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Brass Inserts
http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10102&t=12571		 Page 1 of 2
Author:  dsharp [ Sat Jun 23, 2007 7:58 am ]
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Can anyone tell me where to get brass inserts similar to those LMI carries?

Are self tapping inserts better than regular ones?

Author:  peterm [ Sat Jun 23, 2007 8:05 am ]
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Don,
welcome to the forum....
Author:  peterm [ Sat Jun 23, 2007 8:07 am ]
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oh, I use threaded inserts from Ace hardware. Not sure if the other ones are better.
Author:  Pwoolson [ Sat Jun 23, 2007 8:17 am ]
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mcmaster carr has nice ones.
Reid Tool supply has steel ones that are equally nice.
Author:  JohnAbercrombie [ Sat Jun 23, 2007 8:24 am ]
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Don-
LeeValley Tools sells them as well, though McmasterCarr is probably as convenient (cheaper?) for you in the US.

Cheers
John
Author:  Mattia Valente [ Sat Jun 23, 2007 8:45 am ]
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McFeely's also has 'em. And Lee Valley has outlets in the US.
Author:  WaddyThomson [ Sat Jun 23, 2007 8:46 am ]
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Woodcraft also has them.   Probably most woodworking resources would have them.
Author:  dsharp [ Sat Jun 23, 2007 8:50 am ]
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I've looked into McMaster and actually tried some of their steel inserts with disasterous results (splitting). So, I'm hoping brass will be a bit better. I'm assuming I want a coarse knife-edge outer thread? Or, am I better off with a finer thread?

Thanks for the help!
Author:  Pwoolson [ Sat Jun 23, 2007 8:54 am ]
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Don, I know Mcmaster has brass because I just got some last week. The have both course and fine thread.
I've used the course with very little troubles. I had one neck split on me. I took the insert out, filled the crack with epoxy, clamped it up and the next day I re inserted the insert with no troubles. One thing you might think about doing is drill the hole a bit larger, fill it with epoxy and when dry, re drill it to size, that's good insurance. Also, put clamps on the tennon when inserting them.
Author:  TonyKarol [ Sat Jun 23, 2007 10:43 am ]
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I use the steel ones from HD here in Canada - never split a heel yet - they are course thread, 3/8 hole required.
Author:  dsharp [ Sat Jun 23, 2007 12:41 pm ]
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I've never had a problem with brass or steel inserts in mahogany but I always seem to have trouble in hard maple (What I just split). Would a finer thread work better than a coarse thread insert?

Thanks, Don
Author:  Pwoolson [ Sat Jun 23, 2007 12:46 pm ]
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I just had a brief arguement with John Watkins about this topic last week. His theory is that the finer threads run less risk of splitting the wood. My theory is that the finer threads run a higher risk of pulling out (I had it happen). So choose your risk.
Author:  Doug O [ Sat Jun 23, 2007 12:52 pm ]
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I use the course thread variety and get them from a local industrial fastener supplier.  Any good tool/hardware supplier that caters to contractors and fab shops should carry them.  If you happen to be in the Pacific NW go to Tacoma Screw Products.
Author:  dsharp [ Sat Jun 23, 2007 1:01 pm ]
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I've had the same problem with the finer thread. That's why I stopped using them. I don't make maple necks that often so, it's kind of new territory for me.
Author:  Marc Lupien [ Sat Jun 23, 2007 1:15 pm ]
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Don, I use brass inserts from Fastenal.  Before threading them in maple, i slightly wet the wood with a Q-tip...  the risk of splitting seems to be reduced!
Author:  WaddyThomson [ Sat Jun 23, 2007 1:56 pm ]
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Seems like a tap the right size and thread count would work since they are tapered for a slow start.  Just use the first bit in the hole before inserting the insert (that sounds stupid).  It should 1) Keep it straight, and 2) keep the wood from splitting.  You would only want to run it in for about the depth of the insert threads that way it would continue to tighten up as you turn the insert.  Also, the threads on a standard machine screw tap that size would be shallower than the threads on an insert.
Author:  crazymanmichael [ Sat Jun 23, 2007 2:23 pm ]
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any home depot, lowes, ace, true value, most hardwares. i use liquid soap in the hole and on the insert.
Author:  LuthierSupplier [ Sat Jun 23, 2007 3:10 pm ]
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I use the stainless steel inserts from Rocklers. They are not tapered, and have a hex screw in, so you can use an allen wrench to screw them in. They do not have the ones that I use on their website, but they have something similar HERE
They also have the Brass inserts too. I don't like the brass because it is too soft. I broke one before during insert, and never again. The stainless steel ones are almost impossible to break going in.

