THE GHT BORING BAR

I am planning to build the GHT boring bar, and wanted to get some feedback from previous builders.

The design shows 2 threaded items:

1. a 9/32" X 40 fine adjustment plug type screw, and

2. a 3/16" X 40 tapered locking screw.

Do you have to make both of these screws yourself, or is there a commercial source that has something close that can be modified to this design? Also, if anyone has any modifications or a better design altogether, please share your experience.

Note: This thread is a continuation of a previous thread "TURNING BETWEEN CENTERS", which actually should have been titled "BORING BETWEEN CENTERS". This thread is about a boring bar design by George H Thomas, and described in his book "THE MODEL ENGINEER'S WORKSHOP MANUAL" on page 92. Thank you.

You will have to cut them yourself as there are very few fixings sold in the ME form. They can either be screwcut on the lathe or using a readily available die.

The reason for 40tpi is it gives 0.025" per turn the same as a micrometer though teh lock screw could probably be substituted for soemthing else.

J

PS if you work in metric then 0.5mm pitch may be better.

Sounds like the one Arand Tools sell but could be wrong

Bob

Yes, you'll need to make the 40 tpi screw yourself. The complicated locking system, though elegant, isn't really necessary (IMHO). You can just fit a grub screw at right angles to the toolbit to lock it although you do have to be careful that it doesn't shift the toolbit.

Russell.