Grinding wheels for HSS

I primarly use HSS toolbits in my lathe and over the weekend I
ground a number of HSS lathe bits. I use a Baldor carbide
grinder with Norton 32A46 plate mounted grinding wheel.
I find that I have to dress the wheel very frequently when grinding
tough toolbits like MoMax. I tried grinding a 1/2 inch square
stellite toolbit and it was taking forever to reshape a used toolbit.
I looked through J&L abrasive selection guide and they list
better grinding wheels for tool steels, but I cannot find any better
plate mounted grinding wheels. (I also looked at MSC). Any suggestions
on the best wheel to use for grinding HSS toolbits on a baldor carbide
grinder?
As a side note, greee wheels are list as non-ferrous only and I had
a Norton 39C60 green wheel so I figured I would try it on the stellite
toolbit. It seemed slower than the 32A46. I was tempted to try my
diamond wheel but I was worried I would ruin it.
chuck
Reply to
Charles A. Sherwood
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The best wheel would be a Borazon plated or resin bond similar to a diamond wheel. But these are kind of pricey. Because of the hardness of the HSS its going to wear the wheel down regardless of the type. If the wheel is to hard your going to overheat the HSS, to soft and you will be dressing every 2 minutes. You might want to invest in a cheap 8" bench grinder and put a couple of toolroom wheels on it to rough out the toolbits first before you finish the angles on the baldor.
Charles A. Sherwood wrote:
Reply to
Machineman
I have not found any plate mounted wheels other than green or basic AO. I would gladly pay for a hi tech abrasive wheel, like a 5SG, if I could find one.
Interesting idea. I am not real good at free hand grinding toolbits which is why I spent the bucks on the baldor. Of course I use the baldor to rough out the toolbits before finishing them on the glendo! Yes I need another tool. 8 inch grinder for me! thanks
chuck
Reply to
Charles A. Sherwood
I rough mine out on the 6x48 bench belt sander or the 12" disk. Works fast and saves wheels. 30 grit gets the metal off quick.
Gunner
That rifle hanging on the wall of the working-class flat or labourer's cottage is the symbol of democracy. It is our job to see that it stays there. - George Orwell
Reply to
Gunner
I don't know what the grades were, but most shops I've been in have two wheels for the grinding of HSS. One quite coarse for "roughing", and the second quite a bit finer for finish grinding.
Just keep in mind: Rough versus finish grinding
Good luck!
Reply to
Lurker
Hold on there. You're not allowed to use Orwell's quote because it's obviously a reference to England, and non-applicable to US constitutional law. All this 'flat' and 'labour' stuff is *right* out. Please be so kind as to confine your OT RTKABA stuff along a straight-arrow red, white, and blue trajectory if you please.
Orwell's fame notwithstanding, of course.
Jim
================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ==================================================
Reply to
jim rozen
Why? Before the Brits were neutered at birth, they used to be quite a firearms owning lot. Its in the blood, given the rather large number of Brit Ex-pats that I know here in the States that own quite a large number of firearms.
Seems that the Crown was a bit worried about the Bolseviks gaining favor in England and tossing them out on their asses, so they started removing the guns from the commoners. Shrug..a lesson to the rest of us about the dangers of being a subject, rather than a citizen.
Gunner
That rifle hanging on the wall of the working-class flat or labourer's cottage is the symbol of democracy. It is our job to see that it stays there. - George Orwell
Reply to
Gunner
Do you dress because the wheel has quit cutting, or because it has broken down too much and is rough?
I tried grinding a 1/2 inch square
Where did you locate Stellite toolbits? The only ones I've found in years were on ebay. If you're not familiar with them, you're in for a treat. They perform at a level near that of carbide. Haynes Stellite is tougher at red heat than at room temp.
You are pretty much limited to an aluminum oxide wheel. For sure do not use one made of silicon carbide.
I gather from your comments that you may not be using a hardness in keeping with your requirements. The letter following your designation is all important in that regard. If the wheel dulls up too quickly, the wheel is too hard, so you should drop back a letter or two. If it seems to slough off to quickly, go up a letter or two. (From J to L, for example).
