpg

http://img99.rajce.idnes.cz/d9902/8/8662/8662419_b95110d2ed90dc46750baef03d293214/images/bruska639d.jpg

http://img99.rajce.idnes.cz/d9902/8/8662/8662419_b95110d2ed90dc46750baef03d293214/images/bruska639c.jpg

Axkiker
01-16-2016, 04:00 PM
I may be totally wrong but I think the above is for hollow grinding knife blades.

dian
01-17-2016, 04:24 PM
first "setback": i had to buy four bolts and 10 washers (12 mm). cost me $20 (swiss prices, you know). i consider myself lucky i got them. its really difficult to get hardware over here. there is only one place i know of, that will sell you single bolts and they are selling off their stock, so that source will eventually disappear.

http://i973.photobucket.com/albums/ae218/romandian/3%20224_zps2tpmgvpt.jpg (http://s973.photobucket.com/user/romandian/media/3%20224_zps2tpmgvpt.jpg.html)

well, anyway, after 3 hours of work i have this:

http://i973.photobucket.com/albums/ae218/romandian/3%20225_zps7a8xhyn6.jpg (http://s973.photobucket.com/user/romandian/media/3%20225_zps7a8xhyn6.jpg.html)

i had these teflon pads around and they fit perfectly, so i didnt have to make aluminum washers to center the beam. (the weird spacer on the bolt is just because its too long.)

Toolguy
01-17-2016, 06:40 PM
Not a bad start.:) When you are done you will be glad you built this. It is a very useful, time saving tool.

Glug
01-18-2016, 11:45 AM
What are the primary factors that determine how smooth a belt grinder runs? It is often said the Burr King's run very smooth. Though in my reading comparisons, they aren't perceived to run any smoother than KMG's. Concentricity of rotating components, stiffness and balance would seem to be the primary factors.

What about the significance of direct motor drive vs. belt drive? Does a drive belt offer any vibration dampening, especially with single phase? Shafts mounted on pillow block or flange bearings, locked with set screws, might be a source of concentricity issues?

A quick search on ebay turned up these econo wheel options. I wonder under what circumstances - max rpm, etc - they could be used to produce a more inexpensive grinder?

http://www.ebay.com/itm/Rubber-Mold-On-Steel-Wheel-8-x-2-with-3-4-ID-Roller-Bearing-600-Capacit-/400960874846

http://www.ebay.com/itm/8-x-2-1-2-Rubber-on-Steel-Caster-Wheel-850-lbs-/171780338782

http://www.ebay.com/itm/8-x-2-Rubber-on-Aluminum-Wheel-for-Casters-or-Equipment-600-lb-Cap-/221539896467

http://stores.ebay.com/SERVICE-CASTER-CORPORATION/Caster-and-Equipment-Wheels-

lakeside53
01-18-2016, 01:24 PM
Balance and accurate construction/alignment, but it depends on your speed target. I spent a lot of time making mine "as good as I could" because it is variable from zero to 6000sfm. Rotating components symmetrical from 6061 and 7075 (scrap bin), and a very stiff frame to absorb any work induced movement and I bought a commercial 8 inch contact wheel; it came with a hub that has been balanced to the wheel. You don't want things going astray or vibrating. Mine's silky smooth.


Direct drive verse belt - no material difference. "single phase" motor "vibrations" would be tiny... and unlike a surface grinder wheel, will not be transmitted though a the grinding belt to affect "finish". My pulleys and wheels are solid aluminum, and "massive" in comparison to minor "out of balance" effects of shaft screws or keys. Do the math - make sure your bearings can take the speed of the contact wheel. Easy at 6 inches... more considerations at say 1 inch and 6000sfm.

My belt drive is PolyVee , IIRC 8 J section. Very good at transmitting power smoothly over wide ranges of speed.

ironmonger
01-18-2016, 02:35 PM
What are the primary factors that determine how smooth a belt grinder runs? It is often said the Burr King's run very smooth. Though in my reading comparisons, they aren't perceived to run any smoother than KMG's. Concentricity of rotating components, stiffness and balance would seem to be the primary factors.

My KMG clone is smooth running... the motor turns at 3400 RPM at 60 CPS, turning a 4" drive pulley to give about 3600 SFM and 5300 SFM at 90 CPS


What about the significance of direct motor drive vs. belt drive? Does a drive belt offer any vibration dampening, especially with single phase? Shafts mounted on pillow block or flange bearings, locked with set screws, might be a source of concentricity issues? Mine has a primary drive using stepped pulleys, so I have no experience here.



A quick search on ebay turned up these econo wheel options. I wonder under what circumstances - max rpm, etc - they could be used to produce a more inexpensive grinder?

As Lakeside says, I would strongly avoid any contact or idler wheel that is 'converted' unless you can be sure the bearings are up to the job and can assure wheel balance. The contact wheel that I have came from Beaumont Metal Works (http://www.beaumontmetalworks.com/shop/), and have been perfectly satisfactory. I think that Grizzly has a 10" contact wheel that is quite reasonable if you can fit a bearing into it. At $120 for the Grizzly, the KMG 10" (http://www.beaumontmetalworks.com/shop/item.aspx?itemid=65) wheel seems a bargain for a bit north of $300. Unless you are doing knife work the 6" contact wheel (http://www.beaumontmetalworks.com/shop/) is all you are likely to need. My smallest contact wheel is 1" in diameter. The VFD must be used to slow down the belt as the speed at 3600SFM for this little bearing would be in the neighborhood of 14.000 RPM, so even at 30 CPS, 7,000 RPM, you have to check the temp of the bearings.

Black Forest
01-18-2016, 03:41 PM
Dian, I saw some edge treatment in the photo !!! I knew you would have to do it.

