joining plywood to solid Phenolic ???

[tribalwind]

Hey all, long time'



i’m at the beginning of building a new mobile base for my saw ,

originally was just going to do it all in ply, but i have a nice big piece of 3/4” phenolic that i thought would make a good flat bottom, since the ply is not.
sort of act as a Torsion-Box ,without all the work.
ran into a problem when screwing on the casters. i quickly found out that it does NOT take wood lag screws well! one broke off in the hole and i wasnt even moosing it really!must've been a weak lag i guess...


my solution to the casters is to just drill straight through and bolt them on.i can recess the hex head on top,the bottom will have a lip anyway,proud of the drawers/top etc..



but i’m puzzled how to affix the sides and inner walls. i’d hoped to pocket screw,but that’s out now . i could use L bar with through bolts and screw into the ply,but thats a lot of expensive l-bar ($10-4ft) and hardware.
right now im thinking build the box with a bottom allw ith pocket screws, and just bolt it to the phenolic in a few places…maybe that’d keep it flat enough…or maybe not….
any ideas?

[tribalwind]

i was too anxious to get on with things,
so i went with bolting the casters on through the phenolic and a piece of equally-sized 3/4-ply.
also added bolts in the middle along the long edges, the short sides were flat.
might add one more bolt to the dead-center for good measure.. recessign the head worked,but what a pain, i drilled the pieces separately , though i was being careful with the locating,in hindsight this was a mistake.far better would be to drill right through both so the holes were perfectly registered...
anyhow, now i can move along with the rest of the carcass with pocket-joinery, then get onto making the top (also phenolic)