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fishfrnzy
01-23-2008, 09:04 PM
Just bought the green one with 2 wheels.

What modifications have you all done that have proved benificial?


Also would it be considered foolish to take a white grining wheel I have and epoxy it to say a .125 or .188 thick aluminum desc to use for side grinding HSS?

You guys give alot of good adice on this forum!

Thanks

Mine was a POS out of the box and had to be fiddled with and parts swapped and mahined just to get it to go together. The aluminum castings had extra material in the slots, thwy were not square, and the table mount area on the bottom of the table was not machined parralell with the top. Someone in a previous post said it should be viewed as a semi-finished kit. Boy were they right.

radiotexas
01-23-2008, 10:14 PM
In February 2005 there was a great series of posts on upgrading the HF Carbide Grinder. Do an archive search on "HF Grinder Upgrades."

I checked availability on the diamond and Aluminum Oxide wheels (as mentioned in WJ Hartson's post of 2-27-05) and they are still available (the AO is now $44.31 from J&L Industrial). The diamond wheel is the same price from Enco as quoted in the posts. Part numbers are slightly different: AO wheel is CPW-14210H and the diamond wheel from Enco is 391-5640.

I was getting ready to go buy one from HF until your post came through. So, I looked at the Grizzly website and lo and behold, there is the exact same machine! I am a new member of this site but I do have a lot of experience with machine tools. I've also read a lot of the archive posts from this site (before starting to open my big yap). What I do not understand is which is the original and which is the knock-off or or they both knock-offs of a Baldor machine? Further are they the same machine from the same factory just with different paint.

My experience with HF is that their stuff is generally what I would call "below the line" for someone who wants good economical machines. The old adage of "you get what you pay for." However what concerns me is your description of what the HF machine looked like out of the box vs. the generally positive comments on the machine back in 2005 (from the archives).

Perhaps the wise, old hands here wouldn't mind revisiting the topic and comment. The salient point being has HF changed manufacturers since 2002 and/or is the Griz machine better quality. I can tell you that by downloading the instruction manuals on both machines, the Griz manual is 200% better and more detailed than the HF. But the exploded drawings are almost identical, right down to the same "part number" for each piece!

Thanks to all of you for this wonderful resource. I look forward to reading it every day and hopefully adding something positive from time to time.

Doc Nickel
01-23-2008, 10:27 PM
They're both knockoffs of the Baldor, and I'd bet a paycheck they came from the same factory.

Grizzly tends to specify a better level of fit and finish. Cheap wholesalers like Harbor Freight and Northern Hydraulics tend to get- or even ask for- the cheapest bottom-of-the-ladder they can get. Other dealers like Smithy get a bit better quality, Grizzly and Jet ask for a little better still, and so on.

There's a photo gallery at LittleMachineShop that shows a facoty tour where their mini-lathes are made. There's a couple shots clearly showing the exact same lathe painted different colors; LMS and Harbor Freight red, white for Jet, blue for Smithy, there was a yellow as well...

Same factory, same castings, same people assembling 'em.

For the carbide grinder, the Griz is $50 more than the HF, and while I don't know for sure, I'd bet it's finished a bit better. Certainly looks better in the pics but that doesn't mean anything...

Doc.

lazlo
01-23-2008, 10:33 PM
For the carbide grinder, the Griz is $50 more than the HF, and while I don't know for sure, I'd bet it's finished a bit better.

You're probably right about the better fit and finish Doc, but shipping is going to be a bitch on that grinder -- it weighs 110 lbs.

By the way, the Harbor Freight version is on sale for $129 again. If you have a coupon, it's even better...

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=46727

Bill Pace
01-23-2008, 10:47 PM
While Fish's experience isnt unheard of, I get a strong impression that the majority of the HF's arent nearly that bad.... usually a change of the wheels and some filing/trimming of a few casting glitches will put it to work, --- with many guys saying they worked fine out of the box. And, we ARE talking about quite a lot of machine for $130-150!!

Wholesale Tool has the green & white wheels for $25-27----

http://tinyurl.com/2rmr8t

Dawai
01-23-2008, 10:53 PM
Not had a problem with mine.

Yours must have been made on a MOnday?

Mine still resides on top of the Lathe, where everyone says it should not be because of grit. Still sharpening three or four times a week.
http://img.photobucket.com/albums/v85/ibewgypsie/Lerblond_lathe_001.jpg

macona
01-23-2008, 11:04 PM
EEK!!!!

You have got to be joking!

mechanicalmagic
01-23-2008, 11:17 PM
Mods, Diamond wheel for carbide. White for HSS.

If yours came with green wheels, and are like mine, they can grind Tungsten TIG electrodes, but anything else is a no show. I've tried to give them away on several forums, but nobody will pay the postage.

7018
01-23-2008, 11:41 PM
I got mine about a year ago, Every thing fit good and moved freely. I need to get the new wheels for it, But other than that I'm happy with mine.

Paul

fishfrnzy
01-23-2008, 11:54 PM
Thanks Radio,
I tried a couple searches first but I gues I did not put in right.

The machine itself runs with very little vibration so I kept it.

After Putting tables on and off seveal times trying to get the table to rotate(it was frozen solid and wouldn't budge) Used calipers to check paralellism on table mounting flats and surfaces were out about .010 in 1 inch. They fly cut the surface but the mill was out of tram. When the aluninum die castings were bolted down they gripped the machine so tight the table couldn't rotate. Also checked the 4 aluminum die castings and 2 were out of square by .020-.040 in 2 inches.

