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Guiding in threaded inserts.
http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10101&t=54248		 Page 1 of 1
Author:  James Orr [ Mon Jul 12, 2021 6:06 pm ]
Post subject:  Guiding in threaded inserts.
An expensive and recurring problem for me as of late has been getting my threaded inserts in square. I have a doweling guide that makes drilling the holes square a breeze, but I kept guiding the inserts in crooked. Very frustrating.

So I prepped up yet another neck blank this morning and got to the point of threading them in when I stopped to pause. If I screwed it up again… I didn’t have any blanks left.

Then it dawned on me that my “V-Drill” Guides might be the perfect solution! And sure enough it was. My E-Z Lok bit fit the 1/2” guide perfectly

A handy tip I wanted to pass along just in case anyone else is as incompetent at guiding these things in as me.


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Sent from my iPhone using Tapatalk
Author:  doncaparker [ Mon Jul 12, 2021 6:32 pm ]
Post subject:  Re: Guiding in threaded inserts.
James--

That looks handy! In case you need another way to do it, here is what I do:

I have a long threaded bolt (1/4"-20) that only has threads on the lower part. I cut the head off the bolt. I put two nuts on the threaded part, snug against each other, but high enough up so that there is room for a threaded insert on the very end (last half inch or so). I put this bolt in my drill press with the threaded insert on it. I position the hole in the workpiece under the bolt. Then I hand turn the chuck while lowering it into the workpiece. I DO NOT TURN ON THE DRILL PRESS!!! It is off for the whole operation. Once the insert is flush with the surface of the workpiece (or a little below), just start turning the chuck the other direction to unthread the bolt from the insert. By hand, always!

If you are installing threaded inserts into the butt end of a neck, you probably have to tilt the drill press table 90 degrees and clamp the neck to the table. I don't use threaded inserts in necks any more, but I use them a lot in jigs.

I was worse than useless at installing threaded inserts before I learned this method.
Author:  Ruby50 [ Mon Jul 12, 2021 7:24 pm ]
Post subject:  Re: Guiding in threaded inserts.
Don - no need to hassle with the drill press - click right for 3 shots, text below

https://www.flickr.com/photos/ruby1638/ ... 488198220/

James, your idea is great - where did you get the "V" guide?

Ed M
Author:  James Orr [ Mon Jul 12, 2021 10:52 pm ]
Post subject:  Re: Guiding in threaded inserts.
Ruby50 wrote:
James, your idea is great - where did you get the "V" guide?

Ed M


Thanks, Ed! I got them from Amazon for a mailbox post I made earlier this year using drawbores. This is a link to the set of two, but you can purchase them individually as well: https://amzn.to/3i3XWFh
Author:  James Orr [ Mon Jul 12, 2021 10:55 pm ]
Post subject:  Re: Guiding in threaded inserts.
doncaparker wrote:
James--

That looks handy! In case you need another way to do it, here is what I do:


Thanks, Don! Sounds like another great method. These things were really vexing me. I think the issue is that without something keeping it square, the insert wants to slant to the side to rest on the threads. That's the only thing that makes sense to me. Then again, I could be wrong?
Author:  doncaparker [ Mon Jul 12, 2021 11:54 pm ]
Post subject:  Re: Guiding in threaded inserts.
Yes, that’s pretty much the problem. Your manual pressure to keep it straight is overpowered by the insert’s threads taking the immediate path of least resistance. Forcing it to go in the hole straight, using something more persuasive than hand pressure, is better. I drove more crooked ones than straight ones when I was still trying to do it by hand.
Author:  Aaron O [ Tue Jul 13, 2021 12:55 am ]
Post subject:  Re: Guiding in threaded inserts.
You may be going in crooked because it looks like you have the insert going in backwards.
Personally, I use the doweling jig to drill, and to set the insert. Here’s an old vid.

https://youtube.com/watch?v=62B0T4dImJ8&feature=share

Also, I used to run a step drill in, 1 step (not a full step), to open up the top so the bit was guided in straight. Helped a LOT, prior to using the doweling jig as a guide.
Author:  johnparchem [ Tue Jul 13, 2021 8:41 am ]
Post subject:  Re: Guiding in threaded inserts.
Aaron O wrote:
You may be going in crooked because it looks like you have the insert going in backwards. ...


