deerslayer Posted July 12, 2021 Report Share Posted July 12, 2021 Does anyone know the thread size specification? I can measure one, but I'd like to know what the blueprint says. Link to comment Share on other sites More sharing options...
BillyDixon Posted July 12, 2021 Report Share Posted July 12, 2021 my copy of springfield armory blueprint no. 6301484 date 1 feb 1943 forcollar, barrel shows male threads as 1.750 dia -16 unef-3A , this should give you a good idea what the internal threads will be, just sayn Link to comment Share on other sites More sharing options...
deerslayer Posted July 12, 2021 Author Report Share Posted July 12, 2021 Cool. Ty Link to comment Share on other sites More sharing options...
BRMCII Posted January 22, 2022 Report Share Posted January 22, 2022 Does anyone know the thread size specification? I can measure one, but I'd like to know what the blueprint says.Just saw this from last summer. Need to chase the barrel threads in a Medea partially welded together pair of M3 halves. Did you acquire a 1.75 x 16 Unef tap or die? TIA Link to comment Share on other sites More sharing options...
deerslayer Posted January 22, 2022 Author Report Share Posted January 22, 2022 I did not buy a die. I just ended up buying an Indianapolis trunion. Link to comment Share on other sites More sharing options...
BRMCII Posted January 23, 2022 Report Share Posted January 23, 2022 Thanks........ Link to comment Share on other sites More sharing options...
BillyDixon Posted January 23, 2022 Report Share Posted January 23, 2022 we made our own thread tap,, turned and threaded a piece of oil hardning steel to correct dims, dardened with tourch and quench in oil,, worked fine for a restore threads,,, me thinks an original tap this size would cost a fortune and take forever to get if at all,, get friendly with a local job shop and expect to pay 75- 100 dollars an hour,, just sayn Link to comment Share on other sites More sharing options...
BRMCII Posted January 24, 2022 Report Share Posted January 24, 2022 Asking the community for the tap I need since there must be someone who has needed one for work on the M3/M3a1 receiver barrel threads. Purchase of large and odd spec taps and dies is easy and incredibly cheap from China. Over the last ten years or so, I have acquired half a dozen large sized taps and dies for as little as $30 each plus shipping from Chinese manufacturers. A good example: I got a tap for the barrel ring threads in the receiver of a 1914 Digger for about $48, total, as I recall. Since you can make one, how about making me a short 1.75"x16 TPI Unef tap just for chasing the threads? I have an M3a1 receiver front end with the threaded barrel ring as well as threaded breech end of a barrel for specs....... 1 Link to comment Share on other sites More sharing options...
StrangeRanger Posted January 24, 2022 Report Share Posted January 24, 2022 FWIW I bought a Chinese 7/8-24 tap off EvilBay to chase the threads on a Reising compensator. It was .880 OD. Would have made a nice paperweight. So as always caveat emptor Link to comment Share on other sites More sharing options...
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