What is the difference between imperial and metric guitar pots?

Electric guitars can come with one of two different sizes of potentiometer. Or commonly referred to as pots. There are no hard and fast rules as to what type of guitar will come with which size pots but usually the following applies:

  • “Import” guitars (Japan, China, Korea etc) = metric pots
  • US made guitars = imperial pots

What is the main difference between imperial and metric guitar pots?

The difference between metric and imperial guitar pots

Long shaft guitar pot

One main difference is the size of the bushing on the pot. The bushing is the threaded section of the pot (see photo) and this section passes through the body or control plate of the guitar. On metric pots, the bushing is narrower compared to imperial pots. This means the holes in the body or control plate need to be enlarged in order to fit imperial pots into a guitar which previously used metric pots.

The other main difference is the size of the spline on the pot. The spline is the top piece of the pot which the knobs are pushed onto. Same deal here; the splined section on a metric pot is narrower (and has less splines) than a imperial pot. This means knobs off a metric pot won’t fit on an imperial pot. Some people try to force the knobs on but this is not a good idea as you can easily damage the pot if you use too much force.

The number of splines on each type of pot is typically:

  • Metric pot = 18 splines
  • Imperial pot = 24 splines

This is good to know for when you are shopping for new knobs as quite often the seller will note if the knobs are for 24 or 18 spline pots. Or they may just say they fit metric or imperial/US sized pots.

How do I know what type of pots my guitar has?

The best method to find out is to remove a pot and measure the width of the bushing. Imperial pots have a ⅜” wide bushing (approx 9.5mm). If you are still unsure then please get in contact and I can help you out.

Do the different sizes affect which pots I can use in my guitar?

If your guitar is currently fitted with metric pots then you can still use imperial pots; you will just need to drill out your body or control plate to fit the larger pots. To do this you will need a ⅜” (or 10mm) sized drill bit and a drill. This is a very simple task and very hard to mess up providing you take your time and don’t rush the job.

The holes only need to be marginally larger to fit the larger pots so this means your guitar will have no trouble accommodating metric sized pots if you were to use them again in the future.

Which size does Guitar Sauce use?

i use quality American made CTS pots (imperial) in my wiring harnesses. This means that if your guitar currently has metric sized pots then you will need to drill out the pot holes in your guitar body, pick guard or control plate.

You will also need to purchase new knobs but we have a range of quality guitar knobs to choose from to help take the hassle out of finding your own.

Still not sure?

If you still have questions or need some help identifying which pots your guitar has, then feel free to shoot me a message and I will be happy to help.

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