MOAO came up, asked if I would fix her broom. YES YES YES!!
Never mind that it's actually mine ...
The handle just threads into a hole in the head and had broken. I figured I'd fire up the lathe, grind a bit to do Acme threads and be done by breakfast time. No way; the handle's too big to fit through the headstock hole. Some measurement and inspection revealed the threads are 3/4-4. Not sure my lathe will cut threads that coarse anyway.
I decided to try it on the bandsaw. I first cut off the bodged parts and cut 2" at the end down to 3/4" on the table saw. Then I laid out the threads on the dowel in ink, marking both sides of the thread so I wouldln't get confused about the slope of the thread profile. I used wood blocks clamped to the bandsaw table - which only tilts the wrong direction to line up with the threads- to get the right angle to follow the thread direction, and the compound angle to cut the 14.5degree shoulder. Then, it was a simple matter of following the profile I'd laid out, then switching the angle to cut the other side of the thread.
Actually it wasn't all that simple, took quite a bit of backing and filling, but I did manage to get threads that fit the broom head nice and snug even if they don't look good.
For good measure, I added the braces made from a salvaged aluminum yard sign stake.
As should be apparent, this technique (kludge?) hasn't a ghost of a chance of working on metal, but for wood threaded into plastic, it's fine.
Never mind that it's actually mine ...
The handle just threads into a hole in the head and had broken. I figured I'd fire up the lathe, grind a bit to do Acme threads and be done by breakfast time. No way; the handle's too big to fit through the headstock hole. Some measurement and inspection revealed the threads are 3/4-4. Not sure my lathe will cut threads that coarse anyway.
I decided to try it on the bandsaw. I first cut off the bodged parts and cut 2" at the end down to 3/4" on the table saw. Then I laid out the threads on the dowel in ink, marking both sides of the thread so I wouldln't get confused about the slope of the thread profile. I used wood blocks clamped to the bandsaw table - which only tilts the wrong direction to line up with the threads- to get the right angle to follow the thread direction, and the compound angle to cut the 14.5degree shoulder. Then, it was a simple matter of following the profile I'd laid out, then switching the angle to cut the other side of the thread.
Actually it wasn't all that simple, took quite a bit of backing and filling, but I did manage to get threads that fit the broom head nice and snug even if they don't look good.
For good measure, I added the braces made from a salvaged aluminum yard sign stake.
As should be apparent, this technique (kludge?) hasn't a ghost of a chance of working on metal, but for wood threaded into plastic, it's fine.
