What diamond/green wheel for side grinding on my bench grinder?

Hi, I have a nice 10" bench grinder and would like to mount a diamond or green grinding wheel on it for side grinding lathe bits. Mostly high
speed steel with the occational carbide.
I read and have been told never to grind on the sides of my existing 80 and 120 grit wheels.
I can't afford a dedicated carbide grinder so I want to convert my bench grinder into a more usefull machine. I really only use my grinder for lathe bits.
Any information would be appreciated.
Rod San Francisco
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I'm sorry if my question is vauge.
What I would like to know is what brand, make and model number of Type 5 wheel are you using on your bench/pedistal grinder for HHS tool bits. Also. the same info for carbide grinding..
Thank you in advance,
Rod San Francisco
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I do not use a type 5 wheel to grind tool bits. I just use a regular aluminun oxide wheel. A coarse one to get the general shape and then a fine one that I got at Boeing Surplus. Grinding lathe bits does not require angles to be precise except maybe for threading. And you can get threading bits precise using a cheap gage.
Dan
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Dan, Thanks for your advice.
I would like the option of grinding on the side of the wheel. That's why I was looking for a type 5.
Rod
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Both green and diamond wheels are really unsuited for HSS bits, only carbide. I'd use a aluminum oxide cup wheel of about 40 grit or so for HSS if I was stuck with a bench grinder. Side grinding on a straight wheel really IS NOT the way to go. As it is, I use a belt grinder and a 40 grit belt for rough shaping, 80 grit for finishing with a few licks on a diamond hone plate afterwards. Others will have their own procedures. I have a bench grinder I inherited and was using, it seldom gets any play since I've gotten the belt grinder.
Stan
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In article

If you try to grind steel on a diamond wheel, you will ruin the diamond wheel very quickly. Diamond wheels are for carbide.
For steel you need wheels that do not contain carbon in any form. Aluminum oxide and zirconium oxide are standard.
As others have mentioned, a belt sander is very good for rough shaping HSS.
You will also need to make or buy a holder for the HSS bit you are shaping. Finger holding doesn't work - forces too high, bit also gets quite hot.
Joe Gwinn
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wrote:

Depending on the size..an old drill chuck works just fine for holding bits while grinding. generally an old 1/2" drill chuck will do most everything in the hobby shop
Gunner
"They couldn't hit an elephant at this dist..." Maj. Gen. John Sedgewick, killed by a sniper in 1864 at the battle of Spotsylvania
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I do that too, but the chuck was a bit big and I didn't want to grind it, so I made a holder on the lathe from some 5/8" 1018 steel rod that is smaller and therefore easier to use, but it's slower to insert or remove the bit (as the bit is held by a setscrew).
Joe Gwinn
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Thanks to everybody that responded to my question.
It looks like there is no such 10" type 5 grinding wheel for HSS. But that's no longer a problem with my side grinding question. Several people that I talked to as well as info from groups like this, tell me that side grinding on a type 1 wheel on my bench grinder is OK. Just as long as you don't apply too much preassure. I'm only grinding lathe bits on the side of the wheel and only breifly. All done by hand.
I'm sure that some HSM won't agree. I'm willing to do it because it's my home shop. I would not do it in another shop with first asking if it's OK.
Rod San Francisco
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rodjava wrote:

It sounds to me like you're thinking about what damage might happen to the wheel. The real issue is what damage might happen to _you_. If a wheel breaks from side grinding it's like an explosion, with sharp pieces flying about at great speed.
Be careful, Bob
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If you'd like to read some of my ravings about sharpening HSS, the selection of grinding wheels, and grinders, here's a link of a multitude of posts I've made on the Chaski board. I didn't compile the file, but it was compiled with my approval.
http://www.savefile.com/files/915454
I'm very outspoken about the subject of offhand grinding of toolbits----and have provided some guidelines that you may find useful. Or not. One of the points I make is learning to sharpen HSS without using a tool rest or other cheat devices. If you develop the skill, there is no better way aside from using a tool & cutter grinder.
Harold
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Too big, I don't have enough time left this month.

