Is this an improvement?

[cathead]

This morning after looking over my quick change tool post setup, it looked to me that increasing the surface area on the
base might be an improvement. I guess that remains to be seen but that what I was working on today. I used a piece
of 1/2 inch hot roll material, cut it to size from a big chunk and drilled and tapped a hole in 3/4x16. Also I fashioned a
washer out of some unknownium hard material which was also threaded and welded on to the plate for a little added
holding power for the threads. So you can comment if you wish as to if this is an improvement or not. It was fun to
run some machines and get my hands dirty as usual...It looks to me like the compound casting was broken at one time because of the recessed screws and plating. It seems to hold fine but if I have
gained any rigidity then I will be able to claim it to be an improvement. So there, that's my story today.

 

[Reddinr]

You could do a quick before/after test using an indicator and some sort of a lever-arm clamped into a tool holder.
Put a certain weight at a specific distance on the lever-arm to torque the QCTP. Measure the deflection at a certain point, maybe half way up the QCTP. Repeat for the new setup. Maybe look in a couple of directions.

 

[benmychree]

I think that rigidity is really not an issue, what matters is the bearing of the tool post on the compound and its tendency to slip under cutting forces, your T bolt would not have much effect with that. I have a much bigger lathe, and slippage of the tool post is a problem with it, I have to use an approximately 3 foot length of pipe on the wrench to tighten it to prevent slipping; granted, I do take heavy cuts ---

 

[cathead]

John, I pretty much agree that it won't affect much. Most of the pressure is downward anyhow so as long as it is
not moving around, it would be OK. Scraping the compound or using a plinth might be good for a rigid setup.

 

[savarin]

On the matter of the tool post slipping round I use a thin sheet of brown paper under mine and that solved the problem.

 

[682bear]

I did the same thing on one of my Hendey lathes... the lip on the compound had already been broken in the past and repaired by weld buildup... to hopefully keep it from happening again, I made a t-nut the full width of the compound.

I've also discovered that on most of the older lathes, the top of the compound is not flat... they have worn areas from years of moving toolposts around. I'll take them apart and set the upper slide on my surface grinder and grind it flat. All of my Hendeys were worn, and my South Bend was, also.

-Bear