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It's only defined by the rotation of the bit and the direction of the feed with respect to the rotation of the bit. The grain of the material does not come into consideration when defining whether or not you're climb or conventional cutting. Look at the drawings in the links above.

With the guitar sitting on your bench face up with the router pointing down - feeding the router clockwise will result in a climb cut, counter clockwise in a conventional cut period.

Typically speaking, a climb cut will result in much less blowout compared to a conventional cut.

http://www.stewmac.com/freeinfo/Routing ... -1298.html

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Thanks for that link Mike.

Mike, does that mean you route in a clockwise direction around the entire guitar first, no matter the grain direction? Does anyone else do this?

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http://www.newenglandluthiers.org/conte ... g_Jig.html

go to the bottom and read using the jig...

I think it's six of one and half a dozen of the other...

climb cutting exclusively deals with the issue of hard wood sides...a combination of climb cutting and forward cutting deals with the grain of the top (usually a soft wood)...

I think softwoods cut/route easier than softwoods, and barring a 'defective' piece of wood, climb cutting results in fewer blow outs...

as a note I learned of climb cutting many years ago...tended to not use it because of the difficulty associated with using it in general wood working where typical routes remove a fair amount of material (hence making the router want to fly out of control)...then came a period of time where the material being supplied in the field (as a trim carpenter) was some sugar pine that was what I can only describe as being stringy in its grain structure...when forward routed the result was tear outs in the routed profile (not on the edge, but the whole profile), when climb cut it would furr up but leave the option of being sanded...so at this point I started to use the climb cutting method even though it was more difficult and more time consuming (climb cut on one pass slowly, and maybe even doing 2 or more passes as needed because of the amount of material being removed, and a final pass in the traditional direction) as in the end arguing this or that made no difference to the builder/owner of the house...the desired end result needing to be a finished product that was nice and smooth...in general the painter is not paid to fill a bunch of tear outs in the wood, and while I could of course argue it was the inferior wood, I can guarantee you that argument (while totally true) didn't work...in the end it was best to climb cut, sand a bit (and let the painter do any final sanding to full smoothness after the surface got primed) and make everyone happier...yep even myself as I certainly don't like a builder who is supplying regular work being unhappy with me...

I find that taking your time and using SHARP bits will dramatically reduce grain orientation issues when climb cutting...the same cannot be said with as much surety for forward cutting...

there are many 'happiness is' lines out there...as a full time wood worker since '86 (and part time/hobbyist for most of my life) my version of 'happiness is' are VERY sharp tools...second to that would be power saws with no bearing run out which (because of various factors) is becoming almost impossible to find these days

I first rout around the entire guitar in a clockwise direction (climb cut). The reason you get fewer blowouts this way is because the router bit is taking smaller bites of the material. The bit does tend to push itself out of the work so a firm hand is required on the tool.
A sharp bit and a cutting edge on the bottom as well as the side of the bit will help minimize blow outs on the sides.

For a climb cut, if the guitar is stationary and the router moves, the router goes clockwise around the guitar. If the router is stationary and the guitar is in a cradle, the cradle and guitar rotate in an anticlockwise direction. I've never seen the logic in only doing some sections with a climb cut - just an opportunity to get it wrong, occasionally.

A solid cradle with a guitar in it sliding over a bench has a nice feel that doesn't leave you with the impression that the job is going to run away on you, and is a very good reason for moving the guitar/cradle rather than the router. When cutting rebates, I always go around the guitar twice with a climb cut. Job done.

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I'm surprised no one has mentioned router speed (actually, more scientifically, cutter edge speed) as the primary suspect for generating tear-out like the OP experienced.

I learned (the hard way) that you need to get the bit rotating as fast as safely possible in order to minimize tearout when either climb or conventional cutting. That, plus only take small bites at a time.

The OP is apparently using a Bosch Colt router - variable? what speed? - and what is the bit diameter?

Cheers,
Dave F.

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Cambrian Guitars

"There goes Mister Tic-Tac out the back with some bric-brac from the knick-knack rack"

good point...I don't even think about router speed for the simple fact that none of my routers (an old Craftsman, 2 Porter Cable 7310's, PC 310, PC 690) have variable speeds, and are all pretty old, yet well taken care of and still work nicely...

LarryH's query on climb cutting I'm sure is initiated by the many videos that advise a combination of climb cutting and normal cutting when making a binding ledge...as noted above, I argue for all climb cutting for the reasons I detailed...the only time recently I've done any traditional cut routing was when I was routing out some pilaster panels to receive 1/4" plywood on the back (which would be hidden against the wall) and from the front he 1/2" step down would be covered by lip moulding which would cover any blow outs (and there were many)...simply a time saving measure as it seems every time I get lazy and skip climb cutting it bites me in the butt causing various issues (like throwing away the piece of wood and starting over again) which results in lost labor and materials (which hopefully can be ripped down for something else)

For literally years I followed the conventional part climb,part regular cutting for binding and purfling ledges. Then one day about 5 years ago it hit me like a ton of bricks. Been using climb cut exclusively ever since without any disasters.
Tom

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Very good info, thanks so much for taking the time.

The bit was used on one other guitar 3 or 4 years ago and it's either a StewMac or LMI 1" router bit with bearing kit. Hard for me to tell if it's still sharp though there's no burn anywhere and it cuts very smoothly.

I used this jig.







I have a Bosch Colt as I mentioned and it's a variable speed router, 16,000 - 35,000 RPM with speed settings 1 thru 6. It was set on 5 I believe so that would be 28,000 - 30,000 RPM's? I'm noticing the tear out was worst in the figured lower bout area but not completely isolated there. I'll probably get a new bit for the next guitar to eliminate that as a factor, unless I figure out how to really sharpen this one.

The CA fill is very dark as mentioned but may be OK under epoxy pore fill. I'll know it's there which is never good but this guitar is very much a getting my feet wet again exercise in guitar building so am learning much as I go.

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Larry,

Do you just rely on the rubber mat to keep the guitar still during cutting?
I don't think that's good enough and may be the cause of your rough binding channels.
A proper leveling and hold down clamping system is the norm for this type of binding machine setup.

Dave F.

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Cambrian Guitars

"There goes Mister Tic-Tac out the back with some bric-brac from the knick-knack rack"

I've got a pretty standard clamping tray that I use, secured to a work bench can't remember what they're called - just no picture. Similar to THIS

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To make "wood dough" for filling small blow outs I use lacquer or whatever finish I am using as the binder for the sawdust. This seems to give the best color matched filler for woods that are going to be finished "natural". Epoxy and CA do often give a darker result and are harder to sand.