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I'm trying to get a little more serious about improving process and speeding things up where possible. Sooo, I've been watching a whole lot of Youtube guitar factory tours . I notice that there seems to be no real standard for cut direction so I thought I'd throw these questions out here.

Is it always preferable to use a climb (CW) cut for profiling the perimeter of a body? I don't rough cut bodies first so I guess I'm technically cutting a slot as opposed to running a profile around the outside of a body. I currently run 1/4" non-climb passes (over-sized by 0.02) to depth, then run 1 climb pass at full depth and final size. It works well, I'm just wondering if there's room for improvement.

What about interior pockets (pickup and control cavities)?

When cutting a slot, there's really little difference between climb and conventional milling however, I tend to always climb cut because I'm really cheap and tend to use blanks that are just oversize so the bit will break out of the stock at some point. Aggressive conventional cuts on long grain can lead to a lot of splintering and such.

I also tend to do a rough pass that leaves anywhere from .020 to .040 of material and then come back and climb cut to exact size.

Depending on the rigidity of your machine, conventional cutting can lead to a slightly more material removed and climb cutting can leave a little more material behind than expected. The more aggressive the cut, the more pronounced the artifact. Keep that in mind when planning your cuts. e.g. I sometimes use 1/4" locating pins when machining fretboards which I cut using hole interpolation. If I climb cut them, they end up tight on my dowel pins and conventional a little loose. Either way they're within .001 but just one's tight and one's loose.

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It's funny you mention that Andy, because just yesterday I had a small chip pop out because I had to break out of the edge of a blank while making a conventional cut. Maybe I'll switch to climb cuts

Depending on grain direction and tool position around the profile a conventional (CCW) cut IS optimal but because of the hassle of making a tool path that accommodates grain direction I never bother. I employ reverse direction cutters in situation where guaranteeing the outcome requires it but for the contouring operation around the body profile I just use a climbing cut with another cleanup cut afterwards. I take off about .01" on the cleanup cut with a four flute, 3/4" cutter.

It isn't practical to think in terms of matched sets of opposite turning cutters if you don't have a tool changer but I will say they solve certain problems that ONLY reverse direction cutters can solve. Quite near the end of a neck build I make the cut that defines the final profile of the headstock. The headstock facing, fretboard, and truss rod are glued into position and there is .05" left around the headstock and the facing profile. This is NOT the time to rip out a splinter. I section off headstock profile to isolate the grain direction so that I can attack the grain from an optimal direction. This is the situation in which left and right turning cutter will guarantee the result.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

I haven't played with this for a while but came to the conclusion that climb cutting is generally safer. It doesn't matter whether its profiling or pocketing. Is it just me or does climb cutting leave more fuzz?

On one of my body shapes I climb cut 75ipm .75doc 18K with a .5 EM leave .03" side .05 bottom and then a bottom only finishing pass conventional. Chip packing can be a little bit of a problem so that may be a little greedy on the doc. That's mahogany, the maple cap has already had an overcut when the binding ledge was done. I changed to that because climb for both rough and finish was sometimes chipping the right hand edge of the neck joint and going CCW for the finish seemed to take care of that. Pockets are climb but most are HSM and it only goes CW. OTOH Stuart seems to have a better machinist's approach. I've never tried running my spindle LH rotation.

I'll gladly spend more machine time to avoid rim sanding or possible spindle sander mahem. Usually I just block sand the side with 120 and done.

one trick i use -taken from when machining graphite, is to pre-finish the end of a feature such as a slot therefore eliminating chip out. you only need to bump into the end of the slot 1/2 the diameter of your cutter to do this. for example with a 1/2" wide slot, just move in .25 from the end and to depth. then retract, move to the other end, and then mill your slot normally. for pocketing just cut your feature to size but only go say .05 ~.1 deep. then rough away as you normally would leaving some material on the walls for finish cuts. work great.

regarding fuzz, just use a reverse spiral cutter to finish with. these can be a little trouble when slotting or pocketing and as such need a little space for chips to go. but they really keep the hair to a minimum.

in the metal cutting world, climb cutting vs conventional cutting pertains more to chip thinning and heat control -with climb cutting removing more heat with the chip and providing a better finish, and backlash control on manual machines. maybe not so much of an issue with cutting wood.