Went back to store to trade out tables. traded 2 of the castings. still need to square theseup a little as they are out app .005-.010.

Took 2 of the alum castings and bolted to 3/4 mdf spacee to make the equivellent of a 4" round and put in the four jaw chuck on the lathe, inicated for center as best I could and cleaned up the grooves of excess material. Much better now.

DICKEYBIRD
01-24-2008, 05:46 AM
I bought one from H/F a few weeks ago and it was OK. I had to adjust the aluminum table brackets a bit to get the tables on and I'm going to make an extension for the water cup.

I ordered a diamond wheel from CDCO ($59) and a "white" A/O wheel from KBC ($21.55) Haven't gotten either one here yet to report on the quality. The A/O wheel is reportedly a Norton, the diamond wheel is Chinese.

Mine ran very smooth & powerful right out of the box although several have reported their's vibrated badly until fitted with new wheels.

I think they're a good buy.:)

lazlo
01-24-2008, 11:02 AM
Not had a problem with mine.

Yours must have been made on a MOnday?

Wow, you got lucky David. Seems like most of these (including mine) wobble like crazy out of the box. Like many members here, I had to take off the wheel mounts and turn the back sides of the cast aluminum plates. Big improvement.

One of these days I want to re-machine the shaft bushings behind the wheel plates too.


I had to adjust the aluminum table brackets a bit to get the tables on

I hate those friggin' aluminum mounting brackets. As soon as you loosen them enough to tilt the table, they fall apart :mad:

I didn't see any obvious way to modify them. How does the Baldor 500 (that these were copied from) tilt the table?

Pete H
01-24-2008, 11:23 AM
I have no experience whatever of grinding TC, but I'm going to have to learn because I just inherited about 40 TC cutters in various states of wear and damage. So this thread is very interesting to me.

There was a big discussion over at the "chaski" site a few months ago about green wheels. One of the more-experienced members was very much against using them; said that they basically "hammered" the TC into shape, leaving a bad edge, and recommended using only diamond on TC. He also said that you shouldn't use diamond on HSS (at least not at high speed), because the heat will cause the diamond to dissolve in the steel. Oh, and don't use green wheels on HSS, because it will wear them out in no time.

If I remember correctly, his recommendation was a white AlO wheel for HSS, and a diamond for TC.

Obvious problem, for those of us who pay for our own tools and don't use 'em to make a living, is the cost of a diamond wheel - close to $100 last time I looked.

Pete in NJ

BobWarfield
01-24-2008, 11:30 AM
Another vote: mine ran great out of the box.

I have a nice set of wheels, but haven't put them on. I use the grinder so much I'm tempted to buy a second one so that the nice wheels are there for tool grinding only. Probably won't need it when I get my disc and belt grinders done.

There was a nice thread on this grinder where WJHartson showed off some nice attachments he made for it:

http://bbs.homeshopmachinist.net/showthread.php?t=10497

Here are a couple pix from that thread:

http://www.cnccookbook.com/img/OthersProjects/GrinderMiter.jpg

http://www.cnccookbook.com/img/OthersProjects/DiamondDresser.jpg

I'm going to set up the tables for my belt and disc grinders to match the slot on the HF so tooling will be interchangeable. Then I'll build some nice add ons like those.

Cheers,

BW

lazlo
01-24-2008, 12:05 PM
There was a big discussion over at the "chaski" site a few months ago about green wheels. One of the more-experienced members was very much against using them; said that they basically "hammered" the TC into shape, leaving a bad edge, and recommended using only diamond on TC.

Harold's right: the green Silicon Carbide wheels leave a very harsh grind and a jagged edge on the tools.

But, the "green" wheels the Harbor Freight grinder ship with are not Silicon Carbide. They're painted green :) Seriously. Scratch the surface of the wheel and you'll see that they are white inside. I think the HF wheels are some harsh Aluminum Oxide with a very tough binder. Useless for grinding tungsten carbide cutters for a machine tool.

Carld
01-24-2008, 02:53 PM
Both the green wheels on my HF tool grinder were really green. I guess they send what ever they have. They were in fact to hard to be servicable and I had to replace them.

I worked in 6 different job shops for 17 years and none of them used a diamond wheel. I have been in more job shops than I care to mention and none of them used diamond wheels.

Diamond wheels are for machinists that are very perticular and not really needed. I have done all my machining in my professional life and at home with green wheels for carbide and white wheels for HHS and have always had satisfactory rusults. The only place you may find diamond wheels is in tool and die shops and since I have not been involved in tool and die work I can't be sure about that.

The only diamond dressing wheel I have used is on my KwikWay boring bar tool dresser. It is very slow to remove and finish the carbide cutters for the KwikWay bar. The only way I would even consider using a diamond wheel is to polish the cutter and I am not convinced it is needed.

It's said it imparts a sharp edge on the cutter, but if you look at an indexable insert with a magnafying glass you'll see it is not very sharp and is in fact somewhat rounded and they cut very well.

