Potentiometer Bushing Material

[defaced]

So, heat shrink material does work, but requires some finagling to make it fit. This involves shirnking the tubing around the pot shaft (which results in a ~0.254" OD), allowing it to cool, removing it, inserting it into the knob, and then pressing the knob onto the shaft.

I received the bushings from the guitar electronics site linked in the first post. I haven't measured all of them to see what kind of spread they have, but the one I measured was 0.249" OD, 0.005" wall; they looked about 5/16" long, but I didn't measure. These are extruded, not typical 0.014" wall and bored out. The edges aren't deburred which makes it kinda difficult to push them into a 0.250" hole, so some sanding is in order. I haven't got the magnifying glass out, but judging by the burr, they were parted on a lathe.

[Jazz P Bass]

"
The one thing that is truly outdated about the inch / foot / miles system is that it was designed for the convenience of people conversant with fractions. "
Fractions s*ck!

[J M Fahey]

So, heat shrink material does work, but requires some finagling to make it fit. This involves shirnking the tubing around the pot shaft (which results in a ~0.254" OD), allowing it to cool, removing it, inserting it into the knob, and then pressing the knob onto the shaft.

Why?.
Cut the heat shrink slightly longer, so when heated it tightens around the shaft, but also bends inwards at its unsupported end.
That lip makes it easier for it being pushed into the knob.
You still need to put some sheet material in the shaft slot, to avoid its deformation by the knob screw.

[defaced]

Why?. Cut the heat shrink slightly longer, so when heated it tightens around the shaft, but also bends inwards at its unsupported end. That lip makes it easier for it being pushed into the knob. You still need to put some sheet material in the shaft slot, to avoid its deformation by the knob screw.

I appreciate your contribution, but your approach sucks. I'm an engineer too; stop talking down to me. And please, read my posts before you reply (referring to your first reply in the thread where you clearly didn't read my OP).

Now for your question as to "why":

Because that's the process I came up with at 9PM last night. Further, when the heat shrink tubing is shrunk around the shaft, and in the case of the shaft/heat shrink/knob combination I have it creates an interference fit, when the knob is pushed onto the now heat shrink covered shaft, the heat shrink tubing is pushed downward covering the pot muting thread which requires trimming. While your approach of leaving the heat shrink tubing long reduces this problem (I just tried it), it is still a problem. Now, if the knob were say reamed out with a 6.5mm or F size drill bit, or I used a different knob which had a slightly larger ID, this would resolve the interference fit and eliminate all of this talk of different assembly order, but I digress.

As for the shim, depending on relative location of the set screw to the indicator on the knob (if there is one), and the pots rotational position in the panel and any indicating marks on it, if the set screw aligns with the slot in the pot shaft, tightening the set screw will not damage the pot shaft. Now, if everything doesn't work out to those conditions (there's alot of "if's" in there), then yes a shim will be required. Now since shim stock is both readily available in a myriad of sizes and materials, and is inexpensive, I am focusing on finding material for adapting the diameters.

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the one I measured was 0.249" OD, 0.005" wall; they looked about 5/16" long

The bushings are actually 1/4" in length. The OD and wall dimensions are within +/- 0.001" from those I reported.

Also for anyone else looking for this same information, I'll save you the trouble of contacting the Micro Group. While they specialize in small diameter tubing, they are mainly a carrier of stainless tubing, and their price this material size (at the date of this post, SS prices fluctuate violently at times because of Chrome and Nickel prices) is about 17 bucks a foot. This was for quantities under 10 feet, the next price break was 16 bucks a foot. I forgot to call Enzo's source. I'll get to that tomorrow and report back tomorrow.

[J M Fahey]

Dear defaced.
Really don't understand how can you feel

stop talking down to me.

definitely not my intention but just in case I gave you the slightest reason to think so, I offer my apologies in full.
Happy 2012.