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Engraving with an 0.0120" Bit

Posted: Fri Jul 01, 2016 3:59 am
by madhatter
Juat thought I'd like to show that it is possible to use small end mills with the ShapeOko. I have previously used 0.0150" bits, but I Decided to go a little bit smaller this time and used an 0.0120" bit I picked up from drillman1. The engraving on the back of the board after I oiled it looks almost like it was laser engraved the way the end grain darkened up. It came out better than I thought, and even though the bit is only 0.0030" thinner than the 0.0150" bit, it really helped keep the tearout of the letters to a minimum.

Front
Back
Short Video of the Eagle being cut.

The lines and numbers are cut with an 0.0236" bit and the holes are with an 0.0781" drill bit. The drill bit is a "PC Board" solid carbide drill bit, and I have used one bit for dozens of cribbage boards (typical 3 player board is 120*3 + 3*3 + 10*3 + 1 = 400 holes at 0.30" deep). They really last a long time, and make clean holes. I highly recommend giving them a shot. I use them in bamboo, sapele, katalox, padauk, wenge and purpleheart and they work great in all the woods (and bamboo, which is technically a grass, I guess. . .)

Re: Engraving with an 0.0120" Bit

Posted: Tue Jul 05, 2016 4:24 pm
by JeromyReno
looks great. very clean looking

Re: Engraving with an 0.0120" Bit

Posted: Wed Jul 06, 2016 1:40 am
by madhatter
Thanks. I keep getting "...the smallest bit I will ever need..." and then find one just a bit smaller because I just KNOW I can get a cleaner edge with a specific font and a bit less tearout in a graphic if I just went a little bit smaller.

Re: Engraving with an 0.0120" Bit

Posted: Thu Jul 07, 2016 7:21 am
by zerblatt007
How fast can you run this 0.0120" bit on wood? That is about 0.3mm? :)

Re: Engraving with an 0.0120" Bit

Posted: Thu Jul 07, 2016 3:50 pm
by madhatter
zerblatt007 wrote:How fast can you run this 0.0120" bit on wood? That is about 0.3mm? :)
My settings for this bit are:
Depth: 0.030 in max
Step Down: 0.010 in
Feed Rate: 30 ipm
Plunge Rate: 20 ipm
DeWalt RPM: 24,000

They are probably conservative for wood/bamboo, but it usually only takes 4-5 minutes to make the engraving anyway, so I keep it conservative so I don't break the bit.

The biggest issue with breaking the bits is that the bit is so thin, that even with the precision of the SO3, it is still obvious which lines were cut twice, so I try to break the bit only by sliding my hand into it and slicing my finger open when I am wiping dust off the spoilboard between jobs. I think that it only took three times slicing the same finger to stop doing that. I hope.

Re: Engraving with an 0.0120" Bit

Posted: Thu Jul 07, 2016 4:38 pm
by hatallica
Thanks. I keep getting "...the smallest bit I will ever need..." and then find one just a bit smaller because I just KNOW I can get a cleaner edge with a specific font and a bit less tearout in a graphic if I just went a little bit smaller.
Thank you for sharing your settings & results. When I got the SO3, my thought was that my 0.0625" end mills were for just-in-case purposes ... if I ever dreamed up a use for them. I was not half way through designing my first project before I realized the value of going smaller. Having some empirical results helps immensely.

Re: Engraving with an 0.0120" Bit

Posted: Fri Jul 08, 2016 7:48 am
by zerblatt007
madhatter wrote: The biggest issue with breaking the bits is that the bit is so thin, that even with the precision of the SO3, it is still obvious which lines were cut twice, so I try to break the bit only by sliding my hand into it and slicing my finger open when I am wiping dust off the spoilboard between jobs. I think that it only took three times slicing the same finger to stop doing that. I hope.
:)
You need a shop vacuum handy and in close proximity to your SO3.