Router bit edges

[BillK]

I have access to a fairly sophisticated microscope with photo capabilities. Here are two photographs of the edge of brand new unused router bits, a V-bit and an up cut bit. Tomorrow I'll try to add shots of similar bits that have been used for a while. All are carbide.

Up cut bit

V-bit

[4DThinker]

Thanks for the shots, Billk. I've been under the impression that HSS bits "could" be sharper than carbide, and have gotten smoother cuts in hardwoods using a HSS V-bit than I did cutting the same job using a carbide edged V-bit. The carbide bits keep their edge longer than the HSS ones though. I've had a few V-carving jobs where a fresh 1.5" HSS V-bit was dedicated to the cut and its price was simple rolled into the fee.

Your photos may be eye opening when the available detail can show differences between carbides from different sources, as well as HSS vs carbide bits.

[BillK]

As promised, these are pictures of a used V-bit, the original 90 degree cutter I got with my machine around 2 years ago, and a 1/4" up cut that I've had for around 9 months. Both have quite a few linear inches on them in both plastics and hard and soft woods. As the tool wears the sharp edges round over, often seen as a shiny line on the edge. Both these bits still "cut" but not as cleanly as a new bit would. They produce more tear out and vibration because of the wear, as well as heat.

Just thought I post this for those new to machining and tooling wear.

Used V-bit

Used up cut bit

[4DThinker]

That rounding explains why I never seem to cut my fingers touching/handling an old bit, but will start to bleed just thinking about peeling the wax off a new bit. Thanks again for the photos.