What Would Cause This?

Makes sense. It was aluminum. I was using a non ferrous specific insert. It looks like it is coatedd but down by the tip the coating is gone so makes sense that is what happened.
 
If that is a Korloy AK insert, I don't think its coated. If there is a defect at the tip then a BUE broke off and took a chunk with it. If that is what happened then the surface finish beyond the point it broke off will be rough.

Edit: I took a look at the pic at the beginning of the post and it does look like the surface is rougher beyond the gouge. You need to index the insert and try again but increase your speed and slow down your feed. Use coolant and see how it goes. Do please let us know.
 
It was an insert from Tormach. I got the one for steel gold color and aluminum was chrome color. Speed was probably a little slow at just over a 1000 rpm.
This was a week ago so the part is complete.
 
Ok newbie here, so take it for what it's worth... could this be caused by some kind of a power blip? Compressor startup, a/c start something like that. Causes the head to slow just slightly, for just a fraction of a second. That combined with the spring effect mentioned in an earlier post??

Newb here again so I could be way off, but something like that would be real hard to track down unless your looking for it and find a way to make it repeatable. Some of you guys with experience can just tell me I'm way off base... lol
 
I have experienced aluminium stuck in my lathe inserts. I now know to call this "BUE" so the thread helped me to learn something. As mentioned, the rough cut is the sign. I normally can remove with a knife of carbide pick.

I recently purchased a Grizzly G1008. Same mill as your G1004 but with X power feed. Good to know someone else with this mill.
 
mikey said:
Hmmm, you think you might have developed a BUE and it broke off on its own? That would be my guess. If the block is otherwise squaring fine then your tram is not likely to be the cause. It is also unlikely that the tool or insert is at fault if the rest of the cut went fine and all subsequent cuts are okay.
Click to expand...
I agree the tram is unlikely the cause.
 
MetalMonkey said:
Ok newbie here, so take it for what it's worth... could this be caused by some kind of a power blip? Compressor startup, a/c start something like that. Causes the head to slow just slightly, for just a fraction of a second. That combined with the spring effect mentioned in an earlier post??

Newb here again so I could be way off, but something like that would be real hard to track down unless your looking for it and find a way to make it repeatable. Some of you guys with experience can just tell me I'm way off base... lol
Click to expand...

Interesting thought but I suspect it would not cause a surface defect like that gouge. I could be wrong, though.
 
mikey said:
Interesting thought but I suspect it would not cause a surface defect like that gouge. I could be wrong, though.
Click to expand...
I don't know, it might be. I just looked at the machine he referenced. It's a half size mill. So like the one I got today (Clausing 8520) very similar. I'm also thinking that if the voltage was stolen by something else for a second, the slowdown or blip definitely could cause a problem. That's why we play with surface speeds to get a certain finish, and anything too fast, or too slow will give us less desirable results. Is it the answer.. possibly. Just not enough to draw any conclusion. Try to repeat the exercise and blow the compressor tank and let it cycle while working, see if it causes it.
 
woochucker said:
I don't know, it might be. I just looked at the machine he referenced. It's a half size mill. So like the one I got today (Clausing 8520) very similar. I'm also thinking that if the voltage was stolen by something else for a second, the slowdown or blip definitely could cause a problem. That's why we play with surface speeds to get a certain finish, and anything too fast, or too slow will give us less desirable results. Is it the answer.. possibly. Just not enough to draw any conclusion. Try to repeat the exercise and blow the compressor tank and let it cycle while working, see if it causes it.
Click to expand...

The 8520 has a good reputation amongst the hobby guys. I think Bill Gruby has one?
 
Dave Paine said:
I have experienced aluminium stuck in my lathe inserts. I now know to call this "BUE" so the thread helped me to learn something. As mentioned, the rough cut is the sign. I normally can remove with a knife of carbide pick.

I recently purchased a Grizzly G1008. Same mill as your G1004 but with X power feed. Good to know someone else with this mill.
Click to expand...

Dave, most of the time you cannot pick off a BUE without also cracking off the piece of the insert it is welded to. Occasionally, you can knock it off by increasing speed but most of the time you just have to index the cutter to a new point and correct your cutting conditions to prevent it. Coolant helps to cool the tool at the point of cut and will also help.
 
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