You can practice freehand with 1/4" key stock. Hold it against the motor housing (watch wheel vs fingers) to reestablish the angle. I've found I can grind a lathe bit quite close to final shape with an angle grinder, which cuts faster and cooler than my A36 bench grinder wheel. As with a milling vise, the bit needs to be balanced by another one on the other end of the jaw or it will swivel away from the disk too easily. Soft jaw pads help. It's especially good for the long undercut on an inside threading bit.
This is where I grind steel on the carbide wheel. I sharpen the bit as well as I can on the coarse A36 side, then lightly polish it for a second or two on the carbide wheel, which normally grinds brazed bits. Both leave a hollow grind so that a hand-held stone is self-aligning but has to cut only a narrow strip along the top and bottom edges. I stopped grinding on a face wheel because the flat surface is more difficult to touch up without decreasing the front clearance angle too much.
A conical stone in a Dremel will grind a smooth inside radius easily, for corner rounding & thread end finishing bits.
jw
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snip---

That comes as no surprise. The wheels that come with bench grinders are not suited to grinding HSS, regardless of what you might read. They are far too hard, so they don't cut, they rub, heating the bits instead of grinding them. If you apply that wheel to mild steel, as you proposed, it appears to function better----but HSS is mild steel, and that's the problem. When you match the wheel to the material, it grinds quickly, with minimal heat. I cover all of that in that large download.

I'm not here to say it doesn't work. It does. However, when you grind ferrous materials with silicon carbide, the wheel is instantly dulled by dissolution. Iron has a strong affinity for carbon, which it will gather from any source possible. That's why you shouldn't grind steel with diamonds, unless they are run slowly, well below the point where they achieve red heat.
What you're doing isn't considered good practice as a result. No matter, as long as you're happy with the results. You've be far happier with a diamond wheel, properly applied.
Harold
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I wish I had enough good grinders with the proper wheels for each job, and more importantly enough space for them and the grit they scatter. My pedestal grinder is IN the doorway to the shop. I also have an underpowered but portable 5" bench grinder with a wheel reserved for TIG tungstens and a (chipped) diamond dish wheel for polishing carbide, and a surface grinder. ... I just sharpened my block plane on it, ~0.0001" per pass. It's what made the shop too crowded to add anything else. It blows its sparks and grit at the wood stove, which doesn't care. I couldn't pass it up for $100.
Except for the pedestal and surface grinders I do all grinding and sanding outdoors to protect the other machines from grit. The pedestal grinder is too top-heavy to put on wheels. When I push hard on it, it leans back safely against the door frame.
I think a low-budget home shop could get away with a good-sized pedestal grinder with coarse and fine Al wheels for steel, and for carbide a small portable bench grinder with a SiC and a diamond wheel if you can find a used one cheap. The small diamond saw blades might work??? I put the SiC wheel on the powerful grinder to handle masonry hammer drill bits and chipped carbide lathe tools.
Even the Enco and HF carbide/diamond tool grinders are far more expensive than I can justify, being old and retireded. My stuff is from second-hand stores, auctions and yard sales, what was available rather than the right machine for the job, but good enough for a hobby shop.
A decent belt sander sharpens woodworking tools pretty well. I have an indecent $49.95 belt/disk and a 1x30 Delta, both with sheet metal backup platens that aren't really flat. Otherwise they do most of the work of a fine Al2O3 wheel on the pedestal grinder. I made a new pulley for the belt/disk sander that holds a 6" carbide face wheel but the motor is too small and the table too flimsy for serious grinding.
Jim Wilkins
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On Wed, 26 Nov 2008 09:01:01 -0800 (PST), rodjava penned the following well considered thoughts to the readers of rec.crafts.metalworking:

Don't believe everything you read in a book.... but don't expect to do anything other than light dressing on the side of a wheel, either.
I'd suggest you look for an older American tool, but for $160 you can do the grinding you propose and do it safely.... http://www.harborfreight.com/cpi/ctaf/displayitem.taf?ItemnumberF727
--

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