Monday, October 09, 2023

Repairing an Old Toika Loom Bobbin Winder

A friend messaged me that her new (to her) Toika Loom Bobbin Winder was seized up and wanted to know if I could fix it. I told her I probably could.

She managed to pack it so the spindle came out the side.

Nice design, some sort of pot metal case.

Toika Toijala Finland

The only thing holding it together was this snap ring  (aka Jesus clip, C-Clip, Circlip, etc.)

Out came some snap ring pliers.

I tapped it a few times with a soft hammer to see if the shaft would come out but it didn't. The roll pin up top slipped up though and allowed the spindle and pinion gear to come out, which was a win.

The shaft was completely seized.

So after trying various light hammerings, I resorted to trying the arbor press. I was very gentle - pot metal cases are notorious for fracturing in situations like this but with a little pressure the shaft assembly moved.

Notice full support along the sides of the case.

I had to raise it up with 1-2-3 blocks.

Finally free.

The shaft was pretty galled so I sanded it with some silicon carbide paper. until smooth. I think it had been used without adequate lubrication and the pot metal being dissimilar had bonded to the shaft metal. Makes me think it was aluminum.

That was all it took and it went back together. I very lightly greased the gears and used light oil on the shaft.

 Friend is delighted with it.

Friday, May 12, 2023

Triple Shorting Link for Binding Posts

 What? I have been sorting out my bench power supplies lately and finding that several needed shorting links to connect one of the two outputs to ground. I had one but didn't know what they were called. Long story short I asked on the VETE Facebook group and found that Pomona at least calls them Shorting Links for Binding Posts. Here's the one I do have:

Anyway I CNC milled a few up as Pomona helpfully has a drawing in the datasheet. Made out of brass which isn't as nice as being nickel or gold plated but I had brass and a mill and no money earmarked for something that is easily substituted for with a piece of wire, so...

I whipped these out quickly and created a bit of a deburring nightmare but they work. The nice thing about the design is that they stay on one post and can be slid into engagement on the other.

I have a Tektronix power supply that needed a triple shorting link if I wanted to create + and - supplies at the same time. These single links don't work (I mean they do work but) as there's an offset if you stack two together on the ground terminal. So I designed a triple link, milled it and bent a little tab to make removal easy.

And that was this mornings little project. Look, I blogged again. Also I apparently have three power supplies on my bench now.