I'm going to make a frame for my stuffs, cutting out like 5mm deep holes on each side of the box where I have it extra thick. Then slide the lcd+ frensels down in them.

The frensels and lcd is 2mm thick. Do I need to make the hole wider then the frensel? Like 3mm or what?
The frensels is getting bigger when the gets in higher temp? So I need the hole little bigger or?

I am confused help me.

I used a simple 1/8 inch router to groove my holes. the fresnals and lcd seem to fit just fine. I agree with you, though, that you should leave some room for expansion of the fresnals. I made the grooves and extra 1/16 inch deeper for expansion purposes. I'll see if I can find the actual numbers when I get home.

The fresnels/LCD will expand when heated, but not by much. The rear fresnel will expand more since it's closer to the lamp. Leave about 1-2mm "play" each direction (left/right, up/down). Keep it snug (but not tight) in the vertical plane (back/forth).

If I leave so much will it still be good focus after you example, moves the projector?

I didnt have 1/8 inch (3.2mm) sawblade in sweden, only 2.5mm. Will that be ok?

I don't know. Cut a groove is a piece of scrap wood and see if you can easily slide the fresnal and lcd in and out of the groove. If not, go with one size larger.

You can use the smaller blade, just make two passes and move the stock (wood) 1mm.