Wednesday, May 18, 2011

MT table Mark II

Okay. So my last swipe at this wasn't technically a table, but give me a break. I got busy and couldn't find spare time for... 18 months. /o\

Any rate, I've been on a kick lately and I'm moving away from doing stuff on my computers and moving more towards the analog method of designing stuff: grabbing a damned pencil and a sheet of paper and just sketching it out. I don't know why, but when I write/draw something I seem to retain it for a much longer time than if I type it up. Part of this has led to a desire to get a good old drafting table. But why buy a solid pre-built one when you can build a shaky, hideous one from scratch and save $20?

So I set about designing a drafting table, and about halfway through it occurred to me that I could also fashion it so that I could remove the plywood table top and slide in a sheet of plexiglass later on to easily convert it to a multitouch table later on.

Since it's been 18 months... here's a link to previous multitouch posts (read from bottom up for chronological order).

And here is a link to the Mark II.

It's not as perfectly aligned as I would like it, but I don't think it's half bad for my first woodworking project EVAR and it's sturdy enough I can lean on it. More thoughts after the jump.

If anyone is interested in plans (although it's not that complicated) or has questions about the construction.. hollah.

First thing, some notes on the construction. Materials:

about 6 or 7 1x4x8' boards
pack of 100 6-1 1/4" wood screws
sheet of 4x2 oak plywood (for table top)
8 1/4" carrier bolts (around 2" long, with washers and hex nuts)

If I had this to do over again, I probably would have gone with 20 carrier bolts and put 2 in each board I used them on to provide little more stability and less insanity when trying to get everything lined up.

Tools I used:

* table saw (absolutely key for the 30 degree cuts.. would hate to try it with a circular saw)
* drill with a 7/16" bit (for pre-drilling for wood screws) and 1/4" bit (for carrier bolts)
* at least 3 clamps... helps if 2 of them have a wide gripping surface
* 90 degree clamp for the legs
* builder square and board square
* philips head screw driver
* ratchet wrench with a 5/8" head for the carrier bolts
* pencil
* and, of course, a humble tape measure

The legs are basically held together with wood screws at 90 degree angles. You'll want 30 degree cuts at the top of them to make sure the table top is flush. Due to inaccuracies in measuring and some slight misalignments when bolting everything together, the legs are about 1/32" off from each other, and the inside leg on the front appears to be cut at a slightly higher angle than 30 degrees (probably a mistake when I ran it through the table saw). The important thing is that the tabletop is pretty darn close to being a perfect 3x2' rectangle.

While the table relies on the lower side and back trim for stability, it was really hard to keep all the angles squared up during assembly. This result in varying measurements for the tabletop that drove me nuts trying to figure out... I finally put 2 shorter boards inside the top of the frame to hold the damned thing close to square while I put the top trim on. Unfortunately, since I only used one screw on each end of those boards, it only helped mildly and there was still some last minute tweaking to be done when putting the upper trim on.

The upper trim sides and front are actually pushed up 1/2" to accomodate the thickness of the plywood, while the back is pushed down to be flush with the back of the legs. This lets gravity cradle the plywood and hold it in place without needing to screw it down. This should also let me use a thicker piece of plexiglass, or possibly 2 pieces with something to catch the projected image wedged in between, yet still leave room to catch the laser beams when I get around to installing them.

As for converting it to a laser table, I think I'm only going to use 2 lasers at the top corners and see how that works out. I'm not sure how I'm going to handle mounting (or aligning) them yet, though... but it seems patent that clay and craft glue isn't going to hack it this time. :)

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