Lexan Information

Hello,

My team recently bought some lexan, and we were wondering how to cut holes into It for the screws. How do other teams do this? Thanks.

A simple hand-drill or a drillpress both work fine. The lexan is really easy to drill through.

Alright. Thanks alot!

A sharp tapered smooth size #29, run at high speed, might make a nice thick divot of displaced polycarbonite material that could be tapped for a #8 screw.
I’ve not done it, but I got the idea from a random youtube video where they did the same thing with a ceramic bit displacing into red-hot metal.

Absolutely!

We use an 11/64" drill bit on a drill press. It is just the right size for a good fit for axles and screws. 5/32" works for a tight fit for screws. The actual size of the screws is about 21/128", but you probably will never need the holes to be that close.

According to the book Robot Builder’s Bonanza, polycarb should be drilled with a bit designed for plastic. If a specialty bit is not available start with a small pilot hole, about 5/64", and work larger. Also recommended it 500 to 1000 RPM. Back the polycarb with wood to stop the plastic from cracking. Then don’t force it, which will melt the plastic, and always wear eye protection.

This is ridiculously intense just for drilling Vex legal polycarb. I think what they probably had in mind was polycarb a LOT thicker than what we are allowed to use.

With Vex-legal polycarb you should be able to use any old drill and in terms of diameter near enough is good enough because the screw can widen the hole if it needs to. If you don’t have a drill, you can whack a starting hole through with a hammer and a pointy object like an allen key or a nail and then use a knife or a file or whatever you have handy - but of course the result won’t be nearly as precise.

yeah, we usually just take it to the drill and put the 11/64 drill bit on and just “drill” a hole

Sorry, I have never used polycarb for vex, well ever for that matter. I just came across the information in a book. I found some more information in the same book for cutting thin polycarb using a scoring technique. To use it, first score where you want to cut 5 to 10 times with a sharp knife, to make a deep scratch. place a cylindrical object, such as a 1/4" dowel rod or PVC underneath the scoring. Since crack most likely happen at the edges, start at the edges and work in, pressing equally on both sides of the scoring. Don’t force it, if it won’t break score it some more.

A hacksaw is pretty efficient at cutting through polycarb. I wouldn’t use a dremel, though - it tends to melt the plastic at high speeds…

The thin polycarbonate used in VRC can also be cut pretty easily with tin snips.

I’ve found specialty blades in the market with that work very well with the dremel to cut polycarbonate without the melting issue.

http://www.acehardware.com/product/index.jsp?productId=1292976&kw=rotary+blade&origkw=rotary+blade&searchId=59937913253

If we need a quick cut, we’ll just use regular scissors and it works fine.

Polycarb will bend and take a set well before it snaps, so scoring and then snapping is probably more consuming than just using a band saw. If you run it through the band saw quick enough, it won’t melt (even if you run it through at a normal speed it doesn’t like to melt).