The slot on many of the inserts is a cutting edge to cut the thread. I often see them installed in picture where they are used as a driving slot. Great video by the way! I have that jig and will use it as you do.
Author:  doncaparker [ Tue Jul 13, 2021 9:20 am ]
Post subject:  Re: Guiding in threaded inserts.
Ruby50 wrote:
Don - no need to hassle with the drill press - click right for 3 shots, text below

https://www.flickr.com/photos/ruby1638/ ... 488198220/

James, your idea is great - where did you get the "V" guide?

Ed M


Ed--

You and I are obviously using the same tool! I take it that you are manually holding the top of the bolt steady and vertical with one hand so that the insert goes in straight when you use the wrench with the other hand? That's cool. I might try it with something longer, like a 1 foot section of all thread. I speculate that a longer shaft would give more leverage to prevent tipping. Good tip!
Author:  Alan Carruth [ Wed Jul 14, 2021 12:59 pm ]
Post subject:  Re: Guiding in threaded inserts.
I once made a tap out of a wood screw with the right thread that got things started in a straight line. Since it begins with a very light cut you can control it more easily.
Author:  Mike_P [ Wed Jul 14, 2021 5:48 pm ]
Post subject:  Re: Guiding in threaded inserts.
Alan Carruth wrote:
I once made a tap out of a wood screw with the right thread that got things started in a straight line. Since it begins with a very light cut you can control it more easily.

that kind of answers what I wanted to ask about...

has anybody tried a tap for this?

sure, it's hand held but does have a tapered head to slowly start the threads then cuts them to full depth as you go along...and obviously knowing the exact specs of the inserts is required but I'd be very surprised if the pattern wasn't one typically used and has a tap for
Author:  James Orr [ Wed Jul 14, 2021 11:32 pm ]
Post subject:  Re: Guiding in threaded inserts.
That's brilliant. I wonder if the thread pitch is something standard? I've used two different types with two different pitches. The inserts for softwoods have a course pitch, where the inserts for hard woods are a bit more fine.
Author:  Ruby50 [ Thu Jul 15, 2021 7:54 am ]
Post subject:  Re: Guiding in threaded inserts.
Don - My tool is just a bolt with the head cut off - I thought I might need a longer bolt to hold it perpendicular, but the one I have is fine
Author:  Alan Carruth [ Thu Jul 15, 2021 1:34 pm ]
Post subject:  Re: Guiding in threaded inserts.
The insert makers probably use standard threads, but whether they're wood screw or machine screw sizes is impossible to say in any general way. Take one of your inserts down to the hardware store and start going through the drawers.
Author:  doncaparker [ Thu Jul 15, 2021 4:30 pm ]
Post subject:  Re: Guiding in threaded inserts.
Or, if you have a Thread Detective, you can skip the trip to the hardware store. I checked a common insert with my Thread Detective, and I think m12-1.5 is a pretty good match. There are several different types of inserts, obviously, so test your own. Also, I think a standard tap is going to cut the threads to be less snug than most of us would like to see. It might be best to stick with the self-tapping aspect of these things. Just a thought.
Author:  Mike_P [ Thu Jul 15, 2021 4:44 pm ]
Post subject:  Re: Guiding in threaded inserts.
I did a brief look at McMaster-Carr and it appeared all inserts whether stated for metal or wood had a standard thread pattern...obviously those slated as being for wood had a coarser thread...

good point about possibly being too loose...just use a starter tap (there are 3 types of taps) and only set the thread pattern as opposed to cutting full depth...and in actuality one would probably have to use a bottoming tap to actually get any sort of decent tap because the hole in the heel is not going to be deep enough for a starting tap to do much...in the past I've simply cut off a typical tap from the borg when I had to do a bottomed tap as opposed to going all the way through as I typically do when I find myself with the onerous task of having to be a metal worker...from what I can tell an Irwin tap is more of a starter style, a DeWalt tap is middle of the road

or better yet: https://www.infinitytools.com/101-180g-wood-taps ...not sure I like the hex shank for chucking into a drill, though I've used a DeWalt 12x24 tap chucked into my cordless to tap into 1/4" aluminum and had no real issues other than since it was all done in the field on a wall the usual issue of drilling a square on both axis' hole then tapping correctly so the machine screw sat flush with the aluminum plate

a word to the wise about taps: they can snap and when they do so it's very rare there is enough left protruding to grab with vise grips...if you pay really close attention you will notice the\at there is twisting going on as you bear down when tapping...this puts stress on the tap and eventually it will break, so when in doubt throw a used one away and use a new one...and yeah, just like stripping a bolt it takes breaking a few taps to learn the limits...never try and just keep going forward, rather make a 1/4 of turn then back it off, repeat and rinse...sometimes I'll totally remove the tap and clean it off and clean out any residual in the material I'm tapping.
Author:  rbuddy [ Thu Jul 15, 2021 10:58 pm ]
Post subject:  Re: Guiding in threaded inserts.
I use threaded inserts for bolt on necks. After some experimentation I now have a fairly high level of confidence in the strength of the neck attachment.

