Trigonometry help please, plunge depth for a v cutter!

Quote:

---

Originally Posted by Ulsterman

Touch the tool off at the required Dia that you can measure on the part ---- and program machine to cut to the Face -no trig needed but approach move should include room for the tip -very common practice on combo tools

---

Thanks for the advice Ulsterman, but in this case I really am after the trig as I am coding an application to produce g-code.

Quote:

---

Originally Posted by Jonathan

V-cutters are generally specified by the included angle, i.e. the angle at the tip. In that case the formula is: ......

---

Thank you Jonathan, that is excellent information, just what I need! Will take me a little time to fully digest but will be worth it.

I didn't consider the flat spot at all. Wouldn't have been a disaster, but wouldn't have been correct either!
I asume if I use an insert v bit (such as CNC V Groove Miter Fold & Signmaking Insert Router Bit by Amana Tool) then I could just use Z=d/(2*tan(a/2)) as there would be no flat spot?

The radiused tip/ballnose cutter was also a great thought. I was only considering supporting v cutters but I think you have changed my mind.

Thanks!

(haven't seen "LetMeGoogleThatForYou" before! Almost spat coffee on my keyboard when I clicked it!)

Quote:

---

Originally Posted by cncJim

I didn't consider the flat spot at all. Wouldn't have been a disaster, but wouldn't have been correct either!
I asume if I use an insert v bit (such as CNC V Groove Miter Fold & Signmaking Insert Router Bit by Amana Tool) then I could just use Z=d/(2*tan(a/2)) as there would be no flat spot?

---

There's always going to be a flat of some sort, but for the tool you linked to I expect it would be neglegible. You might as well use the formula with the flat in your program, and just set f to 0 if the flat is insignificant as that results in the same formula as for without a flat.

If you've got the tool to hand, then one way to measure the flat is to spin it round and move the Z-axis down until it just touches. Retract the Z-axis and measure the diameter of the circle left - that's your f.

Quote:

---

Originally Posted by cncJim

(haven't seen "LetMeGoogleThatForYou" before! Almost spat coffee on my keyboard when I clicked it!)

---

It's temping to link people to that quite often :distracted:

Quote:

---

Originally Posted by Jonathan

There's always going to be a flat of some sort, but for the tool you linked to I expect it would be neglegible. You might as well use the formula with the flat in your program, and just set f to 0 if the flat is insignificant as that results in the same formula as for without a flat.:

---

Thats exactly what I will do, thanks again Jonathan :thumsup: