Pinion gear for expression type pedal

[katatoncidean]

Hi all,

First time poster here, but I have built quite a few effects while I was getting my BSEE. So I have someone who wants me to build them a distortion pedal that is built into a wah enclosure. The sweepable control would be the gain (toe down being clean/ no gain that swells into distortion). I have the pedal sounding the way he wants it, but I can't seem to find an A500K pot with the pinion gear. I found this (https://www.tubesandmore.com/products/P-ECB-GEAR), but the people at tubesandmore haven't gotten back to me as to whether or not that will fit on say a 16- or 24-mm knurled alpha pot. I have searched the forum and google, but nothing compelling really came up.

Another thing would be the enclosure it's self. I have read only bad things about the mammoth/ 4site expression enclosure and the lack of documentation for the BYOC enclosure has me weary (mainly just the mounting screw dimensions for my own PCBs). Could you guys suggest any quality expression enclosures so I can give this guy a really solid product?

Any help is greatly appreciated!

Thank you,
Dean 

[anotherjim]

Use an existing wah/expression pedal. Keep it's 100k pot. This controls the LED brightness in a vactrol (LED+LDR). LDR controls the gain.
Ok, you would need a little extra work to match the LED brightness to LDR resistance, but it would save considerable pain for someone in the future when the pot is worn out. Big plus is no scratchy noise as the pot wears.
I think Geofex has some info on this approach?

[digi2t]

Omeg makes 470K long shaft pots in both linear and audio sweeps. Find them on EBay. I use the Dunlop wah pinion, for D shafts, with the circlip. Cut the shaft to length, file one side until the gear fit snugly, and make a light groove with a Dremel for the circlip. You have to thin down the casting in the enclosure a bit, but it works well. (Dual gang pot shown below, but singles available too)



The higher grade solution is a PEC 2W linear pot, with the same gear arrangement. They're military grade pots, long shaft, but tough to find. I get them from ABRA Electronics, which are local to me. You can order from ABRA by net, but it's a $50 minimum buy. Worth it if you have lots of stuff to buy though, they have some great prices on lots of stuff. Their store is like my playground.