I figured half a page of map printout is 5 1/2 x 4 1/4 inches, so I added 3/8
inch on all four sides and came up with 6 1/4 x 5 for the Lexan blank.

I had about a 16 x 20 sheet so I clamped a bar across the stock at the four
inch mark and set to the usual v grooving with the back point of a sharp craft
knife. No joy. So I deepened the score with three passes with the point of the
knife. The bar was right at the edge of my 1/2 inch thick overhanging bench, so
I leaned on it an it snapped cleanly. Then I did the same for two six inch
piece from the four inch width.

I drilled and reamed four 1/4 inch holes for my 3/16 inch jig saw blade for a
square tab on the back panel, but didn't saw or bend it.

I test drilled a scrap #25 and tapped 10-24 threads. Nice material, plenty of
elongation, but clean yield to failure, good tight threads. You use coarse
threads in plastic because the material is so much weaker than the fastener.

I marked everything out with a carpenter's square and Sharpie fine point, and
used the automatic center punch in 14 places, five down each side, and four
along the bottom, more to the outside than totally evenly spaced, as the
division came out one off. I just marked off 1/2 inch increments and picked
every other mark from the outside.

Then I laminated the parts together with double sided Scotch tape, taking care
now to keep it clean, and faced the bench with paper. I drilled 14 places #25
through both parts, and should have held the edges together with pliers. I
separated them and tapped 14 places.

I jigsawed the tab, bent it out by hand (one inch is about as much as I can
handle with my thumb braced), and using the relieved corners to concentrate the
stress, the tab bent out square and flat. Then I marked it and made a mistake,
not thinking ahead, used the drill as a side mill to move the hole, and taper
reamed for the strange 7mm bolts with 5mm button heads. Who ever heard of that?

I loosened the handlebar cap and added the map holder with its 14 screws in
place, then I tightened the screw on the map holder and carefully tightened the
other screw, as the seats were no longer quite square. I'd checked before to
make sure this would work.

All it needs now is a cork block on the back, since it goes booing, but it can
hold anything from a single page of quarter letter size to a whole travel
booklet with the screws backed out. And you can adjust the screws with a dime!

What fun. Too bad there is no rec.crafts.plasticworking, as there is a
rec.woodworking. Too bad they didn't put rw in the heirarchy as rcw. Oh well.

Very nice material, once fabricated it is indestructible. It doesn't crack when
the drill bit goes through the way acrylic does either, and generates long tap
chips as opposed to acrylic dust.

Next step, take it off and belt sand the sides flush with the screw head line.

All this for the new recumbent, a Lightning Cycle Dynamics Thunderbolt SWB
model with 24-35-51 / 34-28-23-19-16-13-11 even double step gearing. 657%
range, and AC and DC generators coming on line soon. Big ones.

The map holder is for the difficult navigation through Tyson's Corner Center
streets, hills, and traffic, to Paradise on the other side of the Dulles Access
Road, starting at Spring Hill Recreation Center. Paradise is the residential
area called Knox Hill or something, and is multi million dollar homes. The
community rec center is a lake. On the other side of Paradise, with its green
lawns, tall trees, and rolling, winding roads, is Difficult Run Stream Valley
Trail, leading to the little beach on the shores of the Potomac.

Why don't you join me some time? Bring a suit; one you like to take off.

Here's to Sun on Skin, Vitamin D, strong bones, and a good attitude!

Skin cancer be damned. (Until I get some.)

I made it as far as the lake last time and realized I didn't bring enough
calories. Water, I had, but three snack bars just isn't enough. Next time I'm
bringing jerkey, snack bars, and fruit.

I have osteoporosis and green leafy vegetables with yogurt dressing, sun on
skin, and more weight in my backpack as I do my errands each week is part of my
therapy. I also take Caltrate but that's just chalk. Just a little
osteoporosis, around 50% of one standard deviation.

Fighting hard, I remain


Yours,

Doug Goncz ( ftp://users.aol.com/DGoncz/ )

Read about my physics project at NVCC:
http://groups.google.com/groups?q=dgoncz&scoring=d plus
"bicycle", "fluorescent", "inverter", "flywheel", "ultracapacitor", etc.
in the search box