a similar tool holder had the clamping screw at a 45deg angle pushing against a shoe in an elongated slot in the tool holder arranged at a 45 deg angle with a radiused top, the clamping action forced the tool bit into the corner of what would have been a square hole so that it could not move around once clamped, and it would hold several sizes of tool bit also, made by the Clark Tool Co. in Burbank Ca. , they also made hole cutters that are quite good and a threading tool grinding fixture that is a real prize (fig 002) It works with both 60 and 29 deg tools, and allows grinding the nose flat and back or front rake. The tool holders that I have will take 1/2" square tools down to 3/8" when similar sized Armstrong or Williams holders only take 3/8" tools. Offset tools, (right and left hand) ALWAYS allow the tool to stick through the back, at least, all of them that I have ever seen.
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How to make the hole in an Armstrong tool holder
- Thread starter ericc
- Start date
All of my holders look like they were broached.
Here's a Williams and an Armstrong, 1/4" bit, one straight and one angled. These are the holders meant for carbide tools, T-0-X tools, so no included rake angle. I use them on the shaper.
And a smaller 3/16" bit Armstrong, straight, but with built-in back rake angle. Also an interesting hole on the underside I'm presuming to help clear chips from the broach.
Don't know if that helps or hinders.
-frank
Here's a Williams and an Armstrong, 1/4" bit, one straight and one angled. These are the holders meant for carbide tools, T-0-X tools, so no included rake angle. I use them on the shaper.
And a smaller 3/16" bit Armstrong, straight, but with built-in back rake angle. Also an interesting hole on the underside I'm presuming to help clear chips from the broach.
Don't know if that helps or hinders.
-frank
The earliest Armstrong holders of that size had 3/16 holes, I had a set of them, they were forged without the recessed area on the sides where the name and numbers are forged in, they were stamped instead; sold 'em on e bay.
I made this one shortly after I got the Hercus lathe. (About 8 years ago.)
I broached it by filing the drilled hole to an approximate square, then forced a 1/4" HSS tool blank through. It probably needed a bit more of the file to allow the bit to slide a tad easier.
I broached it by filing the drilled hole to an approximate square, then forced a 1/4" HSS tool blank through. It probably needed a bit more of the file to allow the bit to slide a tad easier.
More sleeves: http://www.greenbaymfgco.com/12L14-sleeves.php
This is what I will do. It could be brazed, but Tig will work.
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I welded the cap on and added a screw. High fire danger today, so I slacked and used a factory screw. Almost done. Just have to turn the spherical depression in the base. Now you know why I wanted the straight tool so much. It can be used as an expedient radius turner to clean up the depression.
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I applaud your effort and persistence on this project.
Any tool holder can be used for cutting spherical surfaces with an Armstrong tool post. I used to cut spherical mirrors witha 7.5" radius of curvature using the boring bar and its holder. The requirement is that the cutting surface is horizontal with the spindle axis and at the point of contact the cutting edge is perpendicular to a line through the pivot axis of the compound.
Any tool holder can be used for cutting spherical surfaces with an Armstrong tool post. I used to cut spherical mirrors witha 7.5" radius of curvature using the boring bar and its holder. The requirement is that the cutting surface is horizontal with the spindle axis and at the point of contact the cutting edge is perpendicular to a line through the pivot axis of the compound.