Long time readers will be familiar with my Juki LS-321 cylinder arm needle-feed sewing machine, which admittedly hasn't seen a ton of use since I dragged it home.
But I've got a project coming up where I'd like to use it, so there's no better time to knock a few minor items off the checklist.
Now ever since I got the machine I've been aware that the handwheel pulley is not quite running straight.
And it's honestly a complete mystery as to why that might be.
Anyway, I'd previously determined that the pulley itself wasn't significantly bent, but it was in fact the main shaft of the machine that had a wobble to it.
The total runout near the end here was about 300 microns, which doesn't sound like much, but over this short of a distance it's enough to make the handwheel visibly wobble when the machine is spinning.
That wobble translates into an annoying vibration while the machine is running, which isn't ideal. More importantly, it also makes it more difficult to control the machine using the clutch motor, since the tension on the belt will vary as the pulley wobbles, causing the machine to be much more jumpy than it might otherwise be.
So that's what we'll be fixing today.
The procedure is rather simple, we first need to protect the end of the shaft from getting any nicks or scuffs. A piece of 1/2" copper water pipe does this job nicely.
And then we ever so gently coax this hardened chromed rod back into alignment.
Let's just say that it's a good thing they make these machines with a lot of cast iron.
The end result of this precise adjustment was that I got the runout down to about 10-20 microns, which is plenty straight enough for me, and the sewing is much, much smoother now. Another successful fix.
No comments:
Post a Comment