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View Full Version : Did I get a fright today?



bobbybeef
03-23-2005, 04:08 AM
Hullo All,
There I was happily machining a 3/4"mild steel rod in the minilathe. All the gibbs are up pretty tight;the handwheels turn under a tiny pressure and I suddenly put on a mental dream and added 30 thou more than I needed. The HSS knife bit went straight in and a really bad lockup was looking iminent.
By a miracle my hand slipped and knocked the feed wheel back enough distance to allow the lathe to continue. Albeit with smoke and stuff going everywhere.
The point of the story is that on a lathe that I reckoned was pretty well tuned and had operated satisfactorily for over a year
,the quick change tool post,the topslide to which it is attached and the cross slide below that ALL MOVED through I reckon 3 degrees of arc before the situation was stabilised.
In fixing the handles on all these bits I usually finish the job with a tap to lock with a PLASTIC HAMMER.NOT A GREAT WHACK BUT A GOOD FIXING TAP TO MAKE SURE IT IS HOME AS FAR AS IT WILL GO.
This story is told to protect the innocent and let you know that lock up is just around the corner.
Regards to all.
Bob.

wierdscience
03-23-2005, 08:17 AM
Yes I have and do have those heart stopping moments,makes you feel alive doesn't it?

kap pullen
03-23-2005, 08:25 AM
Yes,

Most of us that have been around a while have had a couple of experiences like that.

I threw a 36" cast iron piston off a King Vertical Boring Mill once. Just once!

The boss always said "increase the feed till she comes off, then back off 10%"

I took him serious.

Anyone else?

kappullen

torker
03-23-2005, 08:42 AM
Ha...I was just going to make a similar post!
It's been crazy lately. I'm usually up by about a quarter to 5am. Check out the boards then head down to the shop for a bit before work, work all day beating 10 guage steel into shape with a hammer and torch inside of cement truck drums. Ugly work! Then come home, gobble down supper and head back down to the shop. Was down there last night turning down some hubs for a guy from 4" OD MS with a 1" bore. Was taking .065. DOC (.130 overall cut)with the little SB, standing there half asleep with a pair of pliers to guide any of the errant culverts that where coming off. Wasn't paying attention to the big pile growing underneath. Of course this big pile got picked up and started flailing around. I reached for the kill switch and turned a bit, damn swarf grabbed the pliers right out of my other hand and sucked them into the mess. WHEW!!!! That DID wake me up. I know better than to do this. I was being a dummass! Watch out !
Russ (NOT going to the shop this morning!)

sandiapaul
03-23-2005, 09:10 AM
OK my story...I was slotting big(about 4" across the flats) hex nuts on a big old K&T horizontal. We had them all ganged up with 2 slitting saws doing 2 rows at once. The saws were about 6" in diam. My boss("if the chips are not blue turn it up") had me running it pretty fast. One saw bound up and shattered and a piece of the cutter flew across the shop and just grazed the bill of the cap of the kid cleaning chips out of a W&S. He thought I threw something at him as a joke. I told him he didn't want to know what almost hit him!

Rustybolt
03-23-2005, 09:59 AM
That's just the machine's way of telling you to pay attention.

andypullen
03-23-2005, 10:03 AM
I had a frame slipper for a full sized steam locomotive come out of the 36" G&E shaper I was running. The cutter hit a hard spot, dug in and shoved the 400 pound hunk of steel out of the vise. And kept on going like nothing happened!

I recently sheared the pin in my Clausing's lead screw during a threading operation. Woke me up in a hurry!

Andy Pullen

precisionworks
03-23-2005, 10:17 AM
Bobby,

Same setup as yours, only the workpiece was 4" OD x 36" long & the ends were being turned town for bearing fits. Taking decent cuts (0.175") with the end supported by the live center. Got in a hurry, increased the DOC to 0.250" which was just a little more than the live center wanted.

Got lucky -- only broke the insert, insert seat & insert hold-down screw. Made a helluva racket each time the loose end whacked the toolholder. Stout toolholder, 1x1 shank on a QCTP.

Probably should have used the steady rest...............................

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Barry Milton

lathehand
03-23-2005, 04:55 PM
The guys in maintenance needed ring about 6 inches in diameter, nothing special. The only stock I had that was big enough was a broken piece from a 50hp motor flex coupler.
I chucked up the "aluminum" piece and faced it, bored it, and turned the OD to size. I had a nice pile of chips. The "aluminum" was cutting like cast iron, crumbling into bits.
I was parting off the piece when I saw sparks. Now I was spinning the work quite fast, but not that fast! Sure enough the sparks landed on the chips and I had my first and only lathe magnesium fire.The other oily chips were burning also.
I used a file to spread out the chips and they burned themselves out with no damage.
It took a while longer for my heart to slow down.

BillH
03-23-2005, 05:35 PM
I did the same exact thing on my mini lathe, ofcourse when it happends, it seams like everything goes into slow motion. Have yet to do that on my South Bend, don't think I could anyhow with the flat belt.

matador
03-24-2005, 03:20 AM
A few days ago,drilling a piece of 3/8"flat with a 3/8 drill.too lazy to clamp it down.
Fine until just before breaking through.Drillbit grabs flat,knocks it out of my hand ,swings around and belts me a good one on the index finger joint before I can pull back.
Swollen hand for 2 days,and still throbs a bit at night.
Guess who will use the vise next time? http://bbs.homeshopmachinist.net//biggrin.gif

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Hans

captainkirk
03-24-2005, 07:16 AM
Almost married a girl that turned out to be a real nasty selfish (rimes with witch)gold digger........boy that was a close one, almost cost me my life!

wierdscience
03-24-2005, 07:25 AM
<font face="Verdana, Arial" size="2">Originally posted by captainkirk:
Almost married a girl that turned out to be a real nasty selfish (rimes with witch)gold digger........boy that was a close one, almost cost me my life!</font>

Whew,now that was a close one http://bbs.homeshopmachinist.net//biggrin.gif That's the kind of accident that keeps on hurting.

BillB
03-25-2005, 02:38 AM
You guys make me glad I work on small stuff. More clearance when it sails by your ear. And yeah, flat belt slippage is a _good_ thing.

Kirk, I thought you'd given up on that sort of risk. Didn't you say that instead of getting married again, you were just going to find a woman you can't stand every five years and buy her a house?

BillB