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Board mounted pots

Started by Micpoc, November 19, 2010, 08:22:08 AM

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Micpoc

I've never used board-mounted pots before, and I'm curious how much "play" there is in the posts themselves.  I've avoided them in the past, as my drilling rig and technique has always been a bit dicey, so I want to know if my drilling is even slightly off, am I more or less screwed, or are the shafts posts flexible enough to accommodate a skewed drilled pattern?


jkokura

From my experience, you need to make sure you're very careful in your drilling. Perhaps a 1/16 out is ok, but much more than that... They play in the pots isn't in the post though, it's in the leads. Those leads can be manipulated a small amount.

I recommend drilling and mounting the pots BEFORE soldering them to the board. Then when all the pots are in place, drop the board in on top of them and solder them in. That way, if you have a bad angle or some small orientation problem it can be solve without the struggle and heartache of breaking a solder joint because of your manipulation.

jacob
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crashguitar

I am still pretty new at this, but I did have success with mounted pots on a Zombii build. I was pretty nervous as it was my first attempt at drilling an enclosure as well as using pots mounted to the board.
I did a lot of measuring and made a template out of some card stock I had sitting around. I cut out the holes and it fit pretty good over the pots.
If I remember correctly, I used the same measurements to make a new template without cutting out the holes and taped that to the top of the enclosure. I used a punch to make a small indent where the drill was supposed to go and then took it to the drill press. When I was all done, the pots fit right into the holes without any issues.
All this to say, that if I can do it on my first try at drilling, then it can't be too difficult.

JakeFuzz

I recommend using a center drill. This will drill a very accurate pilot at your punch mark location. Drill just up to the bottom of the larger countersink. Then from there step up your sizes using twist drill bits to the size you need. Using smaller bits to drill your pilot can cause the bit to walk a little, a center drill never walks! Having a good heavy vise helps too.

Micpoc

Quote from: jkokura on November 19, 2010, 10:44:11 AM
From my experience, you need to make sure you're very careful in your drilling. Perhaps a 1/16 out is ok, but much more than that... They play in the pots isn't in the post though, it's in the leads. Those leads can be manipulated a small amount.

"Leads" is what I meant by "posts", like columns (I thought the posts were the "shaft"); I'll try to stick to the correct terminology.  Thanks for clarifying.

I DO have a collection of solid-core wire, including some that is of sufficient gauge for ground tracks in tube amps; I may be better off - considering that my drilling rig isn't going to improve any time soon - using that on regular pots than using the PCB mount pots.