Pickup cavity and control cavity templates for routing?

Discussion in 'Luthier's Corner' started by Flux Jetson, Dec 27, 2012.


  1. Flux Jetson

    Flux Jetson

    Joined:
    May 3, 2012
    Location:
    Colorado River Basin, Arizona
    I'm new to routers. I just got a Bosch 1617EVSPK for x-mas. I've been watching some old guys on You Tube use templates to make name signs.

    I have to guess that there are templates for pickup cavities and control cavities, or at least some method of making one's own.

    Or are most luthiers so hard core that they do it freehand? :)

    I'm guessing a very small bit must be used to achieve the tight radus shapes of some pickup cavities, like the parts of the hole that go around the pickup screw bulges on J pickups for instance.

    I'm a total router gnewb, but I am pretty darned steady handed and a better than average TIG welder and solder jockey, hold an 8" group at 500 meters, and a decent photographer. While those aren't woodworking skills they are eye-hand skills. Even so I don't think I'd be willing to attempt a freehand cut of a pickup cavity, especially one that is precisely fitted around the pickup like J-bass pickup cavities are.

    Any help on any of this stuff? I'm super open to learning new things and I've been told I'm pretty teachable.

    Thank you.
  2. Beej

    Beej

    Joined:
    Feb 10, 2007
    Location:
    Canadia
    Templates and jigs are where it's at when it comes to routing. If I'm doing a one off rout, I'll usually just clamp some stringers around where I want to rout and rout away. If it's for something I plan to repeat, or is a complicated shape, I'll make a template. Everybody does them their own way, but I tend to use MDF for templates and I harden the edges where the bearing will ride with CA glue.

    Many pickup manufacturers and suppliers also sell plastic templates, but I would recommend using it only once - to make a proper template out of MDF or plywood.

    Regarding those tiny radii or the "ears" on a jazz pickup, I typically drill those tiny radii out with a proper sized drill bit on the press, and then use a router and template to clear the rest.

    Also, as a general tip, rout smaller amounts per pass rather than larger (ie, rout down 1/16" at a time in each pass), and it's a good idea to first hog out as much material from a cavity with a drill/forstner before routing as it's much less work for the router.

    Others will have other ideas of course... :)
  3. Flux Jetson

    Flux Jetson

    Joined:
    May 3, 2012
    Location:
    Colorado River Basin, Arizona
    This all makes perfect sense to me :) Thank you.

    My Bosch has this rotating stepped bottom stop that the plunge stop hits. So if you're making a deep cavitiy you can take off about .0625 at a time and just rotate that little bottom stop to the next detent for each pass. It's pretty cool (dunno if that's something most routers have).

    And making an MDF copy of "store bought" templates makes sense in the event the ~good~ one gets damaged.

    And drilling out the majority of the material before routing also makes sense.

    As does using a drill bit in a drill press to create the ~ears~ for the J-pickups, then just route a straight line right through the middle of the drilled holes.

    Using four stringers for one-shot pickup cavities makes a lot of sense too. Do you use a template guide in your router-base and place the router's base on top of the stringers and run the template guide around the inside of the stringers, or do you just set up the stringers so that the router base itself rides along the inside of them and place the router's base directly on the guitar's body?

    Yup, it all seems like very sound advise. :)

    Noted. And thank you.
  4. reverendrally

    reverendrally

    Joined:
    Jun 7, 2008
    Location:
    Sydney Australia
    ALWAYS unplug the router before changing bits... ;)
  5. Register to disable this ad
  6. Smilodon

    Smilodon Supporting Member

    Joined:
    Feb 18, 2012
    Location:
    Norway
    Being a good at welding/soldering doesn't mean that you will be good at freehand routing. Welding/soldering equipment doesn't try to force itself in any direction. A router does. With catastrophic results if it gets out of hand.

