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  1. #16

    Default Re: Using glass for bushings (By: John MacArthur)

    Johnny,

    Thanks for the additional information. Looks like I will need to pickup a copy of Watchmaking to get acquainted with the process and terminology.

    Are the synthetic stones good for this purpose and if so, what type would you recommend?

    Best Regards.

    Carl

  2. #17
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    Default Re: Using glass for bushings (By: cmnewcomer)

    I'm curious if the red ruby is any better than the just
    clear synthetic sapphire? Is it just for looks or all about
    the same?
    Tinker Dwight

  3. #18

    Default Re: Using glass for bushings (By: cmnewcomer)

    Carl -- Yes, the synthetic rubies are actually better for clock jewels. I used some "river" ruby many years ago, and made several fine pallets and some good jewel bearings, but the fracture planes weren't always apparent. I wound up with several bearings that had quite obvious fractures embedded within them. In the Gemcutters site, and likely others, you can choose between dark and not-so-dark stones. I've always liked the darker ones, but all ruby and sapphire is basically the same material (aluminum oxide, or corundum). Sapphire makes good-looking pallets, and I have another set of pics showing that process. "One of these days" I'll assemble the whole series into a single thread on making a high-grade regulator.

    You'll notice that I use a gem-cutting wet diamond blade, very thin, to cut the initial slabs from the raw boule. I use a jewelers "dopping wax" to hold the boule onto a plate of thin glass (welders cover glass, or microscope slide) during slicing and subsequent cutting of the slab into smaller pieces. It also holds the jewel onto the 1/8" brass tubing, for the other work. I also have a number of laps for each grade of diamond paste. Some run directly on WW mandrels, and some run on the high speed spindle as the jewel rotates in the lathe head. I've made all these from copper plate, which being soft and ductile, holds the diamond. I have one watchmakers lathe only used for abrasives, including diamond paste. If you only have one lathe, you'll need to be pretty careful to not contaminate the bearings and slides. Over the years, I've accumulated four, but I'm still pretty careful with the dedicated abrasive one.

    The further polishing and all important inside lapping to size and polishing are coming up, and I'll post pics as that comes along.

    The Daniels book has been a constant source of inspiration and information over the last 30 years - I can't recommend it highly enough.

    Best of luck,

    Johnny

  4. #19

    Default Re: Using glass for bushings (By: Tinker Dwight)

    "I'm curious if the red ruby is any better than the just
    clear synthetic sapphire? Is it just for looks or all about
    the same?
    Tinker Dwight"

    Tinker -- all ruby and sapphire are corundum (aluminum oxide), and so are the same hardness. The color is from very slight amounts of impurities. I guess I'm just a traditionalist. They are all equally good.
    Johnny

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    Default Re: Using glass for bushings (By: John MacArthur)

    Thank you for all the great input! I started out regarding glass as harder than it is I think. Something about leaving hardened steel "glass hard" I think made me make the assumption. My long term goal is to make a watch from scratch and it would be very rewarding to also be able to make the jewels I think. It calls for additional tooling and a whole lot of trial and error before I get anything worth using. I don't have a lathe to spare at the moment either... Later!

    I think ball bearings will be the way to go. But aren't they designed to be lubricated? I'm thinking they will wear much faster without lubrication. I know this guy can be a bit salty so no offense to those suggesting washing the lubricant out. It just made me think of this video: https://www.youtube.com/watch?v=uD7Lzv5fWhs

    Best regards!
    Karl

  6. #21
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    Default Re: Using glass for bushings (By: karlmansson)

    Quote Originally Posted by karlmansson View Post
    Thank you for all the great input! I started out regarding glass as harder than it is I think. Something about leaving hardened steel "glass hard" I think made me make the assumption. My long term goal is to make a watch from scratch and it would be very rewarding to also be able to make the jewels I think. It calls for additional tooling and a whole lot of trial and error before I get anything worth using. I don't have a lathe to spare at the moment either... Later!

    I think ball bearings will be the way to go. But aren't they designed to be lubricated? I'm thinking they will wear much faster without lubrication. I know this guy can be a bit salty so no offense to those suggesting washing the lubricant out.

    Best regards!
    Karl
    You can find a lot of perhaps relevant information at https://www.bocabearings.com/ball-bearings-in-clocks Rex Swensen has done a lot of work on the subject, so no need to reinvent the wheel....

  7. #22
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    Default Re: Using glass for bushings (By: Jim DuBois)

    Thank you Jim!

    I was provided with the link to Boca Bearings earlier but did not manage to find the page you linked. Very informative! I Think I've learned all I need on the subject for now. Thank you to everyone who contributed!

