October 19, 2009

This is not a drill!

Guitar Potentiometers, Semi-Hollowbody Electronics Electronics, Epiphone Riviera P93, Video 28

Next up in the series on guitar pots, I demonstrate how to enlarge the holes in your semi-hollow body top, to accommodate the larger diameter 3/8” pot shafts. Import guitars appear to use slightly smaller 8mm or 5/16” shaft pots.

In the video, I demonstrate using a Unibit stepped drill bit to cut very clean holes. Note you can also place some painters tape over the surface before drilling, to help produce clean edges.

The step bit helps enlarge a hole, step by step, but it’s also useful to have some fractional calipers on hand to confirm the hole size.

28 Comments

John
November 1, 2009 @ 8:22 pm

Good suggestion! Blue tape is one my favorite tools in the shop.

Reply
obviouszebra
November 14, 2009 @ 7:34 am

You are a god amongst men

Reply
MrBUCKETHEADcover
November 25, 2009 @ 12:33 pm

how did you get the pots into the guitar without a opening in the back?

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John Cooper
December 11, 2009 @ 4:03 pm

Thanks for that. A couple people have suggested that- I will add an
annotation to the video at 0:46 for future viewers.

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John
January 23, 2010 @ 9:31 am

Once you figure out the exact position you want to drill, start the hole
with a small (like 1/8″) brad point drill bit. Keep the drill bit
perpendicular to the guitar body. After that, proceed to enlarge the hole
as I described in the vid, using a few successive sizes of drill bits
(don’t need to be brad point). It’s easier to control when you don’t jump
straight to the final full-size bit. Hope this helps– Good luck!

Reply
DrZhivagoBLUES
February 12, 2010 @ 9:13 pm

hola ..cual pot es mejor el pequeño o el grande…gracias………hi what
pot is better the little or the big one…..thanks

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John
February 15, 2010 @ 8:33 pm

I’m not sure one is particularly better than the other. But my instinct
says to go with the larger pots if you can fit them. Smaller pots are
commonly used in pedals, etc, so they’re not necessarily bad!

Reply
Sywrithin
February 26, 2010 @ 12:47 am

K so. I ahve a coil tap pot. I try to put it in….and a little point is
sticking up to not let me put the pot in. Should I bend this little point?

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John
February 26, 2010 @ 8:39 am

I prefer to cut it off. Or bend it if you don’t have good cutters.

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Sywrithin
February 26, 2010 @ 12:55 pm

@johnplanetz, do you know why it’s there?

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John Cooper
February 26, 2010 @ 1:11 pm

It’s a locating tab that can be used in pre-drilled panel assemblies to
orient the pot so that “0” is in the right place. A little slot is drilled
in the panel for the tab to fit into). It’s not necessary for guitars, so
just get rid of it. Cut it, or bend it (when you bend it down, it may just
break off).

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InFuriatedShadows
February 27, 2010 @ 6:17 pm

@johnplanetz, yah it did

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InFuriatedShadows
February 27, 2010 @ 8:08 pm

@johnplanetz, yo I wired up a coil tap. it has sum pretty big noise. When I touch the input jack the crackle is almost all gone…How do i fix?

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capoieragerais18
April 6, 2010 @ 9:54 am

Hey, I’ve an Epi LP and I’ve been wanting to do split coils…can I change the pot to a coil tap pot without much/any mods to wiring etc? Or is it as simple as just installing the tap pot?

Reply
- TheAquariumFish
  April 24, 2010 @ 5:39 pm
  
  @capoieragerais18 its not very hard, if your pickups are already 4 wire its as simple as moving one wire(bottom lug of switch/pushpull), jumping that wire, and attaching another wire(middle lug)
  
  hope this helps. if you change your pickups(which I highly recommend doing) I recommend gfs pickups. theyre about 30 dollars a piece(as apposed to 70+ for most anything else) and they are great quality and the customer service is really top-notch.
  
