John Silvia’s Quick Change Tool Post

This is my version of the quick change tool post by E. Paul Alciatore III as published in the Feburary/March 2010 Machinist's Workshop magazine. I modified his design to hold 1/4" tools and to fit the taig. Instead of using steel for the tool holders, I substituted aluminum. I figured if it was strong enough for the original tool holder it would be fine for this one. As long as I was using aluminum I thought it would be fun to try anodizing, hence the red color.
I made the tool post out of 3/4" drill rod. I also used a piece of the drill rod to make a D-reamer to size the hole in the holders. On the bottom of the post I milled flats to match a 5/8" square hole in the mounting plate. The mounting plate was made of 1/4" steel. Mounting the post to the plate made it easy to mill the large flat on the post at 45 degrees. The large flat is 5/8" from the other side. The combination of mounting plate and post can be mounted on either the left or right side of the taig cross slide and, because of the square hole, it can oriented to cut on the left or right. The base of the post does not come all the way through. When tightened down with the two bolts, believe me, this post is going nowhere! Of course, by using only the bolt through the post it can be used at any angle.
The tool holders are 1 3/4" on a side and 1 1/16" thick. When cutting the corner off the tool holder the side with the fixed bolts needs to be flush with the D-post. The other side is milled 2-3 thousands deeper to allow tightening. I'm ashamed of the knobs, but at $2.50 for 10, they were too cheap to pass up and are easily strong enough.
Mr Alciatore came up with a great design! It is easy and cheap to make. It took me about 1 day to make the first tool holder, but less than two days to make the next 9. It is a lot easier to do them in batches.

John Silvia’s Knurling Tool

John Silvia sent these pics of a knurling tool made on the Taig lathe and mill: 

"I was inspired to make a set of knurling tools based on a picture I saw of an old German knurling tool.  The design and construction was heavily influenced by the material and tools that I had on hand.  As can be seen in the photos I was experimenting with the exact design and dimensions as I made it.  It is somewhat oversized for the taig but I intend to use it someday on a larger lathe with the addition of a second pivot assembly.
Speaking of the pivot assembly, although it looks like brass in the photos, it is made of some bronze I happened to have.  The 1/4" bar for the taig tool holder is attached off center to help raise the tightening knob as high as possible to keep fingers well clear when knurling close to the chuck.
I had planned to hold the knurl pivots in place via set screws; but two sets of knurls that I ordered had shoulders on them that increased their width to the point that there wasn't enough room for set screws, so I had to use a different retaining mechanism made from "hacksaw blades" from the dollar store.  This means that more clearance is required on one side when knurling but this really doesn't matter since the arms can be flipped to put the retaining mechanism on either side.
I'm pleased with the results.  The first thing I knurled is the knob for the tool itself.
If I were making another one for the taig only, I would make the arms shorter.  When I try to knurl a long test piece, a lot of torque is put on the tool holder.  It is difficult to get it secured well enough that it doesn't accidentally pivot when advancing the knurler along the knurlee.  Shorter arms would probably help reduce the torque.  I bought the springs at the local hardware store.  They make it slightly more convenient to use but are not necessary.
This is only the second item of any complexity at all that I have machined myself so please be understanding when viewing the pictures.  This was very much a learning experience for me."