# 1/4” knobs not fitting 1/4” pot shafts



## absolvism (Jul 18, 2020)

Hey all-

I have been using 1/4”/6.35mm smooth shaft PCB Mount Alpha pots in my first 3 builds (from Tayda), and ordering 1/4”/6.35mm knobs w set screws to match from various shops, and most of the knobs do not fit on the shafts..... Of the 6.35mm knobs I’ve tried, only 2 of 5 types actually fit over the 6.35mm shafts. The others can’t get more than halfway on (as seen in pic).

Have any others run into this? Am I doing something wrong? I’m mainly frustrated with the Davies 1510 and MXR 6.35mm not fitting as those would be my main go-to’s. Shouldn’t 6.35mm knobs fit on 6.35mm shafts?


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## K Pedals (Jul 18, 2020)

I have experienced this...
I take a round file and run it around a few times on the inside and then they work fine...


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## moonlightpedalbuilds (Jul 18, 2020)

I have ordered several hundreds of various knobs styles from tayda and never had this problem. My last order was March so... Covid19 might have shrunk them. Send them an email. So they can check with their suppliers.


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## jimmibob (Jul 18, 2020)

Yup had the same problem. There's small burrs right where the set screw hole was drilled. I run a slightly smaller drill bit (15/64) with the drill in reverse to knock them off.


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## absolvism (Jul 20, 2020)

jimmibob said:


> Yup had the same problem. There's small burrs right where the set screw hole was drilled. I run a slightly smaller drill bit (15/64) with the drill in reverse to knock them off.



This actually worked to fix at least the one style of MXR knobs with a metal inner ring that I have. Thanks for the suggestion.


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## twebb6778 (Jul 20, 2020)

I noticed this with my last round of Tayda knobs/pots and just squashed those suckers on ?


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## Chuck D. Bones (Jul 20, 2020)

Most of the knobs I receive have burrs in the hole, either from the casting or machining processes.  I have a 1/4" drill bit clamped in a pin vise sitting in the top of my tool box and every setscrew knob gets reamed.  After first retracting the setscrew


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## justin23000 (Jul 20, 2020)

This has caused so much frustration for me! I need to just start reaming them out before trying to fit them. I always end up trying to squash them on and getting mad. A few times I got them on and then actually busted the pot trying to get the knob off again, twice botched the enclosure finish because of getting rough with it. So yes, it happens. 

The 1/4” bit is such an easy solution! Thanks again Mr. Bones!


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## Barry (Jul 20, 2020)

I keep trying to find the perfect spacer to keep them from sliding to far onto the shaft, and keep them all uniform!


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## Chuck D. Bones (Jul 20, 2020)

I'm thinking that the guys who manufacture in quantities have jigs that set the height and provide an index for the pointer.  Just a piece of plastic or wood the right thickness, with U-shaped notches to fit around the nuts.


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## music6000 (Jul 21, 2020)

Chuck D. Bones said:


> Most of the knobs I receive have burrs in the hole, either from the casting or machining processes.  I have a 1/4" drill bit clamped in a pin vise sitting in the top of my tool box and every setscrew knob gets reamed.  After first retracting the setscrew
> 
> View attachment 5547


I use a 1/4 '' Drill bit also but I ground the Tip Flat with a slight bevel to Knock of any Plastic or Glue that stops the Knob from sitting lower.
The small MXR style & with No Skirt are a good example!


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## Nostradoomus (Jul 21, 2020)

I rip off a tiny piece of paper towel and shove it in there with a computer screwdriver...keeps it sitting up off the enclosure if it’s too long.


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## Barry (Oct 16, 2022)

Nostradoomus said:


> I rip off a tiny piece of paper towel and shove it in there with a computer screwdriver...keeps it sitting up off the enclosure if it’s too long.


I've started saving thin cardboard that I can hole punch and drop in there


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