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T.Hoffman
08-29-2011, 09:53 AM
About a year ago- I got a freebie of a old LW indexing head that looked very neglected, but after lots of hours of full dismantle, cleaning, lubing, etc.. it has been restored to silk-like operation.

http://www.blackfrogmusic.com/pics/temp/LW1.jpg

Problem is, it didn't come with any chuck. And it has an oddball thread size of 2-1/4 x 10:

http://www.blackfrogmusic.com/pics/temp/LW2.jpg

Now that I'm much more confident in doing threading, I have several projects where I could put this old girl to good use. Since I can't seem to find any off the shelf chucks or backing plates with that thread, looks like I'm going to have to make one.

I've never tinkered with any chuck-with-backing-plate configurations, only switching out chucks on my lathe. So I have several questions about doing this operation.

What type of chuck do I buy to attach a plate to?
Best choice of steel type for making a backing plate?
What thickness would you make the plate?

And on the LW unit pictured above, does the plate/chuck just screw onto the threads, or should there be some sort of locking mechanism to secure onto the threads so it doesn't want to "unscrew" while under milling forces in use?

Thanks for the help, I'm sure I'll have lots more questions about this as I go......

firbikrhd1
08-29-2011, 03:12 PM
I'm not sure if this will be of any help but take a look at this link:
http://www.lathes.co.uk/latheparts/page7.html

If it were me I'd probably make it out of cast iron which can be bought as slices of a round from the various metal suppliers or possibly use a semi finished back plate of a smaller size to bore and machine to the required thread/diameter. Perhaps one of these would have enough extra meat.
http://cdcotools.com/item.php?itemid=369

I have seen unthreaded blanks advertised in HSM as well and they are another option. Lastly, if I were really pressed for material I might consider a slice of aluminum round.

One other thought would be to make an adapter that uses the chucks you currently use on your lathe. That way you could simply transfer the chuck, with the work undisturbed from the lathe to the indexing head negating any runout induced by using a different chuck. You could also make a driving device like the one in the photo of the 203-4000 shown in this link to the Enco catalog and place your work between centers.
http://www.use-enco.com/CGI/INPDFF?PMPAGE=479&PMITEM=203-4010

T.Hoffman
08-29-2011, 03:52 PM
There's a whole LW unit on ebay right now going for almost a grand... But at least I can see the correct chuck on there:
http://i.ebayimg.com/t/L-W-Chuck-8-Dividing-Head-4-jaw-Chuck-/00/$(KGrHqR,!kwE1LC7oFIqBNb)LF032g~~_3.JPG

http://i.ebayimg.com/t/L-W-Chuck-8-Dividing-Head-4-jaw-Chuck-/00/$(KGrHqJ,!iYE1MHyVsZsBNb)L,DVwg~~_3.JPG

Looks like is just screws on tight and that's it.
Shure would like to find one of these original chucks, long shot I know.
I like how compact it is to the body of the unit compared to making a backing plate and then mounting to that....

uncle pete
08-29-2011, 04:16 PM
T. Hoffman,
For chucks you'd want what are called Plain Back chucks. You machine a backplate to fit your spindle, Then machine the backplates O.D. and bolt holes to fit the chuck. You'd bolt the backplate to the chuck to provide the interface. For a face plate, Bison sell larger cast iron blank backplates without any machining done. With one of the correct size you could build a faceplate for a direct mount to your spindle. I've only mentioned Bison but I'm sure there's others that offer the same types of chucks and blank backplate castings. To be honest most work using a dividing head like this requires high accuracy so maybe a independant 4 jaw chuck would be your best way to go. Hopefully some of this helps. Nice job cleaning that head to like new condition. One further thought. Depending on your experience level and the complexity of your dividing head spindle you could make a new one to duplicate your lathes spindle. That way everything is interchangeable.