Alistair Hosie
01-24-2008, 03:27 PM
I have a slightly larger version of this machine and find the h f a great buy for the money see mine here Alistair


http://img.photobucket.com/albums/0903/tybachdai/workshopgrinderoverview003.jpg




http://img.photobucket.com/albums/0903/tybachdai/workshopgrinderoverview005.jpg

BadDog
01-24-2008, 03:28 PM
I certainly haven't been "in" that many pro shops (not to notice wheels anyway), but my experience certainly is different. Other than HSM shops, every serious shop I've been into has had diamond wheel grinders. A friend of mine who maintains a sort of "hobby shop" has one he lets me use, and I'll tell you one thing, "slow" is not a word I would use to describe it's ability to cut carbide, but it leaves a mirror like finish and a fine edge vastly superior that the formed/coated carbide inserts (not to be confused with ground inserts which are not at all rounded). Different cutting mechanism.

Anyway, this guy works at (General Foreman I think?) a big job local shop that runs almost exclusively on CNC (and some BIG ones at that). So they use LOTS of inserts, but they also have some manual machines. In any case, I saw 2 Baldors down there and both had dual diamond wheels. And this is in a primarily CNC shop.

I did work in an extrusion die shop as a "design engineer" (glorified draftsman mostly) many years ago, but have no idea what they had. But in general I'm a newbie at this, so maybe my perception is skewed by the limited sample...

Carld
01-24-2008, 03:40 PM
I honestly think most of the claimed rough finishes are the fault of not really grinding the cutter to get a sharp edge and point reguardless of the use of diamond or silicon carbide wheel. I have one friend in business that uses diamond so I will test his wheel if he permits me. He is a speciality shop.

Bill Pace
01-24-2008, 03:46 PM
Well, Carls take on diamond wheels is certainly different from the usual good things said about them......

And my limited experience is indeed in the "good" column. I have one of the 'original' carbide grinders that was made by Delta and I have had 3-4 different 'green' wheels on it and was never especially impressed --- they would cut carbide, it was just a rather slow process with a lot of dipping in the water cup. So, this past Christmas Santa got me one of CDCO's 'cheap' ($65) medium grit diamond wheels, and I was just really blown away with the difference.... almost like the carbide kinda melted off!, and as others have described, such a silky finish!

2 guys, 2 different opinions/experiences !!

lazlo
01-24-2008, 05:01 PM
3 guys, two different experiences :)

I have a diamond wheel on one side of my HF grinder, and it does indeed leave a mirror finish. I'm using a 3M, 220 mesh diamond wheel from Ebay.

Charlie Rose
01-24-2008, 05:24 PM
Ok may as well put in my 2 cents worth.
The "green" wheels are ment for roughing in or removing alot of carbide and steel from the carbide that is silver soldered to a steel shank.Thats not to say you cant use them on solid carbide but they are ment for rough grinding,if you look at the ground edge it will look like the edge of a flint arrow head all chipped.This will cut but you will get better service from your tools if you finish the grinding job with a diamond wheel.Look at the edge of a good carbide insert see how smooth it is? No chips just a smooth sharp edge,and only a diamond wheel will do that.
You can get very rough grit diamond wheels that will remove material very fast but they shouldn't be used on steel of any type. The fine diamond wheels will give you very smooth cutting edges but will remove material slowly.
There is a type of grinder that uses only diamond wheels to sharpen both carbide and HSS tools it does this by going at a very slow RPM and is ment for fine finishing and touching up of tools.
I have never used the green wheels that come from China but the American ones work like I said.

Joel
01-24-2008, 06:50 PM
Mine was also perfect right out of the box. It ran/runs smooth as silk, no interference issues, and the tables perform all functions correctly.
While the supplied 'green' wheels were indeed green all the way through, they were still disturbingly close to complete trash.

Always carefully check out Chinese tools before leaving the store whenever possible. Remember that YOU are the quality control. At a minimum, I will open the box and check the tool operation and motions as best as I can. Sometimes, I even ask to plug in and test prior to purchasing.
If by mail order, purchase from reputable sellers with a reasonable return policy. If I get crap, I WILL be sending the item back for a replacement at the sellers expense. If they can't manage to send an acceptable item after a couple of tries, a refund is in order (this is a rare occurrence). I have yet to lose 1 cent in many hundreds of purchases.

If we accept crap, then we will be sold crap. Enough returns and dissatisfied customers, and the quality will level out to an acceptable point. As it stands now, with items like the toolbit grinder, I don't feel that I am getting what I pay for when compared to a Baldor - I know I am getting an exceptional deal.
Perhaps I should point out that I have had very good luck with 'cheapo' tools and that they have saved/made me quite a lot of money. You just have to go into it with realistic expectations and pay attention, but I bet most everybody here already knows that.

Carld
01-24-2008, 09:42 PM
I know a diamond wheel will put a smoother finish on the carbide but is it really better. You are peeling metal off the work not slicing it like whitling with a knife. It don't really take a perfect edge to peel metal. A lathe tool works like a chisel.

I intend to try it for myself but I really have doubts about a diamond ground tool putting a better finish on the work as many have claimed.

If it makes you feel like your doing a better job then go ahead a use the diamond wheel. As I said it's rare to find a diamond wheel in a job shop.

For good reason in most cases. Green wheels had a hard life in most shops and diamond wheels would have been badly abused. I had a hard time convincing most the machinists in shops I worked that steel shouldn't be ground on carbide wheels. That they should grind the steel under the carbide and then grind the carbide with the green wheel. Even after demonstrating what the steel does to the green wheels I would still catch them grinding the carbide and steel on the green wheel. You have to remember these are job shops not tool and die shops. I even caught some grinding burs off the end of steel shafts on the green wheel. I was very outspoken and not always liked by the workers. The bosses and owners seemed to like me better.