  Reply
  - capoieragerais18
    April 25, 2010 @ 3:05 am
    
    @TheAquariumFish yeah im not sure if it is, im too afraid to go messing with it lol as it has a bit of sentimental value too! what if it isnt 4 wire? would it just be easier to buy new 4 wire pick ups and replace them at the same time as installing the pot? as opposed to modifying the pick ups to make them 4 wire
    
    Reply
    - TheAquariumFish
      April 25, 2010 @ 5:25 am
      
      @capoieragerais18
      ive done both ways and it is easier to buy new pickups. if youre really tight on cash though you dont have much of a choice. you are probably better off replacing the pickups because epiphones are known for having crappy pickups. it isnt really that hard to rewire the stuff anyway. there are tons of diagrams out there for whatever you need.
      
      hope it helps
      
      Reply
      - capoieragerais18
        April 25, 2010 @ 5:28 am
        
        @TheAquariumFish yeah i looked up the gfs stuff and theyre inbelievable prices! think i will invest. Yeah it helps, thanks alot
        
        Reply
riotdiscoman
April 10, 2010 @ 12:22 pm

Something that will also help to prevent chip out is to apply some masking tape over the holeprior to drilling. Hope this helps.

Reply
fishfan67
October 7, 2010 @ 7:45 pm

I have to do this to a les paul copy project. the holes are smaller then the pots are. so should i do the exact same way as you did the semi hollow body?

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Hoopskidoodle
November 17, 2010 @ 10:42 pm

I’d use a hand reamer. A drill could easily get away from a novice.

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lafnbuddha
November 22, 2010 @ 8:16 pm

Great videos~! I’m thinking about swapping out my stock stuff with Push/ Push pots and Duncan 59’s for a coil tap setup on my Epi Sheraton. You’re prefectionista style details have pushed me to pay the shop to do it. Ha!

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1pixle
January 17, 2011 @ 12:04 pm

if you want to protect the finish when elarging holes try using painters tape, it does a pretty good job

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zurdoremi
July 29, 2011 @ 12:36 pm

hi John, great videos, thanks!
I have three 1967 Kent 820 guitars that I use because I love their huge single-coil pickups and sound. all 3 have a “boost” slide switch which literally boosts the volume by about 20%. These switches are all worn and I am trying to find out what slide switch I can replace them with. HINT: I think it’s a ON-ON slide switch but it only has two poles or “legs” underneath. Can you help?

**also would like to match the screw holes on the pickguard.

Reply
- John
  July 31, 2011 @ 2:47 pm
  
  @zurdoremi – I found a couple pics, and just looking from the top, that slide mechanism looks fairly unusual (for a guitar). Two lugs indicate SPST (singe pole single throw). You could try searching mouser or digikey for a comparable SPST slide switch- they’ll have datasheets indicating hole spacing, etc. You might have more luck replacing it with a toggle instead of a slide. Good luck!
  
  Reply
  - zurdoremi
    July 31, 2011 @ 4:15 pm
    
    John,
    yes, I have searched for a two-lug slide switch SPST but no luck, ( the screw hole spacing is standard so that is not an issue), the issue has been finding the ON-ON slide switch. If you find 3 of them for me, let me know, I will pay you via Paypal or as you prefer, you have my e-mail in your SUBSCRIBE list.
    thanks again!
    
    Reply
    - John
      July 31, 2011 @ 8:58 pm
      
      @zurdoremi – with only two lugs, it can only be an SPST on/off switch (if I’m understanding correctly). On-on would require three lugs. Have you opened it up to investigate the wire connections?
      
      Reply
      - zurdoremi
        August 1, 2011 @ 7:34 am
        
        the entire wiring harness and pickups, is mounted on a carton just like in your videos, so I connect a guitar cord to the amp to test components the slide switch in question has two lugs only; 1 hot wire and ground comes from the cord Jack, connects to one lug and to case (ground); A second wire connects from the hot at the middle position of the toggle switch to the second lug. A resistor is soldered between both lugs of the slide switch. Value of resistor unknown.
        
