Lathe Tool Grinding Jig (no Fb)

Inflight said:
I had a little time in the shop so I started my version of the grinding fixture. I made it from whatever material I found in the scrap bin. The steel base is surface ground on all sides and I graduated the aluminum cylinder with 360 lines. I still need to make a clamp and add threaded clamp holes.

View attachment 106432

Matt
Click to expand...


Great improvement. I like the graduations. This would be great to use on the belt sander to touch up tools and especially to sharpen the tangential tool bit.
 
You outbuilt me! :p

Very nice work! I might graduate mine in the same way :)
 
It's not a competition :), I just wanted an excuse to run the surface grinder.

I will say that the graduations were the toughest and most time consuming part of the project.

Thanks for the inspiration!
 
Quick update here. The grinding jig is working very well but for single point threading tools, it does not provide for the helix angle of the thread. To remedy this, I mounted the holder in a small grinding vise at the appropriate helix angle. My tests of before and after show me that even a small amount of clearance is critical to smooth threads.
threading tool jig.jpg


Matt
 
You mean it's not cutting a relief after the edge? I made my jig with a 7 degree angled bottom, to automatically give me relief.
 
I have the 7 degree relief, but I'm talking about rake angle (aka, helix angle). Not such an issue with sharp vee threads, but for Acme or square threads, and especially multi-start threads, it's of critical importance. Check Machinery's Handbook or another good text for proper description and geometry.


helix angle.jpg rake angle.jpg
 
How and what did you use to put the graduations in with ? I've made a few tooling items but can't seem to get a good way to do the graduations on them. I have tried a Dremal bit but wasn't strong and broke. Tried just a steel pointed bit but that didn't seem to work. Maybe I'm just not going at it right. Looks like this holder is for sure on my to do list and will be starting it shortly.
 
Chip Maker said:
How and what did you use to put the graduations in with ? I've made a few tooling items but can't seem to get a good way to do the graduations on them. I have tried a Dremal bit but wasn't strong and broke. Tried just a steel pointed bit but that didn't seem to work. Maybe I'm just not going at it right. Looks like this holder is for sure on my to do list and will be starting it shortly.
Click to expand...

The engraving tool I used was made from the shank of a damaged solid carbide 1/8" endmill. I ground the tip to a cone, then ground a flat across the diameter. With this tool locked (not spinning) in a collet, I dragged the point into the work until the depth looked OK. The work was held in a 5C collet Spin-Index jig allowing the 360 graduation.
 
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