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I am about to buy an end mill from LMI and the 3/32" (1/8" shank) looks like it only comes in upcut. Is that indeed what I need for my 3/32" saddle? Thanks!

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Time is a great teacher, but unfortunately it kills all its pupils - Louis Hector Berlioz

Chansen / C hansen / C. Hansen / Christian Hansen - not a handle.

Christian

Don't do saddles (archtops) but Stewmac has downcut 3/32"....cleaner.

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Dave
Milton, ON

Downcut.

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Cambrian Guitars

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

I use these bits from micromark in my drill press and they do a great job on saddle slots in ebony. I've also used them in a router for cutting rosette channels and they leave little or no fuzz.

http://www.ares-server.com/Ares/Ares.asp?MerchantID=RET01229&Action=Catalog&Type=Product&ID=80247

Downcut's definitely going to be cleaner, but don't remove too much material at once as chip clearance suffers...

Hi Christian,

I think it depends on how you do your jig.

Do you have an accurate plunge base?

If not:
Unlike CNC, it is really difficult to drop a 3/32" bit straight down, rout, then either stop it or pull it up still spinning without making a spot slightly larger than 3/32" on entry and exit (or spin-down spot.) You might want to try an 1/8" bit instead. You could set two blocks as guides, the opening between them as wide as your laminate trimmer or Dremel base plus 3/32". Put a piece of heavy paper (like a thin business card) on one guide, and push the edge of the router base against that paper and drop down for the plunge cut. As you cut, pull the paper out, and go fully down and back using first one guide as a fence, then the other. Finally, sneak the piece of paper back in and run the edge of the router base over it, turn off the router, and let it spin to a stop before you lift it out. (easier to do than to explain)

Obviously, practice on scrap is a good idea.

Here's a source for solid carbide downcut spiral 1/8" router bits (one of them has a 1/8" shank): Carbide.com

Dennis

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Dennis Leahy
Duluth, MN, USA
7th Sense Multimedia

I use upcut, downcut, straight, and they all work just fine for me. Any spiral will make it easier to cut with less chatter on the sides, but if you have a good saddle mill setup even a straight bit should cut smooth. And I've never had any tearout issues with an clean upcut bit, though again, this will probably depend on the stability of your cutting system. Downcuts are not normally recommended for closed slots, but if you move in shallow passes they will work fine.

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Eschew obfuscation, espouse elucidation.