        Reply
        
        John
        August 4, 2011 @ 9:17 pm
        
        @zurdoremi – it’s hard to analyze the circuit remotely, but my guess is that this switches in a resistor in parallel with the volume knob to jack. with the switch off, the resistor is disconnected / open-circuit. With the switch on, the resistor is connected, in parallel with the volume pot resistance, thereby lowering the overall resistance and causing a boost in the volume level. You should be able to replace it with any SPST slide switch with matching hole spacing. Hope this helps.
        
        Reply
noahwayne
August 4, 2011 @ 3:12 am

Excellent video.

Reply
jameschoi999
September 13, 2011 @ 7:03 am

1:42. thats what she said

Reply
- jameschoi999
  September 13, 2011 @ 7:03 am
  
  @jameschoi999 or in this case he said*
  
  Reply
mrcarepig
October 25, 2011 @ 1:34 pm

beautiful guitar

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ChronoGXay
January 4, 2012 @ 2:32 am

How many people tried to blow away the wood chips after he finished drilling? I did. XD

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iloveJCmysaviour
January 19, 2012 @ 9:13 pm

is that guitar a epiphany riviera??

Reply
- John
  January 20, 2012 @ 9:24 am
  
  @iloveJCmysaviour – Epiphone Riviera P93
  
  Reply
michaelsuydam
February 4, 2012 @ 7:15 am

Thanks for the video. I’m just about to put a Jimmy Page mod on my Guild X-155 and noticed that the POTs were larger than the originals.

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Symbiotespider5
April 11, 2012 @ 3:35 pm

do yourself a favor, but a tapered reamer. dont drill into your guitar.

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jpjdo1212
April 18, 2012 @ 10:38 am

can use a round file and just file it out im instaling CTS pots on mine and the chinese ones are 5mm the CTS are 9mm-10mm and where i come from we dont have imperial drill bits ( measured in inches)

Reply
- John
  April 19, 2012 @ 12:33 pm
  
  A round file will work but may be very slow, and you may end up with an irregular shaped hole. Or just use a drill bit (or stepped bit) slightly larger than the pot shaft size. It’s ok if the hole is slightly over sized.
  
  Reply
RkicF8
June 20, 2012 @ 5:05 pm

Lol, do a sanity check, thats a good one. Great videos.

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gwmgbwi
July 13, 2012 @ 6:45 pm

“Don’t touch the jack hole!!!”

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Jerrysway
December 30, 2012 @ 8:39 pm

I put tape over the hole to be enlarged and just use the drill but, it keeps the the paint from chipping. Step bits are nice but not everyone has one of those.

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budubum
February 24, 2013 @ 6:16 pm

hi. that step drill, will that work to drill a whole inside an amp chassis as thick as marshall 100watters?

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David Logeman
April 3, 2013 @ 7:09 am

i really really really wish i’d seen this before i rtied it on my own. 🙁

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Groo some
July 21, 2013 @ 9:55 am

Whoever made one of my guitars should be punished – 7mm holes and seemingly nobody makes that type of pot now. Guess I’ll be doing some drilling!

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mstag
October 15, 2013 @ 11:48 am

To make sure the back goes back on correctly – mark the back and top with a line from a Sharpie pen so you will know exactly how to position the parts when you reassemble.

Reply
- mstag
  October 15, 2013 @ 11:50 am
  
  That went to the wrong video – does not apply here
  
  Reply
M Campbell
February 28, 2014 @ 8:44 pm

Couldn’t have found a better teacher just before my first mod.THX

Reply
MixmanD28
December 20, 2014 @ 11:25 pm

Great!!! Thank you – this is fabulously clear and exactly what I needed to
see at this time.

Reply

This is not a drill!

28 Comments

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