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Router Bits For Gutar Building?

Got a half decent DIY 1/2" router yesterday (JCB RO2100) and I'm looking at bits for building solid body guitars. I have only a little experience of routers (but quite a bit in milling metals and plastics, so familiar with spinny cutters to some degree). In a recent thread, Wealden...

...were mentioned as a supplier of good kit at sensible prices, and I'd be happy to go there.

I'm not so sure of what cutters I need. I assume the 1/2" shank ones are what to go for (stiffer, better torsional grip). I think my main jobs would be trimming the outside to shape, cutting cavities and neck pockets, and the truss rod channel. I'm not planning on doing binding just yet, but probably will eventually. I think I'm okay with rounding over bits (bearing guided, pick a radius, do trial cuts until the depth is right).

For trimming, I'm looking at these...

Can the ones with two bearings be used with one bearing removed, and is that a thing that I might want to do? (Thinking of trimming wood that's thicker than the flute length - start with the remaining bearing running against the template, then move the cutter down as needed.)

Can the 4-flute one be used for general material removal, or is that better kept as a finishing cutter after using another for the main trimming work? If the latter, is it really needed, or is it just a way to avoid some sanding?


Not sure what I should be looking for here. Some of the template trim cutters linked above might suit if they're plunge cutters (but not sure that they are). If so, what flute length should I be considering? (My template material is 12mm MDF, if that helps.) There are also these...

...which look more like plunge cutters (no V notch at the bottom between the flutes). All 15mm flutes in the 1/2" shank sizes - 19.1mm dia for cavities and pockets? What I'm not sure of with these is whether they have the reach for deeper cavities. The shortest distance on the router from collet nut to baseplate is about 12mm, so it looks like I'd have to have the tool inserted part-way to get enough depth (for a 25mm pocket, that would mean the shank is in the collet by about 20mm). Have I got that right? Or is the done thing to remove the template part-way through?

Truss rod channel...

Don't know much about this at all. Square or rounded bottom? What width? Bearing guided? A template with a wide slot and use one of the circular guides that came with the router?

Nobody loves me but my mother... and she could be jivin' too...

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  • TTonyTTony Frets: 22530
    Wealden = yes.  Quality and a good range of cutters and sizes.

    I've got a 1/2" and a couple of 1/4" routers.  I use the 1/2" - with 1/2" bits - for the big jobs, and it eats them.  I use the 1/4" routers for the smaller/lighter jobs were mobility is more important than power.  

    Also bear in mind that the diameter of the cutter defines the radius of any cavity corners, so you might want smaller cutters for thise jobs.

    Depending on how you're tackling the job, sometimes you'll want the bearing on top, sometimes you want it on the bottom.  

    I probably use 6 different cutters (maybe more) for a build.

    No matter how good your cutter, you'll still need to do sanding at the end of the routing stage.

    Re plunge cutting - I generally use a drill press with a forstner bit to remove a lot of the material from the cavities, and then trim it neatly with the router.  If that's not an option for you, just use the router, but just cut a few mm of depth each pass until you've got the full depth of the cavity.  Depending on the thickness of the template you're using, you might need a couple of different height cutters for that approach to work.
    Having trouble posting images here?  This might help.
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  • NomadNomad Frets: 548
    edited March 2016

    Thanks Tony. I also have a couple of cheapie routers that do 1/4" and 3/8". One is minging and destined for permanent installation in some sort of spindle moulder thing, and the other is quite low powered (550W) and reasonably lightweight (but no fine adjust for depth). Got a bunch of cheapie 1/4" shank cutters that probably came with the machines (got them years ago and didn't use them).

    Yes, fully aware of the relationship between cutter diameter and corner radius. Also that sanding will still be needed. I'm tempted to go for the 4-flute trimmer with top+bottom bearings - the blurb on the Crimson site mentions that 4-flute should handle harder materials better, which seems like something worth having. Not sure on whether I'd prefer forstner bits or multiple passes (the larger forstners are a bit of a handful on my little milling machine, which doubles as a drill press).