If you need some hardware and can't get it let me know. I have a really good source not far away from me. Schrauben Jaeger. I could send you whatever you need.

dian
01-18-2016, 04:48 PM
as for the rubber wheels/casters i would think the problem is they are not balanced. i would also not like to find out what they do at say 6000 rpm.

thanks black, i might take you up on that. im looking for 6 14 mm 12.9 bolts with a shaft around 100 mm for my corvette. ill check out their site. can you get single bolts from them? and the edges are an optical illusion. the brackets are milled though on the inside.

Glug
01-19-2016, 10:19 AM
Thanks for the replies. There would be irony in moving from a disc grinder to a belt grinder for the safety benefits, only to have a caster wheel go to pieces at speed.

I am still trying to figure out why Switzerland apparently lacks basic hardware stores. What aspect of the culture, economy, etc, causes that.

cijuanni
01-19-2016, 11:40 AM
I think that Grizzly has a 10" contact wheel that is quite reasonable if you can fit a bearing into it. At $120 for the Grizzly, the KMG 10" (http://www.beaumontmetalworks.com/shop/item.aspx?itemid=65) wheel seems a bargain for a bit north of $300.

The Grizzly is only $81 plus shipping.
http://www.grizzly.com/products/10-Aluminum-Rubber-Wheel-For-G1015/G9242

I have one on my KMG clone at it runs true and smooth.
I didn't fit bearings to the hub, but bearings to a tooling arm with a shaft that the wheel then attaches to.


http://i56.photobucket.com/albums/g164/cijuanni/DSCN5106.jpg

Black Forest
01-19-2016, 04:19 PM
as for the rubber wheels/casters i would think the problem is they are not balanced. i would also not like to find out what they do at say 6000 rpm.

thanks black, i might take you up on that. im looking for 6 14 mm 12.9 bolts with a shaft around 100 mm for my corvette. ill check out their site. can you get single bolts from them? and the edges are an optical illusion. the brackets are milled though on the inside.

I can buy one of anything I want. What thread pitch on the 14mm bolts?

Tundra Twin Track
01-19-2016, 04:31 PM
Would a 6'' x 79'' belts with simalar design of grinder work and could you take the belts and slit them into narrow strips for smaller work.I have 6'' contact wheel and have a chance to get a bundle of Zarconia belts .

Black Forest
01-19-2016, 05:21 PM
Would a 6'' x 79'' belts with simalar design of grinder work and could you take the belts and slit them into narrow strips for smaller work.I have 6'' contact wheel and have a chance to get a bundle of Zarconia belts .

If you have the chance to get the belts then do it. I only buy 150mm wide belts for my 50mm wide belt grinder. I make a slit with a stanley knife at the seam and then just tear the belt into 3 belts. It is a lot cheaper that way.

But I would build a belt grinder with the 6 inch contact wheel for several reasons. First you have more versatility. Second you can build a pipe notcher for it real easy.

Tundra Twin Track
01-19-2016, 11:40 PM
If you have the chance to get the belts then do it. I only buy 150mm wide belts for my 50mm wide belt grinder. I make a slit with a stanley knife at the seam and then just tear the belt into 3 belts. It is a lot cheaper that way.

But I would build a belt grinder with the 6 inch contact wheel for several reasons. First you have more versatility. Second you can build a pipe notcher for it real easy.
Thanks BF
Grinder project a ways away,but has any one had experiance with the Green colored media R and how does it stack up to Zarconia.

Prokop
01-20-2016, 08:32 AM
Following. Or should I say:

Hodně štěstí? :)

dian
01-21-2016, 01:57 PM
The Grizzly is only $81 plus shipping.
http://www.grizzly.com/products/10-Aluminum-Rubber-Wheel-For-G1015/G9242

I have one on my KMG clone at it runs true and smooth.
I didn't fit bearings to the hub, but bearings to a tooling arm with a shaft that the wheel then attaches to.


http://i56.photobucket.com/albums/g164/cijuanni/DSCN5106.jpg

could you please explain how you attached the wheel? the bearing seems to be in that shiny cylinder, but how is that attached to the arm? only one bearing in there?

dian
01-21-2016, 01:59 PM
I can buy one of anything I want. What thread pitch on the 14mm bolts?

i would prefer 1.5 mm or finer. i have surfed their site but find it quite confusing. i didnt find a 12.9 14 mm x 1.5 mm bolt with a 100 mm shank. will try again tomorrow.

RichR
01-21-2016, 02:19 PM
could you please explain how you attached the wheel? the bearing seems to be in that shiny cylinder, but how is that attached to the arm? only one bearing in there?

I think the "shiny cylinder" is actually part of the arm. It looks like a skim cut was taken after it was painted to allow a little extra
clearance for the support arm underneath that the table is attached to.

dian
01-22-2016, 05:29 AM
Thanks for the replies. There would be irony in moving from a disc grinder to a belt grinder for the safety benefits, only to have a caster wheel go to pieces at speed.

I am still trying to figure out why Switzerland apparently lacks basic hardware stores. What aspect of the culture, economy, etc, causes that.

well, switzerland is one if the richest countries and probably the richest country without any natural ressources. it produces expensive goods and services that get sold world wide. to achieve this there is a very high level of specialisation of the workforce. this means that you have a challenging job you are good at, work long hours and then come home and enjoy your free time. it also means that an accountant is an accountant and doesnt know how to do anything else, exept spending the money he makes paying other specialists to do what needs to be done. its extremely unusual that somebody works on his cars or gets involved in building his house. a farmer is a farmer and if his tractor has problems, he calls the service technician. so you see why nobody needs any bolts. there are several doityourself markets, but there are no machines you can buy there that wheight over 40 pounds i guess. the assortments of bolts is beeing reduced on a regular basis, now being something like three sizes each from 3 to 10 mm. its a nightmare as bigger bolts will be sold in batches of 25 - 50 by specialised companies and smaller ones come in boxes of 100. i own several hundert pounds of bolts and nuts, but still need to get some from time to time. i believe the situation is similar in japan and the opposite example would be australia.

lakeside53
01-22-2016, 12:43 PM
We have parts of the USA larger then Switzerland and devoid of almost anything, but we have a mandated postal service, so mail order works well.

