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.RC.
11-16-2010, 04:49 AM
Have put a diamond wheel on my tool and cutter grinder but I need to true it up... It is very close to true but not quite...

How do you dress a diamond wheel?


Also are CBN wheels suitable for High Speed Steel TC grinder work?

davidwdyer
11-16-2010, 05:53 AM
Are you talking about truing up the center hole or the face of the diamond wheel?

I'm pretty sure the surface with diamonds is not something you can mess with. There are ways to "freshen them up" or run them in reverse (since after a while the diamonds get a "set" to them) but I doubt that trying to true them will work. You would end up destroying whatever tool you use, even if it is diamond, and messing with the bonding agent whether its metal plating or some kind of polymer.

If you could true up the hole with a bushing or something, this might work.

oldtiffie
11-16-2010, 05:57 AM
I'd assume that the wheel is true unless or until proven otherwise.

I'd check that the flange/s of the grinding head are true first and if not take a skim cut and true them up (a cup or saucer wheel - aluminium-oxide or CBN will be fine) - on your grinder.

If the diamond wheel is not too bad, I'd leave it "as is" and just let the high spots wear off over time.

CBN will be fine for HSS - and it can work with TC as well if you are careful.

I use as coarse a wheel as I can in every case but keep them dressed. I finish off with a "spring" cut.

T&C grinding is not rocket science at all.

Once you have the principles and the "knack" of it, it is pretty simple really.

But a caution - don't let your concentration or your mind wander and don't hurry either as the T&C grinder will soon "getcha" - as will any grinder.

Evan
11-16-2010, 08:23 AM
If it is an electroplate wheel you cannot dress it. If it is a resin bond wheel then dress it with an aluminum oxide dressing stick or a chunk of a broken aluminum oxide wheel. The dressing action takes place because the binder is removed by the dressing stick which also removes the grit. It is normally not required and if the diamond wheel you have needs it as new it is defective.

JoeLee
11-16-2010, 08:28 AM
Diamond wheels can be dressed, but you have to be careful since there usually isn't more than .125 of diamond to work with. You don't want to dress you wheel away. The other thing is what happens when you remove the wheel and then put it back on ???
It will again look like it needs to be trued. My advise is if your going to dress a diamond wheel keep it mounted to a tapered spindle adapter so it will always be true when remounted.

JL.................

bborr01
11-16-2010, 09:36 AM
Having spent a LOT of time grinding carbide with diamond wheels, I will share what I learned.

1. When you mount a diamond wheel, it should be mounted on the hub/arbor by indicating it with a dial indicator to make sure it is as true as you can get it to begin with.

2. As Evan said, they can be trued somewhat with a silicone carbide stick. Most of the wheels we bought new came with a white stick.

We also had a device for truing diamond wheels. It was a hydraulic dampened spindle with a gray wheel on it. Fairly small, about the size of your hand.
We would put it on the chuck of a surface grinder at about a 10 degree angle from running true with the diamond wheel spindle.

We would bring the diamond wheel in contact with the gray wheel by .001 or .002 inches and the gray wheel would start spinning. Then we would run it back and forth while slowly feeding the diamond wheel into the gray wheel until the diamond wheel was true. A fairly slow, tedious process.

3. Once we mounted and trued a diamond wheel of any kind, it stayed mounted until it was worn out.

Carld
11-16-2010, 11:56 AM
How close is close?

My diamond wheel was out about .002" TIR and I have not had any problem with it as is.

Forrest Addy
11-16-2010, 12:12 PM
Since a diamond wheel is rapidly eroded by grinding steel, I have on rare occasions deliberately ground steel with a diamond wheel to true it.

bborr01
11-16-2010, 12:16 PM
How close is close?

My diamond wheel was out about .002" TIR and I have not had any problem with it as is.

Carl,

The closer, the better. To have .002" runout will work OK, but dead true is a lot better.

About 1/2 of your wheel is doing all of the work.

