Re-pivot tiny pivot HHEELLPP!!

[david pierce]

Digital Tripper,
The last sentence should read not .
I don’t know how to edit these things once they are posted.
david

[arutha]

This kind of re-pivot can be done, even in hardened steel. If I have found this to be correct a size #80 drill bit is .343mm? That is massive
If you look on ebay you do now and again see small sets of watchmakers drill bits come up, they are like tiny little spades and come in boxes with little wooden cylinders to hold the drill bits.
http://www.ebay.com/itm/EARLY-1900S-WATCHMAKERS-DRILLS-KIT-1-NO-RESERVE-/380572614672?pt=LH_DefaultDomain_15&hash=item589be54010
These drill through hardened steel, I know this because I have used them when re-pivoting french clock pivots and they dont come much harder than these. In my hints and tips section I showed how to make a simple flag to help guide the drill, I think Bob shows a thing like it in one of his videos (probably where my idea came from!).
Bob told me this probably wouldnt be accurate enough for doing watch pivots, shhh…dont tell him but I did a re-pivot of .55mm using this method. It is fiddly and takes a little while to set up but it can be done.
Try it, what have you got to lose? Dont run the lathe too fast, these drill bits dont like it.
As for making a new arbor, if it is an unimportant clock or watch, go ahead, if it is something with history and age then surely you want to keep the clock as original as possible?
Paul.

[arutha]

Also sorry if I am stating the obvious but the piece of pivot steel you would be putting into the hole needs to be of a slightly larger diameter than the original pivot as by the time it is polished and burnished it will take the diameter down a fraction. If you have enough meat on the arbor you could even get away with inserting a much bigger piece of pivot steel and then take it down to near size with a graver leaving enough to polish/burnish to size.
This is assuming of course you have a watchmakers lathe, you will find this very difficult with a dremmel as it spins way to fast. If you get stuck, send it to me and I will do it for you.

David,
why on earth do you think it impossible to put a hole dead centre in an arbor? I am no machinery expert but I have done quite a few re-pivoting jobs and find it quite simple? What method have you tried using that has caused you a problem?

[arutha]

Sorry, I have just re-read the original post and it is the flag you are having trouble with, my bad!
Drill through 2 pieces of 1/16th brass slowly, run a piece of pivot steel through the holes so they line up and glue them together, you then have your 1/8th thickness. It would be ok for a couple of jobs but brass being soft wont last too long, the hole will go a little oval after using this flag a couple of times.

[digitaltripper]

@Arutha wrote:

This kind of re-pivot can be done, even in hardened steel. If I have found this to be correct a size #80 drill bit is .343mm? That is massive
If you look on ebay you do now and again see small sets of watchmakers drill bits come up, they are like tiny little spades and come in boxes with little wooden cylinders to hold the drill bits.
http://www.ebay.com/itm/EARLY-1900S-WATCHMAKERS-DRILLS-KIT-1-NO-RESERVE-/380572614672?pt=LH_DefaultDomain_15&hash=item589be54010
These drill through hardened steel, I know this because I have used them when re-pivoting french clock pivots and they dont come much harder than these. In my hints and tips section I showed how to make a simple flag to help guide the drill, I think Bob shows a thing like it in one of his videos (probably where my idea came from!).
Bob told me this probably wouldnt be accurate enough for doing watch pivots, shhh…dont tell him but I did a re-pivot of .55mm using this method. It is fiddly and takes a little while to set up but it can be done.
Try it, what have you got to lose? Dont run the lathe too fast, these drill bits dont like it.
As for making a new arbor, if it is an unimportant clock or watch, go ahead, if it is something with history and age then surely you want to keep the clock as original as possible?
Paul.

Hey Paul !! Thanks for the encouragement. Yes I was trying to drill thru my 3/16″ steel flag that I did my last pivot with on the Adamantine Seth Thomas clock which worked perfectly BTW!! Thank you again for suggesting that I re-pivot it because after just nine days running I could see wear in the silver solder on the pivot. http://www.clockrepairtips.com/forum/viewtopic.php?f=2&t=512#p2626 I should post a picture of the re-pivot I think it came out nice!! Anyway that clock is back to the customer who was thrilled with it.

Anyway #80 is tiny from my perspective. The pivot size is the equivalent of a #79 drill shank. No it is not old, it is a clock from the 1980’s so keeping original part would be good but making a new one would be ok too. I am going to go read up about the flag you made to see what I can learn. I put this one aside for now as I have other clocks to get out but I will be returning to it in about a week.

Thank you again Paul, I will get this re-pivoted…Oh yes I will

Jim

[arutha]

Good luck with it Jim,
just remember nothing is impossible but sometimes buying the tools to do the impossible can be expensive
Glad you got the other re-pivoting job done, that clock will run for much longer now
You can buy carbide drill bits to go through hardened steel but you do have to be very careful with them, because they are so hard they are also brittle. Have you tried one of these for drilling out your flag? Please dont snap one off in a pivot hole either, you will have a monster job getting it out again.
Let us know how it goes.
Paul.

[david pierce]

Paul,
I know that drilling is an accepted method of repivoting and will produce a part that is good enough to work in a watch or a clock, but the result will not be as concentric as a turned part. Drill bits are double lip cutters and a force on one side of the cutter will push the other side into the work removing material. This is called drift and drills drift. If you magnify a drilled hole enough times it will not even look round; it will have a lobed cam shape. This is the reason jig bores are used in tool and die work. If a part requires a precisely located round hole, the hole would first be rough drilled to hog the metal out and then bored with a boreing head. This process would gurantee that the hole would be precisely round and precisely located. This could never be achieved with drilling.The process I described will also produce a hole that will be slightly off but if it is followed up with a turning operation It will put the new pivot precislsely on center.
david

[arutha]

Hi David,
I can only go by what I see through my 10x loupe, having everything lined up in my watchmakers lathe, it looked pretty concentric to me. As I stated in my previous post it is important to leave enough material to burnish the pivot. I think you will have a very hard time convincing most clock and watchmakers this is not the way to go. I would even be prepared to re pivot something for you so you can check it with your measuring devices for inaccuracy?
Paul.

[david pierce]

Paul,
I know that there are accepted practices in watch and clock repair that are certainly good enough to get the job done. There are also factors dealing with the standard watch and clock equipment that are traditionally used to repair timepieces. For example running a broach through a wallowed out hole in a clock plate as opposed to using a boreing bar. A BERGEON bushing machine broaching out a hole will NOT produce a hole that is as precise as a milling machine with a boreing head, however, it is good enough to get the job done and is a faster process. Drilling a hole with a two flute drill bit is less precise than turning an outside diameter in a watchmaker lathe. With a LORCH or WOLF JAHN lathe the precision is there and available (I am guessing you have one of these lathes from your shop picture) . Why not use it to full advantage. In my view as long as the pivot can be turned in the lathe as part of the final process you will get as much precision as the equipment can offer. I know that these views fly in the face of tradition but the fact remains that a turned part will be more precise than a drilled hole. If you have some spare time turn a pivot on a piece of solid bar stock, then, take another piece of solid bar stock, drill a hole in the end and press in a pivot. I contend that the piece turned from the solid will be a more accurate part. Watch jewels are probably the most precise components in a watch and they are manufactured by making the hole first, then turning the outside diameter of the jewel to the hole. The reason for doing this is to ensure the concentricity of the hole and the outside diameter.
david

[Bob Tascione]

Hi Guys,
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!

Bob

[david pierce]

Bob,
The initial problem was sucessfully drilling through steel with a #80 (.0135) drill bit. This is in itself a difficult machining task. The bits are small, fragile and require small precision tools to hold them properly. I would guess that Digital Tripper spent a lot of frustrating time and went through a fair number of drill bits before giving up. I have read articles on both sides of the issue on whether to repivot or make a new staff. I like the cap idea because even though a few more machining steps are required, they are easy managable steps. The cap will allow larger sized and more manageable drill bits to be used and at the same time produce a better end result. This does not mean that drilling a hole into the end of the old pivot will not produce something that works. If most of the repair insustry is using this method then it is an accepted process. It is true that making cap will require a little more machine work, but, if the #80 hole cannot be achieved then what are the alternitives.
I also have a copy of Porter’s book and have seen numerous devices for sale to drill pivot holes. Porter has some very clever solutions for making spade drills with some low cost tools like a pin vice with a hole drilled in the shank resting on the tool post. He also has a design for a pivot drilling machine using a slot car motor. I like his ideas and they produce results that are good enough to get by, however, I also feel that there are more accurate ways to do these things.
david

[david pierce]

Bob,
I just reread your last post. Yes, the drill will also drift drilling the hole in the cap. The differences are a larger drill bit can be used reducing the amount of drift and most importantly, since a new pivot will be turned from the cap, any offset in the hole location will be eliminated. The resulting new pivot will be made to whatever tolerance the lathe can produce.
david

[arutha]

This is a great post and some very useful information is coming from it!
A friend of mine uses cap pivots and if that is the route you wish to take then that is up to you, the cap jobs I have seen from my friend have not impressed me as it is not in keeping with the original look of the part. If you are using a cap that requires turning down the diameter of the arbor to then be pushed on so the arbor is all the same diameter then this would be acceptable on an antique.

