design question

I am not sure if this is the right forum for this question. I am designing a doll house for my daughter. I have a couple questions about tolerances with CNC and plywood wood since I am new to CNC. I would always have to account for shrinkage, extrusion and whatnot with 3d printing, but I am not sure if it is as necessary with milling.

  1. some of the pieces are too big for my machines foot print. To compensate, I designed two pieces with a puzzle piece type joint that will be glued together. I want a tight fit since the glued up pieces should glue up form a single part. Do I need a bit of tolerance between the two joints or can the be designed as exact fits?

  2. This one is not as important however, still looking for advise here as well. Most of the other parts have slot and tab joints. Do I need tolerances here as well or would it be sufficient to have the exact same dimensions I.E. slot is .25 x 1 and tab is .25 x 1. or should I design the tab as .2 x .9? These do not have to be such a tight fit since I do not expect the glued up piece to function as if it was a single piece.

Btw, attached is one of the pieces that I am referencing. the center joints are the ones that I am especially concerned about. these would be milled separately.

Those look like laser cutter plans. Routers can’t cut sharp inside corners.

Tolerance depends on your build and the material. Luckily test cuts are quick and easy. I recommend them on every job.

Yea, thats my current design. its tight because I plan to export it into two seperate DXF files with outside cuts on each. I have updated the design for a .01" clearance between the two joints. I should probably round off some of the sharp edges as well. after that, I will test to see how they perform.

If you use a 1/8" bit then use an 1/8" round on everything and it should cut what you ask. I would start with zero tolerance and see where it is, if you machine is a bit loose it will over cut from vibration.