That is why we would true them and then never take them off the hub until they were worn out, which takes a long time if you don't abuse them.

I have a couple of diamond wheels that have a 1/4 inch bond. I doubt that I will ever wear one of them out.

Brian

J. R. Williams
11-16-2010, 12:20 PM
Norton makes a dressing stick for CBN and Diamond wheels. One number is 38A220-HVBE
JRW

bborr01
11-16-2010, 12:34 PM
This is the kind of dampened dresser that I used to true diamond wheels.

http://cgi.ebay.com/NEW-DIAMOND-WHEEL-BRAKE-TRUING-DRESSER-/310264074557?pt=BI_Tool_Work_Holding&hash=item483d2e113d

Incidentally, we had one rigged for dressing wheels on ID grinders too. Ground a lot of carbide ID's.

Brian

Black_Moons
11-16-2010, 03:45 PM
If this is one of those diamond wheels for a carbide grinder held in place with 4 countersunk screws, You can true it by just loosening/tightening the screws. At least, Thats how I did it on my crappy grinder untill I returned the POS.

oldtiffie
11-16-2010, 03:47 PM
Have put a diamond wheel on my tool and cutter grinder but I need to true it up... It is very close to true but not quite...

How do you dress a diamond wheel?


Also are CBN wheels suitable for High Speed Steel TC grinder work?

Unless I am quite mistaken, the OP's Tool & Cutter grinder is this one - or the one of which it is a clone:
https://www.machineryhouse.com.au/images/154511.jpeg

Here is the wheel mounted on its spindle wheel-hub - which is not balanced:
https://www.machineryhouse.com.au/images/156471.jpeg

at:
https://www.machineryhouse.com.au/Products?stockCode=G198

By its nature, being a tool and cutter grinder, the wheels are not permanently mounted on the hubs. Spare hubs are available if required.

.RC.
11-16-2010, 04:00 PM
I did not think it had a hub.... If it does I will dismount it and take a look and make up a few on the lathe...

Been making a few ISO30 arbours lately with 0.0002" run out (well I am finish turning them on the mill they mount onto) so turning up some hubs should not be too hard..

Carld
11-16-2010, 04:08 PM
RC, if you have the machine tiffie showed then I can see where you want it very true but to do that you would have to have a fixture held dresser. Dressing it with a hand held tool would not do a good job. A dresser mounted to the table would work fine and you could dress it much like is done on a surface grinder.

Evan
11-16-2010, 05:39 PM
Diamond wheels are not all the same even if they look exactly the same. You get what you pay for and what you pay for is diamond grit. The larger the grit size the more expensive it is. The greater the amount of grit compared to binder the more it costs. The life of a diamond wheel is primarily determined by the amount of grit is contains (absent abuse). That can vary by double from 50 percent grit to 100 percent grit. 100% grit is packed as tight as the grains will permit with the remaining space filled with binder.

The life factor is not linear as the amount of grit increases. A low concentration of grit allows the binder to wear away quickly. Adding to that is the low thermal conductivity of a low concentration wheel. The binder is a high temperature phenolic resin that can only withstand around 500 degrees at most. When it overheats it softens and the wheel wears dramatically. That is how a dressing stick works. A high concentration wheel not only has a lot more diamond exposed instead of grit but the diamonds help to keep the wheel cool. Diamond conducts heat about 5 times better than silver so the closer the grains are packed the better the composite conducts the heat to the aluminum wheel.

A low concentration wheel may be attractively priced and it will look about the same but there is no comparison to a high concentration wheel. The better wheel may last 5 times longer at twice the price and cut twice as fast while cutting cooler as well.

oldtiffie
11-16-2010, 05:57 PM
I did not think it had a hub.... If it does I will dismount it and take a look and make up a few on the lathe...

Been making a few ISO30 arbours lately with 0.0002" run out (well I am finish turning them on the mill they mount onto) so turning up some hubs should not be too hard..

Ringer.

I have the same machine.

The hub is mounted on a taper on the grinder hed spindle.