Here In Western WA. I have almost anything at my fingertips if I care to drive, but it's cheaper/quicker to simply hit the buy button and it turns up next day. I can get 4 hour delivery if it's stock 30 miles way. Some items I browse at night and then get surprised by a truck in my driveway next morning. lol.

Taking about driving.. Yesterday I had to drive to a client in downtown Seattle; 25 miles in 2.5 hours. 1 hour back. arghhh.. I expected to see blood and carnage on the freeway, but NO reason for the traffic disaster, lol... work from home today...

cijuanni
01-22-2016, 01:06 PM
could you please explain how you attached the wheel? the bearing seems to be in that shiny cylinder, but how is that attached to the arm? only one bearing in there?

I made a shaft that the wheel fastens to with a nut on the far side.
The close side of the shaft has 2 sealed ball bearings. The bearing seals are those odd colored orange/yellow things.
The double nuts are to adjust bearing preload.
The bearing housing was turned and bored on the lathe, after being welded to that short 2"x1" stub because I can't swing a 20" tooling arm in a 14" swing lathe.
And RichR is right, that is just a skim cut for clearance. I was thinking of attaching a spark shield to that concentric surface, but haven't.

dian
01-23-2016, 11:55 AM
so another four hours into the project. i decided to use the screw heads as hinges.
http://i973.photobucket.com/albums/ae218/romandian/3%20007_zpsjohcjsxl.jpg (http://s973.photobucket.com/user/romandian/media/3%20007_zpsjohcjsxl.jpg.html)

otherwise we have this.

http://i973.photobucket.com/albums/ae218/romandian/3%20015_zpsa8wqf5rc.jpg (http://s973.photobucket.com/user/romandian/media/3%20015_zpsa8wqf5rc.jpg.html)

http://i973.photobucket.com/albums/ae218/romandian/3%20010_zpsti7bpph7.jpg (http://s973.photobucket.com/user/romandian/media/3%20010_zpsti7bpph7.jpg.html)

http://i973.photobucket.com/albums/ae218/romandian/3%20016_zpsngw1jfot.jpg (http://s973.photobucket.com/user/romandian/media/3%20016_zpsngw1jfot.jpg.html)

i dont know what this wheel was in its previous life, maybe on a pallet jack, but when i took a hammer to it to beat it off the shaft it chipped and im having second thoughts to use them (i have several). btw, there are two bearings in there (6204 du) with a spacer between them.

so after 7 hours i have this and i seem to be slow. im counting the time i spend in the shop, including running around to get tools that are not where they were supposed to be (the shop it pretty big, which is a disadvantage in this sence) , but excluding dreaming about the build.

dian
01-23-2016, 12:11 PM
a comment on drilling. if you have a setup like this and you use medium quality drills:
http://i973.photobucket.com/albums/ae218/romandian/3%20006_zpsimzw7bvr.jpg (http://s973.photobucket.com/user/romandian/media/3%20006_zpsimzw7bvr.jpg.html)

contrary to popular belive the holes will be smaller than the drill. i used a 12 mm drill and a 11.98 silver rod would not go in. i drilled with a 9.9 mm drill and the 9.84-9.86 head cap screws would not go in. i had to skim them on the lathe with a sharp (carbide) tool.

about tapping. i use a set of 3 taps, always. i start the first tap by hand:

http://i973.photobucket.com/albums/ae218/romandian/3%20008_zpsvrzg3o8c.jpg (http://s973.photobucket.com/user/romandian/media/3%20008_zpsvrzg3o8c.jpg.html)

then i clamp the piece vertically and go through there with a cordless drill. i have no problems chucking the rectangular taps, btw. as i dont have to break any chips, im not sure this procedure is slower than power tapping and i dont remember a thread not being straight.

this i wanted to be really straight, so i tappet in the mill:

http://i973.photobucket.com/albums/ae218/romandian/3%20011_zpsg3pplrpv.jpg (http://s973.photobucket.com/user/romandian/media/3%20011_zpsg3pplrpv.jpg.html)

and this, btw, is the patented invention to be able to hold both 40 tappers (i see people using two draw bars):

http://i973.photobucket.com/albums/ae218/romandian/3%20012_zpsshuwd5rw.jpg (http://s973.photobucket.com/user/romandian/media/3%20012_zpsshuwd5rw.jpg.html)

dian
01-23-2016, 12:40 PM
so now the question, i have scrounged up these two whels over time. i have no idea how to mout them, although i have about 5 pounds of bearings, not too many are shielded and this is what i come up with:

http://i973.photobucket.com/albums/ae218/romandian/3%20017_zpskw5colke.jpg (http://s973.photobucket.com/user/romandian/media/3%20017_zpskw5colke.jpg.html)

the small wheel is solid on the other side. something tells me i have to use two bearings on the big wheel. i have the stock to make two hubs taking the big bearings and press/glue them into the wheel from both sides . i guess that will be fine. the small bearings are 15 x 35 mm and the bore being 16 mm i might be able to use one. however i dont feel comfortable with that. should i get a double bearing or a roller bearing?

cijuanni
01-23-2016, 02:58 PM
Why don't you make 2 tooling arms with the proper sized shaft for each wheel?

lakeside53
01-23-2016, 03:17 PM
Use two sealed radial bearings on each. On the larger.... make a flanged carrier to hold the wheel.

