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+-- Thread: threaded inserts in walnut (/showthread.php?tid=7337951)
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threaded inserts in walnut - TomFromStLouis - 03-06-2018
I am trying to install a couple of 1/2" diameter threaded inserts into walnut (the insert is 1/2" round with the threads outside of that). I drilled a 9/16" pilot hole in my test piece and the insert simply tore the rim of the hole to shreds as the threads dug into the wood. Same with a 1/2" hole but driving the insert in was more difficult. I presume that sooner or later the threads would get deep enough to just grip as they should but the hole entry would still be a mess. Any ideas?
RE: threaded inserts in walnut - humanrace - 03-06-2018
(03-06-2018, 03:13 PM)TomFromStLouis Wrote: I am trying to install a couple of 1/2" diameter threaded inserts into walnut (the insert is 1/2" round with the threads outside of that). I drilled a 9/16" pilot hole in my test piece and the insert simply tore the rim of the hole to shreds as the threads dug into the wood. Same with a 1/2" hole but driving the insert in was more difficult. I presume that sooner or later the threads would get deep enough to just grip as they should but the hole entry would still be a mess. Any ideas?I tap the holes with a regular metal tap and then screw the insert in. Never a mess. I use "Time Certs" and over the years I bought two taps of each of the 2 sizes I use and ground one down so it's a like a bottom tap. You can use these inserts with standard taps. https://www.grainger.com/category/self-locking-inserts/thread-insert/fasteners/ecatalog/N-8o6?searchRedirect=threaded+inserts
RE: threaded inserts in walnut - MichaelMouse - 03-06-2018
(03-06-2018, 03:13 PM)TomFromStLouis Wrote: I am trying to install a couple of 1/2" diameter threaded inserts into walnut (the insert is 1/2" round with the threads outside of that). I drilled a 9/16" pilot hole in my test piece and the insert simply tore the rim of the hole to shreds as the threads dug into the wood. Same with a 1/2" hole but driving the insert in was more difficult. I presume that sooner or later the threads would get deep enough to just grip as they should but the hole entry would still be a mess. Any ideas?
I use a step drill to make a clean entry after boring for the insert. Doesn't compromise the thread bite further down. Also helps keep the insert from wandering in softer woods.
RE: threaded inserts in walnut - Stwood_ - 03-06-2018
I taper the entry hole after drilling the correct hole size. Then a dab of paraffin wax on the tip of the insert.
Careful with the wax, don't want to get it all over.
RE: threaded inserts in walnut - FS7 - 03-06-2018
I'd recommend checking the pull-out strength of the woods you're using. When I built my daughter's crib, I had originally planned to use threaded inserts in the posts (bubinga) to hold the machine screws that held the turnbuckles that were attached to the mattress frame (that is, the screws that held up my child). I tried a few times in a piece of scrap, and I found that I had to get within 1/64" of the actual diameter to put the insert in without destroying anything. After that, I tried tapping the wood itself, and I couldn't pull out a screw in no more than two threads with all of my weight and a pry bar.
I know that I brought this up at the time, and the pull-out strength of most hardwoods (maple and walnut) is more than enough for machine screws. Yes, they sell knife-thread inserts for hardwood, but I am not at all sure you actually need them. A tapped hole will hold way more than you thought possible. Bubinga might be roughly twice as hard as maple or walnut, but maple and walnut are both excellent candidates for threading.
Something to think about if you hadn't considered it.
RE: threaded inserts in walnut - TomFromStLouis - 03-07-2018
These are all good ideas and I thank each of you.
I am going to try either the tapping idea or the tapered hole because with those I have what is needed. I'll let you know what works.
RE: threaded inserts in walnut - Lynden - 03-08-2018
Are you installing the insert correctly? The slotted end is the end that goes into the hole.
https://www.youtube.com/watch?v=tIhEqoKE8Dc
RE: threaded inserts in walnut - Gary G™ - 03-09-2018
Here’s how not to do it:
https://m.youtube.com/watch?v=BMm8U_LxGyg
RE: threaded inserts in walnut - rwe2156 - 03-10-2018
I've had this happen too even with pre-countersinking but sometimes this is not desireable.
Next time I will use a tap or a screw first.
I think if you used a drill press to maintain downward force it should help.
RE: threaded inserts in walnut - Gary G™ - 03-10-2018
I used the drill press method when I built Alyssa’s crib.
Put the brass inserts into Ribbon grained African Mahogany—no problem.
Walnut is easy compared to it.