Peter Hogstrom Posted April 15, 2011 Share Posted April 15, 2011 Hello you all. Can someone help me with with alittle problem. I have a tread problem. I have a Vmar projekt and I made a misstake when drilling for the puchrod fittings for the elevator. I need to short the puchrod and doing this I also need to extend the treads. The problem is that I can't really understand what cind of treads it is. I do think it is Imperial . The diameter of the tread on the rod is 2,1mm or 0,080 inch. Thats wat my digital caliper says. can some one help me with this. thease small imperial ''measures '' use to have other ''names'' or how I going to explain it. Can someone understand what I am trynig to say? Hope so and that some one can help me. I am hopeless lost when it comes to Imperial measures :-/ I am looking for a threadtap and the ''female' part I don't know the name of. ( sorry) BR Peter H Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted April 15, 2011 Share Posted April 15, 2011 Sounds like it might be 3-48 UNC thread. Smaller sizes of UNF/UNC have a number designator followed by the number of threads per inch. See here for more info. Quote Link to comment Share on other sites More sharing options...
Alan Cantwell Posted April 15, 2011 Share Posted April 15, 2011 3-48 is to big, 2-64s is closer, but i dont think its these threads, the caliper measure 2.1mm the imperial measurement for this is not .080", its .0827" if it measures .080", then its nearer 2.032 this could put it near to a 2mm rolled thread, instead of a cut thread, Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted April 15, 2011 Share Posted April 15, 2011 Possibly, but cut threads often measure undersize. Best bet is to establish the pitch and match the diameter to it... Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted April 16, 2011 Share Posted April 16, 2011 PeterIt is quite possibly a BA thread.My callipers put 8BA at 2.1mm.The BA threads are a descending series of fine threads so are not exact dimensions.See here.Popular with the Model Engineering fraternity. The Japanese found them useful for some small engineering components, which is exactly what the threads were designed for in the first place! Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted April 16, 2011 Share Posted April 16, 2011 You may well be right Simon but a lot of ARTFs are built for the American market and use Unified threads. As I suggested earlier, establishing the pitch is the most reliable start to identifying an unknown thread. BTW, in answer to the last question on the OP, the tool which cuts the male thread is a die.Edited By Martin Harris on 16/04/2011 00:28:03 Quote Link to comment Share on other sites More sharing options...
Peter Hogstrom Posted April 16, 2011 Author Share Posted April 16, 2011 Thank you Gentlemen. Now have I something to work on. I will try to see if I can establishing the pitch aand see it it maches something on these useful documents you Simon and Martin linked here. The M2 is almoust matching when i spinn it on the pushrod but I can pull it out with no problem. So I know for shure it is not Metric. I will check this and next step will be to try to find the tools here in sweden, not so easy I think. But thanks again for the help. BR Peter H Quote Link to comment Share on other sites More sharing options...
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