Clausing 8520 Mill: problem disassembling z-axis shaft housing
Close
Login to Your Account
Likes Likes:  0
Results 1 to 4 of 4
  1. #1
    Join Date
    Nov 2020
    Country
    UNITED STATES
    State/Province
    Wisconsin
    Posts
    1
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default Clausing 8520 Mill: problem disassembling z-axis shaft housing

    Hi folks,

    I recently got this milling machine from a high school shop and am in the process of taking it to pieces in order to get it in good shape again. It worked okay, but there was roughness in both the x and z axes, so I figured I'd clean everything up and replace all the bearings that need it. (The y axis moved smoothly, but I'm cleaning it up anyway.

    I'm 60 years old, have a fair amount of woodworking experience, and am pretty mechanically inclined, but have done almost no machining. I bought a Logan 10-inch lathe a while back, and cleaned that up, too. My 19-year-old engineering student son is working with me on this, and has both more experience and a more nimble mind for this kind of thing.

    That's the background. Here's my problem: I have not been able to get the shaft out of the knee assembly, where the handle interacts with the knee's lead screw. I've got the manual; I've gotten the two roll pins out of the front end of the shaft, as well as the one in the beveled gear at inner end of the shaft. I removed the two snap rings on the front of the shaft, as well as several very thin washer/spacers. Now it does not want to come out. I looked everywhere I could think of online to find help, and someone said that, now that I'm at this point, I should be able to just pull the shaft out. No soap. I made a jig/tool to press the shaft outward to a point by putting a long roll pin in the outer hole on the front of the shaft, and using threaded rod in some rectangular aluminum tube to push the shaft outward: on one side against the long pin, and on the other side against the body of the mill. This worked well enough to pull the shaft out far enough that the front bearing is loose. Now the shaft can move a bit laterally, but will not come out further. In fact, both the pin and the threaded rod bent rather than the shaft moving forward any more.

    Now, the manual shows that there is another bearing on the other end of the shaft, with THREE snap rings (one closer to the front end of the shaft, and the other two on the back end.) The rearmost one looks larger on the small drawing in the manual, and I wonder if I need to get this off before the shaft will come out. The issue with that is that I see no way to get at it. The beveled gear is loose from the shaft, but the shaft sticks into it enough that I cannot remove the gear. The gear won't come off the back way because the gear it meshes with, on top of the knee's lead screw, is in the way. I removed the jam nut on top of the lead screw, but the gears are in the way of each other, and I don't see how to get either out. (I'm not even sure if the one on top of the lead screw is loose now that the jam nut is off. It doesn't seem to be.

    This mill was bought new by the high school 60 years ago, and I know schools beat their stuff. But this one was bought by a shop teacher whose son is now the shop teacher, and he said both of them impress the kids with the importance of caring for tools. It looks to have been treated well. Still, 60 years is a long time. Things have been a bit harder to get apart than they were on the lathe. I've sprayed penetrating oil into the tight spots, so I'll see how that goes.

    I hope someone can tell me what I need to do! Thanks!

    Paul

    PS: My son had fun today making a bolt to replace one that was ruined on the mill. We needed a 7/16 x 20 bolt with a 1/2 inch diameter shoulder of a specific length. He took a 5/8 bolt and modified it on the lathe, then used a cheap die to provide the threads. We don't have the best tooling for the lathe yet, but he made it work!

  2. #2
    Join Date
    Mar 2005
    Country
    UNITED STATES
    State/Province
    North Carolina
    Posts
    75
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    4

    Default Diagrams

    This contains diagrams, might help. Or it may be the same manual you have. :-)

    http://wentztech.com/WebDisk/Metalworking/Clausing/Clausing 8520 Instructions Parts.pdf

    - Reed

  3. #3
    Join Date
    Jul 2001
    Country
    UNITED STATES
    State/Province
    North Carolina
    Posts
    2,132
    Post Thanks / Like
    Likes (Given)
    227
    Likes (Received)
    482

    Default

    Take the nut off elevation screw and lift up the knee (table, saddle, everything)
    just a few inches. This should pull the shaft end of the screw down, and out of
    the gear. Take out the woodruff key.

    -Doozer

  4. #4
    Join Date
    Mar 2007
    Location
    L'Orignal, Ontario Canada
    Posts
    2,322
    Post Thanks / Like
    Likes (Given)
    2370
    Likes (Received)
    984

    Default

    From the linked manual it looks to me that the sleeve 702-014 has to come out towards the front or hand wheel side of the machine and the shaft with it.
    Did you loosen the 1/4-20 x 3/8" set screw that looks to be holding the sleeve in the knee ?
    That may be filled in with paint or filler and not readily visible at first glance.
    There may be more than one set screw in that hole with the inner one being spotted into the sleeve to maintain its alignment and one on top to lock it in that could have been added later if the inner one had a habit of coming loose.
    Jim


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •