Custom space along side the original.
The standard quick change toolpost sold by TS Engineering (now High Tech Systems) is an excellent product. It is a great convenience for Taig lathe as opposed to switch multiple toolposts (with pre-shimmed tools); however, there is one problem that a number of users have had. Because the tool is further from the centerline of the #10-32 screw it has a tendency to rotate while cutting. A number of fixes have been discussed on the web for this--most centering around increasing the friction between the surfaces. Although in several cases it appears that the bolt itself is slightly longer than it should be.
While scanning some of the photos of projects by Jim Knighton on Nick Carter's website I noticed a description of a compound slide that he had modified for the Sherline.
" The biggest shortcoming of the TS Engineering QCTP is that the long 10-32 screw isn't stout enough to properly secure the QCTP to the Sherline's and Taig's table. It twists and turns under load on both machines. The screw simply doesn't generate enough clamping force, and if overtightened the t-slots can deform and/or cause other problems. Rene Teo acknowledged the issue in the Sherline forum and commented that this isn't a problem on larger machines that use an 8mm screw. I decided to take him at his word, and drilled out the QCTP's center insert to 5/16" (that's close enough to 8mm for me). I then drilled and tapped the cross slide table between the t-slots and close to the end so that I could use this much stronger screw. The results are outstanding! "
While I didn't want to drill and tap the crosslide (because I need to vary the position of the toolpost), this gave me the idea to make a new spacer for the tool post. The TS QCTP for the Taig uses a 0.375" spacer to raise the tool post. The provided spacer is a shade under 1.5" in diameter.
I machined up a disk of brass (only material I had that was the right size) 1.5" diameter and center drilled and tapped it for 5/16"- 24. I then drilled two #10 holes offset from the center 0.5" and countersunk them 0.25". These holes allow the disk to be mounted across the two T-slots as well as in just one.
I drilled out the center post to 21/64" (I wouldn't try to go any
larger). I used two .5" (depending on the thickness of the washer
and depth of counterbore you might need 0.375") long #10 SHCS to
secure the spacer to the crosslide and a 2.5" 5/16"-24 SHCS to
secure toolpost to spacer.
So far this modication seems to have solved my problem with the
toolpost twisting.
Custom space along side the original.
All the parts of the modified toolpost.
One way to mount spacer to the crosslide.
Another way to mount spacer on the crosslide.
This page and all of its contents are copyright by Walter Anderson