    Best regards
    Karl

  8. #23

    Default Re: Using glass for bushings (By: John MacArthur)

    Quote Originally Posted by John MacArthur View Post
    I'm in the process right now of making jewel bearings for a regulator I'm almost done with.
    .................................................. ....... I'll post pictures as I complete this process, if there is interest............"One of these days" I'll assemble the whole series into a single thread on making a high-grade regulator.
    Darn right there is interest!

    I had the opportunity/privilege of visiting Johhny in his shop last year and he was very helpful in explaining this jewel making process. But do you think I would remember all of the steps?



    Nope not me. So please, pretty please keep us updated on your progress and I am so glad to hear that you have a "One of these days" write-up planned.

    I believe that there will be a LOT of interest in a thread that would showcase your craftsmanship and be inspiring to all as well.

    "To invent you need a good imagination and a pile of junk." - Thomas Edison
    Best wishes to Ya'll. Sincerely, Jim

  9. #24

    Default Re: Using glass for bushings (By: jhe.1973)

    Thanks for the kind words, Jim. I'm working on these between other stuff - they involve a lot of slow going. I *will* get them on board, though.

    Johnny

  10. #25
    Registered User Jim DuBois's Avatar
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    Default Re: Using glass for bushings (By: John MacArthur)

    Rhetorical question. Why have millions of watches been built with jewels and none built with glass bushings? That alone would give me pause, as glass is a lot cheaper than sapphire or diamond or other jewels used in watches. And capitalists will always be capitalists.....so if glass was a good substitute for jewels and it was much cheaper would it not have been used in millions of watches? I know little to nothing about watches but I do pay attention to the human condition if you will. It is my passing recollection that the jewels used in watches were selected for their ability to accept a fine high polish which then allows much reduced friction when fit properly to hard steel pivots. You all have covered this nicely in comments above. I am also aware that in some conditions glass can be very abrasive, even polished glass. There are of course other characteristics of jewels versus glass where jewels may fair best. In any event I would error on the side of caution and buy synthetic sapphire boules and stay away from glass. The cost of the synthetic products seems pretty reasonable to me. The cost of a jewel, no matter of what it is made is more in the time to make it than it is in the material.

  11. #26

    Default Re: Using glass for bushings (By: jhe.1973)

    I will second that !
    To John and the others - Thanks for sharing your experiences
    Much appreciated Conwae

  12. #27
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    Default Re: Using glass for bushings (By: ccwk)

    Of course I realize that synthetic ruby would be superior to glass, considering how long it has been used and with what success. My question came from a place where I had trouble finding jewels of the size I required and thought that glass would be more easily worked and more easily obtainable than ruby boule. I'm interested in learing lapidary work as well so glass might be a good place to start out.

    For the application I asked about originally I think ball bearings are the way to go in any case. I do however appreciate the input from everyone and I am also looking forward to a more in depth look at making jewel bearings, when it come around!

    Best regards
    Karl

  13. #28

    Default Re: Using glass for bushings (By: karlmansson)

    I'm a bit dubious that a straight-line train would exhibit more problems with pivot location errors than another arrangement. Recall that the force applied to a pivot by a wheel tooth is (mainly) at right angles to the line of centers, though there is some pushing away of the pivot too (which varies with the tooth contact angle through tooth contact). And sure enough, what we see in worn plates is an oval hole whose long dimension is at about a 75-80 degree angle to the line of centers. Probably the worst arrangement, vis-a-vis pivot wear & cumulative position error for a train would be one where the wheels are at this this 75-80 degree angle to the line of centers; which is not always too different from what we usually have in existing clocks! Timepieces generally have train layouts that condense their dimensions to fit their cases.
    One reason that glass has not been used for bushings is that it's so brittle & breakable (compared to sapphire). But probably the real reason is economics: it's a lot easier to sell something for a high price if it's made with rare jewels, rather than broken bottles.
    But consider that brass bushings are considered sacrificial; it's a lot easier to re-bush than to repivot.
    Butter Bearings are really more a system for repair, than just simple bearings. They are sold in sets for specific repair jobs, e.g the Hermle floating balance movement. The pivots fit loosly into the bearing ID, which avoids precision alignment problems. The bearings are as easily set as brass bushings. This enables movementsw with plated pivots to be salvaged, and used, probably, another century- which is a lot more than they've lasted so far! And if you're worried about your rep long after you've been in the ground, just include an extra set or two in the case- that'll certainly earn you a prayer of thanks from some future clockmaker!

  14. #29

    Default Re: Using glass for bushings (By: Bill Ward)

    Very interesting thread. I can't wait to see more.

  15. #30
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    Default Re: Using glass for bushings (By: Accutronica)

    Glass is actually a very viscous liquid. Even a small piece of glass will change shape over time under constant pressure. Large windows get thicker at the bottom versus the top under the force of gravity. I don't know how long it takes in terms of size and pressure, but if you are wanting to use glass to make a long lasting bearing you are probably not going to be happy after a few years.

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