Kind of a newbie question regarding files

Schatznut

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Hello, all -
I'm beginning my adventure into the world of bushing clocks, starting with cuckoos. I've read books and watched videos and have a grasp of the concepts, and am starting to accumulate or make tools. I need some advice on files, however. One of the first steps in the process is to file the original pivot hole to the opposite of the wear so that the drill or reamer will center itself on the original hole. Working on cuckoos, the pivot holes I'll deal with are small - less than 1mm in general, and I'm at a loss about where to buy a round file that tapers down to .5mm or so. Lots of pictures in the various catalogs but no dimensions. Recommendations? Sources? Thanks!
 

KurtinSA

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I've not ventured into the world of bushing clocks...yet...but I did buy a Burgeon bushing tool along with the necessary reamers, cutters, bushings, etc. These go down pretty small and allow for perpendicular cutting. I couldn't imagine trying to do this with a hand file but I guess it's done that way. I'm mostly familiar with 400-day clocks and the oil sinks on the plates help to identify the location of the original pivot hole. With the bushing machine, I believe the process is to step out on larger and larger sizes until the size hole needed is perfectly concentric with the oil sink...maybe there's one more ream after getting to that point, to the final ream size which then accepts the bushing. Again, that's from a person who has only watched a handful of holes be bushed in his limited career. :)

Timesavers has Burgeon equipment and I believe KVM (?) equipment to do bushings.

Kurt
 

bruce linde

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using a bushing machine or filing out the holes by hand both require practice, patience, and magnification. with either method it's all about maintaining the center of the pivot hole.

i did just pop for some more expensive files... very happy with what i received, offered just as step up from what you can get from timesavers but still perhaps less than gorbet/vallorbe escapement files: Friedrich Dick 5-Piece Escapement File Set, German Cut #5

here are some previous threads on the topic: best files site:mb.nawcc.org
 

Schatznut

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Thanks to Kurt and Bruce for the valuable advice and suggestions. I ordered a couple of Glardon-Vallorbee needle files, which are pretty steep price-wise, in #4, #6 and #8 cuts. I'm building my own bushing machine based on ideas I've seen on line and my experience designing machine tools in a prior life. I'm trying to take the "thumbs factor" out of it as much as possible (I have big thumbs and lots of them). Agree there's no substitute for experience, so I'm going to go get all the experience I can handle... Bruce's comment that it's all about maintaining the center of the pivot hole strikes me as being the key to success. A bushing machine that rigidly holds the plate in relation to the arbor is definitely the way to go, but "balancing" the oval hole before making the initial plunge would minimize the probability the bit would walk away from the true center. Hence my quest for files... I've found that the better the tools I have, the fewer and less severe my screwups tend to be.

P.S. Kurt, the clock in your avatar - tell me about it, please. I've got one similar to it dating from 1913, if I'm reading its date stamp correctly, that is a happy little clock. Wonder if they're related.

Clock.jpg
 

Dr. Jon

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For such small holes it is probably better to use cutting broaches than files. These work by turn rather than pushing in an out.
 

Jerry Kieffer

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Hello, all -
I'm beginning my adventure into the world of bushing clocks, starting with cuckoos. I've read books and watched videos and have a grasp of the concepts, and am starting to accumulate or make tools. I need some advice on files, however. One of the first steps in the process is to file the original pivot hole to the opposite of the wear so that the drill or reamer will center itself on the original hole. Working on cuckoos, the pivot holes I'll deal with are small - less than 1mm in general, and I'm at a loss about where to buy a round file that tapers down to .5mm or so. Lots of pictures in the various catalogs but no dimensions. Recommendations? Sources? Thanks!
Schatznut
I can certainly express an opinion and suggestion if you wish and give a location for the next demonstration.

However, I would suggest you try a method (Any method) of bushing to get a general understanding of the issues. If your lucky, you will install the bushing in the wrong location and learn a very valuable lesson. That lesson is that any method that does not address an efficient/accurate method of correcting your own mistakes and those of others will greatly limit your repair capabilities.

In research, you will find that a clock movement can be constructed from bar stock with a compatible Lathe and Milling machine with an envelope the size required. This will not only cover construction, but all repairs including bushing, depthing, wheel cutting or tooth replacement and all other issues requiring no other single purpose machine. The overall cost of two properly selected machines is often less expensive than a whole selection of single purpose machines that never seem to be right for what needs to be done.

