Goofs & Blunders You Should Avoid.

Always ensure the chuck jaws are engaged in the spiral.
Very quickly I set up a half inch wide cut off of a large plastic pipe and used the three jaw to expand outwards on the inside of the pipe so I could true the face.
OK, nice and tight, start to cut and zoom, bang!
two of the jaws flew across the room, they had expanded enough to pop out the spiral but the plastic ring kept them in place so I hadnt noticed.
Luckily I was not in the line of flight.
 
The cost of being lazy and not paying attention.
I was machining a Tee shaped mounting bracket the other day for a small stepper motor.
As a final step, I was attempting to make a larger, shallower countersink hole to facilitate a small taper around the shaft bushing instead of a bigger through hole. I opted to use my mill since the piece was already set up there. Long story short, I went too deep and got into my vice jaws. Ouch !!!!
Luckily, it didn't do too much damage and I was able to smooth off the small boogered up area with a file. Lesson learned.
 
Learned this one last night. When installing hardware on new cabinets, and the new looking box of bits you found in the FiL's collection just doesn't want to cut, might want to check the packaging and see if you inadvertently grabbed a box of left-handed bits...
 
First time ever for this hobbyist. I was side milling a fairly small part held in the vice on two parallels. I taped the part down onto the parallels while tightening the vise. The part being milled was outside the vise jaws. Long story short one parallel managed to slip forward and crash the end mill. Parallel survived, milling cutter not so much.

I took a piece of shipping steel banding and bent it into a U to hold the parallels tight against the jaws and also made sure the part was seated firmly on both parallels.

David
 
brino said:
There were some comments above about removing swarf.
Here's a shot of the acid brush I use to remove swarf and apply cutting oil to the work area:
View attachment 141751

The milling cutter grabbed it, pulled it thru and spit it out the other side.
I am so glad it wasn't my fingers.

I still use it.....keeping it as a reminder......

-brino
Click to expand...

Sorry for quoting an older post, I was away during that time.

Funny! Reminds me of Randy Richard on YT. In one of his videos he shows it in action!

Pretty funny! I'll have to try that sometime!

http://www.hobby-machinist.com/threads/milling-machine-aka-automatic-brush-roller.32385/
 
When running a CNC machine turns your feeds down to 10% on the first part when proofing a new program. This guy in our shop, running a lathe the size of a mini van with a 3 foot chuck and a 6 inch thick boring bar, chucked up a 30 inch cast iron brake drum, hit the green button and let her fly at 100% speed. It knocked the brake drum out of the chuck, it blew the door off the lathe and landed out on the shop floor BOOM. Our shop foreman ran down there and chewed that guy's ass for like 20 minutes. lol
 
When doing an utterly simple calculation it pays to still think about it and double check. I was making an arbor for a 7/8" plain mill cutter. Near as I can recall the old brain figured something like this:

"hmm, 7/8"? Let's see, 3/4" = 0.750 so 7/8" = 0.875"

So I then proceeded to turn it down to 0.750". A simple double check would have prevented it.

Fortunately it was only for 1/2" in length and I had left ample length on my cut off bar stock to fix it.
 
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