Horror Stories About The Chuck Coming Off While Running Backwards

Like anything else,getting a chuck to not unscrew requires experience,skill and discretion. I do not advocate doing it if you are a beginner.

At the least,you can put a big whack into your lathe bed,or mark up the chuck,even if you do not get injured yourself. Even with a smallish,6" chuck,you can get a finger joint RUINED,or a finger broken,if the chuck suddenly unscrews and drops onto the lathe.

Some drill and thread a hole into the neck of the back plate that holds the chuck onto the threaded lathe nose. A piece of brass should be inserted into the hole before screwing a set screw into it,to prevent damaging the threads on your lathe.

There are other,more elaborate ways of safeguarding the chuck from unscrewing,but this is a simple way that anyone can do. I would not screw the set screw really tightly into the hole,as it might force the chuck sideways a thou or 2. Once again,discretion.

Perhaps I should not even try instructing people in what I might be able to do with experience since 1959. It becomes a case of "Don't do as I do,do as I SAY do"!:)
 
After Bob Sakowski mentionned a chuck lock on his G0602 I had a look at the manual.
In case anyone might want to have a look at it there is a picture on p. 27 of the manual.

http://cdn2.grizzly.com/manuals/g0602_m.pdf

Bill, hopefully the persons with concerns about the chuck spinning off the spindle are not just the ones who have actually seen it happen.
 
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My old lathe (4"center height) has a spindle nose with 16tpi. I often have trouble unscrewing it because it's so fine and locks very tightly.
One day a long time ago, I had a largish piece of cast iron to machine, duely at slow speed. When I realised that I had the wrong tool mounted (high rake for aluminium), I just hit the brake pedal to change tools. With the added weight of the CI lump in the 5" chuck, the braking (not emergency braking) was enough to loosen the chuck and it kept turning. By the time my astonished eyes and brain realised what was happening, the bl00dy thing had unscrewed the whole way and fell promply on my foot, heavy workpiece and all.
Lesson learnt.... :( - fortunately only with a small bruise...
Been much more aware of the potential and careful since.

Joe
 
I own a Grizzly 9x20 lathe, which uses an M39 x 4mm spindle thread (IIRC). I did something like what George Wilson describes - drilled & tapped each chuck ¼-20 at a point back of the end of the threads. Once the chuck is in place, I lightly screw in a SHCS to just snug against the spindle nose. I avoid tightening it - as George pointed out, you don't want to push the register off center. But if the chuck were to try to unscrew, the end of the SHCS would jam against the last spindle thread and stop it.

The result might not be very pretty, and I'm sure I'd have to re-dress the threads, but at least I won't end up injured. Luckily, I haven't put it to the acid test ...
 
hman said:
I lightly screw in a SHCS to just snug against the spindle nose. I avoid tightening it - as George pointed out, you don't want to push the register off center. ..
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What is SHCS something something countersunk screw ?
 
BillWood said:
What is SHCS something something countersunk screw ?
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Socket Head Cap Screw. A Socket Head Set Screw (SHSS) might be a better choice for securing a chuck since it could be below the rotating surface thus preventing potential snagging of swarf, rags etc.
 
i've had one come off wile dropping from high to low....(electrically)...i just go to complete stop since then
 
REdington said:
I never even thought about a chuck unscrewing until I saw this. My baby armature lathe is the only lathe I've operated that had a screw on chuck and it doesn't have reverse. I have a 14 X 48 Clausing (L-OO spindle) and would like to get another lathe, a little smaller for small work. It'll probably be one with a threaded spindle and I'll remember this.

Rodney
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Have a laugher for you about reversing a chuck.I built a wood lathe 30 years ago and because I am left handed I thought the motor would be better on the right side of the bed,contrary to every other wood lathe ever made.
I had not noticed a problem at first ,only had done spindle turning up til then.I was given a chuck and decided to mount it. In order to have the chuck turn towards me I changed the rotation of the motor.
Within a blink of an eye the chuck rolled on the floor,thru the open door and landed in a bed of cucumbers 75'-0" away.
I retrieved my chuck,looked around to see if anyone had seen this stupid act,ran back in the shop. I then reversed the rotation and turned the lathe around so it had the motor on the left side ,looking at it.
I can laugh now,scared the heck out of me then.
 
The trouble with peeing on the electric fence might be that you would not be able to STOP!!!!:)

When I was about 7 years old,on the way home from school,I used to stop and look at the cows in a pasture. Leaned on the electric fence TWO times before I got it through my thick head NOT to do that! Gave me quite a jolt,too!!

There was a bull penned up across the street. I used to pull up grass and feed him every day. He was quite gentle,and glad to get the grass,as there was none in his pen. One day that bull got loose,and the men were running all over the place,yelling about that DANGEROUS bull being free!! I had had a very friendly relationship with that bull as far as I was concerned,though I had NOT tried getting in the pen with him.
 
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