Pete

gzig5
08-29-2011, 04:31 PM
I've got the little brother of yours and it takes 1 1/2"-8 chucks so I have a couple that will go right on. I would bet that if you buy a back plate for a 1 7/8" thread, there is probably enough meat to open it up to your thread. You just need to decide what size chuck to use. I would bet an 8" would be about right. Here is one example
http://www.tools4cheap.net/proddetail.php?prod=178back
I've got an L00 back plate from him and it is nice.

davidwdyer
08-29-2011, 05:28 PM
I don't know anything about it, but... it looks like from the picture there is a taper on the nose there. Could it be that it takes some kind of collet too?

RussZHC
08-29-2011, 07:03 PM
Post deleted, misread catalog

lane
08-29-2011, 07:05 PM
Most dividing heads use a 6 are 7 inch chuck. I prefer a 6 inch set true 3 jaw on mine. The backing plate can be made of cast iron are steel.

uncle pete
08-29-2011, 07:40 PM
That spindle nose taper looks like a 5c but I could be wrong. Sharp eyes David.

Pete

T.Hoffman
08-29-2011, 07:55 PM
I don't know anything about it, but... it looks like from the picture there is a taper on the nose there. Could it be that it takes some kind of collet too?

Yup, on my unit there is a thru-hole and draw bar on the opposite side. I *think* it may be for 5C, but not sure. I've seem to have read that LW's had other collet tapers in there, so I really don't know.

I don't have any 5C collets yet to check it.

If it is 5C, I have also thought about some of the 5C-to-chuck adapters I've seen around too:

http://www.shars.com/files/products/202-5447/202-5415Main.jpg

What's the best way to check/measure if it is indeed a 5C collet taper on my LW?

J Tiers
08-29-2011, 08:47 PM
Check the 5C dims at Zagar, or on OWWM, etc. If it looks close, get a $5 collet and see.

But, if you have a reasonable collet, like 5C (I spotted that taper also), you have a good way to hold mandrels for gear etc already, no need for the chuck.....

I have a 3.5" LW, and I have yet to put on a chuck..... (its 1 1/2-8). I usually use a mandrel with center and T/S, and a dog driver that captures the dog tail with setscrews.

Ya, if you want to make dividing plates or that sort of stuff you likely want a chuck for one-sided workholding, but the collets or dog driver are more secure against twisting

mike4
08-30-2011, 04:52 AM
I used a plain back four jaw chuck on a steel plate of about 5/8 thickness when I finally fitted a chuck to my 6" vertex .

The four jaw makes life easier when cutting special shapes to replace previously cast items.

I would make an adapter that would also allow you to transfer the chuck to and from your lathe if possible .

That allows a lot of versatility when working on projects.
Michael

MrSleepy
08-30-2011, 05:05 AM
About a year ago- I got a freebie of a old LW indexing head that looked very neglected

It doesn't look neglected now...very nice job...can I send you my Elliot :)


Rob

Ian B
08-30-2011, 05:15 AM
Lovely restauration job - well done.

On the chuck unscrewing, I'd also be bothered about that. If you indeed make a backplate that threads on, how about then adding a through-spindle drawbar. Tightening this should reduce the chance of unthreading - especially if you use a left hand thread.

I can think of other ways - picking up on the spindle's internal keyway if there is one and using a loose threaded ring to hold the chuck on, but much more complicated.

form_change
08-30-2011, 06:16 AM
A chuck on a dividing head is not like that on a lathe - it doesn't get massive forces put through it. This will depend on what you are doing of course, but for drilling holes or cutting gears (force towards the spindle) there is not going to be much trying to unscrew your chuck.
I want to put a camlock adaptor on mine so I can swap chucks between dividing head and lathe. To lock the adaptor onto the D/H I was thinking of a grubscrew with a brass tip.
Most D/H's I've seen have a 3 jaw as the chuck. Unless you are going to stuff that is not round, I'd suggest that is the better way to go. If you think about centring work in a lathe 4 jaw it usually takes (minimum) a couple of revolutions. On a D/H that is a lot of cranking. I'd also suggest the smallest chuck that you can get away with - a 6" or maybe even a 4". My latest D/H has a 8" and I almost bust a gut getting it mounted. If you make up a faceplate at the same time you make up the backing plate, you can cope with less regular shapes that way.

