Wednesday, September 22, 2010

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.

jsilvia08 jsilvia09 jsilvia10 jsilvia11

1 comment:

  1. Nick,

    That looks like a great job of adopting my QCTP to a smaller lathe. I am delighted to have discovered it here. It neatly proves my contention that the design is easily scalable to almost any size lathe. And the red color is really cool or perhaps hot.

    If anyone is curious about the original article, I have made some revisions since the original publication and have posted the latest version here:

    That is in the files section of the Yahoo, South Bend Lathe group. I believe you need to join the group to get in to see it.

    A delighted
    Paul Alciatore