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Routing Bit?

Discussion in 'Luthier's Corner' started by kirbywrx, May 25, 2004.


  1. kirbywrx

    kirbywrx formerly James Hetfield

    Jul 27, 2000
    Melbourne, Australia.
    Hey all
    Im currently making my first bass. Im up to cutting out my body from my chunk of wood. anyway my wood is 45mm thick, and i cannot find a routing bit long enough to cut it all in one go. Do any of you guys know where i can get a bit big enough?
     
  2. Suburban

    Suburban

    Jan 15, 2001
    lower mid Sweden
    Cut it in two passes!
    First time, the pattern bit will follow the pattern, second pass, it will follow the edge you just made!
    Simple!


    Eehh...you did get a pattern bit, didn't you?
     
  3. kirbywrx

    kirbywrx formerly James Hetfield

    Jul 27, 2000
    Melbourne, Australia.
    A template? Yes, i have a template :D
     
  4. No, a PATTERN BIT!

    Usually a ½" dia 2 flute straight bit with a bearing guide mounted on top. Designed to follow hard templates for accurate cutting.
     
  5. DougP

    DougP

    Sep 4, 2001
    you might be asking alot of your router here. you should use a bandsaw to cut that amount of wood if you have one available.
     
  6. Right, rough the body out on a bandsaw, within a 1/4" of your template outline. That way you are only cutting one side of the material...eases up heat / wear, and helps not tax out your router. Also, when coming to a transition (like the end of a horn) stop your router just before the apex (tip area), and bring the router to the other side of the horn, and rout to where you left off on the other side, "backwards" if you will, so you climb cut the grain...it reduces tear out at the end grain.
     
  7. kirbywrx

    kirbywrx formerly James Hetfield

    Jul 27, 2000
    Melbourne, Australia.
    What what? im confused!! I have a template of the body design that i want. i though i could get a router bit with a bearing on the top, and cut it out so that the bearing sits up against the template and walla.

    i DO have acess to a bandsaw, but wont it be a much cleaner cut with the router?

    Hammy, what was that? im really lost! I dont know what on earth a '½" dia 2 flute straight bit ' is :confused:
     
  8. using a bandsaw to cut out the approximate shape within 1/4 to 1/8 (the closer the better) of the template will make it easier to use the router bit to do the final trimming.
     
  9. DougP

    DougP

    Sep 4, 2001
    yes the router will give you a better cut, but you dont want to use it to cut the shape from the block of wood. you want to rough it out with a bandsaw first. unless you have a 20 HP (LOL) router, you wont be able to cut that much wood in one pass anyways without burning it. basically what you want is something like a laminate trimming bit. they are designed to closely follow a template. but that thickness does pose a problem. i dont know what the luthiers use. do you have a spindle sander available?
     
  10. Bass Kahuna

    Bass Kahuna

    Dec 3, 2002
    West Lafayette, Indiana
    Luthier, Custom Builder
    For wood that thick, if the router bit is not long enough to reach all the way from the top to the bottom, you can work around this with two different router bits.

    First, use a pattern cutting bit with the bearing guide on the top of the bit, and using the template route all the way around and just past halfway down it you can. This type of router bit looks like this:

    [​IMG]

    Then, using a laminate trimming router bit which has the bearing guide on the bottom, flip the piece of wood over, and finish it off from the other side. With the bearing guide being placed at the bottom of the bit, it will follow the contour that you made in the first step above. This type of router bit looks like this:

    [​IMG]

    Hope this helps!

    :^)~
     
  11. FBB Custom

    FBB Custom TalkBass Pro Commercial User

    Jan 26, 2002
    Maryland
    Owner: FBB Bass Works
    Folks, it never hurts to read up on the tools you are using. Most routers come with a manual on safe operation and the folks here who are sounding the alarm are right - trying to take off more than 1/2" on a pass with a pattern following bit is asking for trouble. I generally take 1/8" - 1/4" per pass when cutting cavities, sometimes deeper when cutting to a pattern, so long as the piece is within 1/8" - 1/4" of the final shape. The more wood your bit is hitting when you approach the piece, the less control you have over the tool. Most handheld routers are not safe to operate with very large bits on them anyway.