Do not use silicon carbide or diamond wheels on steel. Steel has an affinity for carbon, and at the high speeds wheels run, the reaction is relatively fast. The diamond or silicon carbide dissolves into the steel, dulling the grain very quickly. In spite of the fact that silicon carbide is a lot harder than aluminum oxide, the dulling from dissolution makes the wheel appear to not be as hard. I don't know that Stellite would behave in a similar fashion, but I've ground it with aluminum oxide wheels with great results. I think the wheel grade you're using is the bulk of your trouble.
A side note. I'm not all that nuts about using a 46 grit wheel for sharpening toolbits, especially for finishing them. I'm inclined to run a 60 grit instead. It will cut slightly slower, and perhaps even a little hotter, but the finish on the tool tends towards a much nicer one. Just my personal choice, I don't mean to imply that should be good for everyone.
Harold
Reply to
Harold & Susan Vordos
I dress the wheel because it quits cutting and just generates heat. I run a diamond point across the wheel using the groove in the table as a guide.
Nothing else to choose from.
MSC only lists these plate mounted grinding wheels: (Norton) 32A46K VBE 32A60J VBE
The 32A60J is great for finishing up or cleaning up a toolbit but is much to fine for roughing out a blank toolbit.
Another approach may be required. I have a Rockwell toolmakers grinder which will mount other wheel types. I looked in catalogs last night and I can buy Norton 5SG grinding wheels in type 5,6 or 12. Can I grind on the side of a type 5 wheel?? A type 5 wheel is a recessed wheel. I have tried grinding toolbits on this machine and it does a great job, but it is much slower than a bench grinder.
Another approach is to buy a 8 inch bench grinder. Can I mount good toolroom wheels on a bench grinder by making a spacer to fit the shaft and the 1.25 inside diameter of the toolroom wheel? I can buy jet or delta 8 inch grinder for about 150. Enco for about 50 and Baldor for 700. I'm sure the baldor is wonderful, but 700 is pretty steep! Will I be disappointed with the cheap enco grinder?
What do I need to get started with CBN. I looked in the catalog and it seems that you need an expenive break type dresser to go along with your expensive CBN wheel. It also said the wheel needs to be running with less than 1 thou runout. How do you measure that? I sure ain't going to touch my indicators to the front of a grinding wheel!
Thanks for the help chuck
Reply to
Charles A. Sherwood
The SG wheel will last longer between dressings than a conventional wheel. However, I agree with Gunner, a belt grinder is the ticket for roughing out a tool bit or any other fast stock removal job. If you don't have one, don't buy a bench grinder, buy a belt grinder instead as they are much more versatile than any bench grinder.
I have a carbide grinder with the 32A60J wheel on it. It requires frequent dressing and there is nothing you can do about it. But to save time and wheel grit, I always rough out a bit on the belt grinder. These days, about the only HSS lathe tools I use are form ground specials and grooving tools made from HSS cutoff blades. Carbide inserts are the only way to go on the lathe if your machine has sufficient rigidity and power.
Randy
Reply to
Randal O'Brian
I have a 1 inch kalamazoo belt sander. Will it do? Belt grinders seem to be in a class of their own! (and price too). I know nothing about belt grinders. What distinguishs them from a belt sander?
chuck
Reply to
Charles A. Sherwood
That's a mistake. Unless you are grinding under power with complete flood coolant, diamond dressed wheels are not to be used. Even on cutter grinders, wheels are normally hand dressed with dressing sticks. Diamond dressed wheels cut very hot. The ultra fine surface prepared by the diamond tends to act like a bearing. Way too much of the wheel surface is in contact at all times because it is so smooth. If you insist on using a diamond to get the wheel smooth, follow up with a roughing pass with a hand dressing stick. NOT the solid boron carbide kind, the ones that measure 1/4" x 1/2" x 3". These do about the same thing to you wheel as a diamond once they start to get dull. Use the 1" square variety that are comprised of fused bits. They tend to keep sharp by constantly exposing new corners of the abrasive. This alone will make a huge difference in how well the wheel cuts.
