Lateral wood screw capacity less than 6D penetration?

[AaronMcD]

I'm not concerned with building code, this is just a personal project.

I am wanting to mount a heavy duty drawer slide into a cabinet with 1/2" plywood sides. One side is exposed so I'd rather not penetrate through the plywood. Since this is a heavy duty slide, intended to support a slide out fridge in a campervan, I want to run calcs to be sure it's not gonna break. The holes in the slides are for #10 and 1/4" screws. I found 1/2" long #10 and #14 screws at Ace Hardware.

Neglecting the 6D minimum, I'm coming up with Mode II failure at 75 lbs for the #10 screws. Due to the thin slide metal I don't think Mode II would happen. I imagine it would be more like Mode III but with pull out instead of screw bending. I'm getting about 90 lbs for a sum of pull out and main member corner bearing failure, but I imagine it would be less. I suppose I could screw into some scrap, stand on the slide and try and pull it out.

http://www.hellodwell.design

 

[Ron]

There's nothing magic about the number of mounting holes in a drawer slide. You can drill more holes and add more screws. Another thought is to use threaded inserts (E-Z Lok or similar) into the plywood. These will give you more capacity and you can use machine screws through the slide instead of wood screws.

 

[Tomfh]

I suppose I could screw into some scrap, stand on the slide and try and pull it out.

Do that. Much more accurate than screw calculations.

 

[AaronMcD]

There's nothing magic about the number of mounting holes in a drawer slide. You can drill more holes and add more screws. Another thought is to use threaded inserts (E-Z Lok or similar) into the plywood. These will give you more capacity and you can use machine screws through the slide instead of wood screws.

Good point on drilling the slide. It comes with a bunch of holes (don't know how many off hand). I was thinking just fill all 1/4" and #10 holes, but then I got worried after seeing that stubby little #14x1/2" screw lol! I used those threaded inserts in other areas of the van and thought of them. They'd go all the way through but maybe more discreet than a nut and washer.

I just had an idea. I can brace the slide with wood straight to the top and bottom of the cabinet (below the front and above the rear). This would also help stiffen up the cabinet sides.

http://www.hellodwell.design

 

[DBronson]

AaronMcD:

The way I'd approach this is to use T-nuts through a, say, 3/8" plywood drawer side then laminate an 1/8" plywood "skin" on to cover the T-nuts if you don't want them exposed. Plastic laminate would also work as a thin covering surface.

Regards,

DB