# cleaning and mounting a 6" Bison set-tru chuck ...



## wquiles (Apr 19, 2009)

Since my Bison 6" set tru needs some serious cleaning (about a year in service!), here is some "hands-on" explanation of how a set tru chuck works ... Will's style, with TONS of photos :devil:

Here is the dirty Chuck. I am using a pad to protect the ways, and a 1" drill rod clamped on the jaws to provide a holding point while removing it:
































To disassemble the chuck there are 3 small screws from top, and 3 larger ones from the bottom:












Each jaw is marked, and each slot is marked as well:






And this is why it was not working as smoothly as when new - it was just dirty after a year of use:

















After cleaning:
















Ready to go back on the lathe:






To set the chuck using the set-tru feature, you mount the chuck, but do not fully tighten the 3 mounting bolts - I would say to use about 75-80% of the actual mounting torque - you basically need to allow for small radial movement by using the 4 set-tru screws. In this picture, one has the key and my finger is pointing to another one:






The idea is to measure about 2" inches away from the chuck's face, and adjust the 4 radial screws until you get the smallest possible reading. I first tried using the same 1" drill rod, but it's surface was not smooth enough, and not round enough - that Brown and Sharpe "BestTesT" (Ebay - used for $25) can sure pick up small movements  . I am using my NOGA holding arm (highly recommended!), to hold the indicator:











I then used a smaller diameter drill rod that I used in the past that is much smoother surface-wise, and after a while, I got the following two shots, describing the total range of movement after going a full revolution, which is less than 0.0005" - not bad :twothumbs











You then finalize the installation by fully applying torque on the mounting bolts, check once again that things did not move (run the indicator again a couple of revolutions), and then pat yourself in the back for a job well done 

Will


----------



## Anglepoise (Apr 19, 2009)

Great pics and description as usual. Question. Can the individual jaws be quickly removed to expose the scroll for cleaning? 
I am not familiar with Bison chucks.


----------



## wquiles (Apr 19, 2009)

Anglepoise said:


> Great pics and description as usual. Question. Can the individual jaws be quickly removed to expose the scroll for cleaning?
> I am not familiar with Bison chucks.



Yes. In fact I first removed the jaws - the scroll can then be cleaned as you rotate it. 

Will


----------



## darkzero (Apr 19, 2009)

Thanks for showing how to adjust these. :twothumbs

Where is the best place to purchase the Bison chuck grease / Fuchs Gleitmo 805 aside from ebay?


----------



## wquiles (Apr 19, 2009)

I bought the Bison chuck grease on Ebay:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&item=310120184475

It is expensive at $30, but I have now done two complete jobs (6" Buck Chuck and now the Bison), and I still have like 3/4 left 

Will


----------



## tino_ale (Apr 20, 2009)

Nice pics :twothumbs

Few questions :
1 - Beside the jaws and slots that you mark in order to match them properly during re-assembly, is there anything else you need to mark? Or can the other parts just go anywhere without problem?
2 - The pics of the dirty chuck look scarry! Looks like there was chips in it. Is this normal? Where do these chips come from?
3 - Is a new chuck as clean and square as yours after cleaning or should one do the same procedure on a brand new one (complete dissassembly)?

Thanks for any input,
nice job anyway!


----------



## wquiles (Apr 20, 2009)

tino_ale said:


> Nice pics :twothumbs
> 
> Few questions :
> 1 - Beside the jaws and slots that you mark in order to match them properly during re-assembly, is there anything else you need to mark? Or can the other parts just go anywhere without problem?
> ...




1. I don't have to mark anything on the jaws. They jaws come stamped from the factory 1 through 6, and each slot for the jaw has the matching stamp number, so getting each jaw into the right slot is easy. For the other parts, they were not marked, but in case they were "fitted" at the factory, I keep them together as individual groups - specially the pinion parts.

2. I use my lathe almost every single week of the year - at a minimum twice a month. When you use a "chip-maching" machine like a lathe, chips are going to get everywhere, specially when you are boring a hole all the way through the part, where chips will come out inside the chuck. Given how often I use my lathe, I just need to do the disassembly/cleaning more often, maybe every 6 months or so 

3. The new chuck is super clean and true when new - no need to disassemble it. Except for cleaning the exterior to wipe off the protective oil/grease/whaever (specially on the mounting surfaces), there is nothing else to do. Of course, you have to follow the same procedure to dial the axial set-tru screws as I showed here.

