I am bringing up a Baldor "carbide" tool grinder, a No. 500 with tilting tables that takes plate-type wheels. I have no intention of using green silicon carbide wheels. My intention is primarily to sharpen HSS tooling. I have seen suggestions posted here to use diamond wheels. I am looking at these, and at the prices they command I don't want to buy them in every grit. I plan to do roughing on a disk/belt grinder and to do just the finish grind on the HSS tools (mostly lathe tooling) with the Baldor. I have questions:
Greetings Grant, The wheels you looked at on the above site are not suitable for grinding HSS at the speeds your grinder runs. The diamond will actually combine with the HSS causing wheel dulling and accelerated wear. BUT, I have some 5" diameter cast iron rod that can be turned and faced and used at lower speeds for lapping HSS with diamond paste. If you want to use tour high speed grinder with HSS you will need to use CBN wheels. CBN is almost as hard as diamond and will grind steel without combinong with the steel. If you want I can have my guy drop off some slices of the cast iron (no charge) to make your own lapping plates. But even these will need to be run slowly to avoid pulling all the diamond out of the lap. Cheers, Eric
McMaster-Carr may be able to special order them for you if no one else carries them.
BTW, wouldn't that Glendo grinder you(?) had FS recently be good for finishing HSS bits? Or maybe you want to "finish" a little more than I'm thinking.
It's running pretty good today, yes. The Baldor no. 500 carbide grinder I just bought vibrated excessively so the seller knocked off about $150 and I got a really great deal. I brought it home and took off one wheel and then it ran perfectly smooth. Today I looked at the wheel - a nice Norton
46 grit gray aluminum oxide wheel - and it looked OK to me so I thought I'd try it again. I carefully remounted it and it ran perfectly true, no vibration. So now I have one gray AlOx wheel and one green wheel. I would like to ask, though, how you found out about these, and which you would recommend? - GWE
Is this grinder a high speed machine? 3450 RPM, perhaps? Slower than 500 RPM?
If you answer yes to #1, why are you considering a diamond wheel? By now you should know that diamond is not compatible with iron based alloys at elevated temperatures. Your only consideration should be aluminum oxide unless you intend to grind carbide.
If you find them let me know. I am currently using Norton AO on my carbide grinder. They work ok, but need to be dressed fairly often because they load up. I bought the Norton plate wheels from grainer but I think MSC sells them now.
They are in a clearance flyer that was in my last MSC order, received last week. I bought a 100 grit. I don't use HSS very much, but I am tired of dressing that damn Norton ALO wheel every time I want to use it. I can always hand hone if I need a bit smoother than the 100 grit will make it. The other wheel is a diamond for brazed carbide, which I don't use very often either. Wish there was a quick-change wheel set-up for Baldor type machines.
Oops, my luck just ran out. MSC has no stock and isn't getting any more, sigh. They're looking for me, they'll let me know tomorrow, but as for now, I'm still looking for CBN plate mounted wheels.
Harold, please take it easy on me. I heard loud and clear that diamond isn't the abrasive of choice for HSS, but lots of guys have told me that borazon or CBN work really well for a finish grind. A Baldor No.
500 is a "carbide grinder" with tilting tables and plate-mounted wheels, and it runs at 3450 rpm. which is *way* too fast to grind HSS with diamond, yes.
Ok, easy it is. However, I can't see a reason to use anything beyond aluminum oxide. I especially can't see a good reason to use a carbide type grinder for HSS. At best, they're too restrictive to be functional.
One of the negatives of using a machine with a table is you'll *never* gain any skill at sharpening. As long as you permit a machine to do the work, you'll not progress. You'll also be limited as to how you can apply your tool steel to the wheel. I refuse to use anything that gets in the way, including a work rest of any description.
I was brought up through the trade when there was almost no insert carbide tooling, and HSS was the order of the day, chiefly because brazed carbide was still relatively new and not nearly as good as carbide is today. I was on the tail end of Stellite, which damned few that are machining today can claim. As a result, we were forced to learn to grind tools, or you had to find different employment. One was taught the basics, then was expected to apply them to sharpening. I can't think of any better advice for the home shop type. Any of the dodges you use to avoid learning will simply hold you captive. That includes the grinder of which you speak.