I'd be using the 60J in a heart beat, and dressing it properly, assuming you wanted to stick with the grinder you're using, and I, too, was going to stick with it.
Truth be known, there's no way in hell I'd sharpen toolbits that way. I use a chest high pedestal mounted wheel with no tool rest. I have available to me any wheel configuration imaginable because I use 7" x 1/2" x 1-1/4" toolroom wheels. You have total freedom to grind angles and chip breakers with no obstructions. It's a learned thing, very uncomfortable at first, but the best thing going once mastered.
When it is diamond dressed, I fully agree with you. Otherwise, I do not.
Truth be known, you can grind on the sides of most any wheel, so long as you don't apply excessive pressure. Light hand pressure does no harm, but think of a guy with a large weldment pushing against the side of a wheel that is fragile and the part is bouncing. That's where you get wheels coming apart. A type 5 is intended to be used on the periphery normally, but a type 6 or 12 is obviously intended to be used in a combination of ways, with the majority of the pressure applied to the side of the wheel, especially in the type 12 wheel. Truthfully, none of them would lend themselves well to sharpening tools unless you were moving the tool past the wheel much the same way one would do using a cutter grinder. I'd stick with a pedestal grinder otherwise.
I can't speak for your choice, but I've sharpened my HSS and brazed carbide toolbits on a custom built pedestal grinder described above since 1967 and have had outstanding success. The grinder has two arbors, one on each end of the 1/2 horse 3,600 RPM motor, which is reversible, one side has a permanently mounted diamond wheel for brazed carbide, the other accepts the toolroom wheels I mentioned. The motor was an old one my father gave me, likely out of the mid 40's. Originally came from Sears. Considering how we use these things, it might be worth a shot at the Enco machine. Still, all you really need is the motor if you follow my design. You'd have to abandon everything already on the one you'd buy except for the shields otherwise. That's a call you have to make.
Very sorry to say I have zero experience with CBN wheels. When I closed the doors on my (commercial) shop there were no such thing, and I have yet to find a real need to explore them. I can only assume that when it comes time to mount such a wheel, just like with diamond use, you'd have to sacrifice a contact point, turning the wheel very slowly by hand, and minimizing the wear. Or, you could carefully cover the wheel face with "Scotch" tape, which is very consistent for thickness. Overlap the tape, then make a clean cut with a sharp razor, leaving a single layer all around the wheel. Requires a very clean wheel surface to be successful. My personal opinion is that unless you're doing this for a living, you don't really have to go to CBN wheels. The simple act of learning to dress your wheels properly will make a huge difference in the outcome of your work.
Sorry I'm not more help.
Harold
Reply to
Harold & Susan Vordos
Belt sanders are a good way to move the metal, but a terrible way to sharpen any cutting tool because of the fact that they round corners. That has the effect of leaving a tool with little to no relief where you need it most, right at the cutting edge. . You're also limited to the nature of the grind, unlike a wheel. If you use your 1" belt, make sure you follow up with a wheel for that sharp edge needed for good performance. You'll be able to see the rounding effect left by the belt when you do, and it will be obvious when you can quit grinding with the wheel as a result.
Harold
Reply to
Harold & Susan Vordos
SNIP
I check mine at zero speed (manual rotation) and interpose a piece of VCR tape.
If you're a bit ham handed and want to be doubly safe use two thicknesses of tape.
The tape thickness is remarkably consistent and a single old video cassette yields several lifetimes supply!
If you need to know the exact tape thickness keep folding and doubling a length of tape until you've got 64 or 128 layers to yield a convenient thickness to mic.
Jim
Reply to
pentagrid
I will look at catalogs and find some dressing sticks.
Hum, you have been a lot of help.
I have a line on a used baldor industrial grinder. That might make the job easier.
chuck
Reply to
Charles A. Sherwood
Which Stellite are you refering to here, Harold? I ask because I snagged a bunch of Stellite #6 TIG rods. I have yet to try them for lathe bits but that sounds like a deficiency I should correct. :-) However, I have used them for some interesting apps. I'll list three:
Build up a blob on the end of a piece of re-bar and shape it to a center punch point in the lathe with a carbide cutter. After a little use it has dulled but since the stuff work hardens, I just re-point it (gently) and that point lasts ages in hard use. I have used it as one usually uses a center punch but also for hot work and center punching concrete for anchor bolt holes.
