okay, I'll bite....what gives?

fatdaddypreacher

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just finishing up a long overdue build and was installing the knobs on the pots. the first one was stubborn, and required a bit of down force, but went on okay. the second one, same thing...except the shaft of the pot pushed out of it's body. is that unusual?. i haven't taken it out yet, so thought i'd check and see how far up the creek i really am before i try to readjust my attitude and engage. thanks.
 

Roxy13

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Some pots have the split shaft wider apart than others. And some have it pushed to close together and the knobs slip on and off too easily. I give them all the eye before I make my wiring harness. You have to be careful but you can push the splits together a little if they seem too wide or use a screwdriver to move them further apart if they seem too close together.
 

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Yeah, that too! Bourns pots can really be bizarre as the bushing is US Spec but they have course splines that take metric knobs.
 

fatdaddypreacher

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i have the wiring kit from stew mac. i think they are cts, and i got the matching spline knobs from them. i'm curious about the pot. can i push it back together, or do i have to take it out and replace it? never seen this before
 

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I don't claim to have the first clue regarding how to proceed. But my first thought was also around metric v US knob splines. Is it possible to post a photo of the pot and the knob bottom?
 

fatdaddypreacher

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i have difficulty posting pics, but i'll see what i can come up with. thx
 

EpiLP1985

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i have the wiring kit from stew mac. i think they are cts, and i got the matching spline knobs from them. i'm curious about the pot. can i push it back together, or do i have to take it out and replace it? never seen this before
If you had to use that much force to get them on, there was a mismatch between the pots and knobs.
 

fatdaddypreacher

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yes, i agree. i didn't get it on, and apparently pushed harder than i realized....forgive me, but i am quite duh man. i may infact have the wrong knobs, and have since removed the pot, and it simply pushed the pot through the threaded shaft housing. i simply straightened the ears on the pot body, replaced the threaded housing and reset the ears. all should be good. i'm fixing to order more knobs. thanks.
 

E.X

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Bourns pots can really be bizarre
Very, yes.
Even between metric knobs, you can't be sure; looser manufacturing tolerances and a coarse splined knob won't fit, even though it's metric.
To be honest i've had more luck fitting US/imperial knobs on them than the other way round.
 

fatdaddypreacher

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I've had that before and I don't think the knobs were right, i ended up drilling the hole slightly bigger
i think that's what i'll try, because the knobs and pots are both fine splines, but the hole in the knob is too small. i'll ease into it. thx
 

failsafe306

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Similar thing happened with me using stewmac cts pots and stewmac knobs, except mine didn’t pop all the way down out the back of the casing, it just moved enough to screw with the operation of the pot. I should not have forced it on in the first place!

What I did was remove the pot, use some needle nose pliers to crimp the tabs back down onto the casing, and reinstall (closing the gap slightly on the pot shaft first). Works like a charm now.
 

cmjohnson

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I hate splined shafts and knobs for exactly these reasons. If I could get all my preferred knob styles in double set screw styles, with internal brass reinforcement ring, I'd use them and pots with smooth brass shafts 100 percent of the time when making a new guitar.

Who HASN'T snapped off one half of the splined shaft trying to spread it out just a little? Or cracked a knob trying to force one on? Or nearly ripped a fingernail off trying to get that stubborn knob pried off?
 

fatdaddypreacher

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Similar thing happened with me using stewmac cts pots and stewmac knobs, except mine didn’t pop all the way down out the back of the casing, it just moved enough to screw with the operation of the pot. I should not have forced it on in the first place!

What I did was remove the pot, use some needle nose pliers to crimp the tabs back down onto the casing, and reinstall (closing the gap slightly on the pot shaft first). Works like a charm now.
it pushed mine completely out, so i unsoldered, removed it and did basically what you did, but had to open the tabs to put it back. it feels good, but won't know how well it actually works til i rewire. thx
 

fatdaddypreacher

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I hate splined shafts and knobs for exactly these reasons. If I could get all my preferred knob styles in double set screw styles, with internal brass reinforcement ring, I'd use them and pots with smooth brass shafts 100 percent of the time when making a new guitar.

Who HASN'T snapped off one half of the splined shaft trying to spread it out just a little? Or cracked a knob trying to force one on? Or nearly ripped a fingernail off trying to get that stubborn knob pried off?
well i'm comforted a bit to hear it's not completely my being such a novice. after 10 years, this is actually only serial number 11. man, i'm a real threat to you guys....i'm coming after ya'll with guns a blazin
 

Roger66

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just finishing up a long overdue build and was installing the knobs on the pots. the first one was stubborn, and required a bit of down force, but went on okay. the second one, same thing...except the shaft of the pot pushed out of it's body. is that unusual?. i haven't taken it out yet, so thought i'd check and see how far up the creek i really am before i try to readjust my attitude and engage. thanks.
I think you mean that the shaft actually went further into the pot, possibly knocking the back of the pot off. If that is the case, you just might be ok. Take the pickguard off and see if you can just push the shaft back up with the pot halfway up to avoid the stops and bend the little tabs back tight that hold the back of the pot on. And dont force it, you caveman! Lol.
Well the first one worked. Yeah, just do the right thing to make the knob fit this time. Maybe slightly ream out the hole in the pot, very slightly so the knob fits, but stays on.
I think you just might be ok. I hope you are. Roger.
 

Roxy13

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Very, yes.
Even between metric knobs, you can't be sure; looser manufacturing tolerances and a coarse splined knob won't fit, even though it's metric.
To be honest i've had more luck fitting US/imperial knobs on them than the other way round.
I've never had any trouble putting metric knobs on Bourns pots.
 

fumblefinger

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I've had the other end issue. Shaft pulls out. Before anyone starts up with the set screws on the Ibanez, I had them all totally loose. Turns out there were some chips in the knob from one of the screw holes that jammed up the shaft.

And it wouldn't be Luthier's Corner if I didn't include a shot of the SR500E post repair.
 

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fatdaddypreacher

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I think you mean that the shaft actually went further into the pot, possibly knocking the back of the pot off. If that is the case, you just might be ok. Take the pickguard off and see if you can just push the shaft back up with the pot halfway up to avoid the stops and bend the little tabs back tight that hold the back of the pot on. And dont force it, you caveman! Lol.
Well the first one worked. Yeah, just do the right thing to make the knob fit this time. Maybe slightly ream out the hole in the pot, very slightly so the knob fits, but stays on.
I think you just might be ok. I hope you are. Roger.
it flexed the plate the threaded collar is on enough that it pulled out of the tabs holding it to the pot body, so i had to remove the pot and put it back on. i think i'm good, but won't work on it til tomorrow. thanks.
 


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