Will


----------



## Anglepoise (Apr 20, 2009)

wquiles said:


> Yes. In fact I first removed the jaws - the scroll can then be cleaned as you rotate it.
> 
> Will



I am still not sure I have the answer I was asking. Looking at the pics, there is a large amount of swarf inside the chuck and scroll. My question was " With the chuck fully assembled,dial in and attached to the spindle, can one simply wind out all six jaws and then clean the scroll?" If you can do this, your chuck will sure benefit from a cleaning on a weekly or daily basis. If you were turning cast iron, your chuck would now be very worn .

Also I would be interested in other comments, but I would never put grease anywhere in the chuck. Yes some manufacturers recommend it but
others don't.


----------



## wquiles (Apr 20, 2009)

Anglepoise said:


> I am still not sure I have the answer I was asking. Looking at the pics, there is a large amount of swarf inside the chuck and scroll. My question was " With the chuck fully assembled,dial in and attached to the spindle, can one simply wind out all six jaws and then clean the scroll?" If you can do this, your chuck will sure benefit from a cleaning on a weekly or daily basis. If you were turning cast iron, your chuck would now be very worn .
> 
> Also I would be interested in other comments, but I would never put grease anywhere in the chuck. Yes some manufacturers recommend it but
> others don't.



Yes, with the chuck fully assembled and dial in, you can simply remove all 6 jaws and clean the scroll. I definitely waited far too long to do it, and yes, I will be cleaning it more often from now on 

Since both Buck Chuck and Bison recommend chuck grease, I went with it, but I read recently in the 12x36 Yahoo group that instead of chuck grease, one could use Way Oil. 

Will


----------



## Anglepoise (Apr 20, 2009)

That's great. Was not sure how those 6 jaws work. Thanks.
I use the following procedure on a very regular basis that works well for me.


At the end of heavy use sessions, especially boring through, wind out all jaws, and quickly clean them individually with toothbrush and compressed air. 

With a ‘Q’ tip, make sure all jaw rails are swarf free.
Then start winding the scroll clockwise, with a ‘Q’ tip in the groove. 
Blow through the spindle bore or use a simple pusher so loose swarf does not fall back into the scroll area.

The chuck face and scroll will now be spotless and can be given a few squirts of ‘Way Oil’ and now wind in the clean jaws starting at #1 and visually making sure that the start of the scroll engages each jaw correctly. 

Total time under five minutes with huge benefits in smooth , minimum wear operation of the chuck.


----------



## wquiles (Apr 20, 2009)

Thank you David for sharing. This looks like a good routine, and simple enough to follow on my chuck as well 

Will


----------



## tino_ale (Apr 20, 2009)

thanks for the info, good stuff to know for newbies!


----------



## cmacclel (Apr 20, 2009)

As soon as I feel swarf binding in my chuck I remove the jaws and clean them and the scroll. I never use grease nor would I want to as it would make the swarf stick more than it does now 

Mac


----------



## wquiles (Apr 20, 2009)

Good point Mac - I had felt some "weirdness" lately. I should had removed/clean the jaws/scroll as soon as I felt something was not "right".

Will


----------



## Mirage_Man (Apr 21, 2009)

cmacclel said:


> As soon as I feel swarf binding in my chuck I remove the jaws and clean them and the scroll. I never use grease nor would I want to as it would make the swarf stick more than it does now
> 
> Mac



Mac believe it or not in my case the grease keeps the swarf out of the scroll. 

I disassembled my Set-Tru a few months ago to clean it. It was a bit nerve racking to say the least. But it had gotten so bad that I could barely close it past a certain diameter. I had made the mistake of squirting oil in there soon after receiving it. The oil seemed to attract the chips like a magnet. What I learned was to not use compressed air to blow into the chuck to clear chips. That only forced them deeper into it. Since having cleaned and re-greased my chuck it's worked flawlessly.


----------



## cmacclel (Apr 21, 2009)

I use compressed air everyday for the past 3+ years to blow the chips out of my chucks and never had a problem. It appears you just got lucky 


Mac


----------



## tino_ale (May 7, 2010)

Hi,
I was wondering : once you have found a low TIR and fully tighten the chuck on it's place, can you/should you unscrew the set-tru screws ?


----------



## cmacclel (May 7, 2010)

tino_ale said:


> Hi,
> I was wondering : once you have found a low TIR and fully tighten the chuck on it's place, can you/should you unscrew the set-tru screws ?


 

No you leave them as is.

Mac


----------



## wquiles (May 7, 2010)

cmacclel said:


> No you leave them as is.
> 
> Mac



+1

Once it is all set, you stop messing with it


----------

