So i got these knobs

[realizewhoitis]

I ordered some knobs from futurlec and they dont fit (http://www.futurlec.com/SwKnob.shtml part number KNOB3).  What have I done wrong?  I am just using standard 16mm Pots from PPP.

[liddokun]

Not sure which model you got specifically, but the first one lists "for knurled shafts", which probably means they don't have a set screw.

You're using 16mm solid shaft pots from PPP, correct? You want the knobs with set screw.

[realizewhoitis]

Not sure which model you got specifically, but the first one lists "for knurled shafts", which probably means they don't have a set screw.

You're using 16mm solid shaft pots from PPP, correct? You want the knobs with set screw.

these have set screws but the head of the shaft wont even fit in

[MarcoMike]

I noticed some pots have slightly larger shafts... that could be your case too

[Kearns892]

Yeah, mine have the same problem. No idea what's up there.

[sean k]

If you have a drill press and a reasonably good vice for it then drill out the knob, it's usually 10ths of mm's so the drill will follow the hole as long as it's snug and not tightly held, to what it needs to be. I use lots of old radio knogs and often have to do this... haven't ever been causght out the other way where the shaft is too small for the knob but even then I'd get some shim.

[trjones1]

The set screw knobs from Futurlec won't fit on standard smooth-shaft pots.  Not everything from Futurlec is at it seems!  There have been many threads about Futurlec's, shall we say, eccentricities.  If you search through them there are good tips for what to avoid. 

I personally like futurlec, but there is a learning curve to figuring out what they are good for and what they're not.  Of course, I would say the same thing about all the places I do mail order from.

[Derringer]

If you have a drill press and a reasonably good vice for it then drill out the knob, it's usually 10ths of mm's so the drill will follow the hole as long as it's snug and not tightly held, to what it needs to be. I use lots of old radio knogs and often have to do this... haven't ever been causght out the other way where the shaft is too small for the knob but even then I'd get some shim.

+1

I found an old stereo left out in the trash one day, harvested the knobs (no set screws) and drilled them out so that they'd fit snuggly on some pots. They've held tight ever since.

[frequencycentral]

16mm solid shaft pots are available with either 6mm or 6.3mm shafts. So are knobs. I got caught out on that one once and had to drill out the knobs to 6.3mm.

[MikeH]

Sometimes there are burrs leftover from where the set screw is threaded through.  If you take the biggest drill bit you have that will fit into the hole on the knob (preferably one the just barely fits with a little wiggle room) and roll it around on the bit while using a hand drill you can clean up the inside of the knob enough so that it will fit on the pot shaft.  Make sure the screw is backed out so that you don't tear it up, and make sure not to take you fingers off either.

[John Lyons]

16mm solid shaft pots are available with either 6mm or 6.3mm shafts. So are knobs. I got caught out on that one once and had to drill out the knobs to 6.3mm.

Yep, got a bunch of them...A pain but doable.

[realizewhoitis]

well i guess thats what im going ot have to do..seems like this is something that should be labeled

[kurtlives]

Drill the knob out with a 1/4" drill bit and your good to go. I use my drill press and a litle table top vice.

[John Lyons]

Except that they need to be larger that the 1/4" bit.
Just wiggle the bit around in the hole and you should be able to reach 6.3.

[moose23]

16mm solid shaft pots are available with either 6mm or 6.3mm shafts. So are knobs. I got caught out on that one once and had to drill out the knobs to 6.3mm.

Same problem here, and same solution as below except I used a 6mm bit.

Except that they need to be larger that the 1/4" bit.
Just wiggle the bit around in the hole and you should be able to reach 6.3.

[kurtlives]

Except that they need to be larger that the 1/4" bit.
Just wiggle the bit around in the hole and you should be able to reach 6.3.

Hmm odd my 1/4" bit works just perfectly. Snug but not an effort to put the knob on.

[soggybag]

I had the same problem. I've had a few of these knobs lying around for a few years. You're inspiring me to drill them out. How do you clamp them without marring the knob?

[Kearns892]

I don't own a drill press. Would it be stupid for me to try this with a hand drill even if its just for a couple?

[nbabmf]

I tried hand drilling some knobs and they broke when the bit caught and twisted the metal insert inside the plastic.  I would probably take a file or Dremel to the pot shafts before I drilled knobs again.

[joegagan]