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http://liutaiomottola.com/construction/Bolton.htm

I'm having great difficulty sourcing the threaded inserts in the UK:

Self-tapping steel threaded inserts for metal, 1/4”-20 internal thread, 3/8” external thread, 31/64" length (part# 90240A001, package of 10)

Of the few places I've found over here advertising metric versions (M6x12.3), none have any in stock.

I'd either have to order from the US or order enough for 100 guitars! Before I do order from the States, does anyone know of a decent UK supplier?

I doubt I'll ever do more than a couple of guitars with this neck joint so I don't really want to spend £60 + on the hardware.

Thanks in advance,

Any good?

http://www.ebay.co.uk/itm/Pack-of-20-M6 ... 0851653736

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"I am always doing that which I cannot do, in order that I may learn how to do it."
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Cheers, Peter, I've used those ones before but this is for a butt joint.
Self tapping threaded inserts for metal. Can't find them on eBay!

Yeah sorry, I didn't read your post properly! I've edited it...

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"I am always doing that which I cannot do, in order that I may learn how to do it."
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https://www.facebook.com/FenskeGuitars

Can't you use wood ones and glue them in?

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
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I suppose. I particularly wanted them though because R.M. Mottola specifically says "I strongly recommend that you do not substitute any other inserts here". He gives his reasons on the link in my OP.

Here's a pic:


I ordered a sample from one place and they sent me all they had: 14mm brass ones, rather than 12.3mm hardened steel/zinc ones. I don't want to use them. (seeing as Mr Motolla uses 12.3mm for steel strings, this tiny classical probably only requires 10mm, so I don't want the 14s!)

One place (Memfast) had the right ones in stock till a few weeks ago and won't have them back for months.

McMaster-Carr or another American supplier would have. And I'm sure there are UK suppliers with them, too, but they don't have proper online shops or aren't easily found on Google. I thought someone over here must've used this joint with these inserts.

Thanks anyway!

Brass ones strip out the threads vy quickly

Although these are from the US, these steel inserts from McFeely's work real well. They also supply the metric driver or you can make your own by cutting off an allen wrench.
http://www.mcfeelys.com/



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Thanks, Ernie, that's what I figured. Definitely won't be using these ones.

And, Rusty, thanks for that. They aren't what Mr Mottola recommends but if they work well I can buy those over here. Apparently he did an article in American Lutherie(?) where he tested the different types and the self tapping metal ones came out on top. Not that i require maximum strength on this guitar but I'm going to be getting more than 2 no matter what so I'd like to have the ideal ones (according to him) for steel string guitars too.

I'm thinking of modifying another design on my subsequent bolt on butt joint necks, so I really don't want to order 250 of them! Guess i'll have to order from the states.

I use a 1/2 in maple dowel in the heel for the insert to bite into. IMO it makes the insert choice fairly irrelevant - they will all bite plenty well when it's not end grain. Still use the steel ones though...

Thanks Tom, I was trying to avoid doing that. I wish i hadn't have chosen this design now, it is a tiny guitar so a mortise and tenon would have enabled a smaller heel. I also wish I'd have ordered these while they were in stock. I had no idea they were so rare over here. The company that sent me a sample of the brass ones said they only ever sold the ones I wanted once so will never reorder!

Nick ...forget what Mottola says ... and forget threaded inserts... the way forward with butt jointed necks is to use hanger bolts, threaded into a 1/2" dowel which is glued into the heel.

Thanks Murray, would a really tiny soundhole make that really awkward? And what do you reckon the minimum heel depth would be?

Cheers,

Hanger bolts are good too and not as likely to split your wood as inserts but you can drill and tap first when using inserts anyway.


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Nick ...you can customize the length of the woodscrew on the hanger bolt, and you can also customise the length of the machine thread.

I don't quite altogether get what the soundhole size has to do with it ...do feel free to elucidate !

Rusty, I have been trying for years to find out what the external thread on inserts is ...with no success.

If you have cracked the problem, and can tell me which tap I can use with which insert ...I will be forever in your debt.

With steel inserts of course, it is possible to cobble together a tap by cutting flutes in an insert and fitting it onto a bolt with a couple of lock nuts, and use a socket wrench ... with brass inserts ...not so much ...

I dont know what it is either, i just grab the metal tap that looks the most like the insert and let the insert finish cutting the proper thread, works for me.
As always, do a test piece first.



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Just getting the nuts onto the machine end through the soundhole. I bought a set of long allen key heads just for this and it seems easier than threading nuts. Forgive my ignorance!

Do many find that heels crack when installing the self tapping inserts?

I fussed with threaded inserts and then I decided to use hangar bolts. Grumpy uses them. They worked well.

Gotcha ...

Oh right! I'd not scene those allen heads! Cool.
Disregard last post, Murray!

FWIW, the brass ones work just fine for me, and I've used them in some pretty high load situations in experimental instruments. However, I always superglue the threads, and I'd venture a superglued brass insert has more holding power than a non-glued fancy steel insert...

Sorry don't know any UK suppliers, but I think McMaster/Carr will ship, and they don't have minimums. http://www.mcmaster.com/#standard-threa ... ts/=q6z94z

John, Murray, are the conical washers unnecessary?

Thanks for the input, Greg! I've got the brass ones so I could conduct an experiment one I've sourced others!

If anyone else has other methods for butt joints this could become a useful thread!

Sure thing!



I'm pretty sure I did this at some point long ago. For sure, they are likely to crack if not reinforced by doweling or similar reinforcement.

John Killin's pic above is the best and most concise wordless explanation of why hanger bolts are the way forward that I have ever seen.