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Woodscrew Thread Cutting

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No1_sonuk: I need to make a part similar to the attached photo.  I've not been able to find anything about how to cut a woodscrew-type thread.  :scratch: The part I want to make needs a longer unthreaded part than the pictured part, and the cross-hole tapped.  Both of those are easy - it's the thread I need help with.  It needs to go into the end of a 1" wood dowel. Has anyone here done this, or got any ideas? Thanks.

Jasonb: Biggest problem is that you will need something like a 2tpi pitch, not many lathes with that unless you can play about with gear ratios but it can put strain on the lead screw. I would use a "V" pointed tool with a small flat on the end, cut the thread then move the cross slide along say 0.010" and cut again, keep repeating this until you have the shape you want. Trying to do it in one go with the correct form tool would again put a lot of load on teh lathe. Jason

andyf: --- Quote from: Jasonb on March 15, 2010, 03:32:26 AM ---Biggest problem is that you will need something like a 2tpi pitch, not many lathes with that unless you can play about with gear ratios but it can put strain on the lead screw. I would use a "V" pointed tool with a small flat on the end, cut the thread then move the cross slide along say 0.010" and cut again, keep repeating this until you have the shape you want. Trying to do it in one go with the correct form tool would again put a lot of load on teh lathe. Jason --- End quote --- Yes, unless you have a huge lathe, you would need a ratio to the order of 1:4 from spindle to leadscrew. If it's a one-off, it might cause less strain to crank the leadscrew by hand, changing the ratio to 1:4 from leadscrew to spindle.   Given that it's going into the endgrain of a dowel, it will be a weak fixing into the wood. A fairly generous pilot hole will be needed to stop the dowel splitting, unless you put a ferrule round it. Given that the metal to wood joint may not be very strong anyway, what about making the head as a separate item, and brazing it to the end of an ordinary woodscrew? Andy

Bluechip: No1_S etc. Don't know what it's for but, if you can make the end bit with a M6 machine screw thread and avoid the woodscrew bit altogether, then .. poke one of these in the end of the dowel. http://www.screwfix.com/search.do;jsessionid=LFQENLXT4AQ44CSTHZOCFFQ?_dyncharset=UTF-8&fh_search=insert+nuts I've used lots of them. I screw them in with some epoxy on the 'self-tappy' part. IIRC the 'tapping drill' is 7.5mm and a 8mm af key drives 'em in .. not sure now, couple of years since I used them. They are pretty secure, but, as has been said, the end grain itself is not very robust. If you trawl about for 'Insert Nuts' ( wait for it  :offtopic: ) you may find other sizes more suitable for your needs. I've only used the ones depicted. Dave BC Edit.. it's the top picture, not the Nyloc nuts bit   :D

John Stevenson: You want what the trade call wood to metal screws. http://www.doorfurnituredirect.co.uk/scpro/bernards/productssingle.asp?prodid=6129 Something along these lines and then screw the part you need special onto the 6mm or 8mm metric thread. John s.

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