Tool for holding pin hole bridges while sanding.
Bridges require prepping before a re-glue which usually involves scraping old glue and clean-up sanding. For years I've used a small scrap of wood with dowel rod pins set at a couple of different spacings to hold a bridge while I sanded the bottom but it was not easy to use. I made the bridge gripper so it was easy to hold and so it could adjust to different bridge pin hole spacings. The feet swivel to adjust to angle of the bridge wings.
A few notes on building.
- I found it useful to chase the 6-32 threads in the slider block with a tap since they are printed slightly undersized. Also, don't print the slider block with fuzzy skin. Fuzzy skin can make parts slightly oversize.
- I put a drop of CA under the head of the 6-32 screw before screwing it into the knob so it doesn't unscrew itself.
- The 6-32 nut keeps the adjusting screwing from moving out of the bridge gripper body. Turn the 6-32 nut so it is lightly bottomed, and add a bit of white glue to hold the nut in that position. The nut is meant to turn with the adjusting screw. It's tempting to use CA to glue the nut to the screw, but there is a good chance you will glue the nut in place which you don't want.
- If the 4-40 and 6-32 screws are not readily available, the 4-40 screws can be substituted with 3mm, and the 6-32 screw can be substituted with 4mm (with a small amount of coercion).
- The pin posts should be printed with 100% infill and a harder plastic like ABS. If that is not available, equivalent lengths of 3/16" wood dowel would work.
- You will need the following hardware or equivalent:
4) 4-40 x 3/8" screws for the swivel feet
2) 4-40 x 1/2" screws for the handle
1) 6-32 x 2" screw for the moving the slider block
1) 6-32 nut to secure the adjusting screw
