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Anybody do better than .0015" runout on a HF jacobs chuck?

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  • CCWKen
    replied
    I have an OLD Jacobs No. 3 that they'll have to pry from my cold dead hands. It's as good as any current precision chuck. Note the patent date.

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  • JoeLee
    replied
    One other thing to mention........... the older Jacobs chucks were nicely ground throughout, including the taper. The newer ones from what I have seen are turned. They eliminated the grinding process as a cost cutting measure I would imagine.
    I've also heard complaints of tapers not holding. I had a new one my self and I couldn't keep the chuck on the arbor, I was sent a replacement which held OK.

    JL...............

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  • Rich Carlstedt
    replied
    Originally posted by JoeLee View Post
    I have to wonder where the bushing would go also............... I have a Jacobs 14 N that I use in my tail stock. I had to play around with the positioning of the chuck on the 3MT arbor until I got the least amount of runout (sweet spot) which ended up being close to .0002
    I rotated the chuck 1/4 turn on the arbor and checked it each time. I also had to check those 4 positions against the two positions that the arbor would fit in the tail stock quill due to the tang. I lucked out with a key hole on top so when I remove it from the tail I always know which way it goes in. I haven't checked it in a while but would assume it may have changed. My test pin was a 1/2 in. ground pin.

    JL...................
    Like Joe, My 14 N had about .003" runout new from MSC.
    Then I checked the arbor, and it was not a "Jacobs" as the ad implied.
    Taking the chuck off the arbor and indicating it showed the .003" and I complained to MSC
    Got a replacement (Jacobs brand) and now have a .0002" reading.

    Buyer beware.
    To the poster, consider yourself lucky if you can get better than .002" on imported chucks ..German/Swiss excluded

    Rich

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  • Jbchip
    replied
    Im doing all of this on a minimill with the R8 holder, have not tried on a lathe.

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  • JoeLee
    replied
    Originally posted by Jbchip View Post
    . Its crazy that china can make jacobs style chuck for $10.
    It may look like a Jacobs on the out side but what are the inners like?????

    JL..................

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  • Jbchip
    replied
    I cut mine out of brass 1.25OD , .65ID and .04 thick tapered down to .02 thick. Then figure out which way the chuck is leaning then position the bushing between the arbor and chuck so when you press together the chuck straightens out. This wont replace a professional big buck chuck but will cut a pretty straight hole. Its crazy that china can make jacobs style chuck for $10.

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  • JoeLee
    replied
    I have to wonder where the bushing would go also............... I have a Jacobs 14 N that I use in my tail stock. I had to play around with the positioning of the chuck on the 3MT arbor until I got the least amount of runout (sweet spot) which ended up being close to .0002
    I rotated the chuck 1/4 turn on the arbor and checked it each time. I also had to check those 4 positions against the two positions that the arbor would fit in the tail stock quill due to the tang. I lucked out with a key hole on top so when I remove it from the tail I always know which way it goes in. I haven't checked it in a while but would assume it may have changed. My test pin was a 1/2 in. ground pin.

    JL...................

    Leave a comment:


  • Black_Moons
    replied
    Now go test your chuck with diffrent sized test bars.

    The runout changes with holding diameter, Most notabley on cheap chucks. Thats why you pay the big bucks ($80?) for something like a glacern chuck.

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  • adatesman
    replied
    Jacobs, or Jacobs-style? Would be surprised to find HF selling name brand chucks.

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  • DR
    replied
    Bushing....? Where does the bushing go? All my Jacobs chucks have tapered mounts, no place for a bushing.

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  • Anybody do better than .0015" runout on a HF jacobs chuck?

    The old $10 one , started out with about .02" runout keep turning it in the arbor until I got to the sweet spot .008 then figured out the high and low spot and made a bushing. Pressed it all together, Using this method I think I can get pretty close to zero runout. Cant get lower than my spindle runout .0005. First post. Anybody tried this?
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