Jerry Kieffer
 

Schatznut

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My files came today and they are beautiful. Their tips measure right at 0.5mm and they taper up to either 1.5mm or 2.5mm, with the #8 being the larger one. Concentrating on getting the bushing machine built; then I have a couple of junk movements I'll practice on before I try to do one of the "keepers." I do have a multifunction machine (lathe/mill) that I use for making tools and car parts. It's much too big for clock work, and its tailstock is a piece of... well, let's just say that it lacks the precision I need.
 

karlmansson

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I've had issues or the same type Before, where the bushings are just too small to get at with a file. Some metal bearings in Watch plates for instance, such as center Wheels. For very small work you can center it on a lathe faceplate and bore the wear out. The ideal way of centering in this case is either with a centering scope or a loupe, as a wobble stick will risk dipping into the worn area giving you a false Reading. A properly finished Point on the stick with appropriate pressure in the unworn part of the bushing should give you a decent Reading though. But seeing the unworn edge of the bushing run true is probably the best way.

You can also use a bushing machine or hand held reamers with a single cutting lip to center the worn hole. Start by marking out the section of the bushing that is worn (a section of the full circle) with a very fine tip marker. Then you can start cutting with the reamer on the whole UNWORN part of the bushing. This method will only work with single lip reamers and not the five sided typ that come either as hand held reamers or that Favorite uses in their jewelling Tools. You want to be able to Control the material removal and locate it to the area that isn't worn so that you can compensate for the worn section. Keep going back and forth on the unworn section until you reach the full diameter that is the circle discribed by the extent of the wear. You new hole should now be on center and can be reamed with any reamer you prefer.

Some people swear by centering on the unworn section in a bushing machine and then clamping the plate down to secure the alignment. I'm not convinced about this method as the Bergeon Tools that I've seen (and the one that I have) all have tolerances in the reamer holder bushings that are far too loose (and reamer holder shafts that are far too long and flexible) to be able to resist the forces of a taper reamer wanting to wander. The only solution using a machine like that for this application would probably be to use a front cutting flat countersink or similar (endmill?) so that the only cutting forces are straight down onto the plate.

Jerry will probably tell you about his way of using a small milling machine to center and bush Clock plates.

Regards
Karl
 

Schatznut

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Sep 26, 2020
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I've had issues or the same type Before, where the bushings are just too small to get at with a file. Some metal bearings in Watch plates for instance, such as center Wheels. For very small work you can center it on a lathe faceplate and bore the wear out. The ideal way of centering in this case is either with a centering scope or a loupe, as a wobble stick will risk dipping into the worn area giving you a false Reading. A properly finished Point on the stick with appropriate pressure in the unworn part of the bushing should give you a decent Reading though. But seeing the unworn edge of the bushing run true is probably the best way.

You can also use a bushing machine or hand held reamers with a single cutting lip to center the worn hole. Start by marking out the section of the bushing that is worn (a section of the full circle) with a very fine tip marker. Then you can start cutting with the reamer on the whole UNWORN part of the bushing. This method will only work with single lip reamers and not the five sided typ that come either as hand held reamers or that Favorite uses in their jewelling Tools. You want to be able to Control the material removal and locate it to the area that isn't worn so that you can compensate for the worn section. Keep going back and forth on the unworn section until you reach the full diameter that is the circle discribed by the extent of the wear. You new hole should now be on center and can be reamed with any reamer you prefer.

Some people swear by centering on the unworn section in a bushing machine and then clamping the plate down to secure the alignment. I'm not convinced about this method as the Bergeon Tools that I've seen (and the one that I have) all have tolerances in the reamer holder bushings that are far too loose (and reamer holder shafts that are far too long and flexible) to be able to resist the forces of a taper reamer wanting to wander. The only solution using a machine like that for this application would probably be to use a front cutting flat countersink or similar (endmill?) so that the only cutting forces are straight down onto the plate.

Jerry will probably tell you about his way of using a small milling machine to center and bush Clock plates.

Regards
Karl
Karl, thank you for all of the excellent advice and information in this post! The suggestion of using a single-flute reamer and nibbling the pivot hole makes a lot of sense. I'll give it a try.

This clock hobby for me is all about learning new things and developing new skills. I've sure learned a lot about what *doesn't* work. Good thing I'm not trying to support myself with it - I'd starve.
 
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