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Step 2About screws
Aside from the nameplate (which needs tiny #4 screws) and masts (which need 1/4" bolts) everything is held together by three sizes of screws. Long screws are 3" long; Medium screws are 1-1/2" or 1-5/8" long; Short screws are 1" long.
Use construction-style wood screws -- phillips flathead, for easy driving with a cordless drill. Get screws rated for exterior use; they have an anti-rust coating.
For driving 3" (#8) screws, first drill 1/8" pilot holes and 11/64" body holes.
For driving medium or short (#6) screws, first drill 3/32" pilot holes and 9/64" body holes.
A body hole lets a screw slide through the top piece of wood without cutting threads; a pilot hole lets the screw cut threads in the bottom piece. Working with plywood, it can be nearly impossible for a screw to draw two pieces tight, if threads cut in both pieces are keeping them apart.
Watch out for my favorite error: drilling a body hole through both top and bottom pieces of wood, rather than just the top piece. The bottom piece gets only a pilot hole.
When your top piece is plywood, you will need to use a countersink to give the screw heads space to sink down flush with the plywood's surface. If the screws in the tray's floor and especially the feet aren't countersunk, you risk scratching your car or whatever else the tray rests on.
Use construction-style wood screws -- phillips flathead, for easy driving with a cordless drill. Get screws rated for exterior use; they have an anti-rust coating.
For driving 3" (#8) screws, first drill 1/8" pilot holes and 11/64" body holes.
For driving medium or short (#6) screws, first drill 3/32" pilot holes and 9/64" body holes.
A body hole lets a screw slide through the top piece of wood without cutting threads; a pilot hole lets the screw cut threads in the bottom piece. Working with plywood, it can be nearly impossible for a screw to draw two pieces tight, if threads cut in both pieces are keeping them apart.
Watch out for my favorite error: drilling a body hole through both top and bottom pieces of wood, rather than just the top piece. The bottom piece gets only a pilot hole.
When your top piece is plywood, you will need to use a countersink to give the screw heads space to sink down flush with the plywood's surface. If the screws in the tray's floor and especially the feet aren't countersunk, you risk scratching your car or whatever else the tray rests on.
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mine too. What I try do do now is clamp the pieces I want to join, drill the pilot hole through both, separate them and then drill the body hole on just the one.