Blind fixing into fairly thin plywood

I know we have a few woodworkers on here who might be able to help with a little problem. I have some laminated 12mm plywood and I need to fix some batten to the back of it. I don’t want to screw through the laminate on the front so limited to fixings from the rear. Standard wood screws won’t be great into thin ply so I was considering something similar but blunter like a cabinet hinge screw like this, but they aren’t ideal for battens:

Any other suggestions?

Nut inserts?

Can’t remember what they’re called, but inserts which screw into the ply into which you can then secure your batten with say, an M5 nut? Used a lot for fixing stuff into underside of furniture

EDIT: 12mm doesn’t give you much to play with – I used them to screw some tripod legs into the underside of 15mm – rock solid.

Pre-drill batten and widen top of pilot hole if nut head needs to be flush.

lots of glue and large area battens to spread the load.

Nut inserts?

Yeah – I can’t remember what they’re called either but …. them.

EDIT ‘Type D Threaded Nut Inserts’ Screwfix sell them

Four pronged T-nuts?

I believe they may be called “insert nuts”. 😆

“insert nuts”.

You’ve been hanging around the wrong kind of holes

Dowels and glue, or just glue.

A threaded insert for wood?

Like this:

https://www.amazon.co.uk/FLANGED-DRIVE-FLANGE-THREADED-INSERT/dp/B0193Y1QXS/ref=pd_lpo_sbs_60_t_0?_encoding=UTF8&psc=1&refRID=Z5VQG5RWM7CXJZ88K0A6

Only problem is the thickness of your ply.

Plenty here including reduced length ones.

http://www.theinsertcompany.com/index.php

Or something like this:

https://www.ebay.co.uk/itm/FOUR-PRONGED-T-NUTS-CAPTIVE-THREADED-INSERTS-FOR-WOOD-FURNITURE-M4-M5-M6-M8-M10-/181230569842

They require a bit of faffing with lining up etc but the advantage of the faff is that you can get them in a perfectly straight line and spaced equally. Will require careful pilot-holing as well (to do it properly) to avoid pushing material through the laminated face.

I think its a bit thin for threaded inserts, maybe I’ll do a test on scrap piece. Trying to avoid gluing it

Depends a lot on what forces you’ve got acting on the fixing – other blind fixing options would be dispensing with the batten and using Keku clips (again screwfix) or flush mount plates

I think its a bit thin for threaded inserts,

If you shop around you can get some pretty tiny ones. I used to tour a set of exhibition units held together with (xxxxing hundreds) of M3 or M3.5 inserts and tiny machine screws. Very shallow fixings but held up to repeated assembly and disassembly over about 6 years and these units were pretty big units in 18mm MDF and birch ply

Aluminium angle either side of the batten.

12mm is plenty. You can afford to go 8-9mm in with a 4.0 wood screw, and use decent glue along the length of the baton. Countersink the baton and put a 5mm screw hole in it. You could always file the tips of the screws (definitely need pilot holes then) but you’d only gain a thread/half.

How deep is the baton? What sort of size are the batons/panels? Depending on all that, I might not even to too bothered about screws; plywood glues very well face-face (that’s what it’s made of, after all) if you can get sufficient clamping force (which is what the screws would provide)

epoxy boatbuilding style?