A spade is a spade and overkill is just that.

lane
01-24-2008, 10:55 PM
It`s like Carld and Charley said. Most shops dont run a diamond wheel ,but if they do a diamond on one side and a green wheel on the other . You go to a bench grinder and rough of the steel under the carbide then go to green wheel and grind just the carbide and its ok to touch the steel . ( A regular alum.oxide wheel is for steel it want grind carbide the green silicon carbide wheel will grind both carbide and steel ) Then just touch the carbide with the diamond wheel for a final sharp and polish.The tool rest Must be set at different angles to do this. Also remember Tool steel cuts like a knife Carbide cut like a bull dozer it does not cut it pushes the metal off. All the carbide suppliers used to pass out little green stoned to dull the edge of inserts at a 45 angle before use. Right wrong or other wise that is the way I was taught to do it in the many different shops I have worked in.

lazlo
01-24-2008, 11:12 PM
All the carbide suppliers used to pass out little green stoned to dull the edge of inserts at a 45 angle before use. Right wrong or other wise that is the way I was taught to do it in the many different shops I have worked in.

Lane, I've often read the same thing in machinery texts. But the explanation I read was that a razor sharp carbide edge is extremely fragile, so beveling the edge keeps it from chipping.

lazlo
01-24-2008, 11:15 PM
As I said it's rare to find a diamond wheel in a job shop.

For good reason in most cases. Green wheels had a hard life in most shops and diamond wheels would have been badly abused.

Sure, that makes sense Carl. I mostly use my diamond wheel to re-sharpen brazed carbide bits. But if I ever need to shape a form tool, I may have to look into getting a SiC wheel...

Carld
01-25-2008, 11:07 AM
Lane, I too have a 1/2" sq. green stick to slightly dress the edge of a carbide tool and was told the edge will last longer if done correctly which is why I never used a diamond wheel or wanted to. I was told the very slight radius on inserts is to sustain the cutting edge under hard loads.

BadDog
01-25-2008, 11:37 AM
Wouldn't that depend on the material? And the machine? If the material is hard, and the machine had the power to push that dull edge using the non-cutting mode, then that makes sense. Same places you would use negative (or neutral) rake tooling on a powerful rigid machine.

But on less powerful and less rigid machines, with material that's not that hard (or interrupted) and (due to machine) not having sufficient DOC and speed for the non-cut mode, then things are different. For these cases there exist positive rake tooling and uncoated ground inserts that come with very sharp edges. I've got a pile of these "ground" inserts that I use to fairly good effect on my lathe when I get into hard or abrasive materials. But my lathe wouldn't have the rigidity or power to begin to push the DOC and speed needed for the non-cut mode.

Right or wrong, that's my understanding. If I'm wrong, sounds like I would be better off to use my little diamond hand lap to knock the edge off those inserts AND the brazed bits I've been sharpening on my friend's grinder. That goes dead against what he's told me, and what I thought I had learned from multiple sources, but anybody can be wrong...

lazlo
01-25-2008, 11:40 AM
I agree Russ -- the amount of blunting you'd want to do would also depend on the rake angle. So with a steep rake angle, you'll have a more fragile edge, and need to blunt the edge more.

BadDog
01-25-2008, 11:50 AM
So, if I understand correctly, you are confirming that I will get better results by lightly stoning the edge to blunt it even on my positive rake ground inserts/bits? I guess it won't hurt to try it on one of my inexpensive ground TPG inserts.

lazlo
01-25-2008, 12:28 PM
No, no -- I was talking about brazed carbide! :)

Carbide inserts are a whole different ballgame. Carbide inserts tend to have a very blunt edge to begin with, especially the molded inserts. Then you put three layers of CVD or PVD coating on top of it, and you've got a rounded edge.

The coatings only really help in high sfpm applications, so uncoated inserts are best for the home shop, but they're hard to find, at least if you're scrounging on Ebay.

BadDog
01-25-2008, 01:08 PM
Almost all of my inserts are uncoated and ground, not molded. As I said earlier, they are VERY sharp, high polish, and not rounded on the edge; which makes them very similar to the brazed bits sharpened on a diamond wheel.

I'm just trying to figure out if most of this "not sharp" and "blunt the edge" discussion is focused/based on larger machines that can run the carbide in the "doesn't actually cut" mode. If so, then it would seem to not apply to the ground sharp positive carbide cutters (insert or brazed) focused more on the shallower cut lighter machines. Or maybe, since the formed/coated inserts are pretty blunt already, then this "blunt the edge" might work well when using a positive rake (having clearance so undercut) in a machine that CAN bury the cutter in non-cut mode.

I dunno, and that's what I'm trying to understand. But I can't imagine that manufacturers shipping ground sharp inserts AND (non Chinese) quality brazed bits are shipping them "too sharp" and expecting us to dull them to get better life. With all the "sophisticated" systems designed to promote finish and longevity, this makes no sense to me. I can see it as being a "part of the process on shop-sharpened bits", but I've seen good quality cutters come dead sharp, got some in my box (or maybe I just thought so and need to put them under the B&L???).

This runs completely contrary of what I think I know, and what I've specifically been told, so I'm trying to figure out how it fits together...

smiller6912
01-25-2008, 01:17 PM
You guys........
I've been watchin' this thread and decided to go to my local HF at lunch to check one out and see it up close.
WELL, at $129 I couldn't leave there without it. It sure looked like a deal to me....

damit, damit anyway.............. sheeeeeeesh!

