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Best Chuck For Dividing Head.

A 6 jaw universal set true is the best...you can always use a 6 jaw as a 3 jaw if you need to, or more often just leave out 1 or 2 jaws to allow access to the part such as to mill a keyway. over the years I have used 6 jaws with 6, 5, 4, and 3 jaws. A 6 jaw chuck holds the part a LOT better for milling... sideways forces are poorly controlled by a 3 jaw with normal jaws, if I HAD to use a 3 jaw I'd get one with top jaws so I could make soft jaws with a lot more contact area.
 
I have a Kearney & Trecker dividing head with a 3-jaw chuck. I recently purchased a South Bend Heavy 10 that didn't have a 3-jaw chuck, so I took the chuck off the dividing head, and made an adapter to use it on my Heavy 10.

I was disappointed with the performance of the chuck; not in the accuracy, it repeated within .002. It took too many turns of the chuck wrench to adjust this chuck for different size workpieces, due to the slow-speed scroll which increases the gripping force of the chuck. And the chuck was horribly out of balance for any spindle speed other than a back gear speed.

I came to the realization that this chuck should be left on the dividing head, as it was definitely matched for it; both in capacity and in accuracy. That is where it is going to spend the rest of it's (or my) life.

I will purchase a new 8" 3-jaw chuck with 2-piece jaws for my lathe. A 4-jaw chuck would be too difficult to dial in, because I do not think that this dividing head has a free wheeling spindle. I suppose that someone will prove me wrong on this. I do not care.

Lord Byron
 
Well, there probably isn't an answer to your "best chuck" unless you accept "it all depends". Smaller round diameter work might go better in a collet. Quick work where concentricity may not be so important, a three jaw. Thin wall, a six jaw. Some work may go well in "pie" jaws milled to accept the parts shape or soft jaws thatg grip easily marred finishes and features. Irregular work, work requiring close concentricity or work requiring a reliable grip use a four jaw. Hell, I've even used a face plate a time or two.

But generally most home work in a dividing head can be satisfied by a three jaw chuck but keep your options open. In the machine shop you never know...
 
Bruce Nelson said:
I have a Kearney & Trecker dividing head with a 3-jaw chuck. I recently purchased a South Bend Heavy 10 that didn't have a 3-jaw chuck, so I took the chuck off the dividing head, and made an adapter to use it on my Heavy 10.

I was disappointed with the performance of the chuck; not in the accuracy, it repeated within .002. It took too many turns of the chuck wrench to adjust this chuck for different size workpieces, due to the slow-speed scroll which increases the gripping force of the chuck. And the chuck was horribly out of balance for any spindle speed other than a back gear speed.

I came to the realization that this chuck should be left on the dividing head, as it was definitely matched for it; both in capacity and in accuracy. That is where it is going to spend the rest of it's (or my) life.

I will purchase a new 8" 3-jaw chuck with 2-piece jaws for my lathe. A 4-jaw chuck would be too difficult to dial in, because I do not think that this dividing head has a free wheeling spindle. I suppose that someone will prove me wrong on this. I do not care.

Lord Byron
Click to expand...

Many dividing heads have a means to freewheel, on the L&W's they had to because they offered an option for direct indexing, the worm was dis engaged from the wormwheel for direct indexing, which used an index device attached to the spindle.

Using a 3 jaw for mill work what I saw was that if the cutting force was applied in the same direction as one jaw, directly between the other two jaws more or less the part could be pulled right out of the chuck. Maybe a finer scroll equaling higher clamping force helps with that ?

Bill
 
Not to rain on anybodys parade - Dividing heads are obsolete, unless you need 27 or 127 divisions. I've got 2 of them & a rotary table. A quick/super spacer will do 99% of your indexing, plus horz. & vert. clamping plus a thru hole. And of coarse my spacer has an adaptor plate for the tailstock off an Atlas lathe. The tailstock is good for centers, pipe centers, spider centers, & if I'm not happy with that, I can use the adaptor plate with the steady rest for end work. :cheers:
 
Blake,

I can think of quite a few times that the parts I was making could not have been made with a super spacer. Several mold cores and a couple of cams come to mind.
JR
 
They just don't make the Super Duper machinery that covers every situation 100%
You can go out and spend $3000.00 on a camera, and guaranteed your going to need a differant lens sooner or later.
You wouldn't need a golf bag or caddy, If you could play the game with one club.
Differant situations call for uneaque measures, thats the rules of the game!
Dave [acme thread]
 
Can't remember the last time I mounted the good 3 jaw scroll chuck on my main lathe but....

I have a NOS, (cleaned off the cosmoline myself, black crackle finish unmarred around the bolt-down slots), L-W 10" dividing head with the factory 6" L-W 3 jaw scroll chuck that came with it and so far, it has proven quite accurate. I'm very careful with it.

By the way, the full name of the company is "L-W Chuck Co.", and it looks like they knew how to build an accurate scroll chuck but no "Tru-set" adjustments.

No, I didn't check it's TIR on the drill press, the vertical was busy with RT on the table when I needed to center drill for that hole layout, only decent pic of the chuck.....:o...besides, I'm not sure my old Index mill is any better than my tight Clausing drill press.....he protested too much....

QUOTE: "Interesting.....nobody has opted for centers and a drive dog." That's the way I use this dividing head most often. Nice new B&S #10 center, tapered mandrel....

