When I first started fooling around with metal working 9 years ago, I
bought a Jacobs 14N chuck and stuck it on an Enco 5/8 ths straight
shank to 3JT arbor. It has ALWAYS wobbled. I figured that it was the
cheap shank and recently removed to replace it with a genuine Jacobs
shank since my machining skills have progressed a little bit beyond
the "mark with chalk, cut with axe stage". Appropriate chuck wedges
wouldn't work but the Enco shank was soft so I threaded it and use a
chunk of ¾ inch dia tubing and a 5/8 ths nut to pull the Enco straight
shank off with minor effort. Cleaned up the chuck and brand new
Jacobs 5/8 ths straight shank to 3JT arbor and gently pressed into
place. A reamer blank chucked in the mill has zero run out. Same
reamer blank chucked in the newly shanked 14N drill, 25 thou runout.
Damn. I must have mistreated the chuck badly over the past 9 years.

Got a new Jacobs 14N chuck with new Jacobs 5/8ths SS cleaned
appropriately gently pressed into chuck and tested with reamer blank
today. 12 thou run out on new chuck and shank. Zero run out when
reamer blank chucked into mill collet. WTH???

As an aside, a new Rhom chuck pressed onto cheap HF drill press has
zero run out.

Any insight on either what I'm doing wrong or how to fix it would be
appreciated.

Regards,
Jim

On Fri, 03 Jun 2005 04:24:00 GMT, JK wrote:


Any insight on either what I'm doing wrong or how to fix it would be
appreciated.

Regards,
Jim


Buy an Albrecht.

But if you wanna use what you have:
Seat the taper well. Install the shank with Jacobs chuck into your mill.
Tap lightly with a deadblow type mallet and check runout. Tap as needed
until you achieve zero runout.

--
Skuke
Reverse the domain name to send email

Do a bit of investigating here. Chuck up your arbor and check if it is
running true without the chuck on it. if not then note the high spot.
Grab the reamer blank with the chuck on one end and the mill on t he other.
Check the run out on the taper in the chuck, note the high side. Assemble
so that high sides cancel. You may find that your chuck is truly wonkey.
Have you had the chuck apart and cleaned and inspected? I went through a
similar situation with a 14n and had the arbor and chuck together and apart
a few times until I lucked on the orientation that worked. What I suggested
above is a bit more scientific.
lg
no neat sig line

"JK" wrote in message
...


When I first started fooling around with metal working 9 years ago, I
bought a Jacobs 14N chuck and stuck it on an Enco 5/8 ths straight
shank to 3JT arbor. It has ALWAYS wobbled. I figured that it was the
cheap shank and recently removed to replace it with a genuine Jacobs
shank since my machining skills have progressed a little bit beyond
the "mark with chalk, cut with axe stage". Appropriate chuck wedges
wouldn't work but the Enco shank was soft so I threaded it and use a
chunk of ¾ inch dia tubing and a 5/8 ths nut to pull the Enco straight
shank off with minor effort. Cleaned up the chuck and brand new
Jacobs 5/8 ths straight shank to 3JT arbor and gently pressed into
place. A reamer blank chucked in the mill has zero run out. Same
reamer blank chucked in the newly shanked 14N drill, 25 thou runout.
Damn. I must have mistreated the chuck badly over the past 9 years.

End of discussion.
JR
Dweller in the cellar

skuke wrote:


Buy an Albrecht.




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I have an Albrecht keyless with a Jacobs arbor 1/2 inch keyless , .023
runout as new , used the cold arbor warm [125] chuck assembly method ,
never tried to correct it as it does for my rough drilling
and I have a Kawasaki keyless that is 35 years old from dad that only has
..0003 .0004 for tight work
in the mill which I don't do much of any more , do you think I can get the
runout out of my Albrecht

I don't understand this at all. What's this business about dialing in a
ground rod? Indicate the spindle taper directly. Run true? Then carefully
put in the arbor alone, and indicate it. Run true? Then carefully put the
chuck on the arbor and install it, and only then put in something round,
and indicate it. If it runs out badly, return the chuck as defective!

GWE

In article ,
williamhenry wrote:
I have an Albrecht keyless with a Jacobs arbor 1/2 inch keyless , .023
runout as new , used the cold arbor warm [125] chuck assembly method ,
never tried to correct it as it does for my rough drilling
and I have a Kawasaki keyless that is 35 years old from dad that only has
.0003 .0004 for tight work
in the mill which I don't do much of any more , do you think I can get the
runout out of my Albrecht

Possible. I see two likely sources:

1) The Jacobs arbor is off center. (It should not be, but I would
expect it of a Jacobs arbor before an Albrecht one.

2) A jaw in the Albrecht has gotten a burr from a drill spinning
in it sometime in the past. (Or perhaps from gripping something
the wrong shape -- Albrecht jaws are nicely hardened. New jaws
are available, as are replacements for *any* part in an
Albrecht. You can built a whole chuck from parts -- but it will
cost a lot more than buying a whole chuck assembled.)

Good Luck,
DoN.
--
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(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
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JK wrote:


When I first started fooling around with metal working 9 years ago, I
bought a Jacobs 14N chuck and stuck it on an Enco 5/8 ths straight
shank to 3JT arbor. It has ALWAYS wobbled. I figured that it was the
cheap shank and recently removed to replace it with a genuine Jacobs
shank since my machining skills have progressed a little bit beyond
the "mark with chalk, cut with axe stage". Appropriate chuck wedges
wouldn't work but the Enco shank was soft so I threaded it and use a
chunk of ¾ inch dia tubing and a 5/8 ths nut to pull the Enco straight
shank off with minor effort. Cleaned up the chuck and brand new
Jacobs 5/8 ths straight shank to 3JT arbor and gently pressed into
place. A reamer blank chucked in the mill has zero run out. Same
reamer blank chucked in the newly shanked 14N drill, 25 thou runout.
Damn. I must have mistreated the chuck badly over the past 9 years.

Got a new Jacobs 14N chuck with new Jacobs 5/8ths SS cleaned
appropriately gently pressed into chuck and tested with reamer blank
today. 12 thou run out on new chuck and shank. Zero run out when
reamer blank chucked into mill collet. WTH???

As an aside, a new Rhom chuck pressed onto cheap HF drill press has
zero run out.

Any insight on either what I'm doing wrong or how to fix it would be
appreciated.

Regards,
Jim


There is more than a chuck different here.

1. different insertion
2. different arbor or at the very least different arbor insertion
at the very least.
might try rotating the arbor to a different engagement angle...

Martin

--
Martin Eastburn
@ home at Lion's Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

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Dear Chuck
Are you sure that it isn't a New York "damn" and a "thank you" would be a
more appropriate response?
lg
no neat sig line

"Tom Quackenbush" wrote in message
...
Well, if that's the way you feel, you can just go to hell.

Warmest regards,
Chuck

Remove bogusinfo to reply.

On Fri, 03 Jun 2005 18:48:38 -0700, Grant Erwin
wrote:

I don't understand this at all. What's this business about dialing in a
ground rod? Indicate the spindle taper directly. Run true? Then carefully
put in the arbor alone, and indicate it. Run true? Then carefully put the
chuck on the arbor and install it, and only then put in something round,
and indicate it. If it runs out badly, return the chuck as defective!

GWE


Grant, Martin, Larry G

Thanks for the insight. I will do as you suggest.

Skuke, JR, I already have an Albrecht. Works like a champ
but I save it for the fine stuff.


thanks to all for the advice.

Jim