On Sunday, January 31, 2021 at 8:03:51 PM UTC-5, wrote:
I did my -27 panel in AutoCAD 2D - this was before I taught myself 3D CAD.. I measured all the instruments and modeled the size of the enclosures in addition screw holes, faces, etc. Fortunately I didn't have any depth-related issues, but on other gliders you need to know where stuff behind the panel is so that requires 3D as Matt describes.

I used a laser cutter to make acrylic models of the panel - maybe half a dozen with various tweaks. I mounted the instruments double check clearances and wedged the whole thing into the cockpit to make sure I could see and reach things - twiddle knobs without interference from adjacent knobs, etc.

Then I laser cut several 1/8" and 1/4" acrylic templates - one thin one with just the instrument bolt holes and a center drill hole in the middle of each instrument face - to start the router bit - and then two templates with the the mount holes plus the instrument holes. This also included 1/16" holes at the corners of any instrument holes that had angled openings (USB plugs [tricky!], circuit breakers, etc. - anything with a radius smaller than the 3/16" template router bit ( https://www.amazon.com/Amana-Tool-Mi.../dp/B010C7W38W ). I started with just the screw hole template and hand marked and drilled maybe four holes so I could bolt the screw hole template to the panel blank and drill the rest of the instrument bolt holes without any drift. I used a drill press for this because it's easy to chew up the acrylic if you do it handheld.

Once that was done I bolted the double templates with the holes for the instrument faces on the front and back of the the panel blank to sandwich it flat and give me a guide. I mounted the 3/16 router bit which has an end bearing to follow the template in a router ( https://tinyurl.com/y5l3shz8 ) I got from home depot that could be mounted with the bit pointing up on a router table ( https://tinyurl.com/y5addzct ). I set the bit depth so that the bearing lined up with the thicker template on the inside of the panel blank. This way the panel face-side template can on the router table and you can see the bit following along the template (note that the bolts that hold the face-side template need to be counter-sunk in the acrylic or it won't be flat to slide on the router table.

It takes a bit of care to cut all the instrument holes without messing up.. I practiced a couple of times on flat 1/16" fiberglass sheet. A key thing to watch out for is if the tiny template bearing seizes. If this happens it will start spinning and will melt the acrylic template at which point you are going to ruin the panel. I always started with a fresh bit and took pauses to see if it was starting to bind. You could probably use a bigger bit to have less probability of failure, but some holes have tight radii so choose your bits wisely. I cut the instruments holes with only a thousandth or two of tolerance for the instruments. If you do this you better be sure to measure the instruments exactly. I ended up having to sand a few openings an extra thousandth or so to get the instrument in.

In the end it worked great, though it was a lot of work. If Rex tells you it was a high-quality job that's a compliment. This was before Rex had his laser. If I had to do it again I'd consider just having the folks at Williams do it.

It's not the sort of thing that you can easily get done commercially because of all the fiddling and the thinness of the panel. Getting access to a laser cutter also can be tricky. I ultimately bought my own, but they are pricy so you'd really need to have another reason to own one.

Hope that helps.

Andy Blackburn
9B
On Saturday, January 30, 2021 at 3:50:01 PM UTC-8, wrote:
On 1/30/2021 5:39 PM, Anonymous wrote:
In the past I’ve used ponoko to laser cut an aluminum template from my cad
model. It’s really a SVG file they need for closed path tracing. They’re
reasonably priced since you do all the hard work ahead of time. They just
cut material and ship to you.

Once received just a matter of mounting to your panel and then cutting with
your favorite fine cutter.

Britton
Interesting. If you're going to go the template route, why wouldn't you
use a thicker material (acrylic?) to make using a router easier?
Minor as NOT a machinist...there are conversations of "climbmilling" vs "conviential milling"...