Hi all. This is a question from someone whose CNC experience is nonexistent, so pardon me if it’s dumb:
As the subject says, can our large CNC cut bevels when cutting plywood? Specifically, if I’m building a box which includes angles other than 90°, will the machine/bits/software allow me to cut the panels with their edges at (for example) 60°? Or is it simpler/better/only possible to cut them square and then cut the right bevel on the table saw?
Thank you!
B
So if you want to make a 60 degree bevelled cut you would need a 30 degree v bit. so basically you take 90 subtract the degree of the angle you want and that would be the v bit you would need.
A V-bit can do this. However, when done on CNC, the cut depth is not always as precise as hand routing, mostly due to sheet warpage. For example a small warpage upward in height widens the “V” and this may or may not be noticeable.
V bits come in 60, 90, 120, and 150 deg full angles. I haven’t seen them in other angles. You could in theory create a bevel with many passes of an endmill or ball mill, but it will take much longer
One option is to bevel them on the table saw. Another would be to use the hand router table, which would be required for any edge features other than a bevel.
I went a few pages in and never found a V-bit in anything but 60, 90, 120, and 150. OK, Amana makes a 45 total included angle insert bit, I did forget about that one.
Engravers are “V”-shaped, as are tapers, but they’re different in nature and use. Notably, they are acute angles (<30 deg) and this do not have substantial width, and generally intended to engrave with the tip Case in point- bits under the term “engraving” wouldn’t likely bevel as needed here.
The original question being “can I bevel to make box corners at other than 90 deg?” I interpret in a more general sense as looking to meet a design’s arbitrary angles, rather than limit to the (45),60,90,120,150 options.
Arbitrary beveling angles can be done with an end or ball mill and multiple passes stepping down- it’s slow, and, again, stepped thus not a true bevel. But it’s an option. It could do different angles without another bit change, too.
I’ve never seen an adjustable-angle bit, nor is there a method I can think of to use any bit to create arbitrary true bevels except a tilting head or other multi-axis machine setup.
If this is a one off project, you may save time cutting your pieces with straight edges on the cnc and cutting the bevel on the table saw.
If you’re going to be making many of these items, it may be worth it to program the cnc.
This is what I would do:
That’s really good info – thank you both!
If/when I tackle this, I’ll try to go with the path of least resistance to start. From what you’ve said, it sounds like that might be to base the design angles around readily available bits (rather than something exotic or a step-down approach). It’s probably smart to also do it in smaller sections where possible – I’m guessing a 4x4 sheet would be less susceptible to warpage than a 4x8. And I’m not opposed to finishing the panels manually, either.
I would suggest planning to cut the bevels first, then actually cut the piece out with an end mill.
The Chamfer gadget in VCarve is a good option, esp combined with a ball mill. Use the largest ball mill you can find.to make it smoother with fewer step-passes. If you use an end mill, the size is irrelevant because it ends in a 90 deg corner regardless of tool diameter.
The chamfer hand routing BIT- with a bearing- could not cut first, since it cannot plunge, but it could in theory be used after. The pieces being cut out would need some sort of hold-down solution. Using hand router bits with the CNC is pretty “out there”. I would think you might want to remove the bearing, since it’s being guided by the machine and not actually following the work. In any case, it brings back the limitation that this bit exists only in certain angles, and requires a bit change to get a new angle. But they do exist in more angles than pointed V-carving bits
Thanks Danny! I think I should be looking at the upcoming CNC classes…