J Head Step pulley Low gear not working
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    Default J Head Step pulley Low gear not working

    I have a J head with the step pulley. I'm unable to switch to low gear mode. The cam ring does not move to the low position and hangs up about an inch before the end of travel. I noticed that one of the screws (cam ring pin) is missing from the cam ring. Therefore it's only lifting on one side so it may be binding?

    What I find suspicious is when I move the lever to engage the back gears the quill will not turn at all. Move the lever back to high gear and the quill moves just fine. Seems stuck. I've never had this mill in low gear so don't know if that is normal or not. I understand that diagnosing these issues over email is near impossible but would like to know about the stuck quill before I order parts since there may be a larger issue in play here.

    Should I be able to turn the quill by hand when back gears are engaged? I can in high gear so I suspect something else may be going on.

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    Quote Originally Posted by caprio View Post
    I noticed that one of the screws (cam ring pin) is missing from the cam ring. Therefore it's only lifting on one side so it may be binding?
    That should be corrected first. The OD of the thread is .245 and it's 32tpi. The length of the thread is about 1/4". The head is round and elongated with a allen head.

    You could turn down a allen screw and thread the end. Use the one you have as a guide.

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    Some diagrams.
    j-head-1.jpgj-head-explode.jpgstep-pulley-partial-view-.jpgj-head-hi-low.jpgj-head-parts-list-1-50.jpg
    If the threads are stripped in the bearing cartridge for #32 pin then new holes should be drilled and tapped. The housing has to come off and the bearing cartridge will need disassembly to do this. Look for the tiny set screws that lock #32 pin in place before removing the pin. Failure to remove the set screw results in stripped pin threads.
    #4 bearing locknut has right hand threads. The two holes in the face are ideal for a face spanner tool, 5/16 pins. If these holes are shot drill two new ones to suit.
    John

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    Quote Originally Posted by caprio View Post
    I have a J head with the step pulley. I'm unable to switch to low gear mode. The cam ring does not move to the low position and hangs up about an inch before the end of travel. I noticed that one of the screws (cam ring pin) is missing from the cam ring. Therefore it's only lifting on one side so it may be binding?

    What I find suspicious is when I move the lever to engage the back gears the quill will not turn at all. Move the lever back to high gear and the quill moves just fine. Seems stuck. I've never had this mill in low gear so don't know if that is normal or not. I understand that diagnosing these issues over email is near impossible but would like to know about the stuck quill before I order parts since there may be a larger issue in play here.

    Should I be able to turn the quill by hand when back gears are engaged? I can in high gear so I suspect something else may be going on.
    You do need to fix the missing bolt issue but do you know that you also have to shift the backgear handle on the right side of the head.

    If you shift the one without the other, it will cause the spindle to lockup.

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    I removed the set screws and have no regrets.

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    Thanks for all the feedback.
    I did get the unit disassembled. I think the problem was the spindle pulley bearing sleeve was stuck in the housing.
    It did not move up and down or even turn freely. I had to remove it with a dead blow. I'm guessing previous owner hadn't used low gear in ages and the grease got old and sticky.
    Whats really odd is the sleeve doesn't fit easily in the housing even after cleaning it up. Went over both surfaces with steel wool and filed the burrs off. I would think that the bearing sleeve should drop it fairly easy but still be a little snug with no play.

    I was considering drilling new holes for the two cam ring pin's or trying a heli-coil to repair the threads. I believe the cam ring pins are 1/4-32 and am not finding a thread insert of that size. Probably the best approach is to just purchase a replacement sleeve. H&W has them for $138.00. I'm hoping the new one will drop in without the size issue.

    Have any of you seen the issue with the bearing sleeve not fitting back into the housing? Just doesn't feel right to have to wet sand the parts to get them to mate properly.

    P.S. Just saw a thread insert kit on Amazon for 1/4-32 but it's over $100! For that price I should just purchase a replacement part

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    Drill and tap for new cam ring pins.
    Dressing the bore I.D. and the bearing cartridge(sleeve) O.D. can be tedious. I have had to knock them out with a deadblow and then dress the high spots. It might help to drill and tap first and then fit the cartridge. Check the I.D. - O.D. dimensions for out of round. When properly fitted the cartridge should slide up and down with finger pressure. Expect that the housing has more defects than the cartridge and that a new one will be just as tight until the housing bore is cleaned up.
    Regards, John

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