Sometimes its the bit, not the stepover causing the problem

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Rcnewcomb
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Sometimes its the bit, not the stepover causing the problem

Post by Rcnewcomb »

I was working on several 3D carvings and was frustrated because I was seeing lines similar to what you get when the stepover is set too large. I was getting it with both my 1/8" and 1/"4 bits.

Upon closer inspection it turns out that the round-nose CMT bits I was using all had little nubs at the point that was causing the lines.

I changed to a good ball-nose bit and the problem went away.

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RoutnAbout
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Post by RoutnAbout »

Randall,

As a tool grinder that is one of the easy things the toolgrinder should see and notice and not allow that to go out the door. This can also happen with a regular flat bottom cutter also. I'll look around at the shop or make one like this intentional and post a picture of this so everyone can see. And then I'll also bring an example of this to show at the Vcarve Conference.

Since this happened on a Ballnose cutter I'm going to assume the grinding operator didn't set the gash deep enough to clean up the overblend on the ball end. If this would have happened on a regular endmill I would say it could because there isn't enough dish on the end or\and the gash wasn't deep enough to clean out the primary cutting edges that meet in the center of the tool. Again I'll bring a couple of this examples to the conference. I'll also see if I can come up with an easy remedy also.
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