Let's see if I can explain what I just tested - Just a few minutes ago I cut two slots 1/8" deep with this 0.123" bit in hard Maple, one with the grain and one across the grain. Now, I don't have a good way to measure that slot other than my dial calipers so I used a 1/8" carbide bit shank, measured it to be 0.124", and it fits in the slot with the grain with a little wiggle room as I would expect. On the slot across the grain it fits like a glove.
At this point I used feeler gauges and set beside the shank to press both into the slot with the grain. At first I tried 0.0015" and it's loose so I tried 0.002" and it's a good fit. I tried 0.003" and I can't get the two into the slot without tapping it in with something harder than my finger and at that point I would probably be compressing wood fibers. With the 0.002" feeler gauge the slot with the grain fits like the slot across the grain. So that tells me this 0.123" diameter bit is cutting a slot about 0.126" wide with the grain and right at 0.124" across the grain and that's about what I would expect.
Also, I just tested backlash and it is between 0.0015" and 0.002". I have a Harbor Freight magnetic base that's just so-so at best but a good dial indicator and I did it a dozen times. I got 0.0025" one time but all the other times were less so maybe that's the mediocre base.
I don't think it's a measurement or machine issue but rather something to do with Fusion 360 and the way it's telling the CNC to cut. But I will find it, sooner or later, I will find it!! LOL!
David
David
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