I have close to zero confidence in using taps designed for metal to tap a hole in wood end grain especially something like mahogany. My attempts along that line have resulted in a rough hole full of sawdust and no threads. It might work in wood side grain but in end grain the combination of the teeth cutting across the wood fibers and friction just pulls the threads out. It's like putting a bunch of saw cuts in a piece of wood and breaking the pieces out for a quick construction lap joint, simply no strength there to hold the threads. If you are determined to try it, practice on some scrap wood.

My best results have been using inserts with very thin threads, drilling a hole sized to just allow the insert to "self thread" its way in without splitting the tenon/heel. So the threads on the insert are compressing wood fibers more than cutting them. Then run some medium CA around the threads to harden the wood and glue in the insert. I take it a step further and make a dowel that will fit in the insert hole I drilled, bore out the center of the dowel for the bolt, and glue it in on top of the insert.

They sell insertion tools for the inserts and they are cheap, kind of a T handle. I always wax the threads on the insert tool so when you remove it, it doesn't bring the insert back out of the hole.

I've posted pics before but I can again if anyone wants. So many advantages to a bolt on neck, I'd charge extra for anything else as a penalty.
Author:  Ernie Kleinman [ Fri Jul 16, 2021 8:01 am ]
Post subject:  Re: Guiding in threaded inserts.
Hi brian , could you plz post a pic of how you put the dowel in ? i am trying to picture your comment. ? We use some spanish cedar , cypress an e, red cedar . sycamore. My method is to drill a slight angled dowel abt 1/2in from the edge of the uke fb. an drill vertically down into the heel. I use 1/8 and 3/16 in allen headed machine bolts. 73, ernie
Author:  rbuddy [ Fri Jul 16, 2021 9:25 am ]
Post subject:  Re: Guiding in threaded inserts.
Hi Ernie

I have a couple necks in progress here and handy for a picture or two.

Good op to show the whole thing. Insert tool, brass inserts I like currently, I think I bought a bunch from Lowes. Relative position of insert in the heel. And the dowel glued in over the insert.

For the insert to come out it would have to overcome the threads, glue, and pull out the dowel. I always chase the threads on the furniture bolts to clean them up so they go in and out of the inserts easily. I think those bolts are stamped and not cut so the threads are mediocre.

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DSCN4057.JPG


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DSCN4058.JPG


A drilling jig I made using hardened Dowl-it drill guide tubes. Clamps to the tenon. Works good, no measuring required.

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DSCN4059.JPG


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DSCN4060.JPG
Author:  James Orr [ Fri Jul 16, 2021 11:17 am ]
Post subject:  Re: Guiding in threaded inserts.
Thanks for sharing that, Brian. I like the Hillmans from Lowe's, too. Once upon a time I had one of those T-handle tools, too. Can't seem to find it now.

In the end, the method I stumbled onto was quick, easy, and successful for me.
Author:  Ernie Kleinman [ Fri Jul 16, 2021 1:59 pm ]
Post subject:  Re: Guiding in threaded inserts.
Good show brian, Looks like maple or birch dowel. I/ve done it your way. But did not like drilling an threading into end grain.So I put the dowel on top of the neck an drill down 2/3 of the way. This way is easier for me as the insert bites into the long grain of the dowel. Good idea abt the T wrench!. thank you very much for posting the pics . A few pics are worth a lot of info !! cheers
Author:  rbuddy [ Fri Jul 16, 2021 2:26 pm ]
Post subject:  Re: Guiding in threaded inserts.
I did one or two with a vertical dowel run through the heel under the fingerboard, and still glued in the hollow dowel over the insert. I think the vertical dowel is a good method on its own too. I dropped the vertical dowel and just went with my current method as I liked it better, but just a personal choice.
Author:  Alan Carruth [ Fri Jul 16, 2021 5:02 pm ]
Post subject:  Re: Guiding in threaded inserts.
rbuddy wrote:
" I think those bolts are stamped and not cut so the threads are mediocre."

I'd guess they're 'chased': the metal is deformed under pressure. This is how they make thread rod, I believe. One tell-tale of this is that the crest of the thread stands out above the rest of the bolt.
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