Drill chuck on live center - why?

I have, from an estate sale, a nice new 1/2" keyed drill chuck mounted to an MT2 live center. The chuck rotates on the center.
What purpose would something like this serve?
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RB wrote:

This set up is often used to true up small electric motor or generator cummutators. One end of the shaft is held in the lathe's chuck, the other by a chuck like the one you've described. The area where the brushes run can then be resurfaced.
Pete
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Pete Snell wrote:

Ah, that makes sense. Holding a small diameter rod between spindle and tailstock, where the stock is too small for a center.
I guess I'll keep it then.
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I wished I had one a number of times. How about holding small diameter rods?
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mounted
How 'bout super-low torque drilling? <G>
LLoyd
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RB wrote:

The same reason as having a live center in the tailstock, to hold something. Three jaw and four jaw chucks with morse live centers on the back side are common in shops doing large tubes or long hollow parts.
John
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    For supporting the far end of something which does not have a center hole -- and for whatever reason *should* not have one.
    Back in the old days, Jacobs made chucks (without keys) for the purpose of supporting the far end of a motor shaft while turning a worn commutator. This one had bronze jaws, V-shaped to support the shaft with out too much contact area, and with a ring to lock the outer shell so you could adjust to be a slip fit on the shaft, and not have to worry about the chuck either tightening or loosening during the operation.
    I have one of these recently sold on eBay -- by someone who thought that it was a standard drill chuck, and had no idea what the locking ring was supposed to be for. Luckily, I recognized it for what it was, and bid on and won it.
    Your chuck may well lbe for this sort of purpose, except designed to firmly grip the motor shaft, and to rotate with it.
    Why not put a photo of your chuck in the dropbox (http://www.metalworking.com ) and post the resulting URL to here so we can take a look at what you have.
    Enjoy,         DoN.
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DoN. Nichols wrote:

Done. Posted as "chuck mounted to a live center" txt & JPG
I don't know how long it will take to show up.
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    [ ... ]

    Ouch -- spaces in the file names, so they will be replaced by the system with underscores '_' to avoid problems with some systems. Spaces embedded in filenames are *evil*. Even a problem to some business versions of Windows -- which started the fad. :-)

    They are there already. You even have a space between "center" and the '.'. :-)
    It looks (from this angle) as though someone took a changeable point live center and machined up an adaptor between that and a Jacobs taper (or the Metric equivalent which is a little different in dimensions). So -- consider it "shop made".
    What is the primary Morse taper there? -- MT-2 I guess, and a step-up to MT-3 and another to MT-4?
    I did something similar to adapt a small (3") lathe chuck from my Compact-5/CNC lathe to a changeable point live center for turning threads in the end of a 3.5" ID aluminum pipe (Sched 40 IIRC). I slid the tubing over the chuck with retracted jaws, then expanded the jaws inside, loosened the headstock chuck a little and cranked the tailstock feed to seat it firmly on the step jaws, and then tightened that end too before cutting the threads. It made threads in the OD at the free end very easy.
    Anyway -- you have a tool which is quite useful when needed, so keep hold of it.
    Enjoy,         DoN.
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"DoN. Nichols" wrote:

Commodore allowed spaces in file names, long before Windows did.
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    MS-DOS's COMMAND.COM could not handle embedded spaces in the file names.
    However, the BASIC interpreter, descended from the Altair Disk Basic (also from Microsoft) bypassed the OS's high-level disk routines, and could create files with embedded spaces in the names. I discovered this in a MS-DOS 2.? system which included a "typing tutor" program. That program created files with embedded spaces in the names (to record the progress of a "student"), and the only way that I could get rid of it was to go into BASIC, and type the command in BASIC to remove a disk file (I forget what the syntax was, but it was in the manual). *That* got rid of it. The normal unix tricks (enclosing the filename in single quotes or double quotes did not work, and the unix trick of preceding the space with a '' *could* not work because MS-DOS used '' as a subdirectory separator.
    I later encountered a similar problem in another system which included a Microsoft BASIC (a computerized spectrophotometer FWIW), but did not include MS-DOS as the OS). However that version of the BASIC did not have the command to delete a file, so I was stuck by the files created by someone else.
    It wasn't until Windows that the command line allowed referencing files with embedded spaces in their names on Microsoft systems. And -- they are regretting allowing that for their business systems and servers, where scripts (.BAT files or the like) tend to break when they encounter spaces in filenames.
    I've never used a disk-based Commodore, so I don't know how the command line handled embedded spaces in filenames. It may be that the design of the command line allowed only on e filename per command, so it could just keep reading until the end of the command line and treat it all as a single filename. If not -- how did you specify on the command line (not to be confused with referencing from within BASIC) a file with embedded spaces. Or was it like the Altiar Disk BASIC, where the BASIC *was* all of the OS that existed, so you had to reference files purely from within BASIC commands?
    Enjoy,         DoN.
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"DoN. Nichols" wrote:

The Disk OS was in ROM, so there was no equivalent to command.com. The filenames were up to 16 characters, and could have a space anywhere you wanted. I used to put a menu on a disk, with two leading spaces and a couple utilities with a single space so that when the directory was sorted, the menu was always the first item. If you held the 'Commodore' key and pressed the 'run' key it loaded and ran the first program on the disk. BTW, Microsoft was involved in the ROM based OS. The commodores would only hold one basic program at a time, but there was a small area of protected RAM where small machine language programs could be run with a 'poke' command.
I still have the books detailing the ROM based OS for the 1541 drives. In fact, I had multiple copies, from friends who moved on to programing newer computers. One was called 'Inside the 1541', but I can't remember the other title and I don't want to go out to the shop at one AM to look. :)
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