Originally Posted by
Treischl
Here are my thoughts on cutting out plywood using a router.
Ask yourself a couple of questions:
Does the layout demand that you use a 1/4 inch bit to cut the parts out? In other words, do you have scrap leftover that would allow you to space the parts farther apart?
Can your machine handle higher feedrates than 60-80 IPM?
If the answer to these questions is yes, then you might want to think about using a 1/2 or 3/8 bit. CNC routing has some things in common with machine shop work. One of the basic rules is that you use the largest tool possible to get the job done. There are a lot of reasons, the first is that larger tools are more rigid. The second is that you can cut faster with them. The third is that you can cut deeper in a single pass with them. You will also find that a 1/2 inch straight flute bit has more chip clearance than a 1/4 inch bit. The straight flute results in less tearout at the surface than an upcut spiral.
Interestingly, a lot of 1/2 inch bits are available that are not solid carbide, so they are about the same price as a solid carbide 1/4 inch bit.
Most of the cabinet work I have done has dadoes that are slightly less than 3/4, so a 1/2 inch bit works really well.
By the way, you mentioned "CNC Router Bits", well, with a few exceptions, there is really no such thing. The bits used in CNC machines are the same bits used in a hand held router. What is interesting is that because of the machine you can climb cut with them all day long, which you would not dare do with a hand held router. Because of the controlled, consistent cutting of a CNC machine you can push a router bit much faster than you could by hand.