# Question about 5" chuck on Grizzly G8688 Mini Lathe



## Jon K (Dec 11, 2012)

Thinking about going to a 5" chuck for the higher capacity both in the jaws/holding as well as the through-chuck.  I know it won't open the spindle, but the chuck is nice to be able to pass slightly over an inch through.

Anyway - with a 5" chuck, 4" stock, can I even turn that down?  I don't know that the cross feed can move that far out of the way.  Thoughts?


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## Richard King (Dec 11, 2012)

You should think about the machine design and putting on a bigger chuck and shaft will it put a strain on the spindle bearings.   I have turned parts like that a few times on a Leblond, but that machine has a HD spindle.  The way I did it was I used a boring bar that you normally bore ID holes.  Set it up on he OD and moved the cutter to the opposite side of the bar.  Need to take light cuts and be careful.


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## AR1911 (Dec 11, 2012)

I'd bet if you are holding a 4" round, the jaws will stick out and hit the bed.


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## Jon K (Dec 11, 2012)

AR1911 said:


> I'd bet if you are holding a 4" round, the jaws will stick out and hit the bed.



Here is an image from Mini-Lathe.com showing a 5" chuck holding 4" stock:


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## AR1911 (Dec 11, 2012)

Jon K said:


> Here is an image from Mini-Lathe.com showing a 5" chuck holding 4" stock:
> 
> View attachment 43634



If the chuck you are looking at is very similar, then go for it.
The spindle can handle it.


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## Jon K (Dec 11, 2012)

AR1911 said:


> If the chuck you are looking at is very similar, then go for it.
> The spindle can handle it.



I am just curious as to how I could do any turning on a 4" stock.  If I set the tool super shallow and at an angle I almost can't see 4" fitting with the cross feed all the way out.


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## AR1911 (Dec 11, 2012)

truly, you need a bigger lathe if you regularly exceed 3" material.

If the mini has to do it, then I'd look at a custom toolpost mounting block in place of the compound.

Another issue you may find is that the lowest speed on the lathe may not have enough torque.
If you run it too fast your work quality suffers.
If you are doing aluminum rounds, you should be OK.


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## Bill Gruby (Dec 11, 2012)

Regardless of the chuck size the jaws will only open till they hit the bed.The outside diameter of the combined chuck jaws will be the same on the same lathe. You probably might even lose on stock size because the jaws on the larger chuck have more mass. Then there is the question if the small lathe will have difficulty turning the extra weight.

I'm afraid you have come to the inevitable crossroad question, "is it time for a larger lathe?" I wish you well with the answer.

"Billy G" :thinking:


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## Jon K (Dec 11, 2012)

Bill Gruby said:


> Regardless of the chuck size the jaws will only open till they hit the bed.The outside diameter of the combined chuck jaws will be the same on the same lathe. You probably might even lose on stock size because the jaws on the larger chuck have more mass. Then there is the question if the small lathe will have difficulty turning the extra weight.
> 
> I'm afraid you have come to the inevitable crossroad question, "is it time for a larger lathe?" I wish you well with the answer.
> 
> "Billy G" :thinking:



I don't really need to turn 4" stock, I am only questioning the ability to.  I really like the 1.18" through chuck size.  I rarely turn anything over 2", but the problem is I tend to want to turn longer pieces than fit through the chuck on the stock chuck.  I think the 5" is useful for me, I just was thinking about the geometry and trying to think of how the tool post would clear something 4" diameter.


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## PurpLev (Dec 11, 2012)

Jon K said:


> I don't really need to turn 4" stock, I am only questioning the ability to.  I really like the 1.18" through chuck size.  I rarely turn anything over 2", but the problem is I tend to want to turn longer pieces than fit through the chuck on the stock chuck.  I think the 5" is useful for me, I just was thinking about the geometry and trying to think of how the tool post would clear something 4" diameter.




for you to take advantage of the 1+ through hole that means you'd have to position the chucks jaws in a reverse order as the image you posted shows. that also means that the jaws will extend +1" out of the chuck making the actual chuck diameter +6" which might not fit in your lathe's work envelope (+7" for holding a 2" rod).


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## Jon K (Dec 11, 2012)

PurpLev said:


> for you to take advantage of the 1+ through hole that means you'd have to position the chucks jaws in a reverse order as the image you posted shows. that also means that the jaws will extend +1" out of the chuck making the actual chuck diameter +6" which might not fit in your lathe's work envelope (+7" for holding a 2" rod).



Hm good point.  I will have to do some measurating tonight.


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## Jon K (Dec 26, 2012)

Welp, I went through with it:




5&quot; Chuck vs 3&quot; Chuck by Jon Kensy, on Flickr




5&quot; all the way open by Jon Kensy, on Flickr




5&quot; holding 3&quot; by Jon Kensy, on Flickr

You can see the 5" chuck all the way open (any more turn of the chuck key and the jaw falls out) clears the ways!  This thing is awesome.  I can fit 3/4" stock through the chuck and spindle no issue.  The chuck can fit like 1 1/8" stock through it.  Very nice!


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## darkzero (Dec 26, 2012)

Nice pics & congrats!


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## Jon K (Dec 27, 2012)

Thanks man!  Yeah so far so good!


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## w6br (Nov 22, 2015)

I noticed that you are using a Grizzly 7X12?? Was there any problems hooking up to the Face Plate??  Also, who did you purchase the 5" Chuck from?? Inquiring Minds want to know?? 

Ron


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## higgite (Nov 22, 2015)

You do realize this thread is 3 years old? Although it says he's an active user under his avatar, his profile says he hasn't been seen since 2013. Hope he answers, but I'd say odds are against it. Try PMing him?

Tom


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