    You have the right idea when it comes to the depth stop. Just remember to always set the correct depth at the lowest part of that revolver. It's very easy to get the counting wrong and route a step too deep.

    As for pickup routes, I think a jazz pickups have the most difficult routing shape. To get the corners of the square part tight you need to use a 1/4" (or 6mm) bit. You won't find one of those with a top bearing, so a collar have to be used. Since the collar will have a larger diameter than the bit you won't be able to make the corners of the "ears" tight. The only solution to make it perfect is to use two templates. One for the ears, and one for the pickup square. The same goes for P-pickups. You could pre drill the ears, but that will require a high quality drill bit and make sure that the drill doesn't move.

    Templates for square pickups are easy. Just use a collar and make the template a bit bigger to compensate for the size difference between the bit and the collar. ("Collar diameter" -"bit diameter") /2=offset

    Also make sure that the collar is perfectly centered compared to the bit. If it isn't you need to compensate thins on the template placement. (Just remember to not rotate the router)

    Using stringers as guides can be done on both the collar and the base. Both have their uses. You can route deeper when running the base along the stringer, but if the work piece is very small there may not be enough space to clamp the stringer properly.


    Oh, and be careful. Routers love to chew on body parts... :eek:
  7. ACNick

    ACNick Guest

    Joined:
    Oct 23, 2012
    Location:
    South Florida
    One lesson I learned the hard way was: Never start the router with the bit inside the template/cavity. My router kicks a little when it starts spinning, and one time that kick pushed the spinning bit right into the side of my template and control cavity. Luckily it didn't do too much damage; even luckier, it hit the wood and not my hand. Of all the tools I've used in my build, the router is definitely the scariest.
  8. Flux Jetson

    Flux Jetson

    Joined:
    May 3, 2012
    Location:
    Colorado River Basin, Arizona
    Um, yea ... I kinda think I get that. I was just illustrating a point. Part of "welding" includes the use of 4hp 8krpm angle grinders that can remove a kneecap or sever a muscle in a blink. The skillset is pretty transferrable I think. Attention to detail and tool positioning are included in the analogy. I was just pointing out that I'm not someone totally new to the use of power equipment and shop/bench safety practices to save responders from trying to figure out where the starting point of replies needed to be.

    Can't 1/4" holes just be drilled in the corners -- just like what could be done for the pickups' ~ears~?


    Drill press? Or perhaps go as far as using my mill? W/workpiece clamps?

    Sorta figured. If the drill bit =.250 and the collar = .350 there is a .100 offset to compensate for. Do I have it right?

    Gotchya, keep the collar's same clock position against the template all the way around the cut. Figure out offset at (let's say) 6:00 and then set up the stringers accordingly -- then keep the 6:00 collar clock position against the template all the way around the pattern (whatever that pattern may be). Yea?

    Understood. Thank you.
  9. Flux Jetson

    Flux Jetson

    Joined:
    May 3, 2012
    Location:
    Colorado River Basin, Arizona
    Yea, I can imagine. I respect the hell out of my angle grinders for the same reasons. Even though I'll be as careful as possible, it may help that the Bosch 1617EVSPK has a soft start, even so I'll take your advice seriously. Thank you for telling me of your experience.

    I used to run a chainsaw in a land clearing crew in heavily forrested areas ... those huge "bow saws" used to scare the crap out of me. I had a SUPER close call once, I fell from a 15 foot tall stack of tree trunks with a large bow saw running at full speed in my hands. I landed on my back holding the running saw out in front of me as I hit the ground. The saw hit me on impact (still wound out at full speed), cut clean through my jeans and even one of my boots, but I only broke two fingers (didn't even get a scratch from the speeding chain!). I was VERY lucky. I came within a couple of millimeters from losing a leg and most of my man-parts. Experiences like that and the one you shared do not ever leave your mind. Horsepower combined with cutting tools are not to be taken for granted.
  10. Rickett Customs

    Rickett Customs

    Joined:
    Jul 30, 2007
    Location:
    Southern Maryland
    Disclosures:
    Luthier: Rickett Customs...........www.rickettcustomguitars.com
    +1, This is rule #1 for router use

  11. Smilodon

    Smilodon Supporting Member

    Joined:
    Feb 18, 2012
    Location:
    Norway
    I'm sorry. I wasn't trying to be condescending. :)

    My point was that cutting tools want to go in one direction, which isn't always the way you want it to go. But I see that you have more tool experience that I initially thought.