Carld
01-25-2008, 01:33 PM
If you are using a carbide tool they are flat on top and normally no pos. or neg. rake is in the cutter or an insert. The rake is in the tool holder. Also most inserts have a side that is perpendicular to the top unlike a brazed tool that has a relief on the sides.

If you take a brazed carbide tool and put it in a QC holder and on the tool post the top of the cutter should be at the center line of the work normally. If you look at the way the cutter removes metal it is sheared off the work not sliced like a knife does. A look at the chips will tell you that. Whether the leading edge that is in contact with the work is sharp as a razor or VERY slightly rounded will have little effect of the chiseling effect of the cutter.

It is a misnomer to say the metal is being cut off the work, it is acctually being chiseled off the work. In fact many times there will be a false edge on the cutter after a pass has finished. With the false edge there the metal never actually touches the edge of the carbide tool and increases the life of the cutter.

The false edge is very evident when machining aluminum. That razor edge you so dearly love may never touch the work you are turning down. Even light cuts are chiseled off the work even though there is less force and heat.

smiller, you'll get to love that grinder and wonder how you got along without it.

BadDog
01-25-2008, 01:54 PM
The TPG inserts I use (almost exclusively when using carbide on the lathe) are flat top with a clearance relief below a sharp edge. These are used (and intended for) using in a holder that provides the positive top rake. They have no perpendicular side, which would clearly indicate an insert for a neg rake holder. I also have a selection of brazed carbide bits (some cheap Chinese, other good quality), some with positive top rake and some with neutral.

Again, I understand how negative and neutral carbide tooling is intended to work, and how it impacts the cut as well as longevity. I also (think I) understand how this is responsible for the "can't take a light cut with carbide" limitations.

However, what I keep trying to get to is, if the edge is not important, and in fact a detriment, why do major insert produces still produce the sharp edged *ground* and polished inserts? Likewise the "good" brazed bits I have came from the manuf with a sharp edge and positive rake with clearance. I've got both of these in C2, C5 and C6.

I've seen the edge effect you mention in aluminum, and I've seen the pits that result when the build-up is knocked off, but I don't see this in the polished TPGs used on steel. Then again, maybe I haven't looked close enough? Likewise for the change in chip structure, maybe I haven't looked close enough. I've got to make a bearing retainer (truck) for a friend of mine tomorrow. It will be made from HR 1018, but perhaps I'll take some time and experiment with the ground TPGs and/or some of my brazed bits with and w/o the edge knocked off.

New question, approx how much flat (radius?) should I put on it? I don't have a "green stick", but my diamond lap that's used to put a fine edge (to my detriment) on carbide will work well enough...

smiller6912
01-25-2008, 05:36 PM
I got it home and while assembling it I found..... the miter gauges needed to be severely adjusted on the plate and fit to the base to even get it to assemble. No big deal but it did need some thought. I used some .030 shims under the side gauge plates to give it room to slid after adjustment and I used a 3/16 angle between the table and the wheels to set a square gap, a little anti-seize on the T-bolt threads and white lithium grease on the bevel gauge pins and tightened everything up. Used a square on the plate to the wheel to set the miter gauge pointers, they were way off.
Everything seams to be working great.
Setup and adjustment took about an hour, no biggie.
So far it seams pretty nice for $129.
Now to go and grind some tools.
See ya................

gundog
01-25-2008, 08:47 PM
I just picked one up myself yesterday and ordered 220 grit diamond wheel for one side. Mine is still sitting in the box but I did open the lid and look at it.

I traded a mill/drill for this machine a while back but I have not used it yet. I may end up selling it I am not sure I have time to learn how to use it and space is tight in my shop.
Mike

http://www.use-enco.com/CGI/INPDFF?PMPAGE=563&PARTPG=INSRIT

JRouche
01-25-2008, 10:03 PM
I have the HF grinder. It still vibrates slightly even with new SC wheels. Kinda depressing. I have a SC wheel on one side and a diamond wheel on the other.. It still works better for me than the bench grinder cause of the flat face.

I also have an Accufinish grinder/lapper with diamond wheels. I love that one. Puts a very fine mirror finish on the tool bit and its more controllable for me due to the speed and stability of it..

Then I have the cuttermaster with diamond also. I have a tool bit attachment for it. I thought I would use it more than I do. Very precise but if the attachment is not already in place its a time eater to swap it in..
JRouche

Lew Hartswick
01-25-2008, 10:21 PM
I know a diamond wheel will put a smoother finish on the carbide but is it really better. You are peeling metal off the work not slicing it like whitling with a knife. It don't really take a perfect edge to peel metal. A lathe tool works like a chisel.

Yep! and have you used a chisel with a "saw tooth" edge? It dosen't
pare (or as you said "peel") very well. :-) Even on wood.
...lew...

S_J_H
01-25-2008, 10:47 PM
I think sharp carbide tooling works great for most of the things I do. No question that a good quality micro grain carbide can take a nice sharp edge and hold it pretty well without chipping.
This is a Seco 21.51F CCGT insert and it is pretty darn sharp and aggressive and takes a nice fine cut. Hard to grind HSS to "better" this insert IMHO.
http://i109.photobucket.com/albums/n48/S_J_H/carbides001.jpg
http://i109.photobucket.com/albums/n48/S_J_H/carbides003.jpg
A modified solid carbide boring bar that will easily take a nice curly chip at even a .0005" DOC in aluminum or leaded steel , yet easily takes .1" DOC as well.
http://i109.photobucket.com/albums/n48/S_J_H/carbides004.jpg
I'll run a 600 grit diamond hone over it now and then to keep the edge.

