Drilling Sandwich (question)

[GAtekwriter]

All,

Quick question about drilling the CP - as it stands, my plan is to place a paper template on top of Lexan which sits on top of a 3/4" plywood CP... I'll also be placing my backup CP underneath that piece.  So I have a CP sandwich that looks like

Paper
Lexan
3/4 ply
3/4 ply

A few questions:

1.  I was just going to clamp the entire assembly together and tape the paper down - any reason that won't work?

2.  Drilling through Lexan - slow or fast?  I read different opinions on Internet searches, but I just know someone here has just done a Lexan drilling routine and knows the best results.

3.  Any further suggestions?  I'm getting real excited that this thing is finishing up!  Woo Hoo!

Thanks everybody.

Jim

[fjl]

1. should work and the paper template itself should act as a protector from minors scratches while working on the lexan. Only reason it wont work is if your drill bit is not long enough to cut through the entire sandwich.

2. I would go with slow just for safety reasons and so when you drill all the way through you won't slam the drill down on the lexan. Plus if you go fast you'll burn the Lexan or cause it to melt slightly.

I'm not sure what is the best way to cut through lexan but I did it last instead of sandwiching it and cutting everything at once. I cut my CP first then laid the lexan on top of that, clamped it down, drilled a start hole at each button location, then used my router with a flush trim bit to cut to exact size of the button holes. This way you minimize any errors like slipping with the drill.

3. No further questions. 

[Vash]

I actually just got done drilling my CP and lexan.  A few tips:

1.  Be sure to remove the lexan circle from the drill bit after each hole.  If you don't, they'll start to accumulate in the bottom of the bit and burn together, in which case it's a real pain in the ass to get out, and the length of the bit shortens substantially so you end up burning everything.

2.  My bit wasn't quite long enough to even make it through the lexan and wood with out burning the hell out of the middle of the wood.  To fix that, I just flipped the ensemble over after I was done and drilled from the other side.  It was quicker and easier and burnt the wood a lot less.

3.  Don't drill both CPs at once.  Honestly, if you go that route and you mess up, you've essentially just ruined the point of having a back up CP, and you'll need to buy two new ones.  Not good. 

4.  Don't put too much pressure (hardly any) on the drill when you're going through the lexan.  It might crack, or it might slip and scratch the hell out of the surface.  Either way, it only takes about ten seconds for it to make it through, assuming you have a sharp bit.  Just hold it on top of the glass and you should feel it give way. 

5.  I put the paper under the lexan.  While it might give additional protection, if you wind up slipping and skidding across the paper, the amount of protection it might offer probably wouldn't be enough to stop a skidding, running drill.  Plus, if it's on top, there's a higher chance of it tearing (at least I would assume) than if it were clipped underneath the lexan and sandwiched there.

Like I said though, I'd drill the two CPs separately.  Just use the first CP as a template for your second, or use a second sheet of paper if the first gets torn too badly.  You could even use a fairly long drill bit and drill straight through the middle of the lexan and two pieces of wood (just a small hole) so you'd know where the center of each button was.  That way aligning your hole saw bit would be easier on the last board. 

[leapinlew]

I did the router method. It's from the second page of my showcase cabinet build. Here is a picture tutorial:



So, the next step is to route the excess plexi off. I did this in several stages that involved a little bit of routing, stopping the router, moving the clamps out of my way, and doing more router work. When finished my CP looked like this:


Preparing to drill:






Good luck

[GAtekwriter]

Thanks for the suggestions, all - I'll take pics and post details once I'm done with the drilling.

Jim

[fjl]

leapinlou,

how did you do the trackball hole?

[GAtekwriter]

I'm wondering the same thing - cutting  3" hole in Lexan seems tricky...

Jim

[fatfingers]

A router with a flush trim bit is a good way.  For mine I just used the trackball mounting bracket as the guide to run my bit along.

Good luck.

[scotthh]

leapinlou,

how did you do the trackball hole?

Here's how Lew did it.
Here's a thread about cutting 3" holes.

[leapinlew]

leapinlou,

how did you do the trackball hole?

Here's how Lew did it.
Here's a thread about cutting 3" holes.

Thanks Scott... for those of you lazy ---daisies---:

Cut the trackball hole today. For those wanting to do the same thing - here is how I did it.

First I created a jig using some spare pieces of MDF.

• The bottom piece is the base. It's big enough to stradle a couple horses and support the weight of the next pieces.
• I used 2 peices with a gap beween them wide enough for the trackball hole. I screwed them to the base
• straddling those 2 pieces I put the trackball plate and screwed it into the scrap pieces under it.
• I put another peice of MDF on top - this is going to be your template piece and you should drill a hole in it big enough to fit your flush trim router bit in. Before screwing your template into the pieces of mdf under it - make sure the flush trim bit is aligned properly. You can look down between the middle and see how it's aligned. Remember, the flush trim bit will cut right through the trackball plate too.

Once your positive the flush trim bit won't eat up your trackball plate, put your safety glasses on (you do have safety glasses don't you?!) and slowly route out the hole while watching it closely.

It'll look like this:




Over to the right you'll see my first attempt. My pilot hole was too close to one side and messed up the jig.



Test fit it on your trackball - it should be a good fit. Now you can place your plexi over this hole, clamp it down, drill a pilot hole to put the flush trim router bit in, and cut out a perfect hole with no fear of ruining your trackball plate. This is an oversized piece of plexi. I'll trim it down once I make the CP.

I went this route because it seemed less risky.



Fits perfect!