I made a cold/hot chisel by the above procedure. Works very well. Loaned it to a friend to knock knobs off concrete. When he returned it, it was still quite sharp and has no chipping on the edge.
I have an older but perfectly serviceable (except for one problem) electric stove. The contacts on the plug-in elements are a bullet shaped copper cylinder molded onto the end of the wire that sticks out of the connector end of the elements. The copper corodes slightly, contact resistance increases, more heat is generated, corrosion rate increases, even more heat is generated, ..., connector mounted on stove top fails. I managed to score one of the last stove top connectors for this model in captivity - mfr wants you to replace element AND connector with "new" expensive style. My fix: melt off copper "bullet", build up Stellite #6 bullet, grind to final shape. Clean contacts on stove top connectors and re-install all. Fix was done in '96 - all contacts are still bright and clean.
Ted
Reply to
Ted Edwards
As usual, I'll jump in on this statement. If you have sufficient rigidity and power to take heavy cuts at high speed, carbide inserts are the way to go when standard shapes will do. The converse as stated above is false. I use carbide inserts for most of my turning and am quite pleased with the results. This is on a Smithy 3-in-1. While I quite like the machine and can get it to do what I want, it certainly does not have a great deal of either rigidity or power.
Ted
Reply to
Ted Edwards
I was under the impression that Tantung works as well as stellite. True or false?
Reply to
Charles A. Sherwood
Ted and I have been at odds on occasion, and this is likely one of the subjects that could easily be debated between us. In retrospect, I'd like to say that what Ted says is pretty much on target. When I clear my mind from my years of commercial machining, I think the only fair statement I would make regards using carbide on light duty machines is that you are not realizing the full capability of the carbide, simply because it is capable of so much more than the machine can provide. On a minor note, carbide can perform at a lower level when not run at proper speeds, but it would be highly unlikely that the average guy would recognize the difference. Often, even in the commercial shops, only when running a production job repeatedly do you start realizing that certain choices of carbide and different speeds and feeds make a difference. Based on that, I'm inclined to fully agree with Ted. Carbide inserts can be useful on small machines.
The one negative is that many substitute the learning curve of hand grinding toolbits, so they are for ever handicapped in that regard. I strongly recommend one learn to grind high speed toolbits, no matter the equipment at hand, unless running CNC, where hand ground tools are not necessarily in anyone's best interest under production situations, anyway.
Harold
Reply to
Harold & Susan Vordos
I'm not sure I know enough about Stellite cutting tools to answer that, Ted. The only thing I know is that at one time I had a piece that was used as a parting tool and I was shocked at the performance. This was MANY years ago, when I was employed in a large shop, where I got my training. I recall leaving the tool in a setup that was being run on both shifts and never seeing it again, nor any other like it.
Only recently did I run across more Stellite in the way of cutting tools, when I bid on, and was successful, on eBay. The only problem was that the guy listing the short pieces, ends left after a custom tool had been made, said they were longer by 1/2" than they were. The pieces I received are still long enough to be used, but certainly not long enough to make a good parting tool, which would have been one of my choices.
On the shanks that I received, which are 1/2" square and 2-7/16" long on the average, all are marked "Haynes Stellite Alloy 98M2". Means nothing to me, but apparently they had more than one alloy.
A point of interest. Included in the Stellite lot were a couple other pieces, same size, remnants that had also been cut with a parting wheel on a cutter grinder, both marked Vascoloy-Ramet Tantung G. Leads one to believe that it shares similar, if not equal, qualities. I have yet to use any of the toolbits for lack of need, so I can't report further.
Sorry to be so late getting back to this, Ted. I had apparently removed the mark I had left on the thread and stumbled across your post strictly by accident tonight when I was checking to see if I had missed anything.
Harold
Reply to
Harold & Susan Vordos

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