Yrs, I did the math in my head. What happens I think the the board vibrates and the frequency of the vibrations is (no wonder) in sync with the spindle speed. Som times the wood hits the gap in the spirit and other times the dod hits the cutting edge.
I think what matters is the ratio of the movement and vibration has some kind of resonance. This is easy to do if there are small whole numbers involved. But now that it appears i missed a decimal place In any case I still think it best explained that the wood vibrates at a frequency that is some multiple of the spindle speed so it keeps hitting the same place on the router bit. If your router is out of balance it would cause this. On Tue, May 24, 2016 at 10:42 AM, Bruce Layne <linux...@thinkingdevices.com> wrote: > I like Chris' analysis, but when I do the math, I get 85 revolutions per > inch instead of 8.5 revolutions per inch. > > Also, my pi is 3.1416, so I get 1.273 revolutions per inch when rolling > the .250" diameter cutter. Chris got 1.33, so his pi must be 3, but I'd > say that's within engineering tolerance. :-) > > > > On 05/24/2016 01:10 PM, Chris Albertson wrote: >> Lets see, 200ipm turning 17,000rpm comers to 8.5 revolutions per inch. >> >> Think about it this way, if you rolled the 1/4 router but over the >> wood you would have 1.33 revolutions per inch. it would not cut at >> all because there is no relative motion between cutter and wood. But >> you are getting to close to this and the spiral pattern of the cutter >> is showing up in the wood. Vibrations at a frequency that is small >> multiple of the repeats of the spiral pattern of the cutter >> >> Try the same cut at a MUCH slower speed. >> >> > > > ------------------------------------------------------------------------------ > Mobile security can be enabling, not merely restricting. Employees who > bring their own devices (BYOD) to work are irked by the imposition of MDM > restrictions. Mobile Device Manager Plus allows you to control only the > apps on BYO-devices by containerizing them, leaving personal data untouched! > https://ad.doubleclick.net/ddm/clk/304595813;131938128;j > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -- Chris Albertson Redondo Beach, California ------------------------------------------------------------------------------ Mobile security can be enabling, not merely restricting. Employees who bring their own devices (BYOD) to work are irked by the imposition of MDM restrictions. Mobile Device Manager Plus allows you to control only the apps on BYO-devices by containerizing them, leaving personal data untouched! https://ad.doubleclick.net/ddm/clk/304595813;131938128;j _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
