After cutting some furniture items out of 1 inch white oak plywood (appleply) the bit (0.25inch compression) was very dull, after another project with just two benches cut from 4 pieces 60x80cm 0.75 white oak plywood the upcut bit 0.25 under the microscope was clearly dull.
So now I have some questions to the ones with experience:
Is oak really that hard to the bits?
What bit brands would be the best (hardest) ones? Mine were Armana, IMO a brand with good reputation?
There are some re-sharpening services. Is it worth to have the bits resharpened? To replace tools after 2 sheets of plywood appears rather expensive.
Is there any browning of the cutting surface? You may have not optimized your feeds and speeds. Pushing the bit too hard will cause burning or overheating to the bit. Plywood can be hard on bits. Was there a lot of cuts in the plywood? Meaning how much cutting did you do? 10 linear ft? 100 linear ft? 1000 linear ft? It may not have looked like you cut a lot, but if it was a jigsaw puzzle (example only) it could be like doing hundreds of smaller projects.
Some woods have a lot of resin in them (not sure about oak). Make sure to clean them every so often. Also, remember any plywood will have a glue of sorts, which is not kind on sharp edges.
Other than the microscope did you find your cutting quality to be lower at all? That’s how I try to judge the “dullness” of a bit, if the finish quality is changing.
I’d say your feeds and speeds also matter. Are you getting nice chips or mainly dust? In the latter case there would be a lot of rubbing forces.
Anecdotal of course, but I like Whiteside.
I work with MDF a lot, which is quite abrasive. I was able to do a real head to head test, same feeds and speeds, same material, same types of projects. I had an Amana Spektra coated 1/4" bit absolutely trashed after running about 20 hours. Cut quality dropped off and inspection under magnification showed why. The Whiteside bit (at half the price) that I replaced it with has over 26 hours on it and it still looks brand new.
I know this isn’t the case here, but when I had my AVID Pro machine, I’d run full depth cuts with a compression bit. With my HDM I tend to do pretty deep cuts with a straight flute bit. This is similar, just don’t plunge with it.
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