knob prob

[newey]

Anyone have a quick tip for using set-screw style knobs on split-shaft pots? The few times I've tried this the knob either won't seat well, I get slippage, or I overtighten the set screw and shear off 1/2 of the split shaft.

And if a split shaft shears off, is a repair possible? I've broken 2 in the past week, once from trying to fit a set-screw knob and the other from trying to widen the split a bit after the halves were crunched together. I'm assuming these were cheap pots, with shafts probably made out of "pot metal" .

[cynical1]

newey -

I always liked the metal knobs better then plastic too.

What I used to do is find a scrap piece of molding (oak) and cut a small piece out of the side. Trim your piece down to where it fits inside of the shaft split snuggly like a shim. A Dremel tool is faster, but a file and sand paper work too. This way, when you torque the set screw in it compresses into the oak and doesn't collapse the shaft.

You can fix it the same way, just Crazy Glue the wood shim and the broken piece to what's left of the shaft. Lightly clamp it overnight and it's stronger then what you started with. When you insert the knob put the set screw on the side that didn't break off. (NOTE: Using a pneumatic wrench at this phase is not recommended ;D )

If the knob hole is larger then your shaft, some cloth surgical tape does the trick.

No engineers were harmed in the making of this solution.

Happy Trails

Cynical1

[newey]

Thanks, Cyn, that sounds like just the workable solution I was looking for. I'll give it a try!

But from now on, I've resolved to buy solid-shaft pots.

[darguitar]

Out of interest, have you tried to line up the screw WITH the split in the shaft before tightening it. I normally get perfectly acceptable results by doing this. Even more so with new pots than old ones.

[newey]

Dar-
No, haven't tried that, I sort of assumed the set screw would need to contact the shaft flush- but I'll give it a try- Thanks!