And my solid carbide endmills are just as sharp as my HSS endmills.

So I do think sharp carbides work very good and hold up well.
No doubt though that you do need to use some care with sharp carbides as they will chip. I seem to have the worst luck with brazed carbides and chipping.
Steve

wierdscience
01-25-2008, 10:51 PM
Almost all of my inserts are uncoated and ground, not molded. As I said earlier, they are VERY sharp, high polish, and not rounded on the edge; which makes them very similar to the brazed bits sharpened on a diamond wheel.

I'm just trying to figure out if most of this "not sharp" and "blunt the edge" discussion is focused/based on larger machines that can run the carbide in the "doesn't actually cut" mode. If so, then it would seem to not apply to the ground sharp positive carbide cutters (insert or brazed) focused more on the shallower cut lighter machines. Or maybe, since the formed/coated inserts are pretty blunt already, then this "blunt the edge" might work well when using a positive rake (having clearance so undercut) in a machine that CAN bury the cutter in non-cut mode.

I dunno, and that's what I'm trying to understand. But I can't imagine that manufacturers shipping ground sharp inserts AND (non Chinese) quality brazed bits are shipping them "too sharp" and expecting us to dull them to get better life. With all the "sophisticated" systems designed to promote finish and longevity, this makes no sense to me. I can see it as being a "part of the process on shop-sharpened bits", but I've seen good quality cutters come dead sharp, got some in my box (or maybe I just thought so and need to put them under the B&L???).

This runs completely contrary of what I think I know, and what I've specifically been told, so I'm trying to figure out how it fits together...

The concept of "sharp" is a wide subject,but in a nutshell what appears to be razor sharp actually isn't.Under mgnification the edge will look like a saw toothed edge with lots of little creases and lines ground into the leading edge and intersecting with the grind lines on the insert face.

The coatings applied to inserts do two things,one they add lubricity to the edge making the material being cut slide over the substrate easier which prevents edge loading(material being stuck to the edge) The second thing they do is partially fill in all the little creases which further aids in reducing edge loading.The less amount of edge loading taking place means less friction and galling on the machined surface yielding a better finish.Edge loading also increases localized heating in the cutting edge which is something carbide cannot tolerate for very long.Rapid,intermitant heating and cooling of the edge will cause it to micro-fracture making the situation worse.This is why the books will tell you to either machine totally dry or use full flood coolant when using carbide.

What Lane and Lazlo mentioned about "dulling" the edge of a carbide tool actually achieves to some degree the same effect as coating the insert.The tips of those jagged little peaks are knocked down reducing the tendancy to catch material and load up,this in turn reduces localized heating to tolerable levels and prevents micro-cracking.

So what is sharp and how can a flat stoned on an edge be considered sharp?If that flat is only a few nanometers wide it's still technically very sharp and will stay that way longer since the jagged edges are "dullled".

If you ever see a ceramic insert up close you would swear it would never cut let alone leave a good finish,but alas they do.Even though they look and feel like a plastic domino rounded edges and all they will cut and leave an excellent finish.

If you want to experiment a little I would suggest trying a small ceramic slip hone charged with some 2-3,000 grit diamond.Just lightly hone the leading edges of an insert say a TPG322 at a 45* angle and see what happens.Just a few quick strokes is all it takes.

Lapidary stores sell the diamond dust and even have plastic PSA discs that are bonded with diamond dust down to 8,000 grit.With water cooling they make excellent hones for carbide.

BadDog
01-26-2008, 01:16 AM
Hmmm, closest thing I've got is a 1/4 EZLap "Fine". The only other thing I've got handy is a 2 side ceramic knife blade hone, not sure how that would work on carbide. It would be interesting to experiment, but not to the point of buying stuff that likely will have no other use for me. Hmmmm...

pntrbl
01-26-2008, 09:59 AM
You guys........
I've been watchin' this thread and decided to go to my local HF at lunch to check one out and see it up close.
WELL, at $129 I couldn't leave there without it. It sure looked like a deal to me....

damit, damit anyway.............. sheeeeeeesh!

I bought one too. Well almost. ;) My store's currently out of stock ..... but that's what rain checks are for.

SP

Carld
01-26-2008, 11:31 AM
Yes Lew, but we are talking about a stone ground edge compaired to a diamond ground edge and they are both sharp. One is more polished than the other.

wierdscience gave a good explanation. The point I am making is the diamond ground edge is over kill and not as important as many think it is.

I will go to my friends shop in Lou. one day this coming week and grind some brazed cutters on his diamond wheel to compair with stone ground.

The thing with a stone wheel is it has to be dressed a lot especially if you want a fine finish. Once the surface has a glaze or shine it is dead and won't cut and HAS to be dressed. I may dress my wheel after each time the wheel is used. That is, grind the edge, dress the wheel, grind the edge, dress the wheel, ect. The green wheels seem more prone to glazing but any wheel that glazes will not cut. All you have to do is remove the glaze. The finer the grit the faster it will glaze over. I don't like a wheel that breaks down fast because it's hard to keep a flat surface on the wheel that's needed for tool sharpening. My last boss bought some soft green wheels once and they gouged to easy and wore away fast. They sure did cut fast though but it was hard to keep a flat surface to grind an edge on.

