45-degree bit techniques?

Is there a creative head that has an idea for how I can make a 45-degree groove with CNC?
The groove should not be continuous all the way through and therefore not possible to make on a table saw.
The workpiece is 700 x 380mm (28x15’) and therefore too large to lie a 45-degree jig in the machine.
(12mm-1/2in plywood)

Any suggestion to bits or other technics?

Thanks in advance
Tom Jay (Denmark)

Screenshot 2021-11-11 at 13.55.31

Only way I can think to achieve this would be (similar to the 90 degree tables, that allow dove tail etc. joinery to be made). You would need to build a 45 degree version or a 90 that pivots to 45, so the bit can remain at the fixed perpendicular to the table position of a 3-axis CNC.

Then you could insert your boards and cut a straight line across them and achieve your goal. There is no reliable way to pivot the CNC Router to allow this to be achieved on the CNC machine itself.

Hope that helps!



Frank Howarth (YouTube) has a CNC table that pivots from flat to vertical for just such occasions!

Found it.
Thank you… -very helpful.
(Vertical CNC Table - YouTube)


I plan to use a 91* V-groove bit to cut the perfect miters.
In my humble opinion and for my purposes, the addition of the physical block to join both sides is an unnecessary complication to fabrication.

Mitre Folding - YouTube

1 Like

Thanks, nice input too.
These bookshelves will be hanging on a wall, so I’ll rather be safer than sorry.

I usually use biscuits if I need to reinforce miters like this. Otherwise, a jig on a router table would be my next choice.

1 Like