Removing taper pins from a clock mechanism

Hi all,
I'm trying to repair a wall clock. It's a "Dufa", built by Etzold & Popitz of Germany in the 1920s or '30s. It's very similar to this one on
eBay at the moment:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&iteme84307091
Although it isn't an exceptionally valuable clock, it keeps good time and was bought new by my great great uncle for his company office, so I'm keen to get it fixed. The problem is that the main spring has snapped. We got a clockmaker to quote for the repair, but the price was high so I want to have a go myself.
To get the spring out one either needs to remove the clock face from the mechanism, or remove the back plate from the mechanism. The former is much more attractive as you don't have to disturb any of the gears. The problem is that small taper pins (1/16" diameter at most) have been used to attach the mechanism to the face, and also to assemble much of the mechanism. However I disassemble the mechanism I will need to remove several of these pins. I know the obvious method of removal is with a pair of long nose pliers, but I tried this without success. I don't want to pull too hard because then if the pin comes free, my other hand will probably fly into the clock mechanism and cause some damage (knowing my luck). A brief inspection suggests to me that the pins are harder than mild steel and that they were hammered into place. I can't hammer them out as the narrow ends all face into the clock mechanism.
Any thoughts? How do professional clockmakers do it? Suggestions would be appreciated...
Best wishes,
Chris
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Christopher Tidy wrote:

U-shaped apparatus , with one leg drilled and tapped for a small , hollow , screw . Hollow screw slides over big end of pin , other leg of "U" pushes against the small end as you tighten (hollow) screw against side of shaft that pin is in ... Did any of that make sense ? -- Snag aka OSG #1 '76 FLH "Bag Lady" BS132 SENS NEWT "A hand shift is a manly shift ." <shamelessly stolen> none to one to reply
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Snag wrote:

Thanks, Snag. That makes sense. Do you know if this is a commonly used tool with a name, or just something you saw once?
Chris
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Christopher Tidy wrote:

I might have seen one once ... don't recall . Just seemed like a sensible way to apply pressure against the pin . I'm just chock full of ideas that someone else thought of first ... <bseg>
--
Snag aka OSG #1
'76 FLH "Bag Lady"
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I've seen taper pins that had been in for awhile that would *not* come out. I destroyed a part once and sawed it in half right down the length of the taper pin and tried to knock it loose. No dice. I mean I *really* tried. It seemed to have welded itself in there somehow. That was steel on steel, though. - GWE
Christopher Tidy wrote:

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Clock taper pins are usually steel in a brass dowel pin. I've had good luck over the years with a sturdy pair of needle nose pliers. You apply pressure to the small end of the pin with the very end of one jaw, while letting the other jaw rest against the side of the large end of the pin. This way you're squeezing the pin into the brass dowel. I wouldn't use this method on a really valuable clock, because if the pliers slip it can put a nasty scrape on the side of the brass dowel. OTOH, it usually gets the pin out without a major catastrophe.
--
Bob (Chief Pilot, White Knuckle Airways)


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Bob Chilcoat wrote:

A few horological sites mentioned adhesives (locktite etc.). Mainly for newer plates but who knows what has been done by others. Maybe a little heat would help, with sinks in place of course.
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I use electronic nippers - like side cutters, but no bevel on outside surface, get a good pry on something, don't cut the pin off. If head of pin doesn't protrude beyond edge of plate, I can usually get something in to push from the other side, sometimes needlenose pushing on the thin end of the pin, using the post for the other tang. Haven't lost one yet, but I DO have a rusty 1720-vintage musical-bells clock in the shop that suffered heat and steam damage in a fire.... Should start on it this week. May have to go with electrolytic rust removal if all else fails/ mark
Christopher Tidy wrote:

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Need to use some stout small needle nosed pliwrs. If possible, push the small end a bit to see if it comes out that way if you have the room. If not, the it is just pull on the fat end. A set ofo flush cutters can also be used but don't try to close them too hard. Clamping right at the post and using it as leverage is a good way in either case. I've also seen pliers with a hole in the end to hold the pin but they are quite rare. I've done a bit of work on pre 1850 watches so I know exactly what your problems are. As to the spring, if the break is in the middle, just untemper (an alcholol flame is what the pros use( for about 3/8" either side of the break and do a slot in one side of 1/3 of the width of the spring and a tounge wiht an arrowhead on it on the other piece and just slip them to9gether. At least, that is what the pros that I've seen do it. For the ends, you just reform the end instead of making the hole and head.
-- Why do penguins walk so far to get to their nesting grounds?
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Bob May wrote:

Thanks for the advice. I had the neat idea of trying to remove the taper pins with a pop rivet tool, but I can't get the tool close enough. I guess I'll have to make do with pliers or make a tool myself. Do you know what those special pliers with a hole in them are called?
I also hadn't thought of repairing the spring. I was going to get a new one.
Best wishes,
Chris
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    Why not modify a cheap pair of needle nose pliers yourself? What I would do is grind or file (depending on hardness) a smooth curve to grip the dowel without maring it, and then drill through from the outside to the crest of the curve -- and a little into the opposite jaw, just a dimple to keep that end from slipping off the small end of the pin.
    While you're about it -- put some tape over the outside of the through hole to catch the pin when it lets go -- otherwise it might go shooting into who knows where. That sort of thing is quite difficult to find when it goes flying.

    You may or may not be able to get a new one.
    Also -- be *very* careful in unpacking the spring if it is in a cylindrical housing. Those tend to come flying out and can hurt you if you are in the way.
    Good Luck,         DoN.
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