# Installing Metal inserts for threads in wood



## MikeTurner (Jun 30, 2012)

I used some 5/16" and 3/8" metal inserts for threads on this project/jig not long ago. It was in soft wood.They worked out fine.

Now I need to put some 5/16"-18 in some oak on this same project.Ive tried drilling different sizes on the holes but I always pull the insert out when backing the guide bolt out…

Im using this method and it worked fine in the soft wood…






Im ready to finish this up. Help!!


----------



## Phil32 (Aug 31, 2018)

It would seem that the drill size would be larger for hard wood like oak. It is also important to let the threads of the insert guide the process. Either the installation of the insert ran beyond the desired point or some other force tore the threads in the wood.


----------



## knockknock (Jun 13, 2012)

Besides tearing the threads (as Phil32 said). Are you backing out the jam nut and then the other nut, before backing out the drive screw (in hardwood the nuts can lock tight on the insert).


----------



## waho6o9 (May 6, 2011)

I would use a 5/16 bolt with a washer and impact the inserts in and then back out the bolt.

Practice on scraps and you'll learn to finesse in the insert.

Proper pilot holes help a lot.

HTH


----------



## pintodeluxe (Sep 12, 2010)

I use the type of threaded inserts that install with an Allen key. You can get them in tighter than the soft brass ones.


----------



## AlaskaGuy (Jan 29, 2012)

> I use the type of threaded inserts that install with an Allen key. You can get them in tighter than the soft brass ones.
> 
> - pintodeluxe


These?

https://www.homedepot.com/p/Everbilt-1-4-in-20-tpi-x-20-mm-Zinc-Plated-Steel-Type-D-Insert-Nut-4-Pack-801884/204274222?MERCH=REC-_-PIPHorizontal2_rr-_-202242363-_-204274222-_-N


----------



## cathode (May 18, 2014)

Oak? Just drill and tap the threads right into the wood. If you're concerned about durability, then flood the hole with epoxy or CA glue, and chase the threads with the tap after the adhesive cures. Wood will hold machine screw threads remarkably well. Even soft woods like Pine can be tapped for bolts with coarse threads, like 3/8 and larger.


----------

