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Picture of Drilling and tapping hardwoods
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Drilling and tapping hardwoods
 
There are several ways to attach threaded metal fasteners into wood fixtures. For example,  inserts and  t-nuts can be used to add  a threaded connection to a jig. But often I prefer to drill and tap threads directly into the wood fixture.  Many hardwoods can be drilled and tapped, however softwoods lack the necessary machinability and holding capacity. The best wood I have used for threading is Jatoba,  (Brazilian Cherry). Jatoba is very dense, hard, fine grained, and threads extremely well. Oak and Padauk are fine also. I find these threaded wood fixtures hold a bolt extremely well.
 
Hardwood is a forgiving material to drill and tap. Use a 5/16” drill bit for 3/8” threads, 7/32”  bit for 1/4 “.  I don’t thread anything less than 1/2”  thickness. Use a standard coarse tap to cut the screw threads. 
 
Making threaded woodworking jigs, clamps, furniture handles and knobs from exotic hardwoods adds a beautiful touch to projects.  Material is not cheap, but these parts are small so final cost is low.
 
LynxSys2 months ago

Do you find that your tapping technique is any different than it is with metal? (E.g. do you use any lubricant? Do you still have to turn the tap backwards to clear chips?)

Bill WW (author)  LynxSys2 months ago

Thanks for looking.

Tapping a hardwood is not too much different than metals, maybe similar to tapping brass. You don't have to be quite as precise when you drill the hole, and I never used a lubricant. Yes, working the tap back and forth is always a good idea.

I believe different hardwoods will tap differently. And softwood does not tap well at all.

Largrin2 years ago
Great ible. I been doing this for almost 40 years, Your advice is good!
Bill WW (author)  Largrin2 years ago
Thanks for the comment.

I had been using threaded inserts, but then realized direct drill and tap would be better and easier.
Ugifer2 years ago
Years ago I skip-raided some incredibly dense hardwood that may well be your Jatoba - it was being used to make fire-doors in a chemistry lab. It looks like the wood in your first picture. I've never known what it is, only that it blunts meal tools!

I have in the past screwed machine screws directly into holes drilled into it because it's so incredibly hard and dense. I think I can feel some hardwood nuts coming on!

Thanks for a useful instructable.
Bill WW (author)  Ugifer2 years ago
Thanks for looking.

Yes, Jatoba is a great, dense, fine grained hardwood. Sometimes called Brazilian Cherry. The lumber I have is heavier than water.

I am now submitting short concise Instructables, The long complicated ones are great, but most do not fit my particular equipment or situation.
rimar20002 years ago
I attest this is very useful, Bill. Often I do hardwood nuts, they serve in many occasions. Your tips are always good.