Jacobs Ball Bearing Chuck Rebuild (14N) Done My Way

[darkzero]

consider where the "press forces" are going when you push down onthe jaws. thru the threaded half parts that the outer sleeve is actually press fit on. if you press on the nose of the tool, the forces are in a different place related to the threaded half parts. . . trying to pull the innards from the sleeve instead of pushing them out. or do i need more coffee ? ? ?

Yup, I did think about it after disassembling the first one. Pressing on the jaws as recommended, the force is through the jaws to the jaw scroll rings. But by pressing on the nose it seems the force would be through the body (opposite end of the nose) to the jaw scroll rings, that is depending on how far down you run the jaws, I backed the jaws down, then ran them up slightly so the rings would contact the body under the nose. The jaw scroll rings is what the sleeve is pressed onto. So I'd rather press on the body instead of the jaws.

On certain sizes of Jacobs chucks, if you retract the jaws all the way, you will damage the tail end of the chuck jaw. I know this for a fact, I've damaged the jaws on a chuck because I retracted the jaws all the way.

Thanks for confirming, I figured that may be the case. After seeing the internals, what I did on the second & third was retract the jaws all the way, then ran them back up until they were just below the nose face. That way the ring would contact the body opposite of the nose & the jaws would not be bottomed out.

Again I don't think the jaws would have been damaged by pressing directly on them but doing it the way I did seems to be fine.

Great write up, thanks.
Where do I get replacement jaws for my Jacobs 16n Super Chuck BB? How much?

What did you use as a cleaning solvent and how did you polish the metal?
Btw, I don't think all of the USA made 16n Jacobs chucks have Hartford, Conn. stamped on them.
I'll fact check this more.

Thanks. As mentioned by 110octane, Enco no longer carries these parts, MSC still lists them but they have been "out of stock" for a very long time. I was able to find NOS on ebay. Not sure about 16N parts.

Yup, that's what I understand too, only the older ones say Hartford on them, & older than that have the older style looking sleeve on them. I believe later ones just say "Made in USA" (no Hartfor Conn), and later than that just Jacobs USA, not "Made in the USA".

I believe the ones that just say Jacobs USA on them are the ones that are iffy & are during the transition, some made in the USA, some not. The ones that list a SVC Kit # (which are the current ones being made) on the nose are the ones that are made in China or wherever offshore. As I understand it, these service kit parts are not interchangeable with the older models.

I just mentioned what I have in case someone trying to follow this had a model that was different internally. Never seen the newer ones so I'm not sure what is different if anything.

 

[110octane]

"I believe the ones that just say Jacobs USA on them are the ones that are iffy & are during the transition, some made in the USA, some not. The ones that list a SVC Kit # (which are the current ones being made) on the nose are the ones that are made in China or wherever offshore. As I understand it, these service kit parts are not interchangeable with the older models."

I agree, this matches the information that I have come across.

Thanks, Geoff

 

[darkzero]

What did you use as a cleaning solvent and how did you polish the metal?

Sorry Emilio, forgot to answer this.

I used Purple Power to clean everything. It's just what I had more accessible. Any degreaser should work fine, (brake cleaner too), just dry everything before they have a chance to rust. The purple stuff didn't removed the thick areas of the old dried caked on grease, maybe if I allowed them to soak. A stiff bristly brush took care of most of it though & I scraped off the heavy areas off as needed. I did soak the balls in the purple stuff, cleaned them right up, no scrubbing needed.

I polished the metal using sandpaper in some areas finished off with scotchbrite. You can get a glimpse in the background of what I used in the photos of the sleeve & body mounted in the lathe chuck.

 

[Cadillac STS]

I didn't know how a chuck came apart until this thread. I had an old 3/4 chuck that always had a catch in it. Got tired of that and replaced it. Now I was able to take it apart and look it over. It was not dirty, if anything dry of lubrication. Also one of the guides at the end didn't let one of the jaws slide easily and the half nut was really rough on both ends not letting the jaws move smoothly. All factory problems. No name part from a low cost stand up drill press. I was able to clear the burr on the one jaw track with a round file. Also able to put the half nut in the lathe and take down the ragged ends.

Now it slides really smoothly and with no hitch!

Had to make one part for my 12 ton Harbor Freight press to press it open then back together:




GREAT forum!

 

[jbollman]

10-17-14

Hellow to all: FYI

I apologize for not commenting sooner since i have had 2 major health issues commencing 1 Year ago - however I am now OK & getting
back to doing some machine work. If any one is looking for a top quality drill chuck I would recommend a ROHM chuck - made in Germany (many sizes available) and distributed by ENCO MFG.. I bought one for my drill press and it has been very good. Also ENCO sells a different chuck called a GOOSE. This chuck ( 3/4" max ) I have used it on my Van Norman mill and it is also good. It is made in Taiwan. If you have any questions please list them on the forum. )

Regards to all,

jbollman

 

[EmilioG]

What's the best approach to removing an old R8 on a Jacobs 16n (old USA model super chuck).
I don't want to damage anything. I've read some horror stories where dynamite couldn't remove the arbors/shanks from
drill chucks. Thanks again.

 

[110octane]

What's the best approach to removing an old R8 on a Jacobs 16n (old USA model super chuck).
I don't want to damage anything. I've read some horror stories where dynamite couldn't remove the arbors/shanks from
drill chucks. Thanks again.

Most of the Jacobs ball bearing chucks I have come across have a very small hole in the bottom of the "well" the jaws operate in. Use a bright flashlight or shop lamp to peer into the chuck with the jaws wide open. I suspect the primary purpose of the hole is to let air escape from the taper cavity so as not to inhibit the fitting of the taper. This same hole may be used to allow a punch to drive out the adapter. Since the hole is a vent it is small so if necessary the whole assembly can be chucked in a lathe and that hole drilled out a little larger. Depending on the size of the chuck I have drilled them up to 1/4" without any adverse effects on the chuck body.

Of course, it goes without saying that supporting the chuck as securely as possible is in order. If a suitable punch will not provide enough force to drive the arbor out, the body of the chuck will have to be heated as a last resort. I had to do this once; I used a propane bottle torch with virtually no discoloration of the chuck body. Just don't go overboard with the heat-it doesn't take as much as we think it would (at least most of the time, otherwise it takes the red heat from an oxacetylene and things are ruined or special).

Regards, Geoff

 

[mattthemuppet2]

great write up! I've always wondered what the inside of a ball bearing chuck looked like

I've taken apart a few Jacobs chucks now and, other than making sure you're pressing straight, they're pretty easy to get apart. Pressing on the jaws could also theoretically allow you to press the body out more straight, but I've nothing more than a gut feeling to back that up! One of the chucks I disassembled (documented on here) was too heavily used. Even with judicious filing to get the jaws and threaded ring running smoothly it still catches and it has pretty poor run out (~0.006in). Another one I did recently, even though it looked and felt terrible (could barely open it), cleaned up beautifully, works smoothly by hand and has less than 0.002in run out.

I used 10% NaOh (lye) to clean mine, grease falls right off! Then a trip through the wire wheel and some Mothers alu polish and it looks like new. Oh, and some waterproof grease that i use for my bike hub bearings..

 

[EmilioG]

Thanks for all of the great information
I wrote to Jacobs/Apex Tool Group and asked about the Jacobs super chuck
and where it is made. I have a 16n SuperChuck and it has the Svc, Kit p/n on it.
It also says Jacobs USA. Wt? I bought the chuck used and it appears old but in good shape.

How do I check for run out? I've been getting good results with my small parts projects so far.
I'll post anything I get back from Jacobs. For now, I will keep looking for a real USA Jacobs 14 or 16n.

Thanks

 

[darkzero]

Thanks for all of the great information
I wrote to Jacobs/Apex Tool Group and asked about the Jacobs super chuck
and where it is made. I have a 16n SuperChuck and it has the Svc, Kit p/n on it.
It also says Jacobs USA. Wt? I bought the chuck used and it appears old but in good shape.

How do I check for run out? I've been getting good results with my small parts projects so far.
I'll post anything I get back from Jacobs. For now, I will keep looking for a real USA Jacobs 14 or 16n.

Thanks

Yes, please do. I'm real curious as to what their response would be. As far as I'm aware, all the new BB chucks say Jacobs USA on them. The ones that only say Jacobs USA are the questionable ones, some are USA made, some are not. But all the ones that list the service kit # on them are the offshore ones & still say Jacobs USA on them, my guess is to throw people off & if questioned they can just say Jacobs is a USA company.

Back when I was a mechanic, I purchased a full set of standard & metric combo wrenches from Matco, all stamped USA on them. Years later I noticed the newer sets no longer said USA on them. My Matco dealer claimed he did not know why & refused to state if they were made offshore or still in the US, maybe he really didn't know, I'm not for sure but that could hurt his sales.

This was when Danaher (who owns Matco) & Cooper still owned Apex tools. Around that time Armstrong tools started releasing hand tools that looked very similar to Matco's line with the same features. Well Danaher & Cooper have since sold the Apex group. Not sure if Armstrong is still Danaher or Apex but Armstrong still offers USA made hand tools. Matco is still Danaher. Same goes for some Snap-On hand tools that used to say USA on them, not anymore. Just cause it doesn't say China/Taiwan/etc on them & they don't admit to anything, well you know, but who knows? :lmao:


ANYWAYS......

I check runout using a ground rod, not drill rod, something more precision ground for better readings, like a gage pin or linear shafting. You could also us the shank of an endmill or reamer. I wouldn't trust a drill bit unless it's a quality one, carbide drill bit would be good. Spin the chuck in your spindle & indicate of the rod. If you don't have a mill you can spin it in the lathe chuck but remember to subtract you lathe chuck's runout from your reading.

No need to find a USA made Jacobs if what you have now is fine. As long as your chuck is doing what you need it to do with good results, just stick with it as you already have it.

Might as well add, I usually use the Jacobs wedges to remove arbors. Most of the time they work for me. Some people hate the wedges. Well the wedges didn't work on these 3 chucks. My chucks already had the 5/32 holes. A bit small but I did not drill them larger, I did bend my punch in the beginning so a larger hole would be better. I heated the body with a propane torch, just barely hot to the touch is all that is needed, them i squited some Kroil on the taper so it seeped in, used a punch through the hole & popped them off, well for 2 of them. You have to be swift about it so heat does not transfer much to the arbor. On one of them I wasn't so lucky. with the body still hot, I just sprayed the arbor with freezer spray (aerosol brake cleaner or canned air upside down would work too) to rapidly cool the arbor & it then popped right out.

Just a word of caution. For the keyed chucks that don't have a hole through the body like on the newer ones, you can drill the hole but DO NOT ever drill a hole though the body on a keyless chuck, doing so will destroy it.