Step 1: Parts List
1. 3" wide hang track at least 20" long
2. 1" wide upright 40" long
3. 5/8 wide upright, 40" long
4. 3/8-16 turn buckle (see drawing: Threaded Block for details)
5. 3/8-16 shoulder bolt 2 pieces
6. 3/8-16 nut - 3 pieces
7. 3/8-16 Knob
8. 1/4" aluminum sheet, 4"x4"
9. Etc. (see the drawings for the rest of parts)
Step 2: Base Asm
weld the bases together, as shown on the print
Drill holes on the base arms
clamp the arms together and weld them to the base
Step 3: Holder Asm
Drill the holes
Assemble the shaft - I used a 12mm shaft from an old printer. Find something similar, that you think will work.
Make sure the asm is not crooked. clamp all the parts to a flat surface.
weld the holder asm pieces together.
Do not weld the shaft. It'll be bolted to the holder asm frame as shown on the print.
Step 4: Holder
try to find a piece of aluminum I've shown on the print (1.1"x1.1"x2.5") or similar in the cut off section
use a drill press to drill the dia 12.0 hole. Use a 1/4" drill first, than the 12.0 mm one.
Make sure it matches the shaft you've got earlier for the holder asm.
drill and tap the M6 holes.
Step 5: Caliper
Print out the drawing (Caliper) Make sure it's to scale
Cut the outline of the caliper out
Lay it on the aluminum stock, mark it with a sharpie
Mark the hole centers with a center punch (through the paper)
Cut it with a jigsaw. Metal (cutting) blade, low speed
Keep the saw blade cooled with water
Step 6: Arms
drill R5 (dia 10.0) holes, make sure you maintain dimension 1.4
attach the arms together
mark and drill the rest of the holes while the arms are attached
follow the print (Arm) to perform the rest of the cuts
Step 7: Threaded Block
cut turnbuckle in half as shown on the print (Threaded Block)
Round the edges as shown on the print
Drill and tap M4 threads
Step 8: Threaded Rod
Cut a window on the Jig to have access to the rod ends
Cut off the turn buckle threaded rod ends (ring, hook), add chamfers
Clamp the threaded ends into the welding jig as shown on the print
Tack both sides, and weld.
Make sure the threads are covered, so they'll not get weld splatter
Step 9: Final Assembly
Use the recommended fasteners to join the parts together
Make sure you add the washers everywhere as shown, to have the proper gaps
Assemble the parts, test the movements.
Diasemble, paint, Re-assemble, ENJOY!
If you want to have the calipers move in synchrony you can add a simple mechanism as I've done
I used an old hand mixer. It had stripped gears, but those were just fine for this purpose
I drilled the worm gears to the right size (see caliper print) and glued to the caliper(s)
I cut off the motor shaft, and added a cover plate, and knob.