My thoughts.
Michael

T.Hoffman
08-30-2011, 08:36 AM
On the chuck unscrewing, I'd also be bothered about that. .

Doesn't look like the stock chuck in the ebay photos has any other locking methods besides tightening on the threads?

http://i.ebayimg.com/t/L-W-Chuck-8-Dividing-Head-4-jaw-Chuck-/00/$(KGrHqJ,!iYE1MHyVsZsBNb)L,DVwg~~_3.JPG

gzig5
08-30-2011, 01:43 PM
That chuck isn't going to come off during a milling operation unless it is being abused but if it makes you sleep better, cross drill for a set screw to bear on the spindle thread and put a piece of lead or soft copper on the end of the screw to protect the thread.

I would be very surprised if the original bore was a 5C taper. Most dividing heads were Morse or B&S taper. Mine is a B&S9 and I thought I've seen the big ones with B&S 12 tapers. It looks like there is a taper adapter in the spindle already that is sticking out past the thread.

There is a lot of taper and other info here: http://shopswarf.orconhosting.net.nz/sindex.html

Btw...I have a scan copy of the instruction sheet for the L&W 6 1/2" head and the index table for the 11", which is also applicable to to the smaller head.

T.Hoffman
08-30-2011, 02:43 PM
I would be very surprised if the original bore was a 5C taper. Most dividing heads were Morse or B&S taper. Mine is a B&S9 and I thought I've seen the big ones with B&S 12 tapers. It looks like there is a taper adapter in the spindle already that is sticking out past the thread.

Doesn't a morse taper have a constant slope to it? This LW has an outward flange at the end, and also has a tang in the interior hole for a slot in the collet. ....which is why I'm wondering about it being a 5C.

I'll go take some more pics and measurements and report back.

T.Hoffman
08-30-2011, 03:30 PM
Here's a pic of the drawbar with internal threads. Best as I can tell it is a 20tpi pitch from measuring down 1/2" and counting peaks out.

http://www.blackfrogmusic.com/pics/temp/LWbar.jpg

The outer diameter of the tube is 1.050".
So right away that rules out it being a 5C since a 5C's diameter is bigger than my 1.050 tube....

The internal diameter of the peaks of the threads is 0.881".

Here you can see the flange and internal tang for the collet groove.

http://www.blackfrogmusic.com/pics/temp/LWcollet.jpg

...after digging around, I think I might be needing a 4C collet here....
And now I look closer, I can't tell if that is "40" or "4C" stamped into the face of the flange.

http://i12.photobucket.com/albums/a214/piniongear/10K%20South%20Bend%20Lathe/ColletDimensionsMedium.jpg

Chart says the 4C has an external thread diameter of .942" at 20tpi, and my internal thread peaks are at .881", a difference of about .061" so that's around .030" of thread overlap each side which seems reasonable?

Am I looking at a 4C arrangement here?

gzig5
08-30-2011, 03:34 PM
Doesn't a morse taper have a constant slope to it? This LW has an outward flange at the end, and also has a tang in the interior hole for a slot in the collet. ....which is why I'm wondering about it being a 5C.

I'll go take some more pics and measurements and report back.

Yes, Morse and B&S are constant slope. But the way that sticks out past the thread on the spindle nose made me think that someone put an adapter of some sort stuck in there. A B&S 12 would be about 1.800" at the spindle nose according to the link I posted, and might be big enough to take out to 5C.

lane
08-30-2011, 07:30 PM
That dividing head has some kind of collet adapter inserted in the spindle . like you may use in a lathe .

Chris S.
08-30-2011, 08:56 PM
The taper doesn't look like a Morse but more like a 4 or 5C but that would be odd too, because there's no lip on the clollet nose. On a lathe, the thread protector is used to easily remove a 5C collet holder by un-threading it so it bares against the lip of the collet holder. Is it possible that it's not a removable holder?

Chris

BTW, very nice cleanup!