Jump to content

Recommended Posts

Posted

Started drilling another balance for my friend. Not for money but for shellack... finally i have this :) 

The staff end is 0.53mm and the hole will be 0.3mm. Just got right the center :)

Now lets pray together that the drill will not break...

Snapshot_20160819.PNG

  • Like 4
Posted

Well, this went wrong. The pinion was to thick and/or the hole is to big compared to the staff diameter and/or i tapped it to hard. 

Snapshot_20160821_1.PNGSnapshot_20160821_3.PNG

Not to mention that the drill was first broken in the hole and i had to turn it out first. 1 of 3 staffs repivoted succesfully until now. Need more experience or better tools  :D

  • Like 1
Posted

I'd encourage you to buy one one for these bow operated old lathes, below euro 100. And from there you could start making more precise tools.

Posted

Learned much from this case however.

First, noticed that the drilling bit batch ordered last time is completely is a waste. The cochleate shape of them is deformed and not regular. 

Second, the method how i wanted to mke this was totally wrong. Now i have found the copy of a hungarian watchmaker book where the procedure is written precisely. One has to drill three time as deep as the diameter of the hole. The pinion with a small taper has to fit in the hole all the way down and has to come off. And then cut it a bit shorter, so if one put it back it will tight fit and not over-stress the hole walls. It is easier to make another pinion until it fits like above than start again from scratch. 

Now i have shaved the staff and started drilling again... with proper drills :)

  • Like 2
Posted


Understood about the taper, good tip. My pivot drilling jig is still in my head, but ordered loads of bits and pieces from China. Waiting for the parts to arrive, so hope I get some of the good micro drills and not a reject set! On your picture of the pivot when you say "just got right the center" - what preparation do you do to the broken pivot? Do you file it flat first or what do you do before you try to get the pilot center? I take it that you found the center on your pivot drilling machine?

Posted
16 minutes ago, Michael said:


"what preparation do you do to the broken pivot?"

Getting the center with a pivot drill indicating that the tool is OK, leading the drill to center. This is done by the female cone which is also slef-made. Need one for all drill size. Currently i have two. 

First i file down the broken tip to get a half-cone ended staff. Like on the pictures. That end will made the staff turning centrical in the female cone. Then i use the drill with the corresponding cone which does not allow the drill to wobble and get the initial hole perfectly centered. From this point you can use smaller drills, since the small initial hole will lead the drill not the female cone. See the cross-section of this on the picture posted previously!

The book suggests to find the center previously by hand. This goes to drilling tools without drill-leading female cone. On lathes "finding the center" with hand is not easy (at least for me :) ). Picture 318 showing "Köldök" which will mislead the drill. 

pivot drilling.jpg

  • Like 1
Posted (edited)
On 2016. 08. 21. at 11:50 AM, szbalogh said:

Well, this went wrong....

Finally a good insertion. The hole is deep down the level of the balance wheel. 

Snapshot_20160825_3.PNGSnapshot_20160825_2.PNG

Edited by szbalogh
Posted (edited)

The extension was falling off two times while turning the pivot. Then i filed down a bit from the end. After that it was holding well and the staff was finished succesfully. :) 

After the video the endshake was also adjusted. The pivot thickness will be fine-tuned by the owner, since that jewel is broken and need a replacement. 

Edited by szbalogh
  • Like 1
  • 4 months later...
Posted

Very innovative!  I have a watchmaker's lathe with a drilling tailstock, but I have it in one place and it's not easy to break down and set up wherever I need it.  Plus your work gets across many of the essentials of repivoting.  I find that to avoid breaking drills I have to be very careful to make sure the lightest touch produces sworf (curlings).  If not,  then the metal has to be annealed, drilled and re-hardened.  Thanks!

  • Like 1
Posted

Scbalogh,

As usual your approach to watch restoration and repair problems is innovative and brilliant. At this point the only thing holding you back is not having better equipment. You have too much talent to be held back by equipment issues.

david

  • 1 year later...
  • 2 years later...
  • 2 months later...
Posted

I’m currently working on my own pivot drilling machine, but I’m having trouble drilling the female centers. Would you mind telling me how you did it? I ground a 3 flats in a piece of hardened silversteel, but the cutter dulls super quick (I‘m using 6mm 4140, maybe that’s too hard)

Posted (edited)

JDG123,

Drilling into a piece of hardened anything is going to present a problem. Ending up with a precision part introduces additional machining issues.  If precision is of little or no concern just center drill a piece of unhardened drill rod and harden it.

