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Main => Main Forum => Topic started by: Benevolance on October 07, 2008, 07:04:30 pm

Title: Forstner bits and sanding lexan
Post by: Benevolance on October 07, 2008, 07:04:30 pm
So, first of all, my 1-1/8" Forstner bit actually cuts a 1-1/4" hole. I looked at the bit, looked at the buttons, and my gut told me it was too big. But I thought, everybody on BYOAC uses the 1-1/8". So I followed the crowd.

I decided I'd test the hole first where I'd be drilling for the joystick. At worst, I've have slight more room for the throw of the joystick. And somewhere between making that decision, setting up the CP to drill, and actual drilling, I forgot my plan. So I drilled the first button hole too large.

Not a big deal. I switch to the 1" forstner bit, which makes a 1-1/8" diameter hole, and drilled the rest of the P1 button holes. Again, is that normal? Or are my bits mislabeled?

Now, my second poor decision was that I had decided to drill the lexan and the MDF together. It seemed like a good idea at the time. Except that with the too large first hole (button 1), the area between the adjacent holes (button 2 and 4) melted and malformed. When I get the buttons on, I think the spots will be mostly covered up. But I've got a bit of slag now between those buttons.

I know Mountain and Javeryh sanded the plexi on their bartop jukebox projects - can I do the same and sand lexan down? Try to salvage the piece? Or should I just save myself some grief and purchase another sheet of lexan?
Title: Re: Forstner bits and sanding lexan
Post by: leapinlew on October 07, 2008, 07:45:38 pm
recut the lexan. It hurts a lot now, but it's better than hurting every time you look at it.
Title: Re: Forstner bits and sanding lexan
Post by: MovingTarget on October 08, 2008, 06:59:12 am
I second the motion for recutting.

Also, I did not have the same problem with my forstner bits.  When I cut my button holes I used a spade bit. 

Also, prior to using the spade bit, I used a regular small bit (I can't remember the size) to drill starter holes where each larger hole would go.  I did this with the lex over the sticker from mamemarquee which was over the mdf.  I did this so I could be sure all the holes would line up.  There was no problem with much melting using the smaller bit first to ensure everything would like up later.

Maybe also of note was that my control panel sticker had small white crosses where I wanted the center of each button and the trackball.

Good luck.
Title: Re: Forstner bits and sanding lexan
Post by: Benevolance on October 08, 2008, 12:22:59 pm
Thanks for the advice, guys. I went and bought another sheet.

I used an awl to mark the center holes. The forstner bit has a spike in the centre of the bit that fits into the hole punched by the awl. It all lined up nicely, aside from the first hole being too large and the ensuing problem with the lexan.

It's disquieting that my Forstner bits might be gimped. At least now I know to take an 1/8" off the size marked. At first I wondered if I had simply grabbed the wrong bit, except upon re-inspection the bits have the hole size emblazoned on the neck. The 1-1/8" bit does indeed make a 1-1/4" hole.  :P