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Upcut or Downcut Spiral bit for saddle slots
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Author:  Chris aka Sniggly [ Sat May 08, 2010 9:33 am ]
Post subject:  Upcut or Downcut Spiral bit for saddle slots

?? I'm conflicted on which one to get.

Chris

Author:  SteveSmith [ Sat May 08, 2010 9:42 am ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

I use a downcut bit.

Author:  Bill Hodge [ Sat May 08, 2010 10:04 am ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

Ditto on the down-cut. You could also use up-cut/down-cut combo bits but at the cost diff, down-cut are my personal preference. I've found Techno Inc. to have some excellent pricing.

Author:  Tom West [ Sat May 08, 2010 10:19 am ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

Straight flute here.
Tom

Author:  Colin North [ Sat May 08, 2010 10:41 am ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

Straight flutes, no problems

Author:  bluescreek [ Sat May 08, 2010 11:29 am ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

As a machinist I won't use a down cut in a non cleared hole. The chips are pushed into the work and can build up heat , not to mention the chips will break off the corners of the bit and not getting a good clean squared cut on the bottom. Up cuts will take the chips out of your work and give you cleaner and sharper inside corners.
I don't own a down cut bit . I use all up cuts. A dull bit is a dull bit . Down cuts have another problem , the end fibers get pushed down giving the appearance of a clean cut , but then the wood fibers break off you have more slop than you thought.
If you have a cleared area to cut they are ok. Think of where the chip is going. That is as important as what you are cutting.

Author:  Howard Klepper [ Sat May 08, 2010 11:43 am ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

Up cut for slotting a bridge.

Author:  Chris aka Sniggly [ Sat May 08, 2010 12:06 pm ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

Thanks a bunch for the input guys. I really appreciate it.

Chris

Author:  TonyKarol [ Sat May 08, 2010 12:08 pm ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

I use downcuts, almost exclusively. I dont route the full depth of a saddle slot at once, only 1/16 at a time with my jig, and clearing the chips doesnt seem to be an issue for me .. they find their way out .. on metal it might be a different story, but they work fine for me.

As they say a lot here .. YMMV ....

Author:  Chris aka Sniggly [ Sat May 08, 2010 12:31 pm ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

Well...I'll provide further clarification here so maybe some opinions can get narrowed down a bit.

I am switching to a 3/16th's saddle (no more 1/8th inch saddles). I like the look and I like the extra real estate. So with that being said, and with the understanding that it's a larger bit......does that change any opinions?

Thanks for the input folks
Chris

Author:  Colin S [ Sat May 08, 2010 1:51 pm ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

As has been said above upcut bits for blind cuts such as saddle slots or truss rod/CF slots where you are cutting a slot the same size as the bit, downcuts will try and compact the waste into the slot.

Colin

Author:  woody b [ Sat May 08, 2010 2:34 pm ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

I use an upcut. I'm sure the chips can find their way out when using a downcut, but the bottom of the slot is smoother (at least for me) when using an upcut.

Author:  Bobc [ Sat May 08, 2010 3:06 pm ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

Here's a link with a pretty good explanation of the difference between up-cut and down-cut bits.
http://www.newwoodworker.com/updowncutbits.html

Author:  SteveSmith [ Sat May 08, 2010 3:30 pm ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

I do mine like Tony K. 1/16" or so at a time so no problem clearing chips with the downcut and I'm also using a 3/16" bit. I wouldn't use it in metal and I also wouldn't use a downcut for a trussrod slot. On the other hand, I haven't done anywhere near as many saddle slots as John Hall ;)

Author:  Bill Hodge [ Sat May 08, 2010 6:53 pm ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

I've been using both up and down cut bits for years and in the case of the saddle slots, (I too like the 3/16 saddle) I have had absolutely no problems using the down cut and achieving beautiful and precise cuts when it comes to the denser woods. Like John I too am a machinist (no longer by trade) but years ago I used to machine pressure fittings for the nuclear power industry and given the nature of cutting metals, absolutely up cut is the way to go in that regard. Either works fine for saddle slots as well as the straight flute so really it's a matter of personal preference. :)

On the rosette and purfling channels I've found the down cut bits to also provide good clean cuts. And for the bindings my preference is the up cut. As was mentioned above, a dull or chipped bit is worthless and should be discarded.

Author:  Daniel Minard [ Sun May 09, 2010 11:48 am ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

I use down cut bits too, & a 3/16 slot. I go in to nearly full depth with a 1/8" bit first, in three or more passes. Then finish up with the 3/16 bit. I am still using my drill press for this operation (not much longer!) & find going in two stages cuts down on chatter.

Author:  Wes Paul [ Sun May 09, 2010 12:27 pm ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

Anyone have pictures of their bridge slotting jig?
I am about to make one might help to get some ideas!

Author:  TonyKarol [ Sun May 09, 2010 4:33 pm ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

sure .... its been modded up since, with locking knobs inot threaded inserts to control the stops on the fence, and I added a depth gauge for final bit depth setting.

I use a PC 7310 lam trimmer riding against the fence.

The bridge in the picture has a 3/16 slot, and is going on a multiscale, hence the pencil lines at the angle, showing where the bridge is parallel to the top centre line

Author:  Colin North [ Mon May 10, 2010 5:55 am ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

Overhead routing using a Hitachi router (3mm straight bit) in a Bosch drill stand.
Base is fixed, set up to make a 3 degree backslope to the slot.
Sled is held against the fence by 10 small springs in drill holes between wooden strips 1 (fixed) and 2(floating).
Take about 5 passes to depth.
Stops are adjustable (wing nuts).
Hope this gives you a few ideas.
Colin. (sorry about the mess!)

Author:  Daniel Minard [ Mon May 10, 2010 11:43 am ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

Very cool jig Todd! It looks rigid enough to eliminate any bit chatter. Do you have a pic of it mounted on a guitar?

Author:  Jeffrey L. Suits [ Mon May 10, 2010 12:38 pm ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

Mine, setup w/Bosch Colt:

Image

Author:  Chris Paulick [ Mon May 10, 2010 10:02 pm ]
Post subject:  Re: Upcut or Downcut Spiral bit for saddle slots

It's at the end of the video.

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