BobSchu
01-23-2016, 03:29 PM
I would make two tooling arms. Different sanding applications will require different radius or convex shapes. Also, you can use different sized wheels to get into larger or smaller spots depending on the project.
The larger wheel, I would make a hub for each side on the lathe with a small lip to center it on the existing hole and an insert hole to press the bearings into. Place it on the wheel and weld it in place a little at a time. These grinding wheels will take a lot of pressure and wear over time and need a good support to stay true.

Black Forest
01-27-2016, 07:53 AM
I went to Jaeger today to check on the bolts you needed Dian. I assumed you need socket head bolts. Is that correct? They didn't have them in stock but will call me with info.

BobSchu
01-31-2016, 09:45 PM
I've been planning on building one of these grinders for quite some time also. One stumbling block I've run into (besides the ridiculous price of steel these days) is what bearings to use for the contact wheels and idler wheels. I made the wheels quite a while ago, but haven't finished the bearing pockets because I haven't been satisfied with the bearings I've found. These seem to be the most common I've found- will they work for this application? http://www.amazon.com/Sealed-Bearing-1616-2RS-inch-Bearings/dp/B002BBQASW

Thanks,
Bob

dian
02-02-2016, 02:19 PM
actually i dont worry too much about the bearings, the speed and load they are going to see is way below specs.

after onother 4-5 hours in the shop i have these two flanges and a spacer. i got it just right, a light sliding fit. they will be glued on on their shafts with a slight preload. i have to admit, that i messed up one of the fits and had to press on a collar. i decided to put the two bearings on the left side of the small wheel, avoiding having to machine a pocket on the right side, reason mainly being, that i didnt like the surface ("inner race") where i would be able to chuck it up.

http://i973.photobucket.com/albums/ae218/romandian/3%20002_zpsmkti9k07.jpg (http://s973.photobucket.com/user/romandian/media/3%20002_zpsmkti9k07.jpg.html)

Prokop
02-03-2016, 08:20 AM
Why do you use rajče for your pictures?

dian
02-03-2016, 09:17 AM
sorry, didnt get that. rajce?

Prokop
02-03-2016, 12:00 PM
sorry, didnt get that. rajce?

I thought these were your pictures:

http://gonza-rytec.rajce.idnes.cz/belt_grinders2/

dian
02-03-2016, 03:58 PM
oh, i remembered gonza, so raice is the host? that is just a site i bookmarked and put on here, because it has such a huge number of different grinders. i believe i saw one on a broom stick. my picts are on photobucket.

why are you asking? what is raice actually?

Prokop
02-04-2016, 07:55 AM
Gotit. rajce means tomato in Czech language - made me think you are Czech too. Sorry for the confussion :)

dian
05-15-2016, 06:46 AM
im back with the project. i had to quit working on it, because i bought three "new" machines, i had to reorganize the shop, build some furniture and of course play with the machines. there were two vacations as well. but now i hope to finish this quickly.

so i put that 150 mm chunk of aluminum i had it the lathe and started boring it for the 24 mm shaft. that didnt go well at all. my go to boring bars kept tearing up the surface, it must be some weird aluminum. i finally found an smallish ifanger bar that did a good job, but it was too late, i had a very rough bore. i happened to have a head cap screw where the head was exactly 24 mm. i pressed it into the bore twice, which improved the finish considerably. in the end it worked out quite well, i got the pulley on the shaft with medium effort of the 8 mm screw.

nex was the 8 mm blind slot. that didnt go well either. i couldt find the box with small hss bits to grind one fitting my slotting tool. so i made another one like this:

http://i973.photobucket.com/albums/ae218/romandian/3%20306_zps2mle8c4g.jpg (http://s973.photobucket.com/user/romandian/media/3%20306_zps2mle8c4g.jpg.html)

lining it up:

http://i973.photobucket.com/albums/ae218/romandian/3%20228_zpsy06wvzy8.jpg (http://s973.photobucket.com/user/romandian/media/3%20228_zpsy06wvzy8.jpg.html)

i honed both sides of the bit on 3000 grit diamond and had a 5° angle on there with 2° clearance cut into the tool. it was not cutting well requiring exessive force and producing chatter. chatter went away, after i put in the bit with zero clearance. at that point i should probably have reground the bit to 15° but i didnt and got the slot done in 0.1 mm steps. the bottom didnt clean up, so i had to go in there with long endmill. the bit even started coming out of the tool, which according to my calculation taking into account the two 5 mm screws means that the force must have been around 250 pounds.

i then proceeded to take out the last 0.04 mm of runout and putting an angle of 0.5° on each side, leaving 10 mm flat in the middle:

http://i973.photobucket.com/albums/ae218/romandian/3%20301_zpsscuyoepw.jpg (http://s973.photobucket.com/user/romandian/media/3%20301_zpsscuyoepw.jpg.html)

http://i973.photobucket.com/albums/ae218/romandian/3%20297_zpsf7pf2gya.jpg (http://s973.photobucket.com/user/romandian/media/3%20297_zpsf7pf2gya.jpg.html)

Rustybolt
05-15-2016, 02:57 PM
I would just like to see what a Swiss junkyard looks like.
I bet it's really well organized.

