# Solder pad holes don't fit pins



## schnerf (May 12, 2020)

So the holes through the solder pads for solder pin pots don't fit the pins when coming through the back. The pins can sit inside it if the pot sits on the component side. Are the holes meant to be beveled or were they not drilled through all the way? If that's the case, should I try drilling the holes wider or should I just use wires and tape the board to prevent shorts if it moves (since it won't be fixed to the case)?


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## zgrav (May 12, 2020)

if you have the right size pots and they have pcb pins on the legs, the should fit through the holes on the PCB. if the ends of the legs on the pots are too big to fit in the holes on the PCB you may have ordered the wrong size pots.

 if your pins at the end of the legs on the pot will fit through the holes on the pcb but do not line up with the holes, the pots may have gotten bent a little during shipment.  you can bend them back in place to fit the holes.  some builders will spread the outside legs of a pot a little so the pot will sit snugly in the holes so they can slightly tweak the position of the pcb before the pins are soldered.

the pots should mount on the opposite side from the components, so the base of the pot is next to the side of the PCB where things have been soldered into place.  that is also why you need some type of insulation on the pot.

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## Robert (May 12, 2020)

schnerf said:


> So the holes through the solder pads for solder pin pots don't fit the pins when coming through the back.



Which PCB, and which pots do you have?   Can you possibly post a pic?


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## schnerf (May 12, 2020)

The pot legs line up and I'm 99% sure they are the correct pots (for example, https://www.taydaelectronics.com/p1-b25k-ohm-linear-taper-potentiometer-round-shaft-pc-mount-l.html). The holes on the board (Glory Hole) are smaller than any I've seen for pots (the holes for the switch are normal). As I said, the holes are also wider on the component side than the back side, which is why I was thinking they maybe didn't get drilled through all the way.


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## Robert (May 12, 2020)

Someone else recently contacted me about a different PCB with a similar issue. 

Have you tried heating the pads with your soldering iron to make sure it isn't just the HASL solder surface blocking the holes?


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## schnerf (May 12, 2020)

Here are pics


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## Robert (May 12, 2020)

That does look like the holes didn't get drilled properly...   I could send you another PCB but since you're already 90% done a workaround might be easier.

You could drill the holes out, but if you do you'll want to solder them on both sides of the board just in case the through-hole plating is damaged...  This is _probably _what I would do.

Another option is to "gull wing" them...  
You could bend the pins of each pot (just the narrow pin part of each lug) down to a right angle and clip them off about 1/2 their current length, then surface mount them onto the back of the PCB.   Just make sure the pins don't go past the edge of each pad.


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## schnerf (May 12, 2020)

Yeah, I just tried heating them and no dice. On the back, the holes are too perfect to be extra HASL surface. 

I'll try drilling it. Now I'm debating would a drill or Dremel be better -- so many choices! I thought about surface mounting them, but I also have solder lug pots. If I was going to go to extreme, I'd just use those and wires, then insulate / suspend / pack the board in safely.


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## Robert (May 12, 2020)

Sent you a PM.


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## schnerf (May 12, 2020)

Update -- Haven't tested anything, but the little ball dremel bit was the perfect size.


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## zgrav (May 12, 2020)

looks good.  I suggest that you solder the pins from the pot on each side of the board to ensure through-hole contact.


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## music6000 (May 12, 2020)

Check for Continuity on both sides of each pad, will tell you for sure!


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## BurntFingers (May 12, 2020)

Nice save! I started using a rat tail file to remove material rather than a power drill as it was just too strong and would rip the pad out. Good times.


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## MightySmallElectrons (May 12, 2020)

Nice work Schnerf!


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## ericwood (May 12, 2020)

I had the same issue with the pads for the pots on the percolator build I did last night; solved by lightly twisting a similarly sized drill bit through to give it some space; there was more than enough pad on the soldering side to make a good connection.


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## moonlightpedalbuilds (May 13, 2020)

Personally, i would not drill the holes unless they are completely blocked. I would grind or nip the tips of the potentiometer instead. I would rather break a pot leg than crack the pcb.


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