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PM-727m New mill has arrived!

Discussion in 'PRECISION-MATTHEWS' started by Sloth2009, Mar 27, 2017.

  1. fradish

    fradish United States Active Member Active Member

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    So the drop I am seeing is when the FF is engaged (#4 is tight, binding #1 to #3) and the quill lock is completely
    loose. I don't see it all of the time. The best explanation of what I feel when lowering the quill (only when lowering)
    would be if the worm gear was missing a tooth and the quill dropped a small amount. I suppose it could also be
    that the quill is catching on the set screw a bit and instead of the quill dropping smoothly it hangs a bit then
    drops suddenly. Maybe there is a rough spot on the quill where the set screw rides?
    The drop is not a huge amount, but it happens.

    What I really need to do is to be much more methodical about characterizing this. I have marked where the
    keyway is on the outside of hub #1, so I can raise the quill as high as it will go and record over multiple
    tries where I encounter this drop (like the keyway mark is at 3 o'clock on the first revolution of the FF and
    9 o'clock on the second.) Having this information might help identify if this seems like a gearing issue or
    maybe it is an issue with the set screws...

    I just need to find time to do this... :)
     
    Sloth2009 likes this.
  2. Sloth2009

    Sloth2009 United States Active Member Active Member

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  3. fradish

    fradish United States Active Member Active Member

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    Short answer, it might have just needed grease!

    I seem to have either fixed my problem or reduced it to the point
    where it is undetectable. I took off the fine feed gear box (not that big of a deal)
    just watch the key and spring. There is a snap ring that was a little stiff, but once
    that was off the worm gear slid off.

    The worm and worm gear both looked pristine.
    No broken teeth or burrs. There was however a blob of grease off to the side of
    the track in which the worm and gear meshed. I spread that out and added some
    more until all of the teeth of the worm gear had a light even coating of grease.

    I then greased the bore of the worm gear and the worm itself. I put it back together
    and there was still a bit of a drop! It was smoother, but not fixed. Since I had the grease out
    I greased the rack on the back of the spindle, a light coating all over the spindle and a little
    in the groove where the set screw rides. After working the feed up and down a few times, I could
    no longer detect a drop.

    Though I'm glad I greased up the worm gear, I don't think that was necessary. I think something
    in the spindle was just sticking.
     
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  4. Sloth2009

    Sloth2009 United States Active Member Active Member

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    I think most of the issues we have run across with the quill feed have been related to how the gears from the quill pinion shaft and the gear teeth on the back of the column mesh together. Keeping the set screws tight and sliding smoothly plus keeping the gears clean and lubed seem to be the best answers for us. Glad you solved your issue!
     
    Last edited: May 20, 2017 at 2:08 AM
  5. Sloth2009

    Sloth2009 United States Active Member Active Member

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    I used the mill to hollow out the micarta handle for this little hatchet. I had most of the hatchet finished before I got the mill. If I ever make another one, I will use the mill to slot in the gas shut off wrench on the handle instead of forging it in. A fireman friend asked me to make it for him to take on safety checks.
    IMG_5622.JPG IMG_5623.JPG IMG_5625.JPG
     
    Last edited: May 21, 2017 at 1:49 PM
    BFHammer, Fitter Bill and fradish like this.
  6. Sloth2009

    Sloth2009 United States Active Member Active Member

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    Got the 5/16" delrin in today. Its a nice sliding fit in the set screw hole and in the column slot. I just made a little plug like I did out of the brass. Its definately a big improvement over the stock set screw. IMG_5630.JPG IMG_5631.JPG IMG_5632.JPG IMG_5633.JPG
     
    tweinke likes this.
  7. Sloth2009

    Sloth2009 United States Active Member Active Member

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    Finally made some tram aids. Split the 2" CR stock down the middle then used a 3/4" end mill to square up the band sawed sides. I drilled and counterbored the holes for the cap screws. Then drilled and threaded the other holes. Also painted them to match the mill. IMG_5609.JPG IMG_5634.JPG IMG_5655.JPG IMG_5656.JPG
     
  8. fradish

    fradish United States Active Member Active Member

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    That is so weird, I had thought of making something very much like that for my mill.
    I never built it, but what you've built is pretty much what I was thinking of.
    I'm a little hesitant to drill into my mill, so I was going to see if I could just
    use a bar clamp down from the top. But I always thought having screw adjusters
    would be better than tapping with a dead blow.

    So, does it make tramming easier and more precise?

    Good Job! Looks very professional.
     
    Last edited: May 23, 2017 at 10:30 PM
  9. Sloth2009

    Sloth2009 United States Active Member Active Member

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    Thanks! My machine should still be trammed in from the epoxy tram, so I haven't used them yet. From what I've read, these screw style tram aids work very well for fine tuning in the head swing. If you decide to make some be careful on the left side of the head when your drill pilot hole since the gib and gib screws are on that side. I tapped the head 1/4-20 for the mounting bolts and the bracket 3/8-16 for the set screw.
     
    Last edited: May 24, 2017 at 1:56 PM

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