lakeside53
05-15-2016, 03:11 PM
..and clean, Even the junkyard dogs are groomed and have manicures ;)

dian
05-16-2016, 04:43 PM
i made the two shafts:

http://i973.photobucket.com/albums/ae218/romandian/3%20303_zpsfm3uty6r.jpg (http://s973.photobucket.com/user/romandian/media/3%20303_zpsfm3uty6r.jpg.html)

http://i973.photobucket.com/albums/ae218/romandian/3%20277_zpsfi1jenyx.jpg (http://s973.photobucket.com/user/romandian/media/3%20277_zpsfi1jenyx.jpg.html)

dian
05-17-2016, 04:46 PM
the wheels on their shafts:

http://i973.photobucket.com/albums/ae218/romandian/3%20021_zpsm5tzpns1.jpg (http://s973.photobucket.com/user/romandian/media/3%20021_zpsm5tzpns1.jpg.html)

http://i973.photobucket.com/albums/ae218/romandian/3%20022_zpskciuwl08.jpg (http://s973.photobucket.com/user/romandian/media/3%20022_zpskciuwl08.jpg.html)

http://i973.photobucket.com/albums/ae218/romandian/3%20023_zpsqiejzcua.jpg (http://s973.photobucket.com/user/romandian/media/3%20023_zpsqiejzcua.jpg.html)

http://i973.photobucket.com/albums/ae218/romandian/3%20018_zpsnauf3rf0.jpg (http://s973.photobucket.com/user/romandian/media/3%20018_zpsnauf3rf0.jpg.html)

wtrueman
05-19-2016, 04:44 AM
Hi all, I used a(n) American car water pump for my main bearing because it is about 2 inches long and is about indestructible. It works fine and I have about two years without problems

lakeside53
05-19-2016, 03:43 PM
I use the water pump bearing cartridges also.

dian
05-25-2016, 03:04 PM
waterpump bearings? interesting. how does that work?

so, in the meantime, thinking about the spring loaded contraption in the drawing, that would have yielded a decreasing down force (at least i think), i realized it would be difficult to make, no flat stock but reckangular tubing. having found this air spring, i thought i would give it a try. its rated at 380 N and it was $15 incl. shipping.

http://i973.photobucket.com/albums/ae218/romandian/3%20032_zpsqpkxujbz.jpg (http://s973.photobucket.com/user/romandian/media/3%20032_zpsqpkxujbz.jpg.html)

aligning every thing:

http://i973.photobucket.com/albums/ae218/romandian/3%20024_zpsfi8hbnp9.jpg (http://s973.photobucket.com/user/romandian/media/3%20024_zpsfi8hbnp9.jpg.html)

http://i973.photobucket.com/albums/ae218/romandian/3%20025_zpsyngvr0fd.jpg (http://s973.photobucket.com/user/romandian/media/3%20025_zpsyngvr0fd.jpg.html)

plunger
05-25-2016, 04:48 PM
Looking good but I think the spring is supposed to go the other way round?

dian
05-27-2016, 01:27 PM
i didnt give that any thought. looking at my cars, yes, they are the other way, thin rod towards down. why would that be? will it leak like that?

plunger
05-28-2016, 10:18 AM
i didnt give that any thought. looking at my cars, yes, they are the other way, thin rod towards down. why would that be? will it leak like that?

It helps with the lubrication. If its your way it wears out quicker.

Alistair Hosie
05-28-2016, 05:43 PM
The Swiss when you think about them, they make the best watches or used to at one time and the best clock movements too. That site is so full of different types of sander quite a number of them had similar ideas within them or so it seemed.
Question ,main wheels that had the rubber or silicon type of surfaces. I am intrigued by the physics behind these designs. Why for example the slots go off to an angle and not straight across ? also, how does one determine the width and also depth? Also the thickness? Also can anyone bring up the post a few weeks ago when someone made their own rubber faces on the wheels as I would like to study it again. I must have spent an hour or more looking through that wonderful site RAITEC and still seemed to only be half way through I loved that thanks to the person who provided it for us. I have quite a mass of stuff piling up and would really enjoy making my own someday, or month LOL also the point about not bothering about using bearings intrigued me could someone elaborate on this. I generally only use my machinery for short stints, perhaps bearings would be non required, I still get the sense in my gut that they ought to be there though even if only for blind reassurance for the ill machine educated like me as opposed to someone who does this kind of thing everyday. Alistair

dian
06-22-2016, 11:51 AM
maybe this thread?

http://bbs.homeshopmachinist.net/threads/70333-Knife-grinder-contact-wheel-make-one?highlight=grinder+rubber+wheel

did somebody say hockey pucks? i guess the slots are angled so you dont get any bumps.

my project got stuck, because the contraption will not track. i feel really stupid, as any cheap handheld sander will track (o.k., there are only two wheels). i play around with it, then walk away, come back in few days, realign, try again again, doesnt work.

well, i found out that tracking is really sensitive to the angulal alignment of the rubber wheel in the vertical plane and im talking fractions of a degree. the belt woud jump off the wheels until i epoxied the bearings into the hubs and the hubs into the wheels. i had a medium sliding fit of those parts, they were very difficult to assemble and disassemble, but that slight movement was enought to make the belt jump. now the belt stays on the wheels. the problem is that i have to misalign the rubber wheel for the belt to stay on the idler. the other problem is that when i reverse the direction the belt goes to the left and hits the bracket in a few revolutions. there is a position where the rubber wheel is tilted clockwise looking from the front and also from the top by several degrees where forward and reverse has the belt in the same position. the clapper is closed completely and the belt is on the right edge of the idler. this cannot be the solution.

http://i973.photobucket.com/albums/ae218/romandian/3%20030_zps8cn6bsfs.jpg (http://s973.photobucket.com/user/romandian/media/3%20030_zps8cn6bsfs.jpg.html)

reverse is important, because then working on the platten between rubber and idler wheels i would like the gritt to go towards the wall. maybe i have to give up this idea, though.

can anybody provide any insight into this? do your grinders track in both directions?

