Having just cracked one of my pro fresnels, despite being incredibly patient...I would like to get them pre cut for 15.4 widescreen. Is brainchild/lumenlab/anyone still doing this????

Thanks,

It shouldn't be that difficult to cut fresnels, provided you're using the correct tools.
Mind if I ask how you're doing it and what tool you're using?

of course not. i did the first bit with a stanley knife (slight crack), the 2nd with the sharp bit of a chisel and i experinted on the spare pieces with a soldering iron:) and a router. i cant find a plex kife in the uk!

while i have you here quasi mojo and i contemplate the money i have spent on fresnels...why is a larger (like the pro) fresnel lens npt sold with a shorter FL? I have a 15.4 lcd and it bugs met that my enclosure is 300 odd mm bigger because of .4 of an inch.

cheers

If I could piggy back, I have a question... Can the fresnels be (easily/well) cut with a table saw or a bandsaw? I was thinking about sandwiching between 2 pieces of plywood to avoid chipping.

If not, I do have a carpet knife ready. But since I already have all these tools...

I have heard that a table saw can split it if done to fast and heat the plastic up and cause damage that way if done to slow.

the price of the tools that I have bought for this pj is double the cost of the pj itself (and the pj is a 1080p expensive mofo)...so a knife - is not going to make me any more broke then I already am...unless if it is forged from the fires of mount doom and encrusted in flawless diamond;)

any fool proof ideas out there?

I have a sure fire method that reduces the risk of cracking the fresnel. It’s simular to the score and snap method but without the snap part. Get your self one of these blades:

Click to view attachment

And modify the point by grinding the cutting edge to be flat. This creates a chisel tip tool that will cut/scoop similar to how a chisel is used on wood or an ice-cream scoop scoops ice-cream. Set your fresnel on something that won’t scratch it with the smooth face up. Cover it with the same material, the paper or clothe material that you get the fresnel in is a good choice. Clamp a metal straight edge on top and your ready to cut. Hold the tool against the straight edge and start dragging it towards you with a firm pressure. You should hear it cutting and get a slither of plastic each time. You’ll need to do this quite few times. If it feels like the tool is jamming or there isn’t any plastic being removed, tilt the tool slightly for one or two passes so that the cut width is widened at the top and the tool can go deeper into the fresnel. You will know when you’re done when the tool starts to vibrate on the grooves on the other side. Un-clamp the fresnel and the off cut will just about fall off.

DJ

sounds easy on paper mate;) - but what is the tool dazzla? Looks like a normail stanley knife that has snapped:) what is the difference between that and a standard kife?

Cutting Fresnels, whats the best way