Landlocked123 Posted June 12, 2015 Share #1 Posted June 12, 2015 (edited) Hi All, John (AKA Jim Ladd) suggested in another forum (Metal Work) that if I was crazy enough, I might want to try to use a jeweler's tap and die. Well I went ahead and picked this up on E-bay for not a lot of $: I've played around with it with some small success. Now....can any one help me use it correctly? Cutting threads is pretty straight forward and easy. I was even, after quite a bit of trial and error, able to tap a hole which fit the threads. My question is basically if there a way to determine the size hole to drill for the tap? I would assume it would be the inside diameter of the thread, but how do I figure that out. I'm hoping there is something simple which has to do with the corresponding holes in the die, but right now that eludes me. Best, John PS. I tried it out tonight and came up with this: The bolt head needs to be filed down a bit but the other end actually screws into the loop. Regardless, if any one has any pointers on how to best use this tool, I would appreciate it. Thanks. John Edited June 12, 2015 by Landlocked123 mtaylor, src and cristikc 3 Quote Link to comment Share on other sites More sharing options...
src Posted June 12, 2015 Share #2 Posted June 12, 2015 (edited) if nobody here can help, maybe a watch repair forum? Sam Edit - nice work btw. Edited June 12, 2015 by src mtaylor and Landlocked123 2 Quote Link to comment Share on other sites More sharing options...
justsayrow Posted June 12, 2015 Share #3 Posted June 12, 2015 (edited) http://en.m.wikipedia.org/wiki/List_of_drill_and_tap_sizes When cutting the threads, go slow. 1/4 turn in, 1/8 turn out. Go slow. Use cutting fluid. Not sure if I mentioned it, but GO SLOW! You will break taps. Edited June 12, 2015 by justsayrow mtaylor, src, Landlocked123 and 3 others 6 Quote Link to comment Share on other sites More sharing options...
grsjax Posted June 12, 2015 Share #4 Posted June 12, 2015 Hi I was taught that the hole for the tap should be the minor diameter of the thread plus the difference between the major and minor thread diameter. Hope that helps. Landlocked123 1 Quote Link to comment Share on other sites More sharing options...
Gaetan Bordeleau Posted June 12, 2015 Share #5 Posted June 12, 2015 (edited) you need to find the table showing which one to use Edited June 12, 2015 by Gaetan Bordeleau Landlocked123 1 Quote Link to comment Share on other sites More sharing options...
captainbob Posted June 12, 2015 Share #6 Posted June 12, 2015 (edited) These charts are correct for good mechanical strength. On a model you do not need that strength. You will have an easier time of it and break fewer taps if you use 95% of outside diameter. In other words you just need to cut enough of a thread so the screw does not fall out on its own. And as justsayrow says' "GO SLOW". Bob Edited June 12, 2015 by Cap'n'Bob Landlocked123, druxey and Canute 3 Quote Link to comment Share on other sites More sharing options...
taner_kalkay Posted July 14, 2015 Share #7 Posted July 14, 2015 0.75 of the screw size is good value for tap holes. Quote Link to comment Share on other sites More sharing options...
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