The inner hub flange is removed from the spindle by using the outer flange which has three tapped holes - two for connecting the flanges and a centre one for clamping the wheel hub assembly to the spindle.

Use the outer two screws to connect the flanges and then a screw through the centre tapped hole in the outer flange to "jack"/force the inner flange off the spindle taper. I use a brass cylinder/spacer in the inner flange bore resting on the spindle to screw down on and to avoid damaging the spindle thread.

I will take a few pics and post them later in the day.

I am glad you posted this thread as I an going to H&F this afternoon and I had forgotten to add a couple more flanges to my list. I can't be bothered making them.

Just a thought though.

The hubs are made with 32mm spigots for the newer 32mm bore wheels. Any older wheels you have may have 1 1/4" (31.75mm) bores so you may have to turn the spigot from 32mm >31.75mm - or make a series of sleeves if you wish to use the 31.75mm bore wheels.

MarkA
11-16-2010, 06:25 PM
I am glad you posted this thread as I an going to H&F this afternoon and I had forgotten to add a couple more flanges to my list. I can't be bothered making them.

G'day everyone,

My first post after lurking for a long time, so please go easy on the noob.

I'd like to second OT's comment, thanks Ringer. I've ordered one to the T&C grinders from H&F, it's on backorder, and I hope to pick it up in the next couple of weeks. In the meantime I've been devouring everything I can find on the subject.

Oldtiffie, the flanges you mention above, are they H&F part G1989? If so, I might get a couple next time I'm there.

Anyway, my thanks to everyone for all the information in this forum.

Regards
Mark

oldtiffie
11-16-2010, 07:09 PM
Welcome to the HSM BBS "board" Mark.

I could do with your help as I was buggered if I could find that item on the H&F web site today - and I thought I knew it pretty well too. Oh well, I guess I was due to have my tail feathers set alight - again!!.

Yes- that's the item:

https://www.machineryhouse.com.au/images/40821.jpeg

at:
https://www.machineryhouse.com.au/Products?stockCode=G1989

I've rung H&F and there is one in Melbourne but more Sydney and they will post them to me from Sydney. I have some other stuff to get as well so I will be over there this afternoon.

I did find the fibre disc (for clamping) to be a PITA if against the inner flange face as it tended not to keep the wheel hard on the flange. I just use it under the outer flange.

"Skim cutting" the face of the inner flange with/on the grinder is good practice - but scribe a reference/location marks on both the back of the fixed flange and the wheel spindle as it will make accurate re-location easier.

I will post the pics of the withdrawal arrangements for removing the inner flange body from the wheel spindle later today as I said earlier.

It is one helluva good and very versatile machine - surface and cylindrical grinding included.

Its as near as I've seen to being the grinding Swiss Army Knife.

There is no need to balance good wheels 7" and under as Norton/Saint Gobain are as good as you will get anywhere - just mount and dress them if required and get going. I get mine from Total Tools as I get very good service and trade prices from them (Braeside, Melbourne).

gmatov
11-16-2010, 11:27 PM
Evan,

Not to dispute, but,

"Diamond conducts heat about 5 times better than silver"

I looked it up and found this:

carbon, diamond 895
silver 429

That is k (W/m K), no?

So, is it on a different scale? Is it 5 times the heat conductivity or more like 2+ times the thermal conductivity?

carbon, graphite (∥) 1950

is more than twice as thermally conductive as diamond. 4 times that of Silver, which I would not have thought.

Cheers,

George

Nothing, really to offer, except that your numbers look off.

Evan
11-17-2010, 02:55 AM
The thermal conductivity of diamond varies from a low of around 900 to as high as 2300 W/m K. Graphite is between 100 to 200. Silver is listed as 406 so at best diamond is 5 times better than silver and at worst twice as good. The conductivity of diamond depends on the number of flaws since the conduction depends on the transmission of vibrations in the crystal. The smaller the piece of diamond the more likely it is to be a single crystal.