    Tried looking last night, and my brain short-circuited with option paralysis. Might be easier of those that already do this were to describe the cutters they use for the various jobs.

    At the moment, I'm considering...

    For trimming around the outside, T8166 - 4-flute top/btm bearing:

    For cavities, and maybe neck pockets, T1688 - 15mm x 19dia top bearing plunge:

    And maybe a longer version of T1688 (but not sure what).

    Going to leave out rounding over bits for now (not sure what radius I like), and I think I can use one of the existing 1/4" smaller straight bits for the truss rod channel. Not planning on doing binding for a while, so no rebate cutter yet.

    Would appreciate suggestions.

    Nobody loves me but my mother... and she could be jivin' too...

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  • SambostarSambostar Frets: 8576
    edited March 2016

    Ha Ha. I got my first proper bits from Wealdon tool too..

    You don't seem like a knob like me though.  I ordered the biggest trimmer bit you can fit in your 1/2" el cheapo router collet.  I think I got a 2" bit.  Tried it on some softwood trusses frist though eh. The play in your cheapo router amplified up with the bit from hell will have you seriously fearing for your life, even the noise and vibrations will, let alone the kickback and splinters flying everywhere.  But it is good for jigsaw cut softwood pergola trusses from templates though.

    You only need a bottom bearing trimmer bit that will cover half the body, the flip it over and use a top bearing bit or just raise the router in the table if you have enough leeway.  Smaller it is, faster it spins, possibly more it might burn, but at least it's safer.  Bit by bit is better, it's like overhead plunge routing.

    I don't know anything about necks, I'd like to try that someday.

    I fancy some fluted bits for finger joints and stuff. I like the way they seem to apparently cut cleaner and take the waste away, though I've never tried them.

    Are they really that good?

    40mm from top to bottom bearing should be plenty to do all the body without flipping it. Depending on whether you take the softplate off your router to mount it or not and how thick your recess plate is in your table.  Obviously, any longer in a cheap router and it will amplify the play in the bearings and wobble.  Believe me there will be play in the bearings.  Actually thinking about it you will have to flip it, but I'd say 30 or 40mm max sounds sensible with a cheaper router.  It sounds like you are fairly clued up and being sensible.

    Backdoor Children Of The Sock
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  • hywelghywelg Frets: 3997
    You will need some 1/4" bits with matching bearings to use as template followers, template on top of the work, bearing above the cutter on the shaft . Treat yourself to a few extra bearings (much cheaper from a bearing supplier than tool suppliers) and the spacers. You will lose the little grub screws that hold the spacers to the bit shaft.

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    tFB Trader
    I'm not very keen on the 4 blade router cutter as it has all the problems of a normal strength cutter. If you look at the link below your see where I tested it for the first time. Then decided I would stick with my two blade down share cutter. There's two pages to the link you can go through it all but the part about about the four blade cutter is at the end of the second page. The other link shows you the the cutter that I would recommend. I've been using this type of cutter for many years, you would be hard pushed to find anything that cuts as well as this for going round the outside of guitar bodies (for hand routing).

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  • NomadNomad Frets: 548

    Thanks all, especially @GSPBASSES for the comprehensive info on the 4-flute straight cutter. I decided not to bother with that and found that I had also added the two-bearing downcut one to my cart from a few days ago. I also got the T1688 housing cutter to see how I get on with it...

    I looked at the numbers for template thickness, pocket depth and router collet at max plunge, and this should work with about 20-25mm of shaft still in the collet. Might need something a bit longer for neck pockets and deeper control cavities, but I'll leave that until I've had a go with this (and I'll order the spare bearings and bits that I forgot to include with this order).

    Had a little go with the router earlier this evening to cut a chamfer on a bit of soft wood (to make a clamp dangler with no-fally-offy hook effect), and it seemed fine - easy to grip and control, and a lot quieter than I expected.

    Nobody loves me but my mother... and she could be jivin' too...

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