Today’s post will cover the removal of the Upright Arm Shaft, or UAS as I am quite fond of acronyms. The UAS has one gear at each end – the shaft lower bevel gear that helps drive the rotary hook gear, and the upper gear that connects with the gear on the horizontal arm shaft in the upper part of the arm.
Before taking off the UAS, there are several other parts that should be removed first, including:
- Rotating hook driving shaft bevel gear back cover
- Arm Side Cover
- Stitch indicator plate
- Balance wheel
Since these parts were removed from Ms. Rusty in previous posts (along with many others), I’m ready to go! Loosen or remove 2 set screws in lower bevel gear. I’m pointing to one of these screws in the photo below.
Next, loosen or remove 2 set screws in Upright Arm Shaft (UAS) upper bevel gear. The easiest way to access these screws is through the hole that the stitch length indicator plate normally covers. I try to show the location of the gear and screws in the next two photos.
Theoretically, the gears should now be loose and the shaft should be able to be pulled out. As always, Ms. Rusty just has to be difficult and the gears do not budge. So I reached for my “go-to” solution to these problems – Break-away to the rescue! I applied liberal amounts to both the upper gear and the lower gear. The nice thing about Break-away is that it has a very pleasant odor, unlike WD-40 and other similar products.
This time I also waited a few hours to let the Break-away penetrate the joints and do it’s magic. As a reward for my patience, the gears came away with just a little coaxing. Here is a photo of the bottom gear right after it was removed.
The top gear was a bit more stubborn, but it came off as well.
There was essentially no rust on these parts, so a quick soak in kerosene removed all the gunk and rust. The next photo shows the UAS and the upper and lower gears after cleaning. The big gear is on the bottom, small (narrower) gear on the top.
Next time – the HAS, or Horizontal Arm Shaft. (I just know you can hardly wait! )