Freehand grinding of Lathe bits

I, too, have a Drill Doctor. It's great. Now you've got me thinking about a fixture to hold lathe bits in it... Dial in your angles and have at it. Oh crap. Now I probably won't sleep tonight.

And hey, wait a minute! the Drill Doctor is an example of a machine DESIGNED to grind HSS with a diamond wheel. I've done hundreds of bits on mine, including a couple of broken ones that needed a lot of grinding, and the wheel still cuts fine.

And hey, wait a minute! the Drill Doctor is an example of a machine DESIGNED to grind HSS with a diamond wheel. I've done hundreds of bits on mine, including a couple of broken ones that needed a lot of grinding, and the wheel still cuts fine.

Our drill doctors will now fail, as it has been pointed out that Diamonds are not HSS steels friend. :>(

O.K. So surface speed would be a maximum of 471 SFM at the outer edge of the 6" wheel. The running wet makes a big difference, too. That would probably work well enough even with HSS. (Harold -- does this sound workable?)

Enjoy, DoN.

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Well ... the diamond wheel on the Drill Doctor is something like

1" diameter. I forget what the RPM was, from which we could calculate the SFM -- but I have always wondered about the choice of diamond for that. I think that it was mostly so they could also sharpen the carbide masonry drills. :-)

I could go downstairs and set up the StroboTac again, but I am under doctor's orders to not work machine tools until tomorrow.

Enjoy, DoN.

From what I remember of reading Norton's publication on the subject: Yes, there is a noticeable degradation of the diamond, but only in terms of production rates. What I mean is that if you have a wheel that will last 10,000 hours grinding carbide, and it only lasts 1,000 hours grinding steel, that's not about to be a problem for a hobby (or even small production) user.

I don't think I'd sweat it.

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It's not that simple. The wheel loses performance drastically, and it happens quickly. It's obvious if you know the difference. I'd sweat it, and plenty, as I have in all of my years in the shop. Why taunt the piranha? Would you also paint your car with a broom? Why not-----it's painted, isn't it? :-)

Harold

Everything I've read indicates that as long as you keep the grind under less than red heat, you should be able to use diamond with no ill effects. It is a good idea to do so wet, however, to keep the wheel free from loading. Once you achieve excessive heat, the diamond is rapidly absorbed by the steel involved. Once done, a wheel is restored to decent performance ONLY by dressing away a percentage of the surface. It's clearly a stupid idea to grind steel unless surface speed is very slow, as in your Glendo.

Harold

Yep, sure does, DoN. While I've never used one of the machines, a friend does, and he's had no problems that would otherwise be very evident.

Harold

Harold has it right. Ive seen newbies take bits to diamond wheels in machine shops...and toast em in a VERY short time.

The owners tend to get really really really pissed off.

Gunner

'In the first place, we should insist that if the immigrant who comes here in good faith becomes an American and assimilates himself to us, he shall be treated on an exact equality with everyone else, for it is an outrage to discriminate against any such man because of creed, or birthplace, or origin. But this is predicated upon the person's becoming in every facet an American, and nothing but an American... There can be no divided allegiance here. Any man who says he is an American, but something else also, isn't an American at all. We have room for but one flag, the American flag... We have room for but one language here, and that is the English language.. and we have room for but one sole loyalty and that is a loyalty to the American people.' Theodore Ro osevelt 1907

?????

Whatever it is, hope you recover soon.

Actually, I bought a mill that looked like it was painted with a broom. A very old, dirty one. Right over the spooge. Don't think I'd like it on a car.

Pete Keillor

The wheel in Drill Doctor is not diamond, it is CBN.

i

For a 6 inch wheel at 3450 rpm grinding dry, I would define rapidly as less than 5 minutes to noticeably reduce the cutting speed.

I do not grind tool bits everyday or even every week, but I think it is kind of like riding a bicycle. Not something that needs to be relearned after not doing it.

Dan

Glendo has been around a fairly long time (> 20 years?) so I'd think problems would have made themselves known by now if they were common.

FWIW, my Glendo has been used mostly for HSS for the past 10 years and I just used it to grind a taper on heavy wall glass tubing. The job went real quick so it would seem that the diamond on the wheel is still "sharp".

I seem to remember mine said diamond. Unfortunately I loaned to someone. Can not remember who I loaned it to. So may buy the one that does split points.

Describes it as a diamond wheel

Mine is diamond.

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That may depend on when it was made. Mine came with a diamond wheel according to the maker. And I ordered a spare when I got mine.

Enjoy, DoN.

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Note that while it does split points fairly well on *larger* bits, it is close to useless doing 3/16" bits or smaller. I was having great problems with mine, someone else in the club was posting that it was doing a great job, so we both brought ours to the club meeting so he could try mine and vice versa. I brought along a drill bit of the size I was trying, and he brought along one of the size he was trying (1/2" or so, IIRC)

Well ... he was able to do a nice job on his bit in my DD, but not able to do anything reasonable with my drill bit (3/16" or 1/4") with either DD.

As I remembered from back when it came from the original maker.

All of them at that site look different from the one I have, which is from the first maker.

Enjoy, DoN.

Looks like I am wrong. I will check mine again.

i