.RC.
11-17-2010, 03:27 AM
My grinder is different to your Tiffie, it has no separate hubs to mount the wheels to, just a 31.75mm spigot on the end of the motor which is concentric to within 0.0003" according to my Tesa 0.0001 dial indicator.

The diamond wheel is out by 0.02mm..

luthor
11-17-2010, 03:56 AM
That's quite good enough for a diamond wheel RC, are you grinding tungsten carbide?

oldtiffie
11-17-2010, 04:21 AM
My grinder is different to your Tiffie, it has no separate hubs to mount the wheels to, just a 31.75mm spigot on the end of the motor which is concentric to within 0.0003" according to my Tesa 0.0001 dial indicator.

The diamond wheel is out by 0.02mm..

Thanks Ringer.

I will deal with that later as I ran out of time for the pics etc today.

I think I can solve your problem easily enough on your machine.

The pics may help others who have the current H&F T&C grinder.

I will do it all tomorrow.

oldtiffie
11-17-2010, 04:24 AM
That's quite good enough for a diamond wheel RC, are you grinding tungsten carbide?

I agree with you Luthor.

0.02mm ~ 0.0008" (8 "tenths") is of no concern at all.

.RC.
11-17-2010, 04:35 AM
That's quite good enough for a diamond wheel RC, are you grinding tungsten carbide?
Sorry that should be 0.2mm

Yes I am grinding tungsten carbide, mostly lathe tools..... Hope to get some carbide end mills in the future.. Was looking at seeing if there are any on US ebay that are just blunt...

The wheel has plenty of meat left on it... It is an AU made one I got it years ago... Must have nearly 1/2" or more diamond left on it... It is a cup wheel..

luthor
11-17-2010, 04:37 AM
Yes, the decimal point location is rather important.

oldtiffie
11-17-2010, 05:11 AM
0.20mm ~ 0.008" is no big dealer or "killer" either although and "side-to-side wobble" may be a PITA.

As it is a "pre-loved"?? wheel, it needs to be checked too as the problem may well be mostly or entirely in or with the wheel. I will cover that tomorrow as well.

.RC.
11-17-2010, 05:57 AM
I find 0.2mm is a bit too much for my liking....Any tool placed up to it freehand jumps all over the place....

pic of the wheel, it has about 12mm of diamond left to wear away on it... It is 6" in diameter

http://img.photobucket.com/albums/v606/OzRinger/diamondwheel011Custom.jpg

luthor
11-17-2010, 06:11 AM
I have the same wheel RC and have been using it on and off for more than 15 years now with still lots of life left in it. They will not grind steel so if you are going to be grinding lathe tools with tungsten carbide welded onto a steel shank you will have to relieve the steel under the insert to a steeper angle before actually trying to grind the carbide. Don't worry about the runout, it will dress itself true.

oldtiffie
11-17-2010, 07:10 AM
I find 0.2mm is a bit too much for my liking....Any tool placed up to it freehand jumps all over the place....

pic of the wheel, it has about 12mm of diamond left to wear away on it... It is 6" in diameter

http://img.photobucket.com/albums/v606/OzRinger/diamondwheel011Custom.jpg

Thanks Ringer.

A previous post of yours prompted me to recall that you have a KO Lee T&C grinder - similar to my other T&C grinder (a KOL clone from H&F):

http://i200.photobucket.com/albums/aa294/oldtiffie/Grinder_work-head_demo/Grind_work-head_demo9.jpg

My other T&C grinder that I referred to earlier (also from H&F) is in the back-ground.

That T&C grinder you have works very well indeed. I particularly like the fine worm and wheel drive for moving the column left-right and the up-down tilt of the grinding head.

The wheel adaptor is fixed to the motor spindle end as you say.

You need to see if the diamond face is out or whether the cup has been damaged or distorted. My guess is that the wheel adaptor is OK but it needs checking as well.