Quote: "Not to rain on anybodys parade - Dividing heads are obsolete, unless you need 27 or 127 divisions. I've got 2 of them & a rotary table. A quick/super spacer will do 99% of your indexing..." My indexing?:D

Admittedly, I do a lot of oddball stuff in my prototype shop but which of your indexing plates sports 13 notches, 17, heck, how about 41?;) I can't get by with just a few "standard" spaces......:cheers: ...jus' loves flexibility...

Bob
 

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Hey - I've got the same L-W dividing head. It came to me with a 3 jaw chuck on it that has 2 piece jaws. The downside it the current hard jaws that came with it are way off (like .040 or more) the plus side is I can make removable soft jaws (finally have some stock to do just that).

I have thought of getting a cheap 4 jaw for it and modifying the 4 jaw to thread directly onto the L-W (it does not have a common chuck thread). The advantage of this is it would also lower the height as the L-W is kind of big for use on a Bridgeport with the chuck installed and vertical.

I've also got the bits to drive with a dog on centers.

Side note on L-W dividing heads - if it is not a universal one (that can be geared into the table) how do you disengage the worm to get it to freewheel? I did not see a way, but I may be missing something obvious as I've used it once so far, but need to make a gear soon.

Paul
 
PaulM said:
Hey - I've got the same L-W dividing head.
Side note on L-W dividing heads - if it is not a universal one (that can be geared into the table) how do you disengage the worm to get it to freewheel? I did not see a way, but I may be missing something obvious as I've used it once so far, but need to make a gear soon.

Paul
Click to expand...
The worm bearing is pressed in an eccentric collar. On the close edge of the main barrel, there are a pair of screws, one on each side of where the shaft goes in, that push against the eccentric collar in little pockets to revolve it a little for take-up, left or right. Remove the left screw and revolve the dividing plate right to disengage the worm from the worm gear.

Make sure the set screw on the dividing plate mounting collar is tight first.

Oh yeah, don't disengage the worm while you're cutting that gear.....:D but do adjust those screws until there is no freeplay between the gears. The left one snugs up the mesh and the right one locks it there.

:cheers:Bob
 
I mostly use 5c collets, as well as 5c step chucks & extra deep step chucks, always with closer rings. Some of the deep step chucks are bored to a common bar size (2", e.g.) and i mill the bar ends and slit them to make odd (non-round) collet inserts. Mostly 'cause it's cheaper than buying new deep collets in the 2" and larger sizes.

Also use 4 jaw chuck, and have a Buck Forkhardt 3 jaw adjust-tru with top jaws, have not had reason yet to use it with pie jaws, but that is why it is on hand.

Some things are done here between centers, and some on the end of expansion mandrels.

Basically whatever it takes. But the large collets with inserts are good for repeat small parts because you can mill into it if necessary for some features, where that would be bad practice in a jaw chuck :eek: It's also hardto beat the grip of a purpose made collet or insert. (soft pie jaws similar advantage, of course, but collets still seem less prone to vibration if the part will fit.)

OTOH, my Hardinge DH's aren't exactly "wide ratio" style. So you give up some versatility for facility of workholding, as long as a part does not take an odd or extended range division.

If I had to have a DH that did not take 5c system, I'd probably want the 3 jaw adjust-true with soft and hard top jaws as being slightly more versatile & better repeating on multiple parts than a 4 jaw. But small 4 jaws are not so expensive as to preclude both.

smt
 
Thanks Bob -

That description helps and I will give it a try (improves of the endless cranking to check the center). I had checked the scans of the instructions previously (I think they are your scans) but I did not catch the "full disengagement" section.:cheers:

Paul
 
Welcome aboard Shopteach!

About attachments, after you "CHOOSE FILE" and it loads in the attachment box, you have to then "LOAD" it to your post. That last step has tripped up more than a few, me included. Another pitfall: exceeding the 19.5KB size limit but luckily, photobucket works very well.

Nice to have the spindle bore capacity to pass larger parts through, to minimize overhang on chuck work. The ability to easily swap between 3 jaw and 4 jaw has to be a plus too.

Bob
 
blake in spokane said:
Not to rain on anybodys parade - Dividing heads are obsolete, unless you need 27 or 127 divisions. I've got 2 of them & a rotary table. A quick/super spacer will do 99% of your indexing, plus horz. & vert. clamping plus a thru hole. And of coarse my spacer has an adaptor plate for the tailstock off an Atlas lathe. The tailstock is good for centers, pipe centers, spider centers, & if I'm not happy with that, I can use the adaptor plate with the steady rest for end work. :cheers:
Click to expand...

The level of accuracy of a dividing head is probably exponentially better than most indexers and super spacers. The dividing head also has the ability to cut helixes, which no indexer does, and it can properly "throw off" some flutes if your making a cutting tool, on and on. And you can easily set a dividing head to any angle you might require without resorting to putting the whole head on a sine plate.

Saying a super spacer makes a dividing head obsolete is like saying a KO Lee universal tool and cutter grinder puts blanchards and other surface grinders on the scrap heap ;-).

Super spacers, and 180 degree index tables, and other indexers existed side by side with dividing heads for all of know history.

For many jobs the quick indexers based on 24 divisions with the ability to block out some indexes ARE quick and easy. 4 and 5 axis cnc REALLY made other stuff obsolete.

Bill
 
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