Whoa Harold! With that logic we should throw away our milling machines and break out the files. Forget files, we need to use stones. And have to walk six miles back and forth through the snow. Harold, I learned how to grind tools by hand and with a grinder and rest. The grinder will put very nice edges on the tools and give you an example of what a good grind looks like and and how a sharp tool cuts. The CBN wheels used on HSS can give the tool a very smooth and sharp edge. Depends on the grit of course. And wheel wear is negligible.
You must have had it good! I had to walk ten miles each way, and the snow was deep---almost up to my hips.
Harold, I learned
So did I. Then I learned how to do it better from guys with proper experience. I didn't close the door on learning.
The grinder
I do that free hand. *Anyone* can do it, all it takes is a little practice.
The CBN wheels
I don't see that as a positive thing. If you're doing repetitive grinds on a production basis (cutter grinder), maybe it has its place, but I can do free hand that which you mentioned, and I don't have to invest a large amount in a wheel that is restrictive. I have no doubt these wheels are good-----damned good----but they do not lend themselves as well to offhand grinding as do aluminum oxide wheels. There are times when you simply must dress a particular configuration into a wheel. CBN for that, too? Why limit yourself to an expensive wheel that can't perform all functions? There are no advantages, and it's far more expensive.
The point I'm trying to make is that all the fancy gadgets in the world won't substitute for learning the basics. Learn the basics-----the rest comes easy.
The best lathe men I ever worked with, one of which was likely the finest man on a lathe of our time, (from South America, and spoke English poorly) all sharpened tools free hand, for the same reason I do and did. Any rest simply gets in the way. That's not to say you can't learn to grind tools with them, but you'll never achieve the level of excellence that others do without them. Grinding proper chip breakers is a good example of one of the limitations when a rest is employed.
I respect Harold's opinion. But I find it very hard to hand grind toolbits with consistant angles and I also tend to generate multi-facets. Also it takes a very talented person to hand grind a 1-2 degree relieve angle for a groove cutting tool.
If you can hand grind toolbits great, but I can't and I don't have the time or inclination to destroy expensive mo-max toolbits. So I use a carbide grinder with AO wheels to grind HSS toolbits. I can very consistantly grind toolbits and touch them up. chuck
Maybe I've lost track of the fact that I may have a little talent! I have never paid for a grooving tool in my life, nor have I used any kind of guide to hand grind them. It's not difficult for me to hit width, which I do with the wheel, not by stoning, and I can do it with a single face grind, it's not chopped up. I also hand grind all my parting tools (typically made from 1/2" square HSS blanks), and did so when I ran my machines for gain. I never felt I had any particular gift, although not all the guys I worked with could hand grind them equally.
One of my friends ran his own shop for years, selling out when a skin condition became more trouble than he could deal with. He always relied on insert tooling or had his custom tools done by a shop with a cutter grinder. He lacked the confidence to do them manually.
Under those circumstances, I agree. You're likely not trying for the exotic designs that can be accomplished freehand, so your method likely serves your needs to your satisfaction.
I'd compare this entire concept to using a computer. Many of the readers here are very adept at running theirs, and rely on systems that would likely be well over my head. I'm content to limp by using Windows and IE, if for no other reason, they do what I expect of them. Maybe if I was better educated in computers I'd have higher expectations.
I see no right or wrong way where it comes to grinding toolbits. My position in that regard is if you learn the basics and apply them well, you'll be set free. It gets down to how important it is to each individual-------just like computers.
Harold, Someday it would be nice to meet you and maybe, just maybe, you might be able to teach me some grinding tricks. Self taught can only go so far you know.
I've stood on the shoulders of some giants (to me, anyway) in the machining industry, so I think I can understand what you're saying. Had it not been for some outstanding guidance early on in my career, I doubt seriously that I would be able to do the things I learned to do. You can carry yourself only so far without additional input. I am the product of those that went before me, I don't claim to know anything that I've created.
You're welcome to pay a visit any time you'd like----and I'd gladly spend a day or two with you showing you how I go about grinding toolbits.
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