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J Harp
10-27-2012, 10:01 PM
Byron;

In the metal backed grinding wheel thread on Third Hand, you show a photo of a guide for grinding the left side of a lathe tool. Do you have guides for grinding the other faces? If so could you post pictures of them? Thanks.

Boucher
10-27-2012, 10:40 PM
For a regular turning tool if I want some side rake and back rake, I grind that top surface first. I set the table at 7° for the side to side slope and freehand the back at the same time. I use this to set the table angle.
http://i109.photobucket.com/albums/n50/boucherbyron/IMG_0070.jpg
then I rough the side using these guides.
http://i109.photobucket.com/albums/n50/boucherbyron/IMG_0071.jpg
http://i109.photobucket.com/albums/n50/boucherbyron/IMG_0072.jpg
I rough the tools on the belt sander and finish on the tool grinder.
http://i109.photobucket.com/albums/n50/boucherbyron/IMG_0073.jpg

For the guides on the belt sander I have added a groove where the guide hooks underneath the table. On the grinder I leave a tab on the bottom that slides in the groove in the table. I use HDPE and Delrin for my guides. Once these guides are used to construct the tool they facilitate the resharpening. It only takes a second to touch up the edge. I am now using the diamond wheel to sharpen tools. There are those that go ballistic at the mention of grinding HSS on a diamond wheel. It only takes a second and produces a great finish. The four picture limit is going to prevent more in this post.

J Harp
10-28-2012, 06:48 AM
Thanks, I've been thinking about making some guides. I usually don't copy anything exactly, but it's helpful to see what others have done.

I have one started for grinding 60 deg. threading tools, but don't have all the details worked out yet.

BigJohnT
10-28-2012, 07:00 AM
Byron,

Nice jigs and grinder.

John

Forrest Addy
10-28-2012, 07:14 AM
Cultivate the eye

Boucher
10-28-2012, 09:00 AM
Forrest, there are some things that improve with age, my eyes are not in that category. I can still grind a tool freehand that cuts as good as the ones produced using the guides, but they don’t look as good. Maybe it is the compulsive perfectionism coming out. I learned to grind freehand on the old 10 –12 inch Baldor grinders with good quality 2” wide wheels. Having the correct grade and quality of wheels is not discussed much anymore but it should be.

The Quality of HSS doesn’t get much discussion either. Quality is declining and one should gather all of the stock that you need. I obtained a box of the old tools from an old machine shop when it went out of business. There are lessons to be learned from studying those old tools. Others have derided the bits from India and China but I actually had decent performance from them until a couple of days ago. Taking very light cuts in gummy steel the point of a threading tool just disappeared ie. Sheared right off.

Gadgetbuilder’s site has lots of good information on grinding guides. Don’t dismiss his directions on grinding a shear tool. Try it you will like it. http://www.gadgetbuilder.com/LatheBitSharpening.html

wawoodman
10-28-2012, 09:45 AM
Byron,
What belts are you using on the belt sander?

Mike

Boucher
10-28-2012, 10:43 AM
Mike, I get my Zirconia Belts from this place. http://supergrit.com/


A commercial version of the old South Bend cutter bit grinding guide is available here:
http://alisam.com/page/14g9f/Metalworking.html


Continuing on with theThreading guides for the tool grinder.
http://i109.photobucket.com/albums/n50/boucherbyron/IMG_0297Small.jpg

A threading guide for the belt sander that shows the tab that hooks under the table to keep it flat.
http://i109.photobucket.com/albums/n50/boucherbyron/IMG_0296Small.jpg

Boucher
10-28-2012, 11:46 AM
Insert type threading tools are nice in that they are easy to use and to change. I got started with the vertical insert that came with my lathe when I purchased it. If I were starting over the lay down inserts and holders would be my first choice.
For several reasons I have been returning to the use of HSS threading tools. Again if I were starting over I would start here:
http://www.tools4cheap.net/proddetail.php?prod=alorisno8axa
If you want inserts that are HSS then Arthur R. Warner co. is the place to go. http://www.arwarnerco.com/c-6-standard-and-specialty-inserts.aspx

They also supply good quality blanks.http://www.arwarnerco.com/c-7-toolbits.aspx
Which brings us back to the subject of grinding our own.

wawoodman
10-28-2012, 05:25 PM
Bryon, thanks for the link to supergrit. What grit(s) would you recommend? I'm be doing primarily 5/16 HSS lathe tools, on a Craftsman (I know...) 2 x 42.

I've actually made my own grinding jig like the SB (and Anilam,) but it's too shabby to post. It works, though. I keep saying that I'll do it again for real, but you know how that goes...

sasquatch
10-28-2012, 05:39 PM
Great posting and pics, thanks, very interesting topic.

Bob Fisher
10-28-2012, 06:18 PM
I like to buy tool bits from used tool places, they are cheap and unlimited in variety. Saves a lot of grinding time and the shapes you can find are amazing. The place by me, Mr O'Tools, has about a bushel, mostly 3/8in. Bob.