# Lock for 3 jaw chuck on Atlas 12x36



## Jim Ciampi (Oct 14, 2013)

I'm considering fabricating a lock for my three jaw chuck,so I can operate the lathe in reverse,but I don't want to reinvent the wheel if it has already been done. Has it?..... Thanks Jim


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## fgduncan (Oct 18, 2013)

Jim Ciampi said:


> I'm considering fabricating a lock for my three jaw chuck,so I can operate the lathe in reverse,but I don't want to reinvent the wheel if it has already been done. Has it?..... Thanks Jim




My first thought is why in the world would you want to do this? A lathe is designed to run one way and take the cutting forces from one direction. I heard of a high school shop class that had a lathe with a reversing switch on it.  One day somebody turned it to reverse, and the next student that turned the lathe on found out just what can happen the hard way. The motor spun the chuck off the back side of the lathe and it rolled across the floor scaring the living bejesus out of several people, including the instructor.  The story is that all reversing switches were removed by the next day. Wonder why!

That being said, here is a picture of a lock on the back of a chuck I used to have on my 10" TH42. If your chuck has a "neck" on the back, this can be cut in 3 or (as in my case) 4 places and a split ring fitted to it.  Tightening is done with the Allen head screw visible on the left. Make sure that the neck is actually threaded and not relieved or when you tighten the lock, it won't work. 

I'll probably put this one on eBay since I bought a bigger heavier duty chuck with reversing jaws.


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## Old Iron (Oct 18, 2013)

You can also make a step collar the locks on the chuck to the spindle. Which I would think it would be better than splitting the back plate.

Paul


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## Jim Ciampi (Oct 19, 2013)

Old Iron said:


> You can also make a step collar the locks on the chuck to the spindle. Which I would think it would be better than splitting the back plate.
> 
> Paul


  With all due respect. There are a number of reasons I want to do this,one of which is I can thread a blind hole if I turn single thread cutter upside down and start from back of hole and run lathe backwards.Another is I don't have to change cutters in holder for certain jobs. There is always more than one way to do a job.With experience comes knowledge. Try it you'll like it......Jim.  PS I already know how to do it I just wondered if anyone else has done it .Some times you get better ideas if you ask.There is a wealth of knowledge out here....Thanks Jim...


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