[PaulRowntree]

Hi !
I am playing around with 3-prong T-nuts (3/8" bolts) and 3/4" plywood for a frame and some components. I am cutting a 1/8" deep 1.05" diameter recess for the nuts to make the surface flush.
Is there any point in applying some epoxy into the recess before inserting and seating the T-nut? Would it stabilize the wood fibres against tearing etc?

Could anyone compare T-nuts with Propells in plywood? I have been buying mine at LeeValley.
Cheers!

[wizard]

If this is an assemble once sort of solution I wouldn't bother. However if you willbe using the threaded inserts constantly it might be worthwhile.

However you need to balance this against serviceability. When the threads wear out repairs will be far more difficult. In some cases alternative approaches may be better in the long run. One approach would be to use some steel bar stock tapped for your threads, inserted into a DADO and screwed in place. Done tight this is very strong but more importantly easy to replace. Another approach, if you have a metal lathe, is to make a large flanged insert much like a tee nut that can be held in place with a few screws.

In the end T nuts are great for moderate use and when the forces always draw the nut into the wood. Cheap is important here too. It is when they are used repeatedly or subject to forces that push instead of pull that they have problems.

[ger21]

There's really no need for the epoxy.
The table in my CNC has 120 1/4-20 t-nuts in MDF, and they hold just fine, with no problems after 2 years of use. And, I use CAM clamps with them, so they also see some horizontal forces.

[PaulRowntree]

Thank you for the help folks!

Cheers!