Grinding a blank lathe tool for parting or cutoff

Yes. Push harder. HSS grinds very slowly until you apply a certain amount of pressure, then the grinding effectiveness suddenly jumps way up.

John Martin

Sure, but the easiest way is to get a dedicated cut-off blade holder and cut-off blades for the big stuff. For itty-bitty stuff, I still grind minis from 1/4" square blanks. Yeah, it takes awhile. Wouldn't care to try it on bigger blanks, either. I use 40 grit belts on the belt grinder for roughing, I'd probably see if I could get something around 20-30 grit for wheels if I was stuck with a bench grinder.

Stan

I knew a fellow who had to custom make some special shaped lathe bits for a factory. They furnished some blanks which were close to what they wanted but needed modifying. What he had to do was soften them up, grind them as desired and re-harden them. The "softening" and the "hardening" is in the cooling process.

IIRC: A quick quince will harden them and a very slow cooling will soften them.

He used plain old lime like you use to alkalize your lawn to cool them very slowly. I think he first got them cherry red and jambed them into the lime and left them half a day or so to cool. I think water will make them too brittle. Oil may be what you need to get it back to tool-hardened condition.

Don't hold me to the exact above, but that's roughly the process and I'm sure we have several here who can tell you for sure!

Al

I use my Makita hand grinder for roughing. Look butt-ugly, but works just fine.

The welding grinder sounded like a good idea. If you have a surface grinder, a

1/32 cut off wheel to slice the bit would be very quick. We keep an old surface grinder permanently set up with a 7" x 1/32 abrasive cutoff wheel. Great for shortening cap screws, dowels and anything else ferrous and hard.

Wes

Yes several. I just "hog" out most of the excess with an abrasive "chop" saw, and finish up on a surface grinder holding the bit in a fixture with the desired side clearance. I'm pretty sure there are some pictures on my home page.

't tell you the titles right now. (would have to change browsers) ...lew...

If you'll select the proper wheel, HSS grinds quite well. If you're using the typical pedestal or bench grinder with the wheel that came with the machine, you can expect more than your share of misery. The wheels are too hard to function well for the material, and there's nothing you can do to improve their performance.

I have hand ground turning tools for well over 50 years now, including parting tools. I don't own a commercial one, preferring the performance of those I hand grind.

You have received some excellent advice regards using a parting wheel to eliminate the majority of stock when starting with a blank. Still, you must hone your skill to achieve good results afterwards. Get a proper wheel and stay the course.

It might pay you to download a large file that was compiled from many of my posts on the Chaski board some time ago. I discuss wheel selection, wheel dressing and HSS grinding in detail, including grinding chip breakers. If you are not well versed in the art, it may prove useful. Or not! :-)

Here's a link:

Harold

Downloading even as I type , Thanks Harold ! I have gotten so much info from this and the other metalworking groups I read , it has helped me more than I can say . The Internet Rocks !

I finally got around to downloading it -- and discover that it is in ".rtf" format -- probably the worst to read with my usual computers. I guess that I'll see whether the Mac has a reader for that.

".pdf" would have been a good format on almost any computer -- or if it is only plain text in there -- what would have been wrong with a plain text file?

Enjoy, DoN.

.rtf = Rich Text Format

MS Word should be able to open it. Or OpenOffice can, if you're into that commie open source stuff like Linux. ;-)

Text has limited formatting capabilities. .pdf would be best except that Adobe's Distiller isn't cheap. If you can 'print' to a postscript file (.ps), there's a ps2pdf utility (that damned open source stuff again).

That much I knew. It was just the lack of knowing a program which would run on my system which could open it.

That may be -- but MicroSoft Word won't run on my Sun Blade

2000 (nor will the parent OS, Windows), so what it can open on other systems doesn't help here.

How about Sun's Solaris 10? Yes, Sun's StarOffice does open it, and it is a partly proprietary version of OpenOffice, but which does a few things that OpenOffice can't do because of proprietary formats.

I didn't see anything in it which really *needed* fancy formatting. Plain text would have been fine -- and a much smaller download as well.

PDF at least has excellent compression to make up for how complex the file is compared to plain ASCII.

I've used ps2pdf (part of the GhostScript package) many times -- for converting scanned machine manual pages to something easy to share with others.

Thanks, DoN.

This crapVista machine wanted to open it with the latest Word product, but I won't use another MSshit product that I haven't used before (earlier machines & OSs).

So I did the Open With and chose the somewhat trusty WordPad, and did a Save As to a .doc file, and everything looked fine.

I know that's not a solution for DoN, but I mentioned it in case anyone else prefers to avoid new spit/yakMS programs.

Damned if I know, DoN. I had nothing to do with the file aside from giving permission to a different party to compile them so they could be uploaded. I had provided the posts for readers of the Chaski board in hopes they might be enlightened. There's one hell of a lot of experience there, and some information that is not commonly promoted. If readers keep an open mind and try some of the recommendations, particularly grinding without a rest, they just may be pleasantly surprised.

Harold

Welcome! :-)

Hope you find it useful.

Harold

On Wed, 10 Dec 2008 09:13:19 GMT, the infamous "Harold and Susan Vordos" scrawled the following:

Plaintext doesn't support graphics, and there were a dozen or so pics in there, 'Arry.

I agree that a PDF would have been cleaner/smaller. C'est la vie.

-- At current market valuations (GM is worth less than Mattel) the Chinese government can afford to buy GM with petty cash. --Bertel Shmitt on kencan7 blogspot

I sort of figured that you had not compiled the file -- just created the content (the important part).

I expect to read it all -- once I comb-bind the printout.

Thanks, DoN.

Where? In the printout from StarOffice, I see no images of any form. However, I *do* see a few white spaces between paragraphs, with one or more '.'s at the left margin.

O.K. I went back into StarOffice (version 7, FWIW), and see the same. Not quite peroids, but tiny blue dots.

And it might have carried the images along in such a way that I could see them.

O.K. Paging through with less, I find some areas which look like encoded binary data (possibly images) with something like:

====================================================================== \b\fs28{\pict\wmetafile8\picwgoal5999\pichgoal4349 ======================================================================

in front -- which sort of looks like a path to an image on a Windows system, but certainly not on a unix variant with those backslashes.

Perhaps someone who can extract it all, including the images, can convert it to a postscript, and from there to pdf, so the rest of us can see the images along with the text.

For all that *I* got, plain ASCII would have sufficed, except for the occasional use of single-character fractions in place of 3/4 and the like.

Enjoy, DoN.

*ALL* knowledge is useful ...

On 11 Dec 2008 02:58:06 GMT, the infamous "DoN. Nichols" scrawled the following:

Strange, I'm running OpenOffice 2.0...oh, that's not StarOffice, is it? Time for a DL, Don. OpenOffice has very seldom failed me. AAMOF, the only time it has was in opening some brand new Word files and creating PDFs from them. I haven't printed this file, either, but now that it's in PDF, it should work fine.

I used OpenOffice to distill it into a PDF file and will email it to you, DoN, iffen that email (listed above) works.

A