Prokop
06-22-2016, 02:59 PM
Check out Subaru timing belt tensioner, they could make excellent idler wheels. I used one to tension a v-belt on my sawmill.

http://porcupine73.com/pics/timing/tensioner-00obw.jpg

dian
06-23-2016, 04:48 AM
i would like to add, that in forward the belt stays centered on the drive wheel nicely, independent of how i tweek the rubber and idler wheel. remember, i put a 1° crown on it (included angle), which is on the low side of what i have read. in reverse the belt moves to the left on the wheel. why? shoud i increase the crown? i read too much will result in problems. i also wonder how all the grinders work, where the wheels are on a pipe going into another pipe. surely there the alignment is not precisely repeatable, or is it?

come on, self build belt grinder guys, where are you?

lakeside53
06-23-2016, 12:09 PM
You will not get the belt to track perfectly forward to reverse. The belt has some slight bias which you are compensating for with the crown and tracking adjustment. Don't increase the crown - that just messes with the belt profile and will stretch it asymmetrically. Even if it worked (by luck) when new you are actually changing it by just running it against the 1 degree... so when you change direction it's now way out.

So....why again do you want reverse? I've never seen a need for it. You are going to have more problem with grit than simply direction of the belt. I find it actually sticks to the belt and flies off at any of the wheels, the majority of course goes straight down to my boots. I put an adjustable close brass sheet wiper on my top platen pulley to stop it slamming bits into my eyes.

dian
08-10-2016, 07:53 AM
on the first weekend after vacation i finally got i done, more or less. i spent an equal time with the alignment issues as i spent building it. i didnt expect that and it really put me off. now i have the belt running a little to the left on the tracking wheel in forward and all the way to the right in reverse. i hear you lakeside, but for some, maybe irrational reason i just want that thing to function in reverse as well.

the grinder now looks like this:

http://i973.photobucket.com/albums/ae218/romandian/3%20332_zpshcqec39m.jpg (http://s973.photobucket.com/user/romandian/media/3%20332_zpshcqec39m.jpg.html)

http://i973.photobucket.com/albums/ae218/romandian/3%20333_zpsbvisz99p.jpg (http://s973.photobucket.com/user/romandian/media/3%20333_zpsbvisz99p.jpg.html)

http://i973.photobucket.com/albums/ae218/romandian/3%20334_zpsnckaywbi.jpg (http://s973.photobucket.com/user/romandian/media/3%20334_zpsnckaywbi.jpg.html)

im using the rest from the benchgrinder for now. as i dont have a 20 mm reamer i had to bore the hole to 20 mm H7:

http://i973.photobucket.com/albums/ae218/romandian/3%20331_zpsdpzgdkgj.jpg (http://s973.photobucket.com/user/romandian/media/3%20331_zpsdpzgdkgj.jpg.html)

the platten is 470 mm so i will be able to grind some pretty long stuff flat and yes, i can take off the belt without removing it.

EddyCurr
08-11-2016, 12:13 AM
Would it be too much of a kludge to add some sort of tracking adjustment feature?

Engaged in one position for forward, moved into engagement in a second position for reverse. Equipped with adjustable stops. Held in position with detents, over-center cams, spring pins or what-have-you .. The mind reels at the opportunities.

.

GEP
08-11-2016, 09:04 AM
What are the primary factors that determine how smooth a belt grinder runs? It is often said the Burr King's run very smooth. Though in my reading comparisons, they aren't perceived to run any smoother than KMG's. Concentricity of rotating components, stiffness and balance would seem to be the primary factors.

What about the significance of direct motor drive vs. belt drive? Does a drive belt offer any vibration dampening, especially with single phase? Shafts mounted on pillow block or flange bearings, locked with set screws, might be a source of concentricity issues?

A quick search on ebay turned up these econo wheel options. I wonder under what circumstances - max rpm, etc - they could be used to produce a more inexpensive grinder?

http://www.ebay.com/itm/Rubber-Mold-On-Steel-Wheel-8-x-2-with-3-4-ID-Roller-Bearing-600-Capacit-/400960874846

http://www.ebay.com/itm/8-x-2-1-2-Rubber-on-Steel-Caster-Wheel-850-lbs-/171780338782

http://www.ebay.com/itm/8-x-2-Rubber-on-Aluminum-Wheel-for-Casters-or-Equipment-600-lb-Cap-/221539896467

http://stores.ebay.com/SERVICE-CASTER-CORPORATION/Caster-and-Equipment-Wheels-

I am in the process of building a belt sander to replace my HF. The rubber lined wheels on e-bay the bearing wont handle the rpm of a sander or am i wrong

boslab
08-11-2016, 09:23 AM
Belt drive is better, even on a circular saw you notice the difference straight off, I bought a bench grinder/sander, I have to say it was a disappointing purchase, so I got a Chinese 6" belt disk combo, much better job
Less vibration
However anything is always better than nothing
Mark

EddyCurr
08-11-2016, 03:44 PM
Belt drive is better, even on a circular saw you notice the difference straight offA belt-driven circular saw?

I am trying to imagine what a belt-driven, hand-held portable power tool type of circular saw would look like.

Is "circular saw" Wenglish for what we call a table saw over here?

.

dian
08-13-2016, 06:04 AM
eddy, what did you have in mind, a second tracking adjustment somewhere with two positions? might get quite involved.

as to the caster wheels, im sure they will come appart at 3000rpm. but it would be worth a try at these prices. put them on and spin the motor at 120 hz for 10 min. maybe they survive?

lakeside53
08-13-2016, 01:12 PM
A belt-driven circular saw?

