how do u cut fresnels and are there any precautions or procedures i need to know?

Thanks

I wold personally use a glass cutter to score it, and then break it along the line. Some people have used razor blades to score the glass if they don't have a glass cutter, and they probably work fine, just don't cut your fingers off.

I used a piece of 12x12mm aluminium angle as a straight-edge and scored many times with a stanley knife. Then, I placed the aluminium angle underneath the score line and gently pressed the fresnel on each side of the angle to snap it. Make sure you use gloves to keep the fresnels clean. compressed air also helps blow out any fresnel 'fragments' that may land on the lens

Edit: Score on the flat side of the fresnel

I wrap them in news paper and send them through the band saw.

do i cut them the same on both sides or doesnt it matter?

It matters... what is currently the center of the fresnel must remain the center after cutting. If you only need to cut one side for clearance you can do so but you must maintain the center alignment in your projector.