Question about Jacobs 14N chucks.

Ken from ontario

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H-M Supporter - Silver Member
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I started another thread a while back asking about Jacobs ball bearing chucks, found a new Vertex instead on Amazon but it is still not available.
I am still looking for a decent ball bearing chuck with a JT3 mount, found a used one (Jacobs 14N) in great shape for under $100, the chuck is attached to an mt2 arbor and the seller can not verify if it has a JT3 mount, I asked him if he can see JT3 or K3 engraved anywhere on the chuck, according to his reply :
Hi, I have looked at the chuck and can't find anything engraved on it. Sometimes it will say what kind of mount it is on the shank but it doesn't say anything there either. I don't think it is a threaded mount but not for certain.
What I need to know is, do all Jacobs14N( 0"-1/2" Capacity) come with JT3 mounts or is it possible that the arbor is threaded? he is selling the chuck as is and is not willing to remove the arbor.
Your help is very much appreciated.
Ken.
 
My 14n's all have JT3s as well . The 18s , 11s and 36s are also all taper mounts . No threads .
 
They can be difficult to separate the chuck from the arbor in some cases. So you may use some penetrating oil on the mount first, let it sit overnight, and I use an aluminum edge to separate them. Make sure the jaws are in good shape and not mangled. I have a used Jacobs 14N that I picked up years ago, it woks very well and fortunately has a very low TIR. I also lightly mount the chuck to the arbor holding a piece of ground rod and check the TIR, then move the chuck around on the JT3 taper to find the position that gives the lowest TIR with that arbor and then mount them together in that position.

You also may look at this chuck which is new. I use the Accupro arbor, I find they have high quality tooling at reasonable prices.
https://www.ebay.com/itm/NEW-ACCUPRO-1-16-to-1-2-DRILL-CHUCK-3JT-MOUNT-63673545/401609150571
 
They can be difficult to separate the chuck from the arbor in some cases. So you may use some penetrating oil on the mount first, let it sit overnight, and I use an aluminum edge to separate them. Make sure the jaws are in good shape and not mangled.
I have wedges (2 sets, different sizes), make separating the chuck much easier.
 
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