I am trying to imagine what a belt-driven, hand-held portable power tool type of circular saw would look like.

Is "circular saw" Wenglish for what we call a table saw over here?

.

Hitachi compound saws are belt drive. I have one. Nice...

EddyCurr
08-13-2016, 01:22 PM
Hitachi compound saws are belt drive. I have one. Nice...Thank you. Did not know that.

Imagine the belt drive contributes to wgt reduction, too. Remember seeing a HUGE compound-type saw (used in log home construction, IIRC). Needed a Paul Bunyon to wield it.

.

EddyCurr
08-13-2016, 01:25 PM
eddy, what did you have in mind, a second tracking adjustment somewhere with two positions? might get quite involved.Perhaps the primary adjustment can be adapted?

Your project, I'll plant the ideas and leave their evaluation & execution to you.

.

dian
08-21-2016, 11:49 AM
i made a support like this:

http://i973.photobucket.com/albums/ae218/romandian/3%20038_zpspswlatuz.jpg (http://s973.photobucket.com/user/romandian/media/3%20038_zpspswlatuz.jpg.html)

http://i973.photobucket.com/albums/ae218/romandian/3%20039_zpsrq4ydb0r.jpg (http://s973.photobucket.com/user/romandian/media/3%20039_zpsrq4ydb0r.jpg.html)

it took quite a bit of work to make it exactly 90°.

i had planed to glue a piece of glass ceramic on the platten. well, the local chimney place just quoted me $180 for a piece of 5 mm "robax". no way im going to pay that. does anybody know of a less expensive european source?

the alternatives are to use hardened glass ($80) or regular float glass ($30). a hardened tool steel plate woul probably be even more than the robax. why do they use glass ceramic anyway? you dont need the platten to live at 750c°, right? is it much harder than hardened glass? did anybody use regular glass and with what results?

for the time being i decided to use the mild steel platten as is. originally i wanted to put the platten on the table and machine it using the horizontal spindle, but being too lazy to take off the vice on the big mill (the other two wont do 470 mm) i filed it more or less flat using my precision beveled straight edge, figuring it was good enough for gluing. so now, still too lazy, i did this and it worked:

http://i973.photobucket.com/albums/ae218/romandian/3%20044_zpsa4x5ixch.jpg (http://s973.photobucket.com/user/romandian/media/3%20044_zpsa4x5ixch.jpg.html)

as was to be expected, there is a hump in the middle, but good news is its only 0.01-0.02 mm. easy to get ridd of.

do i have to polish the platten (a lot of work) or can i get away with just breaking the milling marks a bit? what do you think?

lakeside53
08-21-2016, 12:07 PM
The ceramic glass can take the thermal shock. Regular glass wears rapidly and will crack from the sudden heat on one side from the belt. You "might" get away with tempered plate glass but float glass "untempered" is courting disaster.

Go to a place that repairs and supplies the ceramic glass for fireplaces... they toss out a lot of broken each year and you can simply have them cut it from an old broken part. I had 6 cut from my own broken fireplace ceramic glass. If you want to pay postage I can send you one of mine, but it will be "my size" - 2 1/4 x about 10.5 (I think).

lakeside53
08-21-2016, 12:12 PM
Perhaps the primary adjustment can be adapted?

Your project, I'll plant the ideas and leave their evaluation & execution to you.

.

Mine has a tracking adjustment. Look at my pics... you can see it.

plunger
08-21-2016, 02:16 PM
i wonder how a platen made from granite would work?I have plenty of kitchen sink cut outs.It should be very wear resistant and is super smooth.

dian
08-21-2016, 05:02 PM
good idea. never thought of that. i have suitable granite pieces around. but now its too late, to much work int the angle iron platten.

lakeside53
08-21-2016, 05:14 PM
Granite and heat... it will likely blow out small pieces from the surface. Its amazing how hot the platten gets at high surface speed or with applied pressure on a small spot.

boslab
08-21-2016, 07:36 PM
Your best bet is a porcelain tile, try drilling one, only diamond will do it, and they come in strip sizes, 2x8 or similar, flat glass hard and wear resistant.
Mark

dian
08-22-2016, 03:50 AM
i have polished porcelain tiles 600 x 600 mm to cut it from. yes you have to use hollow diamond bits. i would have to somehow remove the grid structure on the back side. so how hot do you reckon does the platten get? what do i glue it on with? it seems epoxy is out of the question. high temp. rtv?

boslab
08-22-2016, 07:23 AM
We had these Herzog sample prep machines in work, they had solid carbide plattens, one for broke, I think it was beaten with a hammer on a night shift, things like that happen to stressed tired people, they do things they would never normaly do, anyway I used a tile on one of them, an 8x6 a little tight for a 150mm belt, it got stuck down with Dow Corning RTV I think, translucent stink of vinegar aka acetic acid cure, it's still there 4 years later so it must work!
The guy who broke the platten had another wobble and ripped out a computer and threw it in the ladle he was trying to make an ultra low carbon ladle out of, the carbon was coming back high, at which point I had no option other than kick it upstairs as they say
Mark

RWO
08-22-2016, 02:48 PM
I put a carbide platen on my 1x42 machine. Flat carbide bars 1"x 6" and 1/16"-1/8" thick are not too expensive. A pair could be epoxied side by side on the steel platen. Mine has been in service for about 20 years and the epoxy has never failed. The best part is that wear is barely visible after all this time.

RWO

dian
08-22-2016, 04:30 PM
interesting. where can you get them? i would need 6.

