How Big Should Pickup Routes Be?

Discussion in 'Luthier's Corner' started by The Ryantist, Apr 15, 2018.

  1. I'm making router templates in MDF for P&J pickups. The P will be in a pickguard and the J will not.

    An arbitrary number I came up with is to make the template have a .020" gap all around the pickup (P&J pickups). Is that reasonable for a) a raw unfinished wood cavity and b) the pickguard opening? Oh yeah, I'll probably do just a big rectangle under the pickguard to keep things simple where they won't be seen.

    I'm going to try making a template by shimming .020" cardstock (cereal box) all around the pickup and then making a tight fit. The attached picture shows a bunch of rectangles I've cut out and will stick on my main MDF piece around the pickup. The cool thing about this method is the yellow pieces are the only ones that have to be a precise width. Most of the routing will be done with a 1/2" bit, and then I have a 1/4" bit that I'll get into the corners (not the mounting holes). Anyway, I think this same method will work for any thickness of shim so the design is easy to change.

    Any tips welcome.
     

    Attached Files:

  2. Bruce Johnson

    Bruce Johnson Gold Supporting Member Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    I normally design my templates to cut the opening, leaving a 0.030" gap all around the pickup. No real hard reason for that number. It's big enough to allow for some tolerance in the actual size of the pickup cover, but small enough to look neat. Making it 0.020" should be fine, if you have the actual pickup there to work from.

    If you are routing the opening in the wood of an unfinished body, you have to consider what kind of finish it's going to get; how thick the finish is going to build up on the lip of the cavity. For a high-gloss finish, I'll leave 0.060" gap. For a low-build "oil" type finish, 0.030".

    Note that most molded plastic pickup covers have some draft angle on the sides; they are wider at the bottom than at the top, by a small amount. So, the final clearance gap will vary, depending on the installed height of the pickup.

    That's a clever technique for making up a routing template. I like it.
     
    Last edited: Apr 15, 2018
    MattZilla likes this.
  3. That's how I do my routing now, cut precise blocks on the table saw and slide in the non-precise blocks against them. Although I double stick tape it right on the instrument, I don't typically make templates. This has worked really well for pickup covers with a very close fit. After I make the pickup cover I set the fence on the tablesaw 0.060" (ok I don't measure exactly) then cut the blocks for routing.

    In this case I squared off the corners with a chisel, but I've also left them rounded. I hate doing pickup holes with bump outs and no covers because it's so hard to make those bump outs precise, I hadn't considered your idea before, maybe that would make them less painful - with that many pieces, I'd definitely do a template though, not direct on the instrument, there's too many pieces that could move.
    20180319_082713.jpg
     
  4. Paulabass

    Paulabass

    Sep 18, 2017
    Don't you do the 'bump outs' on the drill press first?
     
  5. Yes I've used the drill press in the past, it always seems like I get a little drift and they are not perfect. I prefer to use a router though, with a template it's way more accurate.
     
  6. Paulabass

    Paulabass

    Sep 18, 2017
    Good enough answer. I tried making a decent jazz template, and it wasn't perfect, so I started using the drill press. The last ones I did, I used some templates (not stewmac) I found on the net, and they work well.
     
  7. yeah, templates are nice for those pickups, although the last time I used a StewMac one, my EMG pickups wouldn't fit through the hole - as Bruce mentioned the bottom of the pickup flared out enough to cause problems. I fixed it by filing the flare off the pickup. No big deal, I guess.
     
  8. HaMMerHeD

    HaMMerHeD

    May 20, 2005
    Heh! I design a 0.75mm gap on my pickup templates...which turns out to be 0.0295".

    For cavity covers, I take that down to 0.5mm.
     
  9. Thanks for the input everyone. I made my J template today and I think it turned out great. This is the very beginning of my build (thread coming soon). As someone who is not good at freehanding things, for me good woodworking means good jig-making. :p In theory it would be easier to drill the four mounting tabs with a 0.5" forstner bit and just route the rectangle. But when the gap is this small, if those holes are off by .01", that's half of your gap thickness and it would be noticeable.
    20180415_151605.jpg
    20180415_160916.jpg

    20180415_172315.jpg
     
  10. Ah, got it. I wasn’t picturing what you were going to do. That is a good idea.
     
  11. How did you hold the individual pieces together while you were making the template?
     
    T_Bone_TL likes this.
  12. Woodcraft double sided tape. They were all taped down on the main MDF piece, but they weren't taped to each other. Actually here's one more picture I have of them all taped down just before routing. That tape worked really well for this; it was my first time using it. But you can see in my finished picture above that it lightly roughed up the surface when removing it - hopefully it won't do that on the body wood.

    20180415_161144.jpg

    The pieces labeled "C" and "I" were the only ones that had to have precise widths. For all the others, the gaps don't matter as long as they are smaller than the radius of the router bit. I used a 1/2" bearing router bit for everything at first, which gave me the right size for the mounting bumps. Then I went into the corners next to "F" and "L" with a 1/4" bearing router bit to get the smaller radius on the corners.

    It's a pretty tight fit when the cardboard pieces are in the gaps. So I think I'll use them to center the pickup in the cavity when I'm ready to install, and then use the exiting mounting holes as a guide.
     
    Jisch likes this.
  13. Bruce Johnson

    Bruce Johnson Gold Supporting Member Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Yes, that's a good technique for accurately locating a pickup. Wedge it into the cavity with cardboard shims, centered. Then, pick a drill bit that just slides through the holes in the pickup cover. Use it down through the cover to make a small spot in the wood, like 1/8" deep. Then remove the pickup. Select a drill that's the right diameter for the root diameter of the screws, and put some tape on it as a depth stop. So you don't, you know, drill through the back of the body...Yes, I've done that, but in a long time...

    The larger diameter spotting hole also helps to get the screw started correctly when installing the pickup.
     
  14. Gilmourisgod

    Gilmourisgod

    Jun 23, 2014
    Cape Cod MA
    Is it worth getting into knurled brass inserts for pup screws? I suppose that’s more precise, otherwise it’s just wood screws through the pups and into the body. Springs or foam to pressure the pup upwards?
     
  15. Inserts are definitely "better" than wood screws. I haven't bothered doing that with pickup screws though, there's not much stress on those screws and it's not like they are even moved very often. I guess I just deem it not worth the extra hassle or cost.

    I have used both foam and springs. I find springs to have a longer life (i.e. I've changed pickups and had to replace foam), but I usually just use foam unless the pickup came with springs or I have them on hand.
     
  16. Yes good ideas. I already have these Stew-Mac depth-stop drill bits. Wow I hope I didn't pay that much for them haha! But I've had them for years and they're really useful, not just for guitars.
     
  17. If you can drill and install them very accurately then yes they're nice. But if you put them in crooked they're not very forgiving. I usually only use them for screws that need to be really strong or that will see lots of removal/reinstalling. I'm not even planning on using them in the neck because none of my factory guitars have had them. I think they'd be overkill for pickups. ;)

    In my limited experience foam has been easier to install than springs. I've used a mouse pad on a Warmoth but that was a little bit too stiff. I'll try to find something a little more compliant this time around.
     
    Gilmourisgod likes this.
  18. Gilmourisgod

    Gilmourisgod

    Jun 23, 2014
    Cape Cod MA
    What do you use for foam? Is the foam weatherstripping rigid enough for that?
     
  19. Not sure yet, I'll have to try a few things when I get there. I might use springs if I have some lying around, but they can sometimes be a pain to keep on the screws before installing.
     
  20. I use the foam that comes in the box with EMG pickups. It's got good density.