Door Question

[JunkMan]

I'm getting ready to build my doors, and was going to make them out of pine and hardwood boards, using sandwich type construction, the same as the sides. After cutting the ribs for my hatch out of a sheet of 3/4" 9 ply baltic birch plywood, I noticed that I have enough scrap left to make the doors.

I know that normally it is not a good idea to put screws into the edges of plywood, since they don't usually hold well, but was wondering if the 9 ply baltic birch was strong enough. I already ordered stainless steel piano hinges (should be here Monday), so I really don't want to change my plan and use the ones with the angle on them that are designed for plywood, since I would have to wait a couple of more weeks for them to arrive, not to mention, I have already purchased the others.

The 3/4" baltic birch plywood would be one piece, covered on the inside with 1/4" birch plywood, and on the outside with 1/4" laun, then aluminum, to match the side walls. I would cut voids in the 3/4" to lighten it up, and add insulation.

Would I be better off gluing a 1" strip of hardwood to the hinge side for the screws to go into, or possibly drill larger holes in the 3/4" , and glue dowels in where the screws will go?

Or, should I just go back to my original way, and make the frame for the door out of 3/4" pine, with the edge that the hinge screws into made of hardwood?

The reason I want to use the 3/4" baltic birch, is that I think it will stay flat, where if I glue up a frame out of pine and hardwood boards, there is a pretty good chance it will warp (not to mention, I have the birch already).

[Chris C]

Jeff,

9-ply Baltic Birch will hold a screw in the edge better than any other of the "stacked" woods, but it's still a "stacked wood". So it depends on how much real holding power you're asking for.

[Arne]

If you are using sandwich, why not put a hardwood strip in?

Else, use pilot holes, longggg screws with some kind of goop, like silicone to help hold them in place.

Another thing I plan on doing to my existing tear is to put a steel pin in the jamb by the handle (opposite the hinge) and a groove in the door to give the door support on both sides. I have a bit of sag from the door jostling around while driving and bouncing......

[JunkMan]

Chris,

Since I'm using a piano hinge, I plan to have several screws in the hinge to spread the load.

Arnereil,

Just using the plywood is my 1st choice (and the easiest). The hardwood strip is probably my 2nd option, but I'm afraid that the strip could cause a little weakness in the door. I guess it just depends on how I attach it to the 3/4" plywood.

[Chris C]

Actually, Jeff, the strip would be a better attachment surface. I'd go with a good hardwood on that edge..........maybe a tight-grained oak. Then you'd have the best holding power you can get. Just my opinion, though.

[Slayer]

Or you could use machine screws with nuts and washers. 3/4 inch ply should give you more than enough room to countersink the nut and washer side. I think???

[Arne]

I think I'm confused. I thought the hinge flange would be inside the door jam, not on the exterior of the door... mounted on the exterior gets more shear stress... I don't like shear stress. I prefer tension stress in this case.

[JunkMan]

Arnereil,

You're right, I planned to put the hinge in the door jamb, so machine screws & nuts won't work.

I'll probably go with a strip of hardwood. Was going to start on the doors today, but decided to see if anyone had any better ideas for them, so worked on the cabinets instead.

[Artificer]

Here's my door hinge. The screws go into the door jamb, and into the edge of the door. Both have plywood frames. I used SS wood screws, and pre-drilled the holes to prevent splitting.

I haven't finished the trailer yet, so no idea on how they'll hold up. Worst case scenario is that if they strip out, I drill oversized holes and glue in dowels.