View Full Version : Question about toolholder configuration.

07-24-2011, 11:39 AM
I've been aligning my little CNC lathe and am finally getting it close enough to feel confident about it and make a few more toolholders for it. I made the 1st one with the slit offset because....the one I saw on the web was made that way.:)

Any opinions as to what is the optimum configuration? A) Slit in the middle all the way through. B) Offset slit all the way through. C) Slit in the middle half-way through. D) Offset slit half-way through.

With the slit all the way through, it does lock down tightly with less torque on the screws.


07-24-2011, 11:45 AM
Slit it in the middle all the way through, but before you do that drill three holes. Two should be counterbored to the depth of the socket hard cap screws, clearance hole to the slit and tapped on the other side of the slit.

The third hole (between the other two) should be drilled & tapped ONLY to the slit from one side. Now you have two firm clamping crews and one jack screw to help open it up for removal.

07-24-2011, 12:01 PM
Have you posted details on your little lathe yet? It looks interesting.

07-24-2011, 12:41 PM
Pretty clever P/Man, thanks.

Dave it was supposed to be a "quick" treadmill motor powered ER32 spindle to mount into a little Denford CNC training mill enclosure but I've spent an embarrassing amount of time fiddling with it. Here's a pic of the removable spindle/motor assy. It mounts to the right of the mill table and has a plug in motor power cable, spindle speed sensor cable and power cable for the motor cooling fan. You can also see the speed sensor and disc. That (at least) works very well in Mach.


I just realized I don't have a good overall shot of the whole thing but here's a pic of it back when I cobbled up an alignment fixture using aluminum scraps bolted to the mill table with a piece of drill rod in the spindle collet.


Here's a link to a thread that has some links to other threads detailing my various attempts to emulate a real machinist in making the thing.

The only satisfaction I feel in struggling on with the thing is that if I stumble onto a cheap CNC-able small lathe, I'll have some of the needed widgets and knowledge already in place.

07-24-2011, 01:35 PM

Thanks I will look it over. I like the headstock.
More picture would be great. I have a sherline CNC mill collecting dust. this might be just the thing.
Any reason why you did not sue the head from the mill as the headstock?

07-24-2011, 02:08 PM

I don't think it's of too much concern where you slit it. You don't have that much power be worried about.

When I made my Norman patent style tool post, I did as they did. I used one slit across the single clamp bolt hole. It hasn't moved under interrupted cuts .050" deep in mild steel. And extreme clamping force wasn't needed either.


07-24-2011, 02:42 PM
Any reason why you did not use the head from the mill as the headstock?
DaveYup, the job I eventually want to use it for requires 3/4" aluminum rod and I wanted to be able to pass that size through the spindle bore. I think the Sherline's through hole is only 5/16" or 3/8".

I was originally thinking about using the mill's motor/spindle pulley in situ to drive the lathe spindle via a long belt but that would have required a right angle gearbox of some sort. Too much Rube Goldberg stuff I thought so I proceeded to make a motor drive system using the wisdom of Mickey Mouse.;)

07-24-2011, 07:32 PM
I'm not familiar with the Norton tool post. Do you have any pix?