I have the same wheel RC and have been using it on and off for more than 15 years now with still lots of life left in it. They will not grind steel so if you are going to be grinding lathe tools with tungsten carbide welded onto a steel shank you will have to relieve the steel under the insert to a steeper angle before actually trying to grind the carbide. Don't worry about the runout, it will dress itself true.

I agree with Luthor.

I grind the tool steel shanks free-hand on the pedestal grinder but if it needs to be done on the T&C grinder I use aluminium oxide or CBN and use diamond for the TC although CBN works well enough for "touching-up" TC.

I seem to recall that you have one of these fittings:
http://i200.photobucket.com/albums/aa294/oldtiffie/Grinder_work-head_demo/Grind_work-head_demo3.jpg

Use it to grind your tools - beats "off-hand" grinding hands down" - or better yet adapt it for a "tool-post" like this - even better:
http://i200.photobucket.com/albums/aa294/oldtiffie/Grinder_work-head_demo/Grind_work-head_demo2.jpg

Use as coarse a wheel as you can to minimise over-heating and to maximise material removal. Use a "spring cut" to finish off - follow up with a hand hone stick.

I "hollow grind" all faces where I can as it makes it a lot easier with the hand hone - especially on the machine - as it minimises the times needed to do a hand "touch-up" on the lathe or mill etc.

Wear a face mask - even a cheap one - to keep from breathing in grinding dust - especially TC.

There are many occasions with T&C grinding where guards have to be removed and so dust etc. is not localised.

My T&C grinder similar to yours has a 1 1/4" (31.75mm) spigot as well but I just fit a strip of 0.005" (0.125mm) hard brass shim as a sleeve to pack it out for using the new(er) 32mm (~ 1.260") bored wheels.

If I also recall correctly, you have this book from H&F:
https://www.machineryhouse.com.au/Products?stockCode=L341

If you have it - use it. It is the best $70+ you will ever spend for machining and shop practice - grinding generally and T&C grinding in particular.

MarkA
11-17-2010, 06:48 PM
Oldtiffie,


You mentioned using aluminium oxide, CBN, or diamond as appropriate. Where do you get your wheels to suit the H&F T&C grinder from?

Also, if I wanted to use my T&C grinder for a little surface grinding, what wheel would best suit that? Most surface grinding would be on mild steel, nothing too hard, I don't think.

That said, I don't have the machine yet, who knows what I'll come up with once it arrives :)

oldtiffie
11-17-2010, 09:07 PM
Hi Mark.

You will have no problems using a T&C grinder as a surface grinder - but you will need a magnetic chuck to suit.

I get my wheels from Total Tools in Braeside - near Mordialloc, Melbourne. All are Norton/Saint-Gobain which are premium products with a premium price - but well worth it.

Many/most wheels now have a 32mm bore instead of the older/USA-type 1 1/4" (31.75mm) bore. If your spindle has a 1 1/4" (31.75mm) spindle spigot and you get a 32mm bore just use a strip of hardened brass 0.005"/0.125mm shim as a sleeve - works fine.

I'd suggest a 7"/180mm diameter x 1/2" (12.7mm) "medium-coarse" aluminium wheel as it won't need balancing (no balancing hubs on T&C grinders anyway - mostly), it dresses up nicely, removes most material with out-over-heating or "clogging-up" and gives a quite passable finish as well. Cost is quite good.

Read this lot as it will be a good "intro" and "heads-up":
http://i200.photobucket.com/albums/aa294/oldtiffie/Grinding_Wheels/Grinding_wheels1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Grinding_Wheels/Grinding_wheels1A.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Grinding_Wheels/Grinding_wheels2.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Grinding_Wheels/Grinding_wheels3.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Grinding_Wheels/Grinding_wheels4.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Grinding_Wheels/Grinding_wheels5.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Grinding_Wheels/Grinding_wheels6.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Grinding_Wheels/Grinding_wheels7.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Grinding_Wheels/Grinding_wheels8.jpg

MarkA
11-17-2010, 09:34 PM
Thanks for that OT,

We have a Total Tools here, I'll have to call in and check out their wheels. From memory their selection is pretty limited. Also been checking out some diamond wheels on ebay.

