CNC and what bits to use

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tippie53
Posts: 7011
Joined: Fri Mar 03, 2006 7:09 pm
Location: Hegins, Pa
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CNC and what bits to use

Post by tippie53 »

there are many bits and what am I to use
well this depends on what your cutting and what you want to cut
so ply wood I use a bit caller compression or up and down cut. These bits will cut with a twist in both
directions. I use a fairly aggressive cut taking about .3 passes to a 3/4 in piece.

here is a note?
you want the heat to be dispersed into the chips so adjust your feed rate or cutter speed if you smell burning
if your bit is toasted you were too slow on the feed rate or too fast on the speed of the cutter.

up cuts are good for most solid material.
Shear cuts great for MDF
Down cut I use on pearl
and through cuts on thinner ply

Also note that the feed screws can loosen you will see out of round cuts. This may be that set screws
wear
use a good grade of grease and maintain your equipment
last note
I use a spoil board so I can screw my work to the table without damage to the table or material
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
TEETERFAN
Posts: 342
Joined: Fri Sep 07, 2018 12:43 pm
Location: Kansas City, MO

Re: CNC and what bits to use

Post by TEETERFAN »

Thanks for the good info. Helpful to know the feed rate effects on burning stuff. Perhaps I will cook fewer bits!
Kevin Doty
Kansas City
tippie53
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Joined: Fri Mar 03, 2006 7:09 pm
Location: Hegins, Pa
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Re: CNC and what bits to use

Post by tippie53 »

yes learning feed rate to cut rate is the key
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
Diane Kauffmds
Posts: 3246
Joined: Sun Mar 09, 2014 8:13 pm

Re: CNC and what bits to use

Post by Diane Kauffmds »

Thanks John. Yes, the feedrate is key and a learning curve depending on the machine.
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
tippie53
Posts: 7011
Joined: Fri Mar 03, 2006 7:09 pm
Location: Hegins, Pa
Contact:

Re: CNC and what bits to use

Post by tippie53 »

there is a bit called a compression bit for when your working with veneers it is both up and down cut

also for cutting pearl I use a 1/32 bit
glue the pearl to a board using tite bond of fish glue
allow to set
the feed rate I set at 10 ft min 12000 rpm and I use a spray bottle to use water as a coolant and evacuater
I been getting great results I started to cut my own dots and working on diamonds and squares I do cut my
torch and head stocks by hand but I did load that into the cnc now as well.
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
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