[ex-egll]

Hi, my trigonometry skills, if I ever had any, left me many decades ago.

Is there a formula (or tables) that will give the width of a cut path at different depths of cut using a 60 degree engraving bit?

Thanks

[blinkenlight]

Luckily, it's not too complicated. Assuming the v-bit (with tip angle "A") ends in a point, a line from the tip to the depth we wish to use (let's call it "D") is perpendicular to the width of the bit at that depth ("W"), forming two right-angled triangles in which we can apply sin/cos/tan formulas for relationships between sides. Thus, half of "W" in one of the triangles is equal to depth "D" times the half of the tip angle "A" that belongs to this triangle - so the full "W" is twice that:

W = tan(A/2)*D*2

Of course, tips generally don't end in a perfect point, but have a tip width instead; that however only means our actual cut width will just be that much larger - if the tip width is "Tw", that becomes

W = tan(A/2)*D*2 + Tw

Finally, for a specific tip angle of 60 degrees, that is simply

W = 1.1547*D + Tw

Hope that helps...

[ex-egll]

Blinkenlight, many thanks for taking the time to respond. I was getting hung up over the point vs tip width issue.

Still in the preparatory stages at the moment, we are in an RV in GA and the lathe and mill are on their way. I can finally make Mach3 behave (I think).

Once back in Canada I'll put the theory into practice.

Again thanks for the help

ex-egll