I have a copy of that book, started flicking through the grinding sections last night. Thanks for the scans.

I'll let you know how I get on once the grinder arrives and I've had a chance to "work" with it.

Regards
Mark

oldtiffie
11-18-2010, 12:34 AM
Mark.

Quite often when I want stuff from TT it has to be "got in" as the cost of having it sitting on a shelf is pretty high. They send me a text message when it is in and I either go and get it or have it posted out

They have excellent staff and catalogues etc. and the stuff is only a day or so away - so I have access to what ever is in those lists instead of being limited to what is on the shelf.

They do carry a very big range of the normal "quick-moving" tools and "consumable" items as they are geared toward the "trade" and not so much to "retail".

They carry a lot of "hand" tools and the like but no "machine" tools - other than say drills and welders etc. - as we know it here.

I suggest that you talk to them in store and have a look at their "trade" catalogues.

They are not "cheap" but the service, staff and the stuff they stock as well as their warranty is really good.

I have a "Trade" account there - and I use it.

oldtiffie
11-18-2010, 04:36 AM
I said in a previous post in this thread that I'd include details of the removable grinding hub on my universal grinder - here:
https://www.machineryhouse.com.au/images/154511.jpeg

https://www.machineryhouse.com.au/Products?stockCode=G198

https://www.machineryhouse.com.au/images/40821.jpeg

https://www.machineryhouse.com.au/Products?stockCode=G1989

Here are the pics which should be self-explanatory:
http://i200.photobucket.com/albums/aa294/oldtiffie/Precision_grinding/U-gr-hub1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Precision_grinding/U-gr-hub2.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Precision_grinding/U-gr-hub3.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Precision_grinding/U-gr-hub4.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Precision_grinding/U-gr-hub5.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Precision_grinding/U-gr-hub6.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Precision_grinding/U-gr-hub7.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Precision_grinding/U-gr-hub8.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Precision_grinding/U-gr-hub9.jpg

MarkA
11-20-2010, 04:56 PM
Hey oldtiffie,

I called into my local TT yesterday, and when I asked them for a price on a medium-course ALOX wheel 7" x 1/2", about 3 of the guys looked at me like I'd just sprouted a second head or something.

After much muttering and page-flipping they decided they would ring someone on Monday.

I didn't even bother asking about CBN.

To help make sure I get wheels suitable for the T&C grinder, do you have the manufacturer part numbers for the wheel described above, as well as the CBN wheels you use?

Anything would be appreciated.

Regards
Mark

oldtiffie
11-20-2010, 07:07 PM
Mark.

That is a PITA.

Each Total Tools (TT) shop is a franchise and so they will vary from poor to excellent with some of the rest some-where mid-scale about "good".

It seems that yours is toward the "poor" end of the scale and mine at the top. But mine services a pretty big industrial client base where-as others may not.

I have had occasion to go into other TT stores and have not got what I wanted and left and went to my own TT store and either got it off the shelf or had it ordered in.

If you email or PM me the details of the wheels you want, I will be at TT here in the next week or so and will get you the manufacturer's stock number, cost and availability and will send it to you.

For surface grinding steel, you will need a 7" x 1/2" x 1 1/4" (31.75mm) bore for the spigots on older grinders or a 32mm (~1.260") bore (for newer grinders) aluminium oxide. Tool & cutter grinding will require saucer and cup wheels at least. TC will require CBN or diamond.

Here are some older pics of come of my wheels and my surface grinder. There is no good reason why a good T&C grinder cannot do a good job of surface grinding as my T&C grinders will - and do:

http://i200.photobucket.com/albums/aa294/oldtiffie/Grinding_Wheels/Wheel_balance3.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Grinding_Wheels/Wheel_balance4.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Precision_grinding/Abrasives3.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Precision_grinding/Abrasives2.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Precision_grinding/Surf_Grinder1.jpg