Wooden nuts and bolts

[midnightlunchbox]

Hello folks,

Need a little advice. I fancy having a go at making wooden nuts and bolts for absolutely no reason other than they look quite interesting. I know there are methods that use fancy jigs/routers , CNC routing and there are thread cutting chisels but I really don't want to go to that expense or hassle, I only want to make a few. But I do have access to normal taps and die for metal and wondered if they would work on timber? Has anyone tried this? What timber is best, obviously something hard and tight grained, but I have a decent stock of Lignum, Cocobolo, and Purpleheart, would these be okay or are they too hard? Can anyone suggest a different method that doesn't involve fancy jigs etc?

Any help is appreciated,

Craig

 

[dickm]

If you have a lathe, patience and reasonable hand-eye coordination, then the simple and cheap answer is to use thread chasers. I'm sure someone can point you at sources of these (mine, I think, were from Ashley Isles) but they are not that difficult to make yourself out of flat steel stock.
Basically, they consist of a set of teeth spaced according to the thread pitch, and are pushed/pulled into the wood while moving them sideways so that after one revolution, the next tooth just slots into the spiral being made by its predecessor and so on. Simple in theory, but takes practice.
The great thing is that you can make a thread of any diameter, not just the standard ones from thread boxes/taps, and they cost much, much less.
I needed a weird pitch thread to replace the wooden screw on an old marking gauge. Took an hour or so to file up the chaser from a bit of steel strip, which for a one-off didn't even need to be hardened.

 

[midnightlunchbox]

I never really thought of making them. I don't want to go to the expense of buying thread chasers as I don't plan on doing much chasing but I have access to steel bar so that might be an option.

Thanks!

 

[chipmunk]

Hi Craig,
Sharp taps work a treat in very dense close grained timber like boxwood, cocobolo, lignum vitae, mgrure, tambootie etc. but dies are not much use in my experience - even the best wood tends to chip and lose the thread crests.

I often make small boxwood adjusting screws and nuts with an M8 coarse tap and 20 TPI external thread chaser because that's what I have. Theoretically they are different threads 1.25mm and 20TPI are 1.6% out and the 20TPI chaser is Whitworth 55 degree form whereas the M8 is metric 60 degree form but hey!, they will mate ;-)

Tracy tools sell sets of external chasers which you can use in conjunction with any taps you have (Option 2)...
http://www.tracytools.com/thread-chasers

and The Toolpost sell boxwood...
http://www.toolpost.co.uk/pages/Hardwoods/Timber_Specialities/timber_specialities.html#boxwood

HTH
Jon

 

[midnightlunchbox]

Thanks Jon, I might ask the engineers at work if they could rustle up a simple chaser like that. It wouldn't be difficult for them, and I have access to taps so I can avoid any expense.

 

[chipmunk]

You might find this article interesting...

http://www.jamesriser.com/Machinery/chasers/making_chasers.html

Jon

 

[midnightlunchbox]

It's a pity he didn't show the finished threads!

 

[AndyT]

I agree that it's a fascinating subject. Have you spotted this thread on threads, currently running in the General Woodworking section? https://www.ukworkshop.co.uk/forums/a-wood-thread-thread-t86785.html.

It does include use of a lathe (though maybe not in the way you are thinking of) and this comparison of a tap for wood alongside the same diameter for metal (6tpi vs 10tpi)

It follows on from this earlier discussion in the hand tools section - again, including the use of a lathe - which threw up some useful tips such as the use of CA glue to reinforce the wood before making female threads:

https://www.ukworkshop.co.uk/forums/an-alternative-way-to-cut-big-threads-in-wood-t78726.html

 

[midnightlunchbox]

That is some very interesting reading, I enjoyed both threads containing threads! I am perennially impressed by engineering types who are as good with wood and metal, my skills feel insignificant in comparison. I'm off work ill just now and I have had an ex colleague (with some incredible skills I might add) round for a brew this morning. I was sharing my planned projects and he has a thread cutter (like the axminster ones) he hasn't used in years and said I can have it. So, when I'm up to full speed and I get the threader I'm going to get stuck in.

 

[paulrockliffe]

I don't know if this is already a 'thing', but if I was trying to do this (off the top of my head). I would do something along the lines of:

Make a box, cut a hole to match outside of a dowel at each end. Put a hole in the side to let a router cutter in and then screw the router to the side.

Attach one end of a dowel to a piece of threaded bar with the right thread profile on it and mount an appopriate nut so that it's fixed in relation to the router cutter.

Turn on router, plunge cutter into dowel, then screw rod through the nut to control the cut.

Would need a bit more fleshing out for cutter profile, length of rod, nut placement and how the whole thing is reinforced, but in principle that would work.

 

[timber]

I am just deciding to see if is possible to use a die to cut 3/4x 10 UNC threads onto a dowel made from a 18- to 20 mm piece of BOX. As it is very dense I am not sure if soaking in oil will work?? Would I be better of using CA glue.
What I am making is a knitting needle container out of 20mm electrical conduit.I have made two using nylon but as I have some Boxwood thought I would try that instead, but worried about the breakout. The tap that I use for the internal threads are ok but leave the conduit a bit on the thin side !!
Richard

 

[lurker]

Richard,

I have a pair of chasers I could lend you they are quite fine thread but I have used them with box to cut threads with 30mm diameter and it works quite well

We are about an hour drive apart
Most weekends I visit melton ( parents live there) and work in Leicester
Pm if you want to work something out about midway meet?

 

[lanemaux]

Just for giggles , Tim Yoder does them in his you tube series like this http://www.popularwoodworking.com/woodturning . Bloody heck , I posted a link!!! My son is going to be so proud.

 

[timber]

Richard,

I have a pair of chasers I could lend you they are quite fine thread but I have used them with box to cut threads with 30mm diameter and it works quite well

We are about an hour drive apart
Most weekends I visit melton ( parents live there) and work in Leicester
Pm if you want to work something out about midway meet?

Hi Lurker
I have quite a lot of chasers taps etc. ( Too many) Thanks all the same for the kind offer
It was the thread cutting of the boxwood that I was uncertain of ,do I need to use a CA type glue to help keep the thread from looking too ragged. I will have a go on Smart & Brown metal lathe tomorrow either by keeping a die square to the dowel or using the normal threading technique . Before I try the CA glue
Richard

 

[lurker]

I find box is fine on its own .... Sort of buttery
With beech I use linseed oil