With regard to capping a balance staff, this is something I have not seen done. If you are having a to use a few processes to get a cap to fit surely it would be better just to learn how to turn a new staff? This is a skill that would be used time and again if you are going down the pocket watch route as there are plenty out there with broken balance staffs.
Is capping a balance staff something anyone has done? I would love to see pictures and know about the exact process. Also how long would it take to do this as opposed to turning a new balance staff?

David, I understand completely where you are coming from on the drilling a perfect hole. As a standard process the pivot must be burnished after the new pivot is put in and if you are at all worried about the concentricity then you can always insert a piece of pivot steel of larger diameter than needed and then turn it down to size. This should be standard procedure for a re-pivot anyway. I hope you didnt think I was questioning your advice on this, I just wanted to let you know from my own experience that it is a perfectly acceptable way to repair a pivot and that the finished product is concentric(As concentric as my collets will allow anyway
There is no wrong way to go about a job as long as it provides a good job at the end of the process it does however help if you find a method that is quicker than another and produces the desired results.
Paul.

[david pierce]

Paul,
I want to be questioned. Being questioned and making mistakes are the two of the best learning tools I know. There are numerous techniques and precedures that I have looked at and rejected and others that I know nothing about. I try to read everything about this field I can get my hands on and have watched all of the videos that I knew existed. In the little extra time I have left I try to get on the bench and take watches apart.
david

[Bob Tascione]

This is a good thread!
I’m gonna just fire off a quick response here cuz I’ve got a “honey do” list to take care of for the next couple of hours. If it doesn’t make much sense don’t worry about it. I’ll clean it up a little later tonight. I’ll just respond to a few things you wrote David by pasting quotes and quick responses.

The initial problem was sucessfully drilling through steel with a #80 (.0135) drill bit. This is in itself a difficult machining task. The bits are small, fragile and require small precision tools to hold them properly. I would guess that Digital Tripper spent a lot of frustrating time and went through a fair number of drill bits before giving up.

First off I think your solution was a good one. I was just commenting on the zero chance thing you said which you cleared up.
To this quote,
Yes I agree. Accurately drilling this size hole through steel without the proper tooling would be difficult. For those who may be thinking this would require expensive tooling I’ll throw a little food for thought in here without going off on a tangent and losing the jest of this topic.
Bow, spade drill, staking set. Or bow, spade drill, lathe etc.

“if the #80 hole cannot be achieved then what are the alternatives.”

I suppose brass plates as Paul suggested. Will it work? Not sure cuz I’ve never tried it but sounds feasible and I can’t knock it ’till I’ve tried it. It does seem possible if used only once though. Hope to learn from Jim’s results.

The differences are a larger drill bit can be used reducing the amount of drift

Well, yes if we’re talking about drilling both holes the same depth. Except, we’re talking proportions here just like required blind hole depths for different diameter dowel pins used in our tool making days. I think it would be reasonable to carry over the same fit proportions used for our pivot hole to cap hole. Here’s what I mean. If we assume a 3 to 1 ratio (depth of hole 3 times diameter of plug or pivot) then the depth for the #20 drill (.0135 x 3) would be about .040. If we give the cap hole a diameter of say 1/16″ (.0625 x 3) then we’re looking at a required depth of about 3/16 (.187). So as I said earlier: ‘pretty much equals’. Where I must give some lee way here is that the pressure placed on the 1/16th. drill would definitely be easier to control than on the #20 and since pressure or feed plays such a big role in drill deflection the chances of drift would be greater with the smaller #20 if some type of control isn’t available. But…there is a very simple way to control the pressure when using a staking set and it’s free if you have a few weak old compression springs laying around. Hint: ball point pen pulled apart, remove ink cartage, place over punch (may need to cut plastic back a little) then press just enough to engage spring pressure, activate bow and watch out for hot flying chips…well slight exaggeration I suppose but it does work (wonder if the big Ber has these and what they go for). There’s a little more to this than I’m explaining here as you’re not actually turning the punch but rather a small homemade drill holder with a pulley, and a drill inserted. This whole assembly sits between the punch and work piece. Very simple to make, simple to use, accurate and fun!
We’re kinda splitting hairs with all of this anyway since we’ve already concluded that the pivots for both methods can be dressed if needed. It’s fun though…got to have fun!

I have read articles on both sides of the issue on whether to re-pivot or make a new staff.

Yes lot’s of debate on this subject. Whether it’s good practice or not I don’t know. I personally don’t like to pivot staffs and would rather just make a new one as Paul suggests. It’s a matter of preference though and I don’t have an opinion either way on how someone wants to do it. Arbors are a different story for me though as quite often there’s a pinion that will need to be cut making the whole arbor making process very time consuming. At least it takes me a long time.

I’ve probably skipped some stuff here but getting the evil eye from my guests so got to go.

Enjoy for now and again good thread!

Bob

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