# Using Pin Chucks



## bjbear76 (May 30, 2017)

I spent some time over the weekend delving into the world of kitless and closed end pens.  One issue I ran into is getting the drilled blank to turn true on the pin chuck - I keep getting a wobble.  The blank is well seated on the pin and it turns fine, but results in a slightly out-of-round condition. Is there a trick to mounting the blank on the pin chucks?


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## duncsuss (May 30, 2017)

Does the pin have any runout before you slide the barrel onto it?


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## bjbear76 (May 30, 2017)

duncsuss said:


> Does the pin have any runout before you slide the barrel onto it?



No, it seems like the blank is not perefectly parallel with the pin.


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## hanau (May 30, 2017)

Do you have a dial indicator that you can zero on the pin chuck and turn the chuck by hand? To see if there is any wobble?


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## bjbear76 (May 30, 2017)

hanau said:


> Do you have a dial indicator that you can zero on the pin chuck and turn the chuck by hand? To see if there is any wobble?



yes, I'll check that tonight


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## KenV (May 30, 2017)

Bill,

I HAD one pin chuck that was a loose sloppy fit into the brass tube.  The slop allowed the tube to skew to the side enough to be a problem.  I could compensate with shim stock, but the hassle was not worth the replacement cost, and got an expansion style to replace it.

If there is not slop inside the tube, time for a dial indicator and careful checking.


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## bjbear76 (May 30, 2017)

Maybe I should clarify a bit.  I'm turning an ebonite blank for the cap end of a fountain pen.  I've drilled up to 1/2" of the closed end of the blank.  Since there's no brass tube, is it possible the pin is causing the blank to skew a bit when it "grabs" in the flat of the rod?


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## tjseagrove (May 30, 2017)

Might be digging into the wood which would deform it.
37


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## duncsuss (May 30, 2017)

bjbear76 said:


> Maybe I should clarify a bit.  I'm turning an ebonite blank for the cap end of a fountain pen.  I've drilled up to 1/2" of the closed end of the blank.  Since there's no brass tube, is it possible the pin is causing the blank to skew a bit when it "grabs" in the flat of the rod?



How tight is the rod when you're pushing it into the blank?

The ones that Rick Herrell made for me were a perfect fit, and it was a struggle to get them into the hole because they were acting like a piston in a closed cylinder. (He machined a small groove in the next ones he made for me, to act as a pressure relief :biggrin

If you can push the blank onto the rod with no effort, it's too loose, and you will get some twist when the pin locks in place.


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## Pierre--- (May 30, 2017)

I use pin chucks very often. I would say two things:

First, if the piece is on the chuck without pin and if I pull it suddenly off, I want to hear a "ploc", something like the sweet noise of a cork out of a wine bottle. If not, the pin may hold it tight, but it will be out of center. 

Second, a pin chuck is great for finishing/sanding, not too bad for very light final turning, but very clumsy for roughing. So I use the tail stock as long as possible, which mean a little extra-length ebonite I turn out at the end. 

Hope it helps.


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## KenV (May 30, 2017)

bjbear76 said:


> Maybe I should clarify a bit.  I'm turning an ebonite blank for the cap end of a fountain pen.  I've drilled up to 1/2" of the closed end of the blank.  Since there's no brass tube, is it possible the pin is causing the blank to skew a bit when it "grabs" in the flat of the rod?



Sounds like a sloppy fit and the ebonite is not held straight.


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## bjbear76 (May 31, 2017)

Sounds like a sloppy fit and the ebonite is not held straight.[/QUOTE]

That's exactly what it was.


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## duncsuss (May 31, 2017)

bjbear76 said:


> That's exactly what it was.



Glad you got that sorted out


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## Texasshipagent (Jul 14, 2017)

bjbear76 said:


> I spent some time over the weekend delving into the world of kitless and closed end pens.  One issue I ran into is getting the drilled blank to turn true on the pin chuck - I keep getting a wobble.  The blank is well seated on the pin and it turns fine, but results in a slightly out-of-round condition. Is there a trick to mounting the blank on the pin chucks?





If it's rod, insert as close to the check as can get, I have a small chuck with center drill that I placed a wobbler on to make sure concentric then marked the MT with marker as to fit in rail stick same place each time

Once the rod spins at high RpM the center is clear , I sit in a chain so eye level and make sure nail center 

The switch chuck to drill 

Best to drill small the step up to size as can get chamfer with larger bits and first few mm of bore may be larger , another tip is drill 2mm in reverse as slow speed to start the bore then switch back

Different materials drill best at different speeds some need some lubricant that part is trial and error but don't force ease in, take out cool lubricant , brush off swarf the. Drill again 

Should hit center every time 

Otherwise your chuck is not true , a dial indicator will help, more then .0002 you got an issue , maybe bent pin jaw or simply chuck or insert not threaded complete to lathe stock 


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## Texasshipagent (Jul 14, 2017)

To add then loose Jaws and slip rod out to desired work space , if removing completely sometimes
I make and trade the pin jaws as to place back in same spot when rechucking 


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