RWO
08-23-2016, 02:05 PM
I think I bought mine at MSCdirect.com, but it's been a while ago. They occasionally appear on ebay, but the available sizes vary a lot.

RWO

boslab
08-23-2016, 03:40 PM
wrong stuff
Mark

dian
08-24-2016, 06:19 AM
i found this:

http://www.ebay.com/itm/THIN-RECTANGULAR-ALUMINA-CERAMIC-SHEET-No-502-/291449780827

would that be any good? $32 is not too bad.

plunger
08-24-2016, 06:28 AM
My platen shows signs of wear but it is now 5 years old .Cheaper to replace with same when it wears unless you use it 5 hours a day.

RWO
08-24-2016, 03:35 PM
i found this:

http://www.ebay.com/itm/THIN-RECTANGULAR-ALUMINA-CERAMIC-SHEET-No-502-/291449780827

would that be any good? $32 is not too bad.

Might work. Certainly hard enough. My only concern would be friction heating of the thin section and it's effect on the epoxy bond to your steel platen. But it is so cheap, it's worth a shot.

RWO

QSIMDO
08-24-2016, 11:27 PM
High-temp RTV silicone?
Use it on exhaust systems and sticks like s*** to a blanket.

dian
08-30-2016, 10:45 AM
everytime i ran the grinder over 25 hz i got scared. so i made a belt guard like this:

http://i973.photobucket.com/albums/ae218/romandian/3%20045_zpslq7ofzsw.jpg (http://s973.photobucket.com/user/romandian/media/3%20045_zpslq7ofzsw.jpg.html)

this is the prototype swarf collector (well, it might become a permanent prototype):

http://i973.photobucket.com/albums/ae218/romandian/3%20048_zpscsmu02v7.jpg (http://s973.photobucket.com/user/romandian/media/3%20048_zpscsmu02v7.jpg.html)

here with the top for use with the platten:

http://i973.photobucket.com/albums/ae218/romandian/3%20047_zpscqj8axvj.jpg (http://s973.photobucket.com/user/romandian/media/3%20047_zpscqj8axvj.jpg.html)

because the grinding rest points down towards the center of the wheel, the guard can be higher in front without interferring. on the other hand i cant grind round radii (only eliptical) like this. if i ever need round, i will have to make another arm for the toolrest, that puts it level with the center of the wheel.

i checked on the porcelain tiles i have and they have a 0.2 mm bow in them, which i consider too much. i could probably find an area with only 0.1 mm bow, but i would have to cut out four sides. the tiles are also too thick, 10 mm.

dian
09-03-2016, 04:28 PM
i always knew the tracking wheel, that started life as a pallet jack wheel or similar, was a temporary solution. when running the grinder at 30 hz for a couole of minutes the short handle would get quite warm. well, this is what happened:

http://i973.photobucket.com/albums/ae218/romandian/3%20040_zps8tlqza7e.jpg (http://s973.photobucket.com/user/romandian/media/3%20040_zps8tlqza7e.jpg.html)

http://i973.photobucket.com/albums/ae218/romandian/3%20042_zpsw6llgjnd.jpg (http://s973.photobucket.com/user/romandian/media/3%20042_zpsw6llgjnd.jpg.html)

i have a few of those, so it not a problem, but its a warning for everybody wanting to use some kind of castors on the grinder. they are just not made for the speed. the hot bearings probably didnt help either.

i have been thinking about how to glue the (probably) polyurethane tire back on. what to use? contact cement? will that dry after i press the tire on? the same for rtv type stuff. a two part adhesive would be best. epoxy is too brittle. what else is there'

plunger
09-03-2016, 05:18 PM
aluminium?

dian
10-05-2016, 06:43 AM
yes, its aluminum.

this is a 16 mm chuck on the wheel.

http://i973.photobucket.com/albums/ae218/romandian/3_zpsr1amzajg.jpg (http://s973.photobucket.com/user/romandian/media/3_zpsr1amzajg.jpg.html)

when i made the flange i chucked up a 16 mm pin and faced the flange to that so the pin would run true. so now there is some wobble and it needed balancing. the contraption is a little to long and one of these days ill make one with a screw on chuck, but i dont even know if they exist it 16 mm.

the is a bronze brush and will need balancing as well:

http://i973.photobucket.com/albums/ae218/romandian/3%20357_zpsk2mqrhqo.jpg (http://s973.photobucket.com/user/romandian/media/3%20357_zpsk2mqrhqo.jpg.html)

i had a 3m 777f belt i got from the local 3m dealer on a comlimentary basis. unfortunately i found out they will only sell 6 belt of each type ($15 per belt). i had no idea what belts to get and where, so i looked online and found a knifemaker supply site that offered starter kits. they comprised orange ceramics in low grit, green lubed "j" flex in medium grit and felt backed micron variety in high grit. so i figured thats what i need and ordered an assorted pack of each with overlapping grits, so i can compare the performance. this was from the states and i have to say the new shipping policy of ebay is great the 26 belts got here for under $20 including customs fees and vat. total expence around $130. the ceramics are by fandeli, the others no idea.

http://i973.photobucket.com/albums/ae218/romandian/3%20356_zpsdspqeudr.jpg (http://s973.photobucket.com/user/romandian/media/3%20356_zpsdspqeudr.jpg.html)

i also found a 14 pack of belts fron china for $27 with free shipping, so i got those as well. they were advertised as 180 cm and thats what they are (i had hoped it would be a mistake or a rounding difference) so they are a little to short. that means i cant use them with the platten (or i will have to mill a longer slot) because the idler is to low. but still nice to have some cheap belts for some work, like grinding brake pads perhaps.

what belts is everybody using?