Jig for making lampshade from slides

I made a jig today.

It’s for excellent neighbor Janna, who is a maker. She wants to make a lampshade out of a collection of old 35mm slides, like this:
Attachment 49511

Each slide needs four holes, centered on each side and 3.8mm from the edges. Janna has an HF bench top drill press. She makes jewelry so she’s adept at bending little rings that will be used to join the slides.
The jig is to help her make the holes in the slides.

I milled a 2.000 x 2.000 slide-sized cavity about 0.062” deep in a piece of 3/16” aluminum. While I had it located in the mill where I could use the DRO, I also drilled a #60 hole 0.150” from the back of the cavity and centered on it in the other dimension. Then I strongly clamped the ally to a 3” x 6” piece of 11 gage steel and drilled two holes #43 thru both pieces of metal After separating them, I tapped the holes in the aluminum #4-40 and drilled out the steel holes to #33 which is the clearance drill for #4-40 machine screws. I countersunk the holes on the back side of the steel.

I reassembled them using the machine screws to secure them together tightly. I was going to pin them together with two 0.1250” dowels for best location accuracy, but the #4-40 screws actually seem to do the job. Then I put a #60 drill in the chuck, engaged the hole in the aluminum piece freehand and drilled thru the steel back plate. Here’s what it looks like:
Attachment 49512

The cavity is 1/8” shorter than a slide in the horizontal direction, so it’ll be easy to pick a slide out of it with a fingernail to rotate it. To use this jig, she’ll chuck a #60 or 1mm drill in her DP, engage the hole in the jig, lower the quill until the jig meets the table and clamp the hell out of it so it’s located securely. She doesn’t have a collection of welding clamps so I’ll weld some 1/4-20 threaded studs on the back of the steel plate to engage the slots in her DP table. I visited HF today to photograph the DP table with a ruler sitting on it, so I know the dimensions of the slots and center hole. (Neighbors are on a road trip)

Once that setup is done, I figure she’ll be able to drill all four holes in a slide in less than 10 seconds. She has more than 100 slides to do.

I’m not confident that the ½” keyed chuck in that HF drill press can grab a #60 drill, so I may need to make a shank that’s maybe 1/8” dia with a #60 hole thru it, insert a drill bit and put an autogenous TIG weld on the back end. Or, maybe just Loctite #609 would suffice. Runout on that DP and chuck are Chinese precision so I think it’d probably snap skinny carbide drill bits, but probably will be OK with HSS.

I’m also wondering if this rig could be used as a punch: maybe make a punch the chuck could grab with a short bit of 0.040 TIG tungsten in the other end. I think that might actually work better with cardboard slides than drilling. Plastic slides might be tougher to punch but I suspect that they’d respond better to drilling than cardboard.

I love being retired and having excellent neighbors.