Wood Threads vs. Metal Inserts

[BCam]

This is an interesting video. I'm not sure how his findings transfer to plywood but it wouldn't be hard to conduct your own tests. I don't think the wood threads would function as well in particle board or MDF:

https://www.youtube.com/watch?v=S4SnrbGwGpI

[N147JK]

Wouldn't want to use threaded inserts for a critical structural assembly. I wonder if a course-thread wood screw has a much higher holding power?

[BCam]

Originally Posted by N147JK

Wouldn't want to use threaded inserts for a critical structural assembly. I wonder if a course-thread wood screw has a much higher holding power?

Probably, but I was thinking of this in lieu of using metal inserts for whatever reason you might be considering them. Traditional screws might not stand up to being removed and reinstalled as well.

[SheepShagger]

Originally Posted by BCam

This is an interesting video. I'm not sure how his findings transfer to plywood but it wouldn't be hard to conduct your own tests.

If plywood is solid hardwood ply like Baltic bitch, and through the ply not in between then yes would be similar, if normal plywood with junk soft wood core then totally different. I’ve been tapping solid hardwood ply years, MDF will be similar results but does seem to benefit from ca glue. Corse thread wood screws (with correct pilot) seem to be just as strong, but only 1 time use and if not over torqued. Without the pilot very different results. Well that’s been my experience anyway as a home woodworker for ~30 years I have tried those inserts a few times over the years, but never got as good results as tapping.

[JWA]

For me when attaching something to plywood I'll try designing to use good quality t-nuts, my preference being the more professional 4-prong types.

They do allow for multiple insertions and removal as needed or wanted and have great holding power due their bigger back side footprint. Almost regardless the substrate they work very, very well.