spindle speed and feed rate

[emily]

Last time I used a 1/8" straight bit on Douglas fir, the bit snapped halfway through the job. I did some reading and I believe I have the spindle speed set to slow and the feed rate set too high. Anyone know of any good resources to reference for spindle speeds and feed rates for different bits?

[Deleted]

www.cnccookbook.com/g-wizard-machinists-calculator-2/?utm_expid=2217679-261.NbERDloaQF-c632C-fLaOg.1

G-Wizard free for 30-day trial and has data for woods in addition to metals.


www.harveyperformance.com/machining-advisor-pro/ free for their specific tools, just pick one like yours.

Check the manufacturer of your bit for the f/s data they provide but likely it will be for metal and not wood.

You likely had cut path issues as well, we can't tell though without you providing more information. Your CRV file will have everything we need to tell you what the problem was.

[stevem]

Normally, when a bit snaps, it is caused by the feed rate being to high. If you posted your CRV file like what Fean suggested, the problem may be easily fixed.

[Deleted]

Having the feed rate too low can also cause a bit to snap because of heat build up from rubbing or built up edge; recutting chips; too much tool deflection due to chip thinning, or many other reasons so you want to be in the Goldilocks region and not too fast or too slow. Then there are axial Depth of Cut (DOC) and radial DOC too. G-Wizard can help with all of these.