What Wood to use!!!!

[KBs PensNmore]

I've been asked to make an item similar to an oversized coach screw. The problem I'm having is that the timber breaks/chips off on the "threads", which are approx. 6mm deep x 6mm wide with approx. 1mm flat to the next v.
Have tried Blackwood, Pinus Rad. and Camphor Laurel.
What would be an ideal Australian timber to make these from PLEASE???
Thanks in advance,
Kryn

[brendan stemp]

If you could get some Yellow Box would be ideal. How big a piece do you need? I have some offcuts I could send you. The other option would be the desert timbers. You need hard short grained timber.

[pampelmuse]

There is not much consensus on this as there are not many timber threaders out there. Search for IanW's input to this forum or under 'wooden threads' or 'threading timber or 'timber threads' etc for some suggestions.

[tea lady]

Kwila takes threads well apparently! :cool: Is that Australian? :hmm: You certainly need closer grained stuff than pine, blackwood and camphor! :shrug:

What are you making the threads with? We want pics and all that! :D

[dr4g0nfly]

If I read your question right, you don't want to put a thread on a turning but want to create a giant wood screw thread (coach bolt).

As I see it unless you leave the base of the thread, where it meets the screw shank, thicker than would look right you'll always have the problem with weak/short grain as it runs up the length.

Personally I'd be tempted to cut a piece of timber such that it was cross grained but looked like a spindle. That way the grain should hold the thread you want.

I turned a piece of oak like that once (minus the thread) to enable me to explain the way wood does it's thing (shrinkage, growth rings and medulary rays etc.). So I can tell you it feels a little strange having the constant change of with and against the grain on a spindle but it can be done.

Post a piccie of the final piece please.