On the other hand you don't ever dress a diamond just clean it as I understand it.

In the theme of the original post I think the HF tool grinder does as good as a Baldor even if it don't have the same quality. The Baldor and the HF grinders have nearly the same shipping weight so unless the Chinese are putting a lot of lead in the motor to make it feel heavy they must be built very similar.

Has anyone pulled the HF grinder apart to see what the motor looks like?

Benesesso
01-26-2008, 01:35 PM
Wouldn't the use of the toughest grades of carbide resist sharp edge chipping/cracking, yet still be a lot harder than HSS?

DICKEYBIRD
01-26-2008, 02:09 PM
I got my diamond and white A/O wheels today and am in the process of installing them.

2 things I noticed right away:

1) The stock aluminum shoulder bolts were all dead loose except for 2. If you're going to use the wheels yours came with, I'd suggest checking those bolts.

2) The hubs are .003" oversize and the wheels won't fit. I'll have to figure out a setup and try to accurately turn them down.

Did anyone else have to deal with the oversize hubs? If so, how'd you set up?

lazlo
01-26-2008, 04:00 PM
Wouldn't the use of the toughest grades of carbide resist sharp edge chipping/cracking, yet still be a lot harder than HSS?

It sure does. The smaller the carbide grains, the more cobalt binder can be used == a tougher insert.

C1 is micrograin carbide, very high toughness, highly resistant to edge chipping.

C5 - C7 is coarse-grained carbide, with much less cobalt binder == harder, much more fragile insert:

http://www.parlec.com/asset/view/20/v_p_Insert_Carbide_Grades.jpg

Your Old Dog
01-26-2008, 05:12 PM
Lane, Lazlo and CarlD, where the hell were you when I was getting put through the wringer here when I professed that engravers put "pre-wear" on a freshily sharpened chisel by putting a piece of 4/0 jewelers sandpaper on some 1/4oz leather and taking one shot back about 2" to intentionally remove the perfect edge. The tips tend to break much less and the Polish effect gets imparted to the cut you are making. If you push down on the sandpaper it sinks into the leather a bit and that little bit is enouch to clean up a cutting edge. Essentionally, that's what a strope does on a razor. You can accomplish the same thing by charging a leather strip with green chrome polish and using same as the other process.

The last time this came up the popular thought was sure, remove the edge off your tools and then try to cut steel? :D The one lousy thing I had to contribute to the forum and they shot me down, worse then that, they laughed :D

As for the grinder. I must be doing something wrong. Mine worked straight from the store and the green wheels leave a great finish on my HSS bits. My green wheels are green all the way through and both the same grit?


Did anyone else have to deal with the oversize hubs? If so, how'd you set up?

Yes, someone else did replace and as i recall he had a slick idea to get them to fit but I don't remember who. It has to be in the archives somewhere.

DICKEYBIRD
01-26-2008, 06:07 PM
I finally got both wheels on and running smooth...but not as easily as I thought. When I started, the thing ran smooth as could be with the supplied wheels.

I took both hubs off and made a tight fitting arbor to chuck them in the lathe. I took a tiny bit off the OD and the new wheels then squeeked on nicely. I checked the face of the hubs and they were out quite a bit so I skimmed off about 015" and they then ran true.

I checked the runout with the hubs bolted on and it was very good. I'm not sure if the spacing for the 6mm bolts was off on the hubs or the wheels or both. I kept trying different combinations until the bolts were centered as best as possible.

The diamond wheel spun up smooth & true by itself but that KBC white wheel was way off. It shook so bad it killed the 75W bulb within 10 sec.! After truing up the inner edge, the outer edge and finally the face, it ran smooth again. This is my first "professional" wheel so I don't know if that's normal or not. I expected better to be honest.

Now I need some input on how to deal with all the %^@#% grinding dust that flys around! I had my shop vacuum rigged up next to the wheel thinking it would get the majority but it only sucked up a portion of it. I have the grinding worktable located as far from my other machines as possible but it really needs to be in a separate building.

Next time, I guess I'll wait 'til a pretty day and roll it outside! That stuff is like plutonium. :(

lane
01-26-2008, 09:11 PM
The TPG inserts I use (almost exclusively when using carbide on the lathe) are flat top with a clearance relief below a sharp edge. These are used (and intended for) using in a holder that provides the positive top rake. They have no perpendicular side, which would clearly indicate an insert for a neg rake holder. I also have a selection of brazed carbide bits (some cheap Chinese, other good quality), some with positive top rake and some with neutral.

Again, I understand how negative and neutral carbide tooling is intended to work, and how it impacts the cut as well as longevity. I also (think I) understand how this is responsible for the "can't take a light cut with carbide" limitations.

However, what I keep trying to get to is, if the edge is not important, and in fact a detriment, why do major insert produces still produce the sharp edged *ground* and polished inserts? Likewise the "good" brazed bits I have came from the manuf with a sharp edge and positive rake with clearance. I've got both of these in C2, C5 and C6.

I've seen the edge effect you mention in aluminum, and I've seen the pits that result when the build-up is knocked off, but I don't see this in the polished TPGs used on steel. Then again, maybe I haven't looked close enough? Likewise for the change in chip structure, maybe I haven't looked close enough. I've got to make a bearing retainer (truck) for a friend of mine tomorrow. It will be made from HR 1018, but perhaps I'll take some time and experiment with the ground TPGs and/or some of my brazed bits with and w/o the edge knocked off.