    Bite the bullet and at least skim the owners manual, or better yet, get a book on router basics from the library. It might seem like a pain in the ass, but you will probably learn some handy tips in the process (like climb cutting, spiral upcut and downcut bits, etc.).
     
  12. Kirby, the bit illustrated on the top is the what I'm talking about. 1/2" diameter - 2 cutting blades (flutes) - straight flutes - follower bearing mounted on top.

    I happen to use the Big Kahuna's method for most of my thick work. The combination of the 2 bits gives a nearly perfect cut.

    For router bits, it's a rule of thumb that you don't cut deeper than the bit's diameter.
     
  13. Bass Kahuna

    Bass Kahuna

    Dec 3, 2002
    West Lafayette, Indiana
    Luthier, Custom Builder
    Very good point.

    Several other good safety tips with routers:

    - ALWAYS wear hearing protection. They are louder than you think they are.

    - ALWAYS wear good eye protection.

    - NEVER pickup a moving router when you're done with the routing task. Always wait for the router to spin down completely. Trust me on this one. I ruined a pickup routing hole once by picking up the router before it stopped spinning and it took a chunk out of the side of the pickup cavity.

    :^)~
     
  14. Tim Barber

    Tim Barber Commercial User

    Apr 28, 2003
    Serenity Valley
    Owner: Barber Music

    What he said.
     
  15. kirbywrx

    kirbywrx formerly James Hetfield

    Jul 27, 2000
    Melbourne, Australia.
    Cheers all!! ill cut the thing i 2 passes.

    I heard someone mention blow out points? i know what they are, but how do i avoid them..go with or against the grain or what??
     
  16. Rapscallion2112

    Rapscallion2112

    Apr 21, 2004
    Detroit
    hmm im not sure what exactly your trying to do. but it sounds like your goin for a bass body with a router. bad idea. too much work on the router. try a bansaw or jigsaw, the jigsaw may not work as well but its still better than a router. use the router for cutting out pickup and electronic cavities and neck pockets.
     
  17. Sorry Rap but you're way off base here. Routers have been for years, and continue to be, one of the best ways to shape a body. I use a nice set of templates and I can have a body completely cut and shaped (with neck and pup inlets) and ready for final sanding in just about an hour.

    While you're taking that same hour or so sanding and shaping your edge back to your layout line, we'll all be moving onto other parts of the build.

    No, routers are perfectly fine for this use. All of the major manufacturers use them. All of the boutique builders I know use them and most, if not all of the members of the MIMF use them.
     
  18. By blowout point, I suggest they are anywhere the endgrain is introduced at a narrow area of the outline, like a horn end. I usually will rout up to close to the end of the horn, then bring the router to the other side of the horn and complete the area in the opposite direction.

    Here's why: the bit spins clockwise. You work your router around the outline of the template counterclockwise. this is conventional cutting in re: to the cutter. When you reverse the router in re: to the outline and mill it clockwise along the template, you are climbcutting the grain, especially at the tips of horns, and it minimizes tear out.

    Dependent on what wood you use, you'll almost always get some tear out, and it's best to keep it to a minimum.
     
  19. Rapscallion2112

    Rapscallion2112

    Apr 21, 2004
    Detroit
    hmm, sorry about that. I didnt think that routers could really handle all that work. I can see how it can be used to help shape out the body once its been cut with a bansaw, but I didnt think it could do all the cutting by itself. Mistake on my part. my bad.
     
  20. Rap, that's what Hambone is sayin...roughcut the shape on the bandsaw, then finish with a handrouter, in multiple passes, with bits shown above.

    The difference between hand routers and their CNC brethren is spindle speed and power. The bodies I cut on the CNC from blocks are being tooled by high-carbon coated straight flute bits, spun in excess of 18000 rpms. All fed by some beefy motors, and at high feed rates (400-500 ipm) there's the difference. A handrouter could never safely accomodate that set of variables.