Jacobs rubber flex

Red1fire · May 31, 2017

Looking to install a Jacobs rubber flex collet wheel on a Heavy 10R with a 1-7/8" 8tpi spindle. Wont likely be able to find an original with matching thread. Any ideas on how to match one up?

kitno455 · May 31, 2017

Replace your spindle. They are cheap enough, and the extra through bore is great.

allan

Red1fire · May 31, 2017

Not sure if the spindle can be replaced, the heavy 10R has the cast iron bearings not the sleeve style. so not sure, any thoughts.

iwananew10K · May 31, 2017

it is a direct swap.

Danny VanVoorn · May 31, 2017

You can probably find one for the A type spindle and machine an adapter to fit it or get one of the Key type (96F1?) and put it on an adapter plate on it. The later one looks like a Jacobs super ball bearing chuck and has bolt holes just for that.
Dan

PmGRacer · May 31, 2017

I turned up a new mounting hub that bolts to the Jac collet body with a 1 1/2" -8 thread for my 10k. The Mounting hub bolts through the front of the collet body. So replacing it with one that will work on a 10R isn't a major ordeal. It I have a print I can post in the morning.
Here is a pic of the hub that came with the chuck.

Pic of the new one mounted on my chuck.

Pic of front with collet clamp removed.

Spanner tool to install and remove chuck from spindle. There are three 0.312" dia x 0.312" deep holes 120 degrees apart on the hub to facilitate removal/install.

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Illinoyance · May 31, 2017

Danny VanVoorn said:
You can probably find one for the A type spindle and machine an adapter to fit it or get one of the Key type (96F1?) and put it on an adapter plate on it. The later one looks like a Jacobs super ball bearing chuck and has bolt holes just for that.
Dan

Yes!
I obtained a key type chuck for a type A spindle. I made a backplate to mount it on my SB 10K.

tobnpr · Jun 1, 2017

I have the Model 50 like that shown above on my 9A.
"Downside" is that the max collet size for the 500 series collets is 1.06", while the larger Model 91/900 series collets that go to 1-3/8".

Go for the larger Model 91 setup if you can find it.

Red1fire · Jun 2, 2017

Thanks will do that. Would love to see the print. I'm so invested in 1-7/8" tooling that it would be hard to turn back and do a spindle change.

Red1fire · Jun 2, 2017

Can the D1-6 or the LO be converted in the same way. don't see a way to remove the lo or d1 style spindle hubs. No visible screws in the front of the chuck.

PmGRacer · Jun 2, 2017

After doing research on those chucks the mount hub is integral and can't be removed. You have to find one the will fit the lathe spindle. I wanted that style for my 10k but could not find a 1 1/2-8 threaded one. Most were D1's or Long Tapers.

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iwananew10K · Jun 2, 2017

it can be done,at least with the A type...Stephan Thomas show his in this thread..

http://www.practicalmachinist.com/v...he-chuck-262197/?highlight=Rubber+flex+collet

note Paul's reference to the 91-f1 plain back style.

PmGRacer · Jun 2, 2017

I forgot about that thread. Came across it when I was researching those chucks last year. I "settled" on the 50 series for ease of mounting to a small threaded spindle. The only "drawback" of the 50 is the 1.060" diameter limit. There are a couple 96-F1 chucks on eBay right now which uses the same collets as the 91 series so you can go up to 1.375".

My dad has a 96-F1 on a 6" Atl$s lathe. It is a little different using a chuck key but does not affect usability. Very rigid and convenient chuck. Something to consider anyway.

Example from eBay. The main body of the chuck just bolts to whatever hub you need to make.

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Red1fire · Jun 2, 2017

Picked this up a few weeks ago for 75.00 never seen one before. Thought it may come in useful for cutting on things with clearance issues. Jacobs Headstock Chuck No.59B 1-7/8-8tpi the guy had a 1-1/2" 8tpi also. its still there if anyone wants the link.

Red1fire · Jun 2, 2017

Here is one without the back not sure how this assembled any thoughts on how this can can be modified.

tobnpr · Jun 3, 2017

Here is a NOS for 1-1/2"-8 tpi, only a few hours left for a crazy price, no collets:

NOS jacobs Flex Collet Spindle Nose Lathe Chuck L 91-F1 1-1/2"-8tpi South Bend

The problem with these is the spindle "stickout"- because of the larger collet size, the chuck itself is entirely proud of the spindle- you can see in one of the pics how long it really is. It would take some kind of custom adapter to reduce that (if it could be done at all). I don't recall offhand the spindle bore of the 10R (10L not a problem)- but the same issue may be at hand.

I wouldn't be a fan of the headstock chuck type. The Model 50 and 96 both can be adjusted like a Set-Tru chuck to reduce TIR. While I have over a thou runout at my spindle- a tenths indicator in the collet nose barely MOVES.

PmGRacer · Jun 3, 2017

I would agree on the 91 overhang. I adjusted my 50 true within a tenth or 2. I probably should check it every time I re install it but it seems to be within a few tenths. I'm sure it's off center slightly but I am happy with the accuracy, if I really care about the accuracy I can double check the trueness and re center it.

I do like the minimal over hang the collet face is maybe 3/4" past spindle nose. It is very rigid. Noticeable especially when parting steel. My Bison chuck has way more overhang than the 50 does. Sometimes parting off steel in the Bison I will get chatter. No chatter in the 50.

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Red1fire · Jun 4, 2017

I saw that chuck too. sent the seller a message offering 400.00 and was told in a nut shell to buzz off. its been listed for 8 or 9 months or so and have a feeling it will be listed for another 8 months. They really do stick out. don't see a reason for the extended adapter length when i find one will cut a shorter version if possible. wasnt aware they could be adjusted in a tru just fashion. Thanks for the info. the search continues.

Monarchist · Jun 4, 2017

Red1fire said:
Here is one without the back not sure how this assembled any thoughts on how this can can be modified.

View attachment 200201

View attachment 200202

Go find and download the original Jacobs poop-sheet for any of their systems you have an interest in. There are at least three such critters, if not more.

My one, for the 9XX series, D1-3 back, goes through 'bump' centering OF the fit to that separate back, and as a side-effect, shows how it all goes together.

That, plus a bit of your own experience, and you should have all the 'roadmap' you need to fit one up.

All the 'complex high technology', that exists at all in a RubberFlex system was in figuring out the chemistry to bond just the right synthetic rubber to the steel blades so it would resist oil, emulsion coolants, solvents, heat, stress, yadda, yadda... AND NOT too-easily separate for many long years of service. Jacobs - and whomever chemists or rubber-makers they worked with did succeed at that. "Don't try that part at home", it cannot have been all that easy.

The rest is dumb as a box of rocks and bleeding obvious.

PmGRacer · Jun 4, 2017

Never thought I would see this but I just came across this on eBay.

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Jacobs rubber flex

Aluminum

Titanium

Aluminum

Diamond

Titanium

Aluminum

Stainless

Hot Rolled

Aluminum

Aluminum

Aluminum

Diamond

Aluminum

Aluminum

Aluminum

Hot Rolled

Aluminum

Aluminum

Diamond

Aluminum

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