Tag: Repairs

For reasons which are, trust me on this, not relevant here, we now have a third Kenmore 158 sewing machine: a freebie that sat under a roof leak in an unused room some years ago and wasn’t cleaned before being stored. Even though not much water got inside the covers, the bobbin winder shaft froze solid.

Two black screws hold it to the cover and provide a slight adjustment of the tire-to-handwheel distance:

Prior to this adventure, I soaked the shaft in penetrating oil for a week or two, but to no avail.

I didn’t take any before-the-repair photos, but it looked like this afterward, with the new tire installed…

From the top right (looking over the handwheel):

Notice the small rectangular hole just below the larger section of the shaft in the protruding part of the pot metal housing. That’s supposed to be an oil hole, but it’s also a fine water inlet.

From the top left:

The two obvious screws remove the obvious parts, but beware the compression spring:

And the torsion spring:

Some experimentation with a strap wrench rotated the wheel on the (still firmly frozen) shaft, which suggested the joint was a press fit without a setscrew, splines, or adhesive.

Grabbing the shaft lightly in a machinist’s vise, resting it atop the bench vise, and giving it a few shots with a drift punch drove it downward through the housing:

More gentle beating produced this heartrending scene:

Water just isn’t any good at all for unlubricated steel in a pot-metal bushing…

Anyhow, the shaft & housing cleaned up well, although they look a tad grody, and everything went back together in the reverse order.

I added a drop of light oil through the lube port, chucked the shaft in the drill press, spun it for a minute at low speed to wear off a slight binding, and it’s all good again.

The bobbin winder atop the Kenmore 158 sewing machine has a rubber tire that contacts a ribbed ring on the inside surface of the handwheel; the clutch knob disengages the main shaft and you run the motor at top speed. As you’d expect, both age and wear take their toll on the rubber, to the extent that the winder on Mary’s machine stopped turning. I swapped it for the slightly less decrepit winder on the Crash Test Dummy, but that was obviously a stop-gap measure.

I mistakenly thought the metal wheel consisted of two plates that clamped a rubber disk in place, with no possibility of removal:

The fact that the spare parts list didn’t include the rubber disk helped convince me.

Eventually, I stumbled over replacement “tires” on, of course, eBay that suggested how to dismount them:

Yup, that sucker slides right off.

Anyhow, the replacements seem to be standard industrial O-rings, rather than the original tire with a flattened rim:

The new tires measure 28.94 mm OD on the bench (I don’t trust that last digit, either) and 29.56 mm OD installed. The (hardened and cracked) old tires measure 29.94, 30.06, and 30.28 mm OD on the bench; that’s a radius anywhere from 0.2 mm to 0.4 mm larger. The winder’s mounting screws provide a very small adjustment range that helps a bit.

Knowing that I needed an O-ring, I checked the assortment of “standard size” O-rings I bought many, many years ago, which once again failed to offer up anything suitable. To the best of my knowledge, that kit has never had the right size; apparently, every application uses a different standard.

The O-ring definitely puts less rubber on the handwheel than the tire, but seems to drive the bobbin winder well enough to fill a handful of bobbins without any of the previous drama.