Jacobs 3JT R-8 arbor

Aukai

Aukai

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For a 14N super chuck. Is there a decent quality arbor for home/hobby without going to a 200 dollar arbor? If not I'll pass on the deal for the chuck.
 
I suggest getting a 3/4 straight shank, then cut it in half. The R8 arbors require too much clearance under the quill. Not that big a deal if you have power knee. I just checked my Albrecht which is mounted this way on a $4 Chinese 33JT to 3/4, .001 TIR.

Don't over think it, it's just a drill chuck
 
I have these on one of my keyless chucks & one on one of my 14Ns. Pretty nice for the low cost. Electroless nickel plated. They used to be $13 shipped on Amazon when I bought them. I'd still buy them today.

PRO-SERIES R8 TO JT3 DRILL CHUCK ARBOR (3701-0138)

<ul><li>Pro R8 to JT3 Drill Chuck Arbor</li><li>Made of 20CrMnTi alloy steel</li><li>Electrolysis nickel coating</li><li>Premium hardened & all ground body for extended tool life.</li><li>Thread of Drawbar End: R8- 7/16" -20</li><li>Maximum RPM is 8,000</
www.absimporttools.com www.absimporttools.com
 
Thank you everyone, and thanks for the links.
 
MrWhoopee said:
I suggest getting a 3/4 straight shank, then cut it in half. The R8 arbors require too much clearance under the quill. Not that big a deal if you have power knee. I just checked my Albrecht which is mounted this way on a $4 Chinese 33JT to 3/4, .001 TIR.

Don't over think it, it's just a drill chuck
Click to expand...

I guess I don't understand that statement. If you're referring to the distance between the quill and the table the R8 arbor does add a little over 4" to the length of the assembly, but only during the installation and removal process. Once it's installed in the spindle it only adds about 1/2" to the overall length.

I used to use a 3/4" collet and a 3/4" straight shank on my drill chucks. A few years ago I switched to an R8 arbor, mainly to simplify installation, and changing tooling. With the collet and straight shank arrangement you have to install and remove 2 pieces of tooling when changing from an end mill to a drill chuck. With the R8 arbor there's only 1 to install and remove.

As for R8 arbors I use the Shars brand for both the N14 and N18 chucks.
 
projectnut said:
I guess I don't understand that statement. If you're referring to the distance between the quill and the table the R8 arbor does add a little over 4" to the length of the assembly, but only during the installation and removal process. Once it's installed in the spindle it only adds about 1/2" to the overall length.
Click to expand...

Yes, I am referring to the overall length of the chuck with R8 adapter. The additional 4 inches is an additional 20 turns of the knee crank each way, down and back up. That is also the reason that I cut my 3/4 shank in half (actually less). It requires slightly more overhead clearance than a collet change. It is, of course, a matter of personal preference. I do not believe that either has an advantage when it comes to accuracy. Mine is .001 TIR, and it is, after all, just a drill chuck.

WP_20200211_07_56_34_Pro.jpg
 
Thank you for the insight, I have power feed on the Z, which makes it easier to drop in and out.
 
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