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David
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I left the bit below the spoilboard and forgot it was there; moved the gantry back and snapped a $40 compression bit - ugh!

From my camera in the shop I made a short video that's on my FB page so if you don't have FB then I guess you're not going to see this -

David
 

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Yep, almost new bit, too. I even thought about it being below the spoilboard but then I walked away to throw a paper towel in the trash and promptly forgot it was that low.

David
This happens with old age and with lots on your mind. You start out going North and get distracted, end up going West and then start back North again like nothing happened, except you forgot you were distracted. The best time to prevent "accidents" is before they "can" happen... the old folks variation of Murphy's law. The Law of Gravity is also something that can make things happen also, typically things fall towards the center of the Earth, so use Murphy to prevent Gravity. Lay things down that are likely to fall over anyway, rakes, brooms, tall lengths of wood, etc. OR place them into a corner where you can't bump them over.
 
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I left the bit below the spoilboard and forgot it was there; moved the gantry back and snapped a $40 compression bit - ugh!
Glad your error did not result in an injury.
Once again it just proves the machine only does what the operator tells it to do. AND it does not care if what you tell it to do, makes sense or not.

I had a $200 Interapid indicator in the spindle, got distracted and started the spindle up. OOPS,,,,,, threw that indicator with enough force to alert all my coworkers of my error.
 

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David
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I had a $200 Interapid indicator in the spindle, got distracted and started the spindle up.
Oh no!! When I trammed my spindle and had a dial indicator mounted in the collet I made certain the 240v wasn't turned on so no way the spindle could run.

But you are correct - the machine did exactly what I told it to do. It would be nice if it could sense 'stoopid' but then it becoming self-aware is a scarier thought. :eek:

David
 

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Ahh, the wonders of CNC. The machine does exactly what you tell it to, for better or worse. Its one of those things that always gives me a chuckle when someone from the "CNC aint real work" crowd comes out, cause despite popular opinion the machine doesnt think for itself. Not yet at least

I feel your pain though, ive made my way through more end mills doing stuff like that than i care to admit to. Well, mine are somehow worse, since they were on a manual mill... On the bright side you only snap and end mill slamming it manually into the vice once twice five times before you stop making that mistake
 

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David
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I feel your pain though, ive made my way through more end mills doing stuff like that than i care to admit to.
I guess the only 'good' thing about this is it's the first time in the almost 5 years I've had the CNC, so that's not bad. Still don't like it, though. :)

David
 

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David
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Looks like it twisted the mechanism before it snapped. Is everything still aligned/in working order?
It flexed a bit, hard to do on a machine this rigid. I'll check it all out tomorrow but it seemed like it was ok at the initial glance.

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I guess the only 'good' thing about this is it's the first time in the almost 5 years I've had the CNC, so that's not bad. Still don't like it, though. :)

David
...lucky bastard. I think i broke your record in the first 5 minutes of having my little CNC router. One particularly memorable crash had the machine, somehow, thinking the bit was 300mm above the table. Said machine only has about 80mm of travel in the Z. Not sure how it happened, but i know i realized the problem when the program started and sent the bit down, through the workpiece, through the spoilboard, and almost through the aluminium table, all under rapids

Didnt know if i should be pissed it happened or impressed that the tiny spindle made it through almost everything
 

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First: I am very pleased that you were not hurt.

Second: I am amazed that you captured it on video. Few people "record everything" and then have something to analyze later. I am quite impressed with that.

Third: It reminds me of what happened to my ancient dovetail jig when I first tried it out. I didn't tighten the router height adjustment enough and the router slipped down while I was cutting the dovetails. It got a bit too low. Yes, pun intended. :p

Dovetail Jig Loose Collet.JPG
 

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David
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...lucky bastard. I think i broke your record in the first 5 minutes of having my little CNC router. One particularly memorable crash had the machine, somehow, thinking the bit was 300mm above the table. Said machine only has about 80mm of travel in the Z. Not sure how it happened, but i know i realized the problem when the program started and sent the bit down, through the workpiece, through the spoilboard, and almost through the aluminium table, all under rapids

Didnt know if i should be pissed it happened or impressed that the tiny spindle made it through almost everything
I've done that. I set Z zero on the spoilboard for Longworth chucks because that keeps my spoilboard fairly flat and pristine. But when I started doing them I was setting Z zero on top of the workpiece and that was problematic because BB is anywhere from 0.465" to 0.490" and my work file is set for 0.480". So that's why I switched to setting Z zero on the spoilboard; now it doesn't matter how thick the BB is because the cutter still stops at the spoilboard.

Well, I pulled up an old file and forgot that it was set to the top of the workpiece and I promptly set Z zero on the spoilboard. When I hit the button it took off at 175ipm through the BB and 0.480" into the spoilboard and began cutting. Even with good reactions it took a second or two to process what was happening because nothing seem out of order - it cut just fine. But it didn't 'sound' right so I stopped it and then realized I was cutting almost a full inch of material at 175ipm. The machine, spindle, etc. didn't complain at all, just did the task I had 'told' it to do. But it left a very deep arc groove about 6" long in my spoilboard!

David
 

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David
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First: I am very pleased that you were not hurt. - Me too!!

Second: I am amazed that you captured it on video. Few people "record everything" and then have something to analyze later. I am quite impressed with that. - I have a camera set up in the shop so I can walk away for a minute and still keep tabs on the CNC when it's running. It has come in handy a few times but only to capture dumb stuff I've done, not for any CNC issues. A while back I was able to capture accidentally cutting at 600ipm on a Longworth chuck!

Third: It reminds me of what happened to my ancient dovetail jig when I first tried it out. I didn't tighten the router height adjustment enough and the router slipped down while I was cutting the dovetails. It got a bit too low. Yes, pun intended. :p

View attachment 425098
And handheld that had to be a bit of a shock when you hit that dovetail jig! Hope the only thing injured was your pride (and the dovetail jig).

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And handheld that had to be a bit of a shock when you hit that dovetail jig! Hope the only thing injured was your pride (and the dovetail jig). David
The router and dovetail jig were given to me by my father-in-law. He had not used them for years, and had no printed instructions. He could not remember how to use them. I took them home, but didn't really know what I was doing. Neither the router nor the jig had instructions. I failed to tighten the router height lock, which was just a plain wingnut.

You can see from the two gouges in the dovetail jig that I wasn't aware of what was happening right away. I was looking down on it, and the dovetail bit was into the boards, hidden from view. The aluminum gave more resistance than the wood, but not enough for me to know what was happening. It was so new that didn't know what to expect. I stopped cutting when I started to make that second gouge and happened to notice aluminum shavings coming out in the mix of sawdust. :-(
 

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5 years before a mishap is exceptional....expensive lesson when it's your money.
When I was green in CNC milling I snapped a 3/4 Dia. carbide end mill $$ ...after the shock of the noise I'm checking myself for shrapnel (blood) as the guards on that machine were thin ...nope I'm good except for my shaking hands.
These machines must have a manual home button for Z at least ..right?
 

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Thanks David, Tool and others, it's comforting to know that far better wood workers than me "mess" up.

Non wood working, but sort of like CNC: In the '80s I was programming a TSR, it couldn't use DOS for file I/O, I had to write very low routines for it. A small math mistake led to my telling the floppy disk heads to go to a place that didn't physically exist. There was a whole lot of head banging before I got to the power button.
 
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