Lathe (re)Setup Question

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BROCKWOOD

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I have a 25" long bar that I've started turning to size. It is centered in a 4 jaw chuck & supported on a live center in the tailstock. Now I understand that with a lathe dog in use the part can be removed & reinserted as needed. I guess that requires the dead center in the chuck remaining in place. Can I not remove the bar & simply re-center it in the 4 jaw chuck?

Mine is a combo & the lathe needs fixing to finish this bar into what I'm making. Meanwhile, I need the mill portion to make a few parts for the lathe repair. On paper I see no reason the part could not be dialed back in. I defer to those with experience though. Am I missing something?

289455
 
Usually one would dial in a center in the four jaw and recut the center to be true with spindle. Then you would mount your bar between centers. This would keep the centers true throughout the process allowing you to take your part off and on the machine as you wish. Doing it the way you have it you have to dial in the work every time you remove.
 
Thank you Cadillac! I don't have any 'dogs' as I intended to plan my order of operations in a way that put their purchase further down my list. Yes, you confirmed my thought, because it is an independent 4 jaw, it can be re-dialed in without worry. Now if, the part needed to constantly be removed & re-inserted: Dog's would definitely move up on my list of things to buy. As is, I don't mind a little inconvenience / practice.


Wonder who will take Fenner's 4 jaw speed dial belt this year at the Bar Z Bash ;-) {not this novice}
 
Make a dog ! Not that hard to do . :)
 
Also, you haven't mentioned how accurate the work needs to be on that shaft. If 0.010" is good enough, you're fine, but... if it has to be <0.001", yes, then the centers should be used. Also, depending upon the depth of cut, that shaft may deflect, with the result being that the middle of the shaft will end up thicker than the ends. It all depends upon its end-use.
 
Thank you kb58. Yeah I need to just make dogs as mmcmdl suggests! The project shaft is going to be a dog driver on a B&S no2 Dividing Head. It's a B&S taper going into it, so tolerances will become important. But, I am glad that IF the lathe had to quit - it was before I started on the taper!
 
I have dogs . I don't use them as I don't have a lathe any longer :big grin: I really need to put these items below for people that can use them .
 
Make a fare offer on the dogs. I see a real lathe in my future.
 
I see a chain saw or 4 in my future , so I guess I'll put the dogs on here . ;)
 
As mentioned above, your way can be done but depends on how accurately you can rechuck the part. A .0001'' dti would be necessary and even then it might not compare to using a centre.
Using a centre and drive dog would be so much easier and reliable.
 
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