Square corners

[ljdm]

Been a few posts asking how to get as close to square corners as possible. I need to duplicate some door panels in mdf, have the bits used in the attached profile. What method can I use to get corners as square as possible? Was thinking of using the 2 bits in the profile, then running a 1/16 bit in corners (outside corners)to clean it up/square it. Gotta be a better way.
5165

[richards]

Lou,
With the two cutters that you have, I don't know of any way to get truely square corners. The test I use is to simply hold the cutter in my hand and lift it at 45-degrees. A V-cutter will make a 'square' corner, but other bits won't.

[ljdm]

I know the 2 bits won't do it, that's whay I thought maybe draw a vector line on outside and inside of bead, and run a 1/16 ball or end mill. There would be a triangle area in each corner to machine out. Lot of figuring. The only way I can see is with at least 3 bits

[richards]

Assuming that corner is at a 90-degree angle and that you're using a 90-degree V cutter, you could move both the X-axis and the Y-axis TAN(cutter angle / 2) * Z-axis depth. In the doors program, the formula to cut the left-top corner using the 'C' language is:

void SQNorLT(FILE *fp)
{

[ljdm]

Guess there's always the manual method - corner chisel is faster than bit changes, re-zeroing, and creating the toolpath.

[rhfurniture]

Yup - I would stop wasting time thinking, get a sharp chisel and a small square of abrasive, and you will be streets ahead up to fifty doors, 2nd z axis and the rest. You could possibly use the bottom small diameter of the ovolo bit to clean out the top outer corner a bit.
Personally as a maker of small numbers of high end things, I am particularly interested in use of hand-tools plus cnc in making parts.

[sawkerf]

I use those same two bits along with a 1/16 veining bit to achieve a "square" corner. Obviously not a true square but certainly an industry standard for MDF doors. I used the same bits on my Ritter door system before I got my bot. Good luck.

[ljdm]

Do you run the 1/16 along the top and bottom of the bead? How do you get the triangular piece at the top of each corner?