    It could, but you still need to do a bit of cleanup afterwards. A larger diameter bit won't remove material all the way up to where the drilled hole is. (If it could, the larger bit could also make the corner.)

    If you have access to a mill then you won't have any problem doing that at all. In fact, I wouldn't bother doing the pickup routes if I had access to a large enough mill. Simply marking up the exact position directly on the body and just milling out the shape will probably be more exact and less work. (Unless you are making several copies of the same body)

    No. You have to divide that by 2. .100 is the difference in diameter. The offset on each edge of the template will be .050

    No. Compensate on all four sides and keep the router facing the same way relative to yourself. Two reasons for this:

    1: Handling. You want to hold the router with both hands without hanging over it. You then need to either be able to walk all the way around the work table (may not be a problem for you) or you need to re position the work piece 4 times. (More work)

    2: Accuracy: a misaligned collar will only alter the position of the cut relative to the template. This is easy to compensate by adjusting the placement of the template. If you keep the router facing the same way relative to the edge of the template you will alter the scale of the cut. You could also have problems with cutting more wood than intended in corners if the left/right offset is less than the offset towards the template.



    And now onto a point I forgot in my last post:

    Cutting direction.

    This point is very important, but often overlooked. You want to always cut towards the rotational direction of the router. Don't move the router the way it wants to go. Doing this will make the bit grab and you have a router out of control. Believe me, it's scary. :eek:

    There are some cases where this doesn't apply, though.
    Read a bit about it here: http://www.newwoodworker.com/clmbcuttng.html (Just keep in mind that a hand router will move the opposite direction compared to a router table. Same rotational direction, but the bit it upside down)
  12. Beej

    Beej

    Joined:
    Feb 10, 2007
    Location:
    Canadia
    This may apply to using a plunge router, but in my experience, using a fixed router, starting it in the air and then lowering it into the cavity is MUCH more dangerous. When using a fixed router in a cavity, I hog it out first and then start the router when it's in place, but not in contact with the wood. Make sure you always clamp your workpiece to the bench first...
  13. Beej

    Beej

    Joined:
    Feb 10, 2007
    Location:
    Canadia
    Again this is my experience, but I don't look at climb cutting as the panic-inducing danger action that is alluded to in the link there. Definitely more dangerous when you are using a router table with a free workpiece to climb cut, but if you're work is clamped and you have a firm grip on your router and are familiar with the torque it produces, then it's not necessarily as ill-advised as that link would have one believe. YMMV...
  14. Doner Designs

    Doner Designs Steve Doner Gold Supporting Member

    Joined:
    Jun 2, 2012
    Location:
    Metro Chicago Area
    Disclosures:
    Doner Designs is an alias for Steve Doner
    I am not very experienced with this, but sure would echo the scary comments.

    Two little tricks that worked out well for me:

    - For pickups with "ears" like MM and J, I have sometimes cut the ears with a drill.

    - For the straightaways, I use a dremel cutting wheel to start the outline. If the body is already finished this avoids potential chipping of the finish.

    I have never used templates. I just put down masking tape and draw the outline of the PU using the pickup itself and then move real slow.

    Generally I use a hand drill with a step bit to make a good sized starter hole in the middle.
  15. Flux Jetson

    Flux Jetson

    Joined:
    May 3, 2012
    Location:
    Colorado River Basin, Arizona
    THis is a great idea!

    So far from what I can tell using a router isn't too much different than using a mill, in the aspects of cutting direction, and a few other considerations. And it isn't much different than using a high horsepower angle grinder on steel in other aspects. After that is comes down to some pretty basic power equipment useage rules (clamp the workpiece down, don't get above the powertool, be aware of the cutting tool and it's whereabouts at all times, disconnect main power before changing bits, and so on).

    I have many years (four decades) of experience in hard core metal fabrication involving metal removal as well as metal buildup. I think those years will benefit me greatly in the use of the router. So I feel fortunate to have somewhat of a head start. As always my primary concern is safety .. top of the list.

    But just because I have that experience doesn't give me an instant "expert" rating on the use of the router, and I get that. Fortunately the members here have offered excellent advise that I intend on using. The last thing I want to be is ~that guy~ who thought he knew it all, on his way to the ER with two fingers hanging on by a couple of tendons like loose shoelaces. I learned a number of things here, thanks for the input everyone. :)
  16. Smilodon

    Smilodon Supporting Member

    Joined:
    Feb 18, 2012
    Location:
    Norway
    Isn't the "rules" about cutting direction opposite on a mill, though? When I mil in the same direction as I would with a router the finish isn't as good as going the opposite way. Especially milling at high speeds in some aluminum alloys. (But then again, I don't really know what i'm doing... ;) )

    If that happens, let's hope that the surgeon know what he is doing. :smug:
  17. Flux Jetson

    Flux Jetson

    Joined:
    May 3, 2012
    Location:
    Colorado River Basin, Arizona
    The point is that one must be aware of these things, something that one that is familiar with the mill is accustomed to paying attention too.

    That's all I meant.

    :)
  18. thebassbuilder

    thebassbuilder

    Joined:
    Mar 7, 2012
    Location:
    Spartanburg SC
    Disclosures:
    guitar builder, Meyers Guitars
    You are whimps with a router. I change the bit with it pluged in and at full speed. Makes bit changing a lot faster ;).

    If you need a template for a control cavity go to Stew Mac. They have them along with pick up templates. I will tell you some of the templates may be off a little compared to the pick up you are using. They work great with American made pickups but not import ones. Talking about Jazz bass only. Pbass template seems to be a little bigger not too bad.
  19. Flux Jetson

    Flux Jetson

    Joined:
    May 3, 2012
    Location:
    Colorado River Basin, Arizona
    Wow, thanks for this. I'm getting ready to dig in to my first project here very soon.

    http://www.talkbass.com/forum/f8/x-bass-experimental-3-pickup-bass-948548/

    So I'll do some practice on some scraps for a little while, then get started! I'll hog out the bulk of the cavity with a flat bit in the drill press first ( I have a large set of those) then finish up with the router. At least that's the plan.

    For this first project I'm just going to make a sortof universal bathtub pickup cavity. This bass is going to have a few different pickups installed in that same spot as trials. I figure this bathtub cavity is a great first project.

    Thanks for the template info!

    :)
  20. thebassbuilder

    thebassbuilder

    Joined:
    Mar 7, 2012
    Location:
    Spartanburg SC
    Disclosures:
    guitar builder, Meyers Guitars
    The bathtub idea is a good one for what you are doing. I have a build going now that I have done the same thing on the neck pickup. It is going to have a pickguard so it will all be covered in the end. I am doing a MM pup in the bridge so I did have to rout that one out as it will be seen. That is the one pup (MM) that varys greatly between American and import as well (Imports are wider than American). Post your work when you get it going or post a link to here if you have already started a thread.
  21. Flux Jetson

    Flux Jetson

    Joined:
    May 3, 2012
    Location:
    Colorado River Basin, Arizona
    I already have posted a link to the project ... it's in the post right above your last one! :) Post #18 ... see it there? .... "X-bass .... "

    :)

    This bathtub is also in the neck location, pickguards cover multitudes of sins!

Share This Page