Removing Captive Pinion - Redux

Discussion in '400-Day & Atmos' started by KurtinSA, Aug 4, 2019.

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. For the new NAWCC home page
    Click this image at the upper left corner of this page.
  1. KurtinSA

    KurtinSA Registered User
    NAWCC Member

    Nov 24, 2014
    3,514
    125
    63
    Aerospace Engineer (Ret.)
    San Antonio, TX
    Country Flag:
    Region Flag:
    I asked about this a while back...here's the previous thread:

    Schatz 53 - Removal of captive center arbor

    I'm down to a number of Type 53 clocks that need some work, so I thought I'd give it a shot. I did manage to purchase sets of clock and watch hollow punches plus a small anvil. What I haven't figured out yet is the support to hold the plate while I drive the pinion off the arbor. That's got me baffled. But I figured it can't be held on that tight, right? Before starting, I measured the gap between the pinion and the front plate and it's right at 0.4mm.

    The Type 53 has the two upper legs which are riveted to the front plate so they can't be removed. I straddled the plate across a couple of 2x4s and got out my punches. Note also that the center arbor on these clocks have a small threaded portion, then a square section for the minute hand, then the round arbor. I found a punch that slipped over the threaded portion and bottomed on the beginning of the square section. I pounded a bit then checked my results. Uh oh, the corners of the square section were flaring out a bit. So I found another punch that slipped over the square section and seemed to bottom out on the round part of the arbor. With some more pounding I was able to drive the pinion off...mostly.

    The punches seemed to mushroom the ends of the round arbor, certainly the square section was damaged. I got out my small file and lightly took the burrs off and was able to easily slide the pinion off. I checked the minute hand and it still slips back over the square section.

    So, what did I do wrong? How do I avoid the damage to the front end of the arbor? As far as I can see, the front plate didn't bow any as a result of this.

    Thanks...Kurt
     
  2. Harry Hopkins

    Harry Hopkins Registered User
    NAWCC Member

    Nov 16, 2011
    546
    38
    28
    Retired Instrument Technician
    Mason, IL
    Country Flag:
    Region Flag:
    Just guessing here but I would say that you need to find a way to support the plate other than wood. The wood probably has enough give to it that it requires heavier blows with the hammer plus if you are using 2x4's I doubt you are supporting the plate near the center arbor so the plate is also flexing a bit when you use the hammer causing you to have to hit harder and more times than necessary. A crows foot like this one is an inexpensive way to support the plate if you don't have an anvil similar to the one shown in the referenced thread.
     
  3. KurtinSA

    KurtinSA Registered User
    NAWCC Member

    Nov 24, 2014
    3,514
    125
    63
    Aerospace Engineer (Ret.)
    San Antonio, TX
    Country Flag:
    Region Flag:
    #3 KurtinSA, Aug 4, 2019
    Last edited: Aug 4, 2019
    Harry -

    You are correct...I didn't have anything to support the plate near the arbor. I was hoping to use this, which I bought from HomeDepot:

    Simpson Strong-Tie CPS Composite Plastic Standoff for 4x4-CPS4 - The Home Depot

    But because of the posts on the plate, it wouldn't sit on the post support. I think it would work with a plate without any posts on it. It's harder than wood, but certainly softer than a metal as in the ones identified in the previous thread.

    The crow's foot you referenced...it's made of steel...wouldn't that be harmful to the softer brass?

    A friend has a split stake. It's a couple of steel plates that pivot on one end and have a series of holes drilled down the center...the center of the hole is where the plates come together so there's half a hole on edge plate. The steel plates are held up on the ends with some blocks. I haven't seen anything like that available. I'm not in a good position to machine anything, although the split stake concept might be doable...need to find some parts I guess. Just noticed some split stakes on Amazon...but for watches...need something for clocks.

    Kurt
     
  4. Harry Hopkins

    Harry Hopkins Registered User
    NAWCC Member

    Nov 16, 2011
    546
    38
    28
    Retired Instrument Technician
    Mason, IL
    Country Flag:
    Region Flag:
    The anvil I use is hardened steel and it does not mark up the plates but it has a very smooth finish. If you are concerned that the crows foot might damage the brass you could put a layer of masking tape on it. I think you will find that when supported securely and near the center arbor that it will take a lot less force to remove the pinion than you think. Of course a proper fitting hollow punch is important but it sounds like you have that covered.
     
  5. KurtinSA

    KurtinSA Registered User
    NAWCC Member

    Nov 24, 2014
    3,514
    125
    63
    Aerospace Engineer (Ret.)
    San Antonio, TX
    Country Flag:
    Region Flag:
    Wouldn't the crow's foot you showed have some bounce to it? I'm guessing the one end gets snugged up in a vise, leaving the split crow's foot parallel to the bench. The plate would be slide over the crow's foot but likely the center arbor would be several inches away from the post that is secured in the vise.

