Union Lock Adjustments

[Cumberland Highpower]

I picked up a Union Lock head today that looks to be in really great shape, nice and tight.  I believe it was not used much since rebuilt from the looks of it.  (None of the factory black paint is worn off of the shuttle/bobbin housing).

Now, it does work of course, I swapped it with another machine head to test it out.   It seems to work well, just needing some wax cleaned out.  But...I am a little perplexed at the noise it makes.

All the UL machines I've seen and the 2 I have here make a light gear gnashing sound when running, but this head makes extremely loud gearing sounds.   Especially near the shuttle.

Everything looks rock solid and tight, maybe too tight...But is excessively noisy.  I almost feel like the gearing is too tight.  Is there an adjustment I don't see that allows the shuttle to move up and down?   Seems like when I run it by hand by the flywheel I feel a little excessive "gnashing" of the gears.

Anyone happen to have a service manual for the UL? I've never needed one but maybe I do today

[Wizcrafts]

Before you start turning 4 sided screws, does your ULS have the new gear driven servo motor setup? If so, that may be the sound you are hearing. Those motors are geared high and tight.

You can start troubleshooting the binding by raising the shuttle drive compartment a little. This will increase the slack in the shuttle drive gears, but if that was the cause of the noise and grinding, it is a cheap fix. Inspect all paired gears to see if there is foreign material in the teeth. Move some of the gears laterally if they are too tight.

I always ran my ULSes a bit loose. They were noisy, but never bound up or gnashed the gears. There was something special about the clashing and clanging of metal on metal when I floored the beasts at 800 spm (15/second)!

[Cumberland Highpower]

Hello Wiz, It's only a new head I picked up.   I placed in on one of the standard motor tables to test out.  Same old twin belts/standard motor w/pulleys under the table. (I haven't gotten as far as the new servo motors yet)  The gearing sound is in the machine head no doubt, sounds near the shuttle.     I thought there might be an adjustment to raise the shuttle but I haven't seen it just yet.  I'll take a closer look.  

I've owned UL's since 2009, having bought my first during the recession.  Back then allot of shops were dumping machinery pretty cheap.  I've run it a fair amount and to date only adjusted 2 points for wear and changed the stitch length.   I've never had any issues, although I hear many complain about the UL's......I get the feeling that it's the heavily worn machines that are the problem machines?

Edited October 13, 2021 by Cumberland Highpower

[Wizcrafts]

The entire shuttle housing can be raised, but I don't remember the details. I do recall that if you back off the tapered pins that the clearance increases between the driving gear and the shuttle gear.