Screw thread identification

[Bev ArcherParticipant @bevarcher94647]

Hi,

My first posting on this forum. I'm trying to restore some fairly old model aero engines that I inherited from my dad. The first one I've tackled is a K&B Torpedo 15 and I'm puzzled by the threads on the head and cylinder retaining bolts. They appear to be 7/64" and 40 tpi. I suspect this is a Model Engineer Screw Thread but none of the tables I've looked at go below 1/8". Did American manufacturers use the M.E. thread?

Would anybody know what this thread is and is it possible to get taps and die to suit?

Bev

[Bev ArcherParticipant @bevarcher94647]

[JasonBModerator @jasonb]

Quite likely 4-40 UNC which is 0.112" dia so allowing for the crests being a bit undersize close to your .109" ( 7/64)  below 1/4" dia the US system uses numbers much like the old UK wood screws did.

Should be able to get taps OK try here

Edited By JasonB on 05/01/2014 18:27:16

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Bev, and here **LINK**

Regards Nick.

[Bev ArcherParticipant @bevarcher94647]

Many thanks to JasonB & Nick. I've now ordered taps and a die. When I get these engines finished I'll post some photos (when!!)

Bev

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