I always glue in a maple dowel that is bigger than the insert into the end grain where the insert will go. Then I drill for my insert, and just screw it in. No problems! Also, don't use the tapered ones, I think they don't hold as well. I've used them before with success, but why chance it.

Good luck!
Tracy
Author:  John Watkins [ Sat Jun 23, 2007 10:06 pm ]
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I've tried them all and the fine threaded brass, non-taper, non-locking have worked the best for me. I've probably used them on about 600-700 necks and have never had one split or pull out. They cost more than the hardware store variety, but it's worth it when you consider the costs associated with a failed neck.

My procedure is to bore the hole to the absolute minimum diameter (.338") and then tap it with a 9" long 3/8-12 tap that I made for this purpose. I tap half depth for Mahogany, Walnut etc. and full depth for Maple and Rosewoods. I then install the inserts with a 9" long installation tool. The length assures that it ends up straight.

One drop of thin CA for insurance and you're done.
Author:  ballbanjos [ Sat Jun 23, 2007 11:22 pm ]
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Has anyone tried the inserts mentioned in this article?

I've tried brass coarse thread inserts and have had a horrible time with the threads stripping out (pre-tapping as others have mentioned here seems like a good idea though).  The article above seems to make sense in that most of the inserts available were designed for knock-down furniture and things like that--definitely not for threading into hardwood end grain. 

The self tapping inserts for metal sound like a good idea, but I wondered if anyone had experience one way or the other with them for this application.

Dave
Author:  dsharp [ Sun Jun 24, 2007 1:23 am ]
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I was looking at getting those but wasn't sure that they would be the best option. I was thinking about it last night and came up with an idea similar to John's solution. So, I think I am going to follow John's methods.

I was looking at McMaster's website this morning and noticed they don't list the external thread size for their inserts. Without that info, I won't be able to get the right tap. Is there another source with more info? I'll keep researching.

Thanks All. I appreciate it!!

Don
Author:  ballbanjos [ Sun Jun 24, 2007 1:33 am ]
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[QUOTE=dsharp]
I was looking at McMaster's website this morning and noticed they don't list the external thread size for their inserts. Without that info, I won't be able to get the right tap. Is there another source with more info? I'll keep researching.

[/QUOTE]

They appear to be 3/8-20 external thread.  I bought some and am giving them a try.  They tap into maple quite easily and go in nice and straight.  I've got to give them the torture test before I'd be willing to pass judgement on them though.  So far, on my test piece, I've not been able to pull them loose.

Dave
Author:  ballbanjos [ Sun Jun 24, 2007 7:02 am ]
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I had a chance to do some strength testing in bigleaf maple today using the self threading McMaster inserts.  I did two tests.  For the first one, I tightened a single bolt up to about the snugness that I'd use on a neck and used a maple stick to apply the kind of stress that a neck under abuse might apply.  I couldn't get the insert to budge.

For the second test, I ran a single bolt through a 1/4" thick stainless steel bar on top of a spacer with a 1 inch hole in it and torqued the bolt until the insert started pulling free.  It did eventually pull free, but it took about as much torque as I could apply with a 6" allen wrench, and it bent the bar pretty bad before the wood let go.  I doubt that the torque I applied would have stripped steel, but it would have definitely stripped aluminum, and a wood screw with similar torque applied would have either broken or stripped out.  At least in bigleaf maple, I think it's strong enough for a neck joint with plenty of room to spare.

Dave
Author:  dsharp [ Sun Jun 24, 2007 7:43 am ]
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Sounds Good! What size hole did you drill to install the inserts?

Thanks, Don
Author:  ballbanjos [ Sun Jun 24, 2007 9:05 am ]
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I used 11/32" pilot holes.  I think that the "insurance" of a drop of CA isn't a bad idea--my test piece didn't have that, but I would imagine that it wouldn't hurt anything and might add even a bit more strength.

I'm not sure how these self threading fine thread inserts will do in softer woods.  I'll have to give 'em a test in mahogany and see what happens.  I'm betting it will still be stronger than what my experience was with the coarser threaded brass inserts.  I know that those CAN work well--other folks have proven that time and time again.  But I sure haven't had any luck with them!  I must not have been holding my mouth just right...

Dave
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