Locating odd sized potentiometer

Any reccomendations on a company who may have an odd sized pot I am looking for. I need a mini pot with the 8mm import sized bushing, but need the bushing to be 16mm long, and a solid shaft vs split shaft. Pcb mount would be a plus, but not 100 necessary as I can just solder in wires from each post to the board if need be. For reference I am working on an ibanez sr400 bass guitar with the active electronics. Someone somehow broke the shaft on it in the past.

[glebert]

Have you tried contacting Ibanez to see if they have replacement parts?

[bwheat]

I have, They just sell the whole pcb board for 120 bucks. They don't offer replacement pots for the board mount stuff.

[nevetslab]

Can you provide a picture of the pot, and the pot value/taper? It might be that one of us have something in our respective bone yards that would retrofit. The trouble with buying a pot that's designed to a specific package for a product is it's an OEM part that is bought in production qty's by that mfgr. NOT a generic form factor that you'd find thru normal sources (Mouser, Digi-Key, Allied, Newark, etc). For all I know, what's on the Blackstar amps in my boneyard would do.

[Enzo]

Agree^^^

They are custom made for the amp maker, not off the shelf. That doesn't mean we won;t find out they are identical to something.

[glebert]

Are they like these?

https://reverb.com/item/6593152-iban...t-board-preamp

[bwheat]

Very similar, my preamp board is slightly different. I will add a picture if I can figure out how too, I always have a trouble with that on this forum. It is a b500k. I think looks very similar to some I have found, but all are either the thicker 3/8 flange for the US stuff, or 19mm long vs this one which is 16. I suppose I could put an extra nut and shim one of those a bit if I had to, but would like to see if there is something more similar in fit as the oem style. This one also had the solid smooth shaft and not the split shaft.

[nevetslab]

BiTechnologies P160 Series Pot example

Using the information you've presented, and digging thru my database, I can put together a part number (that you won't be able to buy without large quantities), but this will show you all of the options that will get you close to what you are looking for:

BiTechnologies P160 Series 16mm Pots.pdf

Using this P160 Series pot, I can call out the features to build the part number as follows:

P160KNPD-0E30B500K, which calls out forward-facing PCB terminals, No detent, 6mm dia x 12mm L smooth shaft, 7mm dia x 18mm L bushing, 500k linear taper.

Granted, not 8mm dia bushing x 16mm long, but this is a start

[nevetslab]

Very similar, my preamp board is slightly different. I will add a picture if I can figure out how too, I always have a trouble with that on this forum. It is a b500k. I think looks very similar to some I have found, but all are either the thicker 3/8 flange for the US stuff, or 19mm long vs this one which is 16. I suppose I could put an extra nut and shim one of those a bit if I had to, but would like to see if there is something more similar in fit as the oem style. This one also had the solid smooth shaft and not the split shaft.

Glad you figured out how to post the photo. How is your machining skills? Do you still have the broken shaft to which the knob was attached? It is a tricky move, but, I have a couple times been able to drill into the pot-side of the broken shaft, as well as the knob-side of the broken shaft, and using a #2-56 blind-hole tap, tapped both sides of the broken shaft, then cut a # 2-56 screw, carefully threaded it into the pot end of the shaft, and thread on the broken shaft. The hardest part is getting the hole centered, since the break looks recessed below the end of the bushing. It's a drill-press operation, Number drill bits (0-60 are typical in a set). and getting the pot body clamped in a machinist vise, though you could make it easier by mounting the pot into a clamp-able bracket and mount the pot in a hole so it gets locked into the bracket. I'd take that approach vs clamping a round item as best you can. If you mess up, the shaft wobbles from one or both being uncentered. I've had it work out both ways. Just a thought

[DrGonz78]

Would any of these be a match?

http://shop.ibanez.com/c/parts-acces...potentiometers

Edit: I guess they are not pcb mount but some stiff wires attached could get the job done.

[bwheat]

I am not sure if any of those have a long enough threaded bushing on them. Some with the solid shaft though. If I knew I could get a matching knob with set screw to center and lock on the split shaft I would go that route, just not trying to have a bunch of mismatched knows if not necessary, they do make some little sleeves to put a set screw knob on a split shaft pot though.

[bwheat]

Glad you figured out how to post the photo. How is your machining skills? Do you still have the broken shaft to which the knob was attached? It is a tricky move, but, I have a couple times been able to drill into the pot-side of the broken shaft, as well as the knob-side of the broken shaft, and using a #2-56 blind-hole tap, tapped both sides of the broken shaft, then cut a # 2-56 screw, carefully threaded it into the pot end of the shaft, and thread on the broken shaft. The hardest part is getting the hole centered, since the break looks recessed below the end of the bushing. It's a drill-press operation, Number drill bits (0-60 are typical in a set). and getting the pot body clamped in a machinist vise, though you could make it easier by mounting the pot into a clamp-able bracket and mount the pot in a hole so it gets locked into the bracket. I'd take that approach vs clamping a round item as best you can. If you mess up, the shaft wobbles from one or both being uncentered. I've had it work out both ways. Just a thought

I have had some ideas similar. I used to have access to metal lathe and I could possibly just cut a new shaft for it, but I am not sure with my current tools I could actually fabricate a new shaft, I can take the case apart and get the pot torn down and the shaft out, I will look into something that connects something to the end. If I had access to the lathe still I could pull the shaft out, tig on a piece on the end, it appears to be aluminum, and cut the welded part down and put it back together.

[bwheat]

I have had some ideas similar. I used to have access to metal lathe and I could possibly just cut a new shaft for it, but I am not sure with my current tools I could actually fabricate a new shaft, I can take the case apart and get the pot torn down and the shaft out, I will look into something that connects something to the end. If I had access to the lathe still I could pull the shaft out, tig on a piece on the end, it appears to be aluminum, and cut the welded part down and put it back together.

Let me revise I guess, on a pot that the rotor can be removed from the shaft my idea might be possible, I disassembled this one and it is pretty much impossible to seperate the shaft from the rotor as it is crimped into the plastic rotor. I will look into possibly tapping it and using a stud to attach a new part to get a knob on. I have a nice drill press, bits, taps and all that, so it is a possibility for sure if I can't locate something that will work. It would be rather easy to get a hole drilled and tapped into the shaft itself.

[bwheat]

https://www.ebay.com/itm/M2-x-4-5mm-...r=531312977072

One if these with the head turned down 1mm would be about perfect for this type of repair.

[g1]

I disassembled this one and it is pretty much impossible to seperate the shaft from the rotor as it is crimped into the plastic rotor.

Are you sure? I've had success more often than not popping these off and snapping them back on again. You may have to file the crimped metal a bit, but usually they still stay put when reassembled.