New question, approx how much flat (radius?) should I put on it? I don't have a "green stick", but my diamond lap that's used to put a fine edge (to my detriment) on carbide will work well enough...

Dont ask us . we are like you . Go to your carbide supplier and ask him. Sanvic,Valenite ,Kenmetal ,Iscar Thet can explain it and give you a course in how to use carbide . they all have a class.

wierdscience
01-26-2008, 11:04 PM
Hmmm, closest thing I've got is a 1/4 EZLap "Fine". The only other thing I've got handy is a 2 side ceramic knife blade hone, not sure how that would work on carbide. It would be interesting to experiment, but not to the point of buying stuff that likely will have no other use for me. Hmmmm...

Hit it with the Ez-lap,couple stokes should be all it needs.

Pete H
01-26-2008, 11:15 PM
Question -- will a boron nitride "dressing stick" work on TC ?
-Pete in NJ

DICKEYBIRD
01-27-2008, 08:17 AM
I guess my experiences with a freshly bought H/F grinder are on topic to the OP's thread.

I decided to widen the slot in the 2 tables to match the more substantial miter attachment I had made to fit my Ishimura grinding rest and the home-made disc sander I finished a couple weeks ago.

I shimmed and clamped the 1st table nice & flat on the mill and tried to dial in the slot parallel to the X axis. The D.T.I. was doing truly weird things and I began to think the recent D.T.I. fix mentioned in another thread had haunted the darned thing. It kept telling me the slot wasn't straight and sure enough, when I sighted down the slot, both sides were parallel but gently curved about .015" off of straight! Their mill table was out of whack or something. I guess that's why they make the supplied miter gizmo so loose.:(

lazlo
01-27-2008, 10:13 AM
Again, I understand how negative and neutral carbide tooling is intended to work, and how it impacts the cut as well as longevity. I also (think I) understand how this is responsible for the "can't take a light cut with carbide" limitations.

However, what I keep trying to get to is, if the edge is not important, and in fact a detriment, why do major insert produces still produce the sharp edged *ground* and polished inserts? Likewise the "good" brazed bits I have came from the manuf with a sharp edge and positive rake with clearance.

Russ, the edge is important. But a sharp edge is fragile, and a blunt edge is durable. So just like on HSS, you use a high rake angle (i.e., sharp), edge for soft metals and finishing cuts. But that sharp edge will shatter on interrupted cuts, or a big DOC.

So if you're turning the splines off a car axle, you blunt the edge, or better -- use a negative rake insert. A negative rake angle has a similar, but more pronounced effect to dulling the edge: it gives more support to the edge.

smiller6912
01-27-2008, 11:44 AM
....Now I need some input on how to deal with all the %^@#% grinding dust that flys around! I had my shop vacuum rigged up next to the wheel thinking it would get the majority but it only sucked up a portion of it. I have the grinding worktable located as far from my other machines as possible but it really needs to be in a separate building....
A separate dirty area is a very good idea, I have some old shower curtains on a 1/2" alum conduit track around my sanding, grinding, blasting area, it helps some. Also, try putting 1/4"-1/2" of water in the tray under the table so that a lot of the dust is stopped and trapped and doesn't fly around so much, it isn't perfect but helps a lot.
I had to try something, my '65 'Stang is about 4 feet from my "dirty area":mad: .

DICKEYBIRD
01-27-2008, 04:17 PM
Well that was interesting. I straightened out the crooked miter slots in the tables and widened them to fit my own miter attachment. I measured the width of the table mount bosses on the grinder's frame and started adjusting the table brackets to fit them more snugly. After trying several combinations of spacings and curses, I found that the brackets weren't even close to square!

I thought at first it was all the green paint slobbered under them and scraped all of that off. I ended up having to flatten one face on some 180 paper on a glass plate and then bolted them to an angle plate and mill the bottom face square. It took about .015" to clean them up.

When those details were finished and the brackets adjusted properly, the tables now adjust OK. I set the table angle on the diamond wheel end to match the a brazed inset boring bar I crashed a while back. It had a good sized chip knocked off but I was able to reshape it and put a nice mirror finish on the the damaged edges. I put a slight radius on the tip with a little EZ Lap stick.

It's hard to capture it in a picture but I'm very happy with the result. Disregard the buggered appearance, the carbide is still solidly brazed on and the cutting edge is good.

http://i57.photobucket.com/albums/g227/DBAviation/BoreToolSharp.jpg

S_J_H
01-27-2008, 08:36 PM
Well I made a stop this morning at the local HF. Dog gone it all but one of these Grinders ended up in my cart.
Well my impressions are that it is a nice machine for the money. It runs very smooth. I was impressed by that. The table angle brackets are pretty low quality and need work.The table surfaces are very good and do not rock at all on a surface plate.
The green wheels ..I don't know. Don't seem as horrible as I have read. No problem grinding quickly on some brazed bits with little heat. Resulting finish not that bad and is usable for sure.They are definitely not painted green. Not a bad machine.
Steve

Oldbrock
02-08-2008, 01:37 AM
EEK!!!!

You have got to be joking!
Your'e getting a new lathe soon I take it. Your bed will last another 7 weeks. Peter