Results 1 to 11 of 11

Thread: Tools to cut and drill lexan

  1. #1

    Tools to cut and drill lexan

    Bought a windshield for my utv, and it does not fit exactly right, so I need to grind off a little near the hinges, and maybe drill a new hole and move the hinge up a bit. It is a folding windshield. Can I use my right angle grinder to take a little off the edge, and how about using a high speed steel drill bit to drill a hole. Never worked with lexan, can someone advise me the proper way and tools?

  2. #2
    Join Date
    Jan 2016
    Location
    Longmont, CO
    Posts
    810
    a file or belt sander will work for shaping, a grinder may spin too fast and cause melting. for drilling, a HSS bit is good, but you want to use a slow speed to avoid melting. you are looking for a nice spiral chip as if you were drilling mild steel. also, use a center punch as its easy to slip off your point.

  3. #3
    Join Date
    Jun 2010
    Location
    Upland, CA
    Posts
    1,344
    The normal 118* or 135* metal drills can break sheet plastics unless used very slowly far from an edge.

    Use 60* angle drills made for plastics for regular use.
    https://www.amazon.com/Norseman-Acry.../dp/B003BQOFFQ

    For use on a small project use Brad Point drills and slow speed.
    Last edited by Greg R Bradley; 01-17-2018 at 2:26 PM.

  4. #4
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
    Posts
    12,298
    Quote Originally Posted by Greg R Bradley View Post
    The normal 118* or 135* metal drills can break sheet plastics unless used very slowly far from an edge.
    Is this true for Lexan (polycarbonate)? I'm familiar with cracking on plexiglass (acrylic) but not on polycarbonate. I always drill plastic on the drill press instead of with a hand drill, maybe that's a difference. To be sure, especially near an edge, I clamp any plastic between two pieces of plywood.

    What I don't know is if there are different grades of polycarbonate. You might contact the windshield maker and see what they recommend.

    The Lexan I'm familiar with is quite tough and somewhat flexible. Once contractors installed a protected guard "shack" from Lexan inside a secure facility where I worked. I tried shooting through a piece of scrap with a 9mm handgun cartridge. This made a significant bulge but the bullet didn't penetrate and the piece didn't crack. This was in the '70s so I can't quite remember but I think the piece was over 1/4" thick. (I wish I still had that piece - I have no idea where I put it!)

    JKJ

  5. #5
    Join Date
    Jun 2010
    Location
    Upland, CA
    Posts
    1,344
    Quote Originally Posted by John K Jordan View Post
    Is this true for Lexan (polycarbonate)? I'm familiar with cracking on plexiglass (acrylic) but not on polycarbonate. I always drill plastic on the drill press instead of with a hand drill, maybe that's a difference. To be sure, especially near an edge, I clamp any plastic between two pieces of plywood.

    What I don't know is if there are different grades of polycarbonate. You might contact the windshield maker and see what they recommend.

    The Lexan I'm familiar with is quite tough and somewhat flexible. Once contractors installed a protected guard "shack" from Lexan inside a secure facility where I worked. I tried shooting through a piece of scrap with a 9mm handgun cartridge. This made a significant bulge but the bullet didn't penetrate and the piece didn't crack. This was in the '70s so I can't quite remember but I think the piece was over 1/4" thick. (I wish I still had that piece - I have no idea where I put it!)

    JKJ
    Actually, I was forgetting how different they were. Plexiglass will crack even when you use a center punch lightly near an edge. Lexan will crack but most of my experience with that was mounting holes for lexan motorcycle windshields where you are drilling a 1/2-3/4" hole for the rubber or plastic mountings. So I'm thinking Lexan for small holes would probably be forgiving.

    Pic of the final custom WS on my R1200RT. Finally got it to be dead smooth when it reached absolute top speed on the loooong straight at Willow Springs :
    R1200RTws.jpg

  6. #6
    Join Date
    Feb 2003
    Location
    McKean, PA
    Posts
    15,593
    Blog Entries
    1
    I would not use an angle grinder, you will melt the lexan.

    I've drilled holes up to 1/4" diameter in lexan using ordinary twist drill bits and light pressure. You can cut lexan on a table saw and even up the cut on a jointer.
    Lee Schierer
    USNA '71
    Go Navy!

    My advice, comments and suggestions are free, but it costs money to run the site. If you found something of value here please give a little something back by becoming a contributor! Please Contribute

  7. #7
    Join Date
    Jul 2005
    Location
    Cincinnati Ohio
    Posts
    4,731
    I work with Lexan most everyday at work.
    I just use a Jig saw with a metal/ plastic blade to cut. Sometimes a bench top bandsaw also with a fine tooth blade.
    I use a hand file to fine tune the edge.
    I have and use a set of Harbor Freight twist bits after I use a punch to locate the hole. Never a problem cracking, Let the bit do the work.

    All the above done with the protective film still on.
    Last edited by Dave Lehnert; 01-17-2018 at 5:10 PM.
    "Remember back in the day, when things were made by hand, and people took pride in their work?"
    - Rick Dale

  8. #8
    Join Date
    Dec 2008
    Location
    Northern Michigan
    Posts
    4,973
    I heat the bit up with a torch, always works for me.

  9. #9
    Join Date
    May 2008
    Location
    Peshtigo,WI
    Posts
    1,395
    If you want to make a drill bit safe for drilling into lexan, brass or any other soft material you can "dub" the cutting edges. Practical Machinist has an excellent illustration on how to do it at this link http://www.practicalmachinist.com/vb...l-bits-183967/. I've done it carefully on a grinder or even using a file. It prevents the bit from screwing itself into the material and lifting it off the work surface.
    Confidence: The feeling you experience before you fully understand the situation

  10. #10
    Several things. Polycarbonate (Lexan) is extremely impact resistant but keep holes preferably 2 material thicknesses away from the edges. If the part is large (over 12" in any dimension) drill your holes 1/32" oversized. Lexan has 2-3 times the expansion and contraction of most metals. This will prevent both buckling and tearing. The advice about low speeds and feeds is correct.

    Disclosure: 40+years in non-metallic manufacturing and distribution.
    Dave Anderson

    Chester, NH

  11. #11
    Join Date
    Jun 2013
    Location
    Neither here nor there
    Posts
    3,831
    Blog Entries
    6
    In addition to the above, you can use a torch to very lightly go over the edges and it will smooth them out- but practice first, because you can melt it and it will bubble and- well- obviously you don't want that!!! I helped make a giant "Lite Brite" for a children's museum and we had to heat the cut edges of the pegs to get them to transmit light, otherwise they didn't light up on the tips. I just used a MAP Gas torch and lightly went over the ends. The lexan melts into a smooth edge if you just lightly brush it with the torch.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •