# Jacobs #3 Chuck/Rust inside



## 65arboc (Aug 6, 2014)

Hi all,

  I bought a used mill a few months ago and in a box of accessories that came with it I found a #3 Jacobs chuck on a MT3 taper. The thing is stuck and won't turn. I tapped it with a hammer and a lot of rust dust is falling out:angry:. Knowing it hasn't been used in a long time, is there any way to loosen up this chuck and get the rust dust out of it?  Also can a person disassemble a Jacobs chuck without special tools? If this isn't the correct sub forum, please move it.

Thank you,

Jim


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## Shopsweeper (Aug 6, 2014)

I had this with a smaller chuck once.  I did the following:
1. Electrolysis with using an old PC Power supply and a rebar sacrificial anode.
2. "baked" it dry in makeshift incandescent light bulb "oven".
3. Lubed it with grease.
4. Put it to work.

I never did open it up, my theory was to try that AFTER de-rusting it.  I am not in the Evaporust camp.  Lots of smart people use those kind of products, but I am not among them.  Electrolysis has never done me wrong.


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## John Hasler (Aug 6, 2014)

65arboc said:


> Hi all,
> 
> I bought a used mill a few months ago and in a box of accessories that came with it I found a #3 Jacobs chuck on a MT3 taper. The thing is stuck and won't turn. I tapped it with a hammer and a lot of rust dust is falling out:angry:. Knowing it hasn't been used in a long time, is there any way to loosen up this chuck and get the rust dust out of it?  Also can a person disassemble a Jacobs chuck without special tools? If this isn't the correct sub forum, please move it.
> 
> ...



http://www.jacobschuck.com/keyed-drill-chuck-repair-guide

Would that taper by any chance be threaded for a 3/8-16 drawbar rather than with a tang?  If so would you be interested in selling it?

- - - Updated - - -



Shopsweeper said:


> I had this with a smaller chuck once.  I did the following:
> 1. Electrolysis with using an old PC Power supply and a rebar sacrificial anode.
> 2. "baked" it dry in makeshift incandescent light bulb "oven".
> 3. Lubed it with grease.
> ...



I'd be reluctant to use any kind of chemical or electrolytic rust removal on an assembled device with seized moving parts until all attempts at disassembly had failed.


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## JimDawson (Aug 6, 2014)

Here is another repair video

https://www.youtube.com/watch?v=97jlPVPn19Q


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## 65arboc (Aug 6, 2014)

John Hasler said:


> http://www.jacobschuck.com/keyed-drill-chuck-repair-guide
> 
> Would that taper by any chance be threaded for a 3/8-16 drawbar rather than with a tang?  If so would you be interested in selling it?
> 
> ...


Sorry John it has a tang and thanks for that link. I don't have a press so how would I get that sleeve off?


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## 65arboc (Aug 6, 2014)

JimDawson said:


> Here is another repair video
> 
> https://www.youtube.com/watch?v=97jlPVPn19Q


Jim, great help! Thanks a lot.


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## mattthemuppet2 (Aug 6, 2014)

I've got a bunch apart using pvc pipe of the right diameter and a small bench vise. That was kind of hairy for the 1/2 Jacobs but it went fine. The 3/8 one was a piece of cake. A bit fidly to get back together but not hard if you take your time


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## kd4gij (Aug 6, 2014)

Soak it with PB blaster,Krole, or 50/50 ATF flude and accidtone.


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## 65arboc (Aug 7, 2014)

Got it apart. I soaked that thing in PB Blaster, actually immersed it, all day yesterday. It was still a bear to get the ring off as I beat on it for about a half hour before it began to movehew:. There is no rust on the jaws or the threaded split ring but the housing had plenty of surface rust on the inside where the jaws slide. I got most of it cleaned up last night except the bores where the jaws slide. I'm going to use a dowel rod slotted for a piece of emery to smooth out the bores. BTW I think this is one of the good ole boys as the jaws and the housing are marked 1-2-3 so I can't get them in the wrong hole, for sure made in the USA by a craftsman. Should be good as new when I get done. The info I got here on this forum really helped with this project. You guys are GREAT!

Jim in Pa


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## kd4gij (Aug 7, 2014)

Glad you got it. Get that thing cleaned up and lubed and you will have a nice chuck.:thumbsup:


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