Feeds and speeds for Beech


(BH) #1

Hello guys!
Christmas is coming and the presents are waiting to be made. I´m gonna make some outer boxes for “bag in box” wine and need some advice on feeds and speeds. Since its almost impossible to get hold of exlusive woods where i live i have to use some glued up beech (of unknown orign). First question is: where does the line between hardwood and softwood go in CC? I´m allways afraid when i start a job that the defaults given by CC gonna cause a crash :wink: .
Second: Does anybody have a starting point feeds and speeds for beech? I´m using a #201 .25" endmill to cut 9 mm deep pockets in the material. The router is the dewalt. Finish count more then speed.

Best regards.


(William Adams) #2

Hardwood vs. softwood is actually decided by biology — so one has poplar, a deciduous “hardwood” which is softer than southern yellow pine, a coniferous “softwood”.

A better thing to look at is the janka hardness rating:

http://tinytimbers.com/janka.htm

The CNC Cookbook folks looked at it a while back if memory serves, and I may have stuck a copy on the wiki somewhere — it would be neat to so how the hardness matches up w/ appropriate feed / speed rating.

Wood is more forgiving, and variable than metal though (I’d suggest starting with the mahogany numbers from: https://docs.carbide3d.com/support/#tooling-support ), so usually one can just use a reasonable setting — see: https://www.precisebits.com/tutorials/calibrating_feeds_n_speeds.htm for a good technique to dial things in.

Once you’re confident of the machine being mechanically sound, with solid workholding and if you’re taking reasonable sized chips the best way to get a good surface finish is to leave a roughing clearance thicker than your average chip, then take a finishing pass. Some tricks on that:

  • use a new / sharp endmill — HSS is sharper than carbide and may be warranted on some projects
  • some folks will actually spray a finish to harden the wood before the finishing pass — pricey, but in certain softwoods esp. this seems to work well
  • use a downcut endmill such as our #251 — got a fabulous finish on some bamboo flooring on my last wood project.