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Good thread with interesting points on both sides of the issue!
I saw my name mentioned by Paul and thought I would jump in here.
First congratulations Jim on your successful pivot job!
Also to you Paul for knocking out a a tiny and good pivot using the same tooling tech. as used on clocks. I think I
mentioned something in the videos that similar tooling can be made for pivoting watches but must be much more
precise and should be hardened. Looks like I should have said “Should” and not “Must”! You proved me wrong on that
one so let’s just say I think a persons chances of success will be greater if closer tolerances and much better
finishes are increased as the job and tooling gets smaller. The finish on the locating angle in the fixture will
become increasingly important when locating smaller arbors. A tiny bit of roughness or chatter on the locating
surface may have no ‘noticeable’ effect on eccentricity on a large clock arbor where the same finish may throw a
tiny watch arbor all over the place. Hardened steel will not only keep the hole from wearing out but also will
permit a much better, highly polished surface than a softer steel and will of course lessen the possibility of grooving this surface by
the arbor. I would think the brass jig would work for a one time shot. Curious to see the results as I’ve never
tried using brass for a watch pivoting jig/flag.
For those interested these pivoting attachments are available for watchmakers. They attach to the tailstock
and can be adjusted to different sized holes for drilling. They are available through Horia, Bergeon (I’m pretty
sure) and mine is from Boley. All that’s required is a watchmakers lathe and a house that can be mortgaged. If
someone out there wanted to start making precision tooling that would sell for reasonable prices I think you would
have a good business going! Oh wait…the name ‘Sincere’ keeps flashing in my mind! If they aren’t already making
them it’s probably just a matter of time. I’ll take a pic of the tooling today and will post it up here for anyone
interested. You’re pretty up on Sincere products David so maybe you know if they are already making something like it.
Yes I agree Paul. Convincing watch and clock makers that capping should be done ‘rather’ than pivoting might be a very
hard sell. Although on occasion there are cases where Davids method would be the only option other than making a new part, since we
are talking about efficient watch and clock repair techniques I too would recommend pivoting in the majority of cases.
David when you stated:
the odds of putting a hole dead center into the end of a staff are about zero. What I would recommend instead would
be to take a short piece of drill rod that is slightly larger in diameter than the staff and sink a short hole into
the end that is about 2/3 the diameter of the staff.
I interpreted this as meaning pivoting not being an acceptable way of making the repair because the completed job
would not be good enough for clock or watch repair. I may be wrong but it seems that Paul read it the same way?
Whether being acceptable by the industry or not isn’t really the issue here, at least not for me because up here all options are on the table. Whether a repair technique is good enough for clock or watch repair is far more important and interesting to me as is any alternative.
I see that you cleared this up last night by saying that it is an acceptable method but just not as accurate. I
agree with you that turning the final pivot will be more accurate than just drilling and inserting. Yep for sure.
Here’s how I see it though. Since the risk of run out from drilling the cap pretty much equals the risk of run out or drift in
the arbor drilled for a pivot and a clean up cut can be made on either the cap or inserted pivot if necessary, then
as far as I can tell, there’s no real advantage of capping over pivoting since capping requires more steps than pivoting.
Whether using a jig/flag as in this case or catching center with a graver and then drilling small holes with a spade
drill I think you’ll find that with some practice and TLC you’ll be able to knock a pivoting job out quickly and
accurately. Certainly accurate enough for most watch work. Also Jim since you’ve already had success at pivoting a bit larger pivot/arbor and have expressed a desire pivot this one then by all means I think you should go for it.
Paul gave a link to an ebay auction for spade drills. You can also purchase them from material houses. A popular
name is ‘Mascot’. Not sure if they’re still making them but worth a look. Also many watchmakers just grind their own
spade drills. There may be some info online on how to make them if anyone has an interest. Also there’s a small
book/manual called “How to Make Tiny Drills Quickly, easily, & accurately by Robert Porter that shows the exact
process. It’s a good little book (mine has 15 printed pages) that I’ve had for some years now but would think that
it’s still around.
I’ll take some pics of the tooling and will try to put it up here a little later today.
Adios for now and Enjoy!