Cannot tighten any more screws or the piece will crack. Can someone help me?
sculpfun roller video engraving
Tighten what screws? What issue is screws not tight enough causing?
Not enough video to determine if slippage is the issue. Common answer for this is put weight in the part or put a rubber band around the part and the rollers.
Your video is not available anymore. Here are some tips on using a Sculpfun roller: Rotary roller - Diode Laser Wiki