    Kurt
     
  6. sjaffe

    sjaffe Registered User

    Dec 25, 2012
    419
    2
    18
    Engineer
    Santa Rosa,CA
    Country Flag:
    Region Flag:
    I don't have one of these in front of me and there were no photos attached, so if there is something on the other side of the plate that is fairly well attached (pressed on) there are two ways you can do this. Neither is beating on the end of the arbor. As you have unfortunately discovered, this is a good way to mushroom the end of the arbor or bend it. Even using a press instead of a hammer can result in damage. You want to work between the plate and the pinion. One way is using two screwdrivers that have had the ends bent at a 90 degree angle so that they function as miniature pry bars. Rest each against the plate and gently lift the pinion using both pry bars simultaneously. Sometimes the item being removed (e.g. gathering pallet) has a tendency to fly across the shop never to be found again, so it's a good idea to put a rag over the works while you are prying. The second approach is to use two small wedges with a slot cut in each. The beveled sides face each other so the top and bottoms are parallel. Squeeze them together and your pinion breaks free.

    Stan
     
  7. KurtinSA

    KurtinSA Registered User
    NAWCC Member

    Nov 24, 2014
    3,514
    125
    63
    Aerospace Engineer (Ret.)
    San Antonio, TX
    Country Flag:
    Region Flag:
    Stan -

    Interesting. However, one thing I noticed...and didn't expect...I had to drive the pinion almost the entire way on the arbor shaft. I had expected that after maybe 0.5" of movement it would have been free to slide by fingers. So using some kind of prying mechanism would be problematic.

    Kurt
     
  8. sjaffe

    sjaffe Registered User

    Dec 25, 2012
    419
    2
    18
    Engineer
    Santa Rosa,CA
    Country Flag:
    Region Flag:
    You just need to add shims under the pry bars, more shims as the pinion travels down the arbor. I've heard of people using pennies.

    Stan
     
  9. KurtinSA

    KurtinSA Registered User
    NAWCC Member

    Nov 24, 2014
    3,514
    125
    63
    Aerospace Engineer (Ret.)
    San Antonio, TX
    Country Flag:
    Region Flag:
    OK, I was going to ask how you protect the brass plate from the steel pry bars.

    Kurt
     
  10. victor miranda

    victor miranda Registered User

    Jan 13, 2017
    355
    40
    28
    computer programming stuff
    Baltimore
    Country Flag:
    Region Flag:
    a schatz 53 is the clock I have used for all my experimenting.

    I am not sure I am following your description kurt.

    there are two gears on the center arbor, the wheel and pinion inside the clock plates
    and the pinion on the outside to drive the motion works.

    on a small drill press I put a vise ...
    I used a pair of brass rectangle bars about 3/8 inches thick and bridged across the open vise.
    placed the bars as close to the wheel as they would allow.
    set that onto the vise
    put the nut on the end of the arbor.
    used a 1/4 inch drill rod as the press anvil
    and used the drill press to push the arbor off the outside pinion.
    it took only took a little pressure to remove. about what is needed to drill a 1/16 hole into brass.

    the gear came loose after about 3/16 inches of arbor pressing.

    it was harder to press it back on because I had to drill a hole into one of the afore mentioned bars.
    and make a rod to press the arbor at the collar for the inside wheel.

    I can imagine you can do much the same with a block of wood with holes drilled to clear the
    riveted posts and the center wheel, in place of the brass bars.

    pressing back to together may take a little more ingenuity.

    victor
     
  11. KurtinSA

    KurtinSA Registered User
    NAWCC Member

    Nov 24, 2014
    3,514
    125
    63
    Aerospace Engineer (Ret.)
    San Antonio, TX
    Country Flag:
    Region Flag:
    Ah...using the hand nut on the end to push against. I like that idea. I don't have a drill press around, though.

    Kurt
     
  12. MartinM

    MartinM Registered User

    Jun 24, 2011
    3,039
    95
    48
    Male
    Medical Insurance Systems Analyst
    El Dorado, CA
    Country Flag:
    Region Flag:
    I wouldn't use the actual hand nut for pressing. They strip way too easily. Find a steel nut the right thread and use that.
     
  13. KurtinSA

    KurtinSA Registered User
    NAWCC Member

    Nov 24, 2014
    3,514
    125
    63
    Aerospace Engineer (Ret.)
    San Antonio, TX
    Country Flag:
    Region Flag:
    Do you happen to know the thread size off hand?? ;)

    What if you used the original hand nut but put the minute hand on as well? That gives a more secure situation for the nut to push against.

    Kurt
     

Share This Page