If high precision is required a lot of additional steps will be  necessary.   Several machining techniques are required to make the ID and the OD concentric with each other. This is a problem also faced in the manufacture of collets.  

A drilled hole will not be precise nor will it be particularly round.  The way a round hole is achieved is with a single point boring cutter.  To make a high precision tool start with a piece of oversize, unhardened  drill rod. Face cut and drill the center drill with a  center drill bit.  Follow up with a normal bit the size of the pilot end of the center drill and deepen the hole to allow clearance for a small boring bar.  A small boring bar can be made by taking a small two flute endmill cutter and grinding off one of the flutes.  Bore the sides of the center drilled hole with the tiny boring tool at the same angle as the drill with very small cuts. That should give you a precise angled hole.  Turn the drill rod around and do the same thing to the other end.  Next turn the part you just made on centers down a few thousandths over the desired finished OD.  Now you will have a precision center and the OD will be concentric with the ID.  Harden the tool by heating it.  After heat treating put the part back on centers and turn (or grind) the OD to its final dimension.  Since the part will be hard this will  require an extremely hard cutting  tool like carbide, ceramic or CBN.  

These are a lot more steps than most watchmakers would want to take but the result will be an extremely precise and concentric cup center.     

Edited by david
Posted

Riiiiiight, that’s actually a lot more steps then I’d be looking for. The thing is, the centers I’d like to have should be about 1mm in diameter, so a boaring bar probably won’t be practical for me (I‘m doing this on a modelengineers lathe). 
I can’t just use a center drill, because there would still be a flat from the chisel edge. Do you have any ideas other than my makeshift form cutter? It has a very negative rake, maybe I could make the same sharp tiped cone again and file down one half of it flat like a Seitz reamer? 

 

Posted

JDG123,

A Seitz reamer is a one trick pony.  Its only purpose is to size a hole to its final diameter.   If a tapered hole has a diameter larger than you want you can always reduce the size by taking face cuts.

Posted

My comparisons to the Seitz reamer is mostly about the shape. A cone cut in half.My smallest boring bar is a Komet with around 3 mm in diameter, with that I also won’t get a „sharp pointed“ cone. I do have a 3mm endmill I could modify, but my lathe doesn’t have a quickchange toolpost, getting that boringbar on center would be almost impossible. 

On my watchmakers lathe I could use a graver to find the center and cut a cone, the problem is, that my toolsteel gravers don’t cut the 4140 and my biggest collet is a #50 (the material has to be 6mm...)
 

 

 

