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Thread: Looking for Ideas - Cutting Lexan Disks

  1. #1
    rwanttaja's Avatar
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    Looking for Ideas - Cutting Lexan Disks

    I'm trying to come up with a way to easily cut out disks of Lexan to a given diameter.

    A fly cutter would be ideal...but I don't want the center hole that a fly cutter normally produces. I want to end up with an unblemished disk of clear plastic. This isn't a standard size, so a hole saw won't work. And since the disks are to fit existing holders, a reasonable amount of precision is needed.

    The only thing that comes to mind is to clamp down the plastic and use the fly cutter without the pilot drill. Any other ideas?

    Ron Wanttaja

  2. #2

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    Sounds like you need to modify a hole cutter, which is an arm that comes off a center drill that has two adjustable cutting blade.

    The modification is to shorten the center drill to where is it below the cutting edge of the blades. Put a thin sheet of plywood or something on top of the piece you want, clamp it with the plexiglass, and go to town.

    https://www.amazon.com/Adjustable-Ho...s_id=256292011

    [edit]

    Sorry, you mentioned "fly cutter" which is probably the same thing I'm thinking of.

    Frank "Why are all your tools ground down?" Giger
    Last edited by Frank Giger; 05-09-2021 at 04:36 PM.
    The opinions and statements of this poster are largely based on facts and portray a possible version of the actual events.

  3. #3

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    Maybe a 3" (or whatever size) disc of 3/4" wood with a pilot hole half inch deep but not all the way through. The disk would fit in a scrap of plywood with a three inch hole.

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    Dana's Avatar
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    Band saw?

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    FlyingRon's Avatar
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    Holesaw without the pilot bit.

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    rwanttaja's Avatar
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    Quote Originally Posted by Frank Giger View Post
    Sounds like you need to modify a hole cutter, which is an arm that comes off a center drill that has two adjustable cutting blade.

    [edit]

    Sorry, you mentioned "fly cutter" which is probably the same thing I'm thinking of.
    Yes, close, but yours at least has two arms. This is what I have:
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    Quote Originally Posted by FlyingRon View Post
    Holesaw without the pilot bit.
    Yes, but hole saws come in specific sizes, and I need something that'll be between the sizes. Their sizes are also the OUTSIDE diameter, and I'd actually be needing a specific inside diameter. Though I'll have to look at my 3" hole saw, the ID might be close.

    Quote Originally Posted by Dana View Post
    Band saw?
    Part of the problem is that I will probably want to produce several of these, and am hoping to reduce the amount of cutting and filing to fit.

    The thread on the P-51 panel got me to thinking about building simulated instruments for a similar replica panel. I used Solidworks to design the instrument bezel, fitting into a standard hole and designed to take a piece of glass/plexiglass/lexan. The problem is, the lip is only about 0.1" wide. Since the simulated instrument has to fit into a standard hole, changing the size to match available tooling isn't really an option.
    Name:  instrument.JPG
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    So I'd love to be able to use a standard setup and crank out a number of these. Once I get the front bezel settled, I'll start working on the back half of the instrument, to include the face and the needle.
    Name:  instrument face2.jpg
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    Ron Wanttaja
    Last edited by rwanttaja; 05-09-2021 at 07:22 PM.

  7. #7
    Jeff Point's Avatar
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    How about a laminate bit in a router? Use other tools to make a template disc out of Al or plywood and duplicate it in plexi using the laminate bit. Carpet tape could attach the plexi blank to the template.
    Jeff Point
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  8. #8
    steve's Avatar
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    I worked at a ski boot factory 41 years ago. We would stamp out shapes that resembled a bowtie from 4x8 sheets of lexan. Our lexan was .125 thick. The cutter was thin tool steel with a knife edge along one long edge. These thin lengths of tool steel were embedded in a slot machined in a thick wood base plate. Think of a giant cookie cutter. We had a big hydraulic press but you might could use an arbor press to make a few if your stock is thin enough.

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    Should work with no pilot in the drill press if you go real slow and clamped tight.

  10. #10
    rwanttaja's Avatar
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    Quote Originally Posted by Jeff Point View Post
    How about a laminate bit in a router? Use other tools to make a template disc out of Al or plywood and duplicate it in plexi using the laminate bit. Carpet tape could attach the plexi blank to the template.
    That's a very good thought. Using the router didn't occur to me, probably because they scare the bejesus out of me. But that would certainly work, and I have several types of laminate bits.

    This is where Solidworks and a 3D printer come in handy. I can draw up and print the pattern for the laminate bit, including any handling aids needed (like a countersunk hole dead center for a bolt).

    Ron Wanttaja

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