THE GHT BORING BAR

[johnsonbarParticipant @johnsonbar]

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.

[johnsonbarParticipant @johnsonbar]

[JasonBModerator @jasonb]

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.

[SpringbokParticipant @springbok]

Sounds like the one Arand Tools sell but could be wrong

Bob

[Russell EberhardtParticipant @russelleberhardt48058]

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.

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