March 16, 2026
Description
My bathroom vanity was sagging in the middle so i printed a replacement leg. I wanted to develop my own easily printable thread form that was self locking so i used this opportunity to do that. I designed it by wrapping a helix around a 1in diameter pin (foot) and then swept a thread form that is simply a 30 degree angle (relative to plane perpendicular with the helix) that matched the helix pitch. I found a pitch of 0.375" worked well to give me sufficient adjustment and thread height for this size. My original print was made on-size and nearly fit, so i simply offset the faces of the screw by 0.005" per side and it fit perfectly. I applied a small amount of grease to the thread. The screw is self-locking and feels tight but adjustable. I assumed #10 countersunk screws would be ideal.
As designed the leg is 5-3/8" to 7-¼" long (remaining stable) - this allows it to fit in the intended application easily. I think this thread form could extend more than that though.
The baseplate is probably too large (4.75" x 3") and thick (0.25"). I would change that for other uses. I printed using 5 wall layers - that seems strong enough but it may be worth experimenting with.
Please remix freely but with attribution.
License:
BY