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing

    • No registered users viewing this page.
  • Topics

  • Posts

    • This was what I was afraid of. The movement is not one of the generic black square modules. Remove the movement from the clock and try prying it open very carefully, without breaking the plastic tabs. The plastic might be brittle from age. Clean the wheels and check the battery contacts for corrosion. Check the PCB for bad solder joints. Take plenty of photos along the way.
    • One of the problems with trying to Photograph Phils things are that his enjoyment was building these things so they tended to E falls on what will see if I can find some earlier pictures or any pictures I wasn't even sure because I was looking for that specific picture for somebody else and even it got the last version and that would have been the last version. You will note that he put the indexing on something that he could unscrew it or whatever and it can slide back out of the way so the rest of the lathe can be used as a lathe. With the lathe cut are actually coming down from the top I was there once where he demonstrated how to cut a pivot with the setup it was really beautiful. Older set up if I remember it's not a worm gear assembly in the thing in between the stepping motor and the holding block I believe this particular one was like a 100 to 1 gear ratio. Earlier version with watchmaker's lathe. Even looks like he is the watchmakers bed and then switch to something he made. Then I do have other pictures and things of the rotary stage in use. In the raw so if you tube videos here is an example of one were somebody's mounting a three jaw chuck. At one time there were available on eBay they were not cheap but if you're patient like I was I found one cheap on eBay. After you watch the video it look at his other videos he is a whole bunch of other examples of the same rotary stage. That I do know there are other pictures examples and possibly videos you just have to track them down. One of the minor issues of finding this particular tech sheet for the unit is I believe it was a custom manufacturer and the company change their name but I remember the new name here's a link to the company https://www.ondrivesus.com/rino-mechanical-components                
    • Escapement adjusting always interesting and depending upon the reference always confusing. Okay maybe it's not always confusing but it does lead to confusion. I have a PDF below it's actually a whole bunch of separate stuff including a hand out that came from a lecture that's on you tube. Then from that we get this image Consequences of doing things especially if you do things out of order or you do things for the wrong reason. Oh and even if the watches working I made the mistake one so showing my boss how tweaking the banking pins on a full plate on the timing machine made the amplitude get better and now he thinks that's what they're for and I don't think a fully grasped exactly what horn clearance means. Consequence of doing things. Notice what it says about opening and closing the banking pins and total lock? So yes I've had that on a full plate where it won't unlock at all and that's the banking pins or a combination of things basically. So banking pins unfortunately get moved. One of the ways to tell if it's been moved is the look straight down at the end of the fork with the balance wheel removed. Power on the fork push at the one side look at it push it to the other side also look at it and compare anything with the center reference the balance jewel and see if both sides of the same. No guarantee after the same there in the right place but at least are the same typically when people play with things one side will be way off from the other because they had no idea what they were doing at all because of course it's a full plate and you really have to paying attention and even then there's still hard to do. Then the other thing that comes up like it shows below is people often adjust the banking pins to do all those other things as opposed to horn clearance which is all that it's therefore and maybe bonus Guard pin clearance although you're supposed to deal with the guard pin is a separate thing like single roller gets bent in Or out or sometimes physically gets moved in and out. Some full plates older escapement's typically pallet forks held together with screws and you can actually unscrew and move the entire assembly in Or out more complications to deal with.     Escapement handout wostep nscc.pdf
    • If he was much younger and some sort of sports player it wouldn't be a problem. They would be in there and doing surgery and he'd be back on the field in no time. Unfortunately when you get older little things are bad and big things can be really bad so not good at all.
    • Where I work everything incoming watches whatever detailed descriptions are taken entered into a computer program and photograph of each item. Then ideally although it depends on who's doing the paperwork detailed descriptions can be quite good other times there lacking. Like I really like it with pocket watches if they would record the serial number it avoids confusion later on. Then when watch repairs are completed that is also entered in. It's one of the amusements I learned when I was in school instructor had a shop and commented about the important aspect of keeping detailed records of repairs. Because oftentimes a customer who got a new crystal will come back later on when the watch doesn't work and expect you to fix the entire watch for free. Then you can remind them that they just got a crystal. Strangely enough that keeps coming up or occasionally comes up where I work now. One of the problems of using the service marks on the case is that in the case of pocket watches oftentimes that's not the original case. Then case marks? What I was doing warranty work for a company I used to describe a code number in the back of the case and it would tell me the next time I see the watch that basically what I did I made no attempt at keeping track of customers because we had literally thousands of them I think they sold 30,000 of these watches and they would come back by the hundreds because they had a lifetime warranty. Yes that's a story all of itself but I would put a code number that would reference what was done to the watch the last time and think I had a date in there somehow so it did tell a story if you knew the code. Another shop I once worked out the number would reference the page in the book. So other than knowing we had been in there you would have no idea what happened because you have to go look at the page in the book to see what happened. Then the problem of how you examine a watch you should examine the watch in detail every single time to avoid complications. Although on vintage watches and this is a of amusement I have at work when people ask something and I say of the watches done when it leaves. This is because on vintage oftentimes problems won't show up until the watches much farther into the repair like it's now running and you discover things that you can't discover before because it wasn't running to discover them that also become sometimes difficult to have exact rigid prices are estimates of repairs or in the case of a pocket watch you may not find out if a casing problem to later on when you case it up in the watches running. I was just thinking for all those people that would like to leave a mark maybe you should learn to do what some of the past watchmakers did? Leave a mark but leave it in such a way that no one will ever find it? Typically not done for repair purposes but done for other reasons like identifying it's legit. I have a friend with a Gruen watch and one of the Roman numbers the bottom line that just looks like a line under extreme magnification actually says Gruen watch company or something equivalent. So here's a link showing how to mark your watch without being seen although that's not the actual title. So if you can learn micro engraving you can engrave the watch someplace probably just about any place you just have to remember where you put it. https://cnaluxury.channelnewsasia.com/obsessions/how-to-prove-if-watches-are-authentic-secret-signatures-182516  
×
×
  • Create New...