Saturday, May 19, 2012

HAS Reassembly

The Horizontal Arm Shaft, or HAS as I like to call it, is the next part I put into Ms. Rusty. Ms. Rusty’s driveshaft has 5 pieces. There is a 6th piece, which is a bushing near the needle bar area, but I couldn’t manage to remove that during the disassembly process so it is still in it’s original place.
The 5 parts that were removed are shown in the next photo. The long bar at the bottom is the HAS and the four part at the top, from left to right are the stop motion flanged bushing, the feed cam & feed lifting eccentric, the bevel gear, and finally the needle bar crank.
So in the following photos there are several key marks that should be noted. The stop motion flanged bushing attaches to the end of the HAS that has a hole that goes all the way through the shaft. This becomes clear when you see the set screw, which is quite long.
The set screw of the feed cam & feed lifting eccentric sets in the groove of the HAS. This allows for some adjustment when the vertical arm shafts are put into place. The bevel gear has two set screws and one of these lies against the flat indentation on the shaft.
Next-set-shaft-set-screw_thumb5 Shaft-gear-set-screw_thumb4
Finally, the needle bar crank attaches to the end of the shaft that has a hole that does not go all the way through the shaft. This hole holds the set screw in the needle bar crank.
Now that we’ve gone over the major landmarks of the shaft it’s a simple matter of placing the shaft into the machine, right? Ha, ha, ha, ha, ha! That’s what I thought. Then I discovered that I didn’t adequately protect the rear entry hole from powder coating and the HAS wouldn’t even fit into the hole.
After the use of some strong language and thoughts of having several adult beverages, I remembered that I had a Dremel tool with a sanding attachment. This little gadget helped remove the excess powder coating. It took patience and time so as to remove only the powder coating and not any metal because it is important that the HAS fit well and not have a lot of play. I also made a final pass of the opening with extra-fine sandpaper to make the surface as smooth as possible. Unfortunately my frustration with the excess powder coating made me forget about my camera so there aren’t many pictures of the next few steps. Sorry!
Now, with the surfaces properly prepared (or repaired), I oiled all surfaces with sewing machine oil and THEN the shaft passed easily, yet firmly, through the proper holes in the machine. The easiest way to reassemble the HAS is to pass it through the rear of the machine (the balance wheel side) and as the tip becomes visible in the side arm hole, slide the feed cam & feed lifting eccentric and the bevel gear onto the HAS. It helps to make sure these are also well oiled with sewing machine oil before sliding them on. Don’t tighten the set screws just yet.
When the end of the HAS passes through the front bushing, attach the needle bar crank and tighten the set screw. Then attach the stop motion flanged bushing to the other end of the HAS. This may take the use of a rubber mallet as this bushing fits rather tight. Please take my advice and make sure the set screw hole is aligned with the hole in the HAS before you tap on the bushing – you will save yourself a lot of frustration if you take this precaution. After the bushing is on and the set screw tightened, turn the shaft by hand. Make sure it turns easily with no binding and without much play. If there is, you will either need to adjust the bushing closer to or farther from the end of the shaft.
Lastly, line up the lifting eccentric and the bevel gear and tighten the set screws. You may have to do some fine tuning on these later on, so don’t worry too much about placement at this time for these two items. Here is a quick photo of how things should look:
Next time I’ll cover the reassembly of the Thread Take-up Lever mechanism. That went much smoother than the HAS and is actually pretty easy to do. Hopefully you’ll find it interesting.

1 comment:

  1. Way to go! I just know you'll have it sewing a mean stitch very soon. Great job.