Bushing

Discussion in 'Clock Repair' started by orso, Mar 18, 2014.

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  1. orso

    orso Registered User

    Jun 9, 2013
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    Finally I decided to try reamer bushing (up to now have done it with broaches). So, I both a KW reamers set at Timesavers together with the bushes I needed; they are all 2.7 mm; reamer #3 to be used. The reamer is 2.68 mm. I'm a little concerned because the bushes don't seem to fit tight; I mean I can't push them in by hand, nevertheless when using the smoothing broach the tend to come out. I'm learning a lot, mainly trough this board, but I understand I still have a long way to go. Is there anything I might do wrong? Is the .2 mm tolerance the standard?

    Thanks a lot

    Andrea
     
  2. hookster

    hookster Registered User
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    I presume you are reaming by hand, and not using a bushing machine? If so, as you get close to breaking through with your reamer, be sure that you are going slow and are doing the final reaming straight down. That may be your problem. Since I do this manually, I usually check to see if the bushing is near to fitting just before the reamer breaks through. I then put the bushing in place, put a small one inch by one inch (by I/8th inch thick) hard steel plate over it and then strike the plate to drive the bushing into place. You can also use an appropriately sized punch, but be sure not to position it off center and mar the plate. Finally, are you reaming from the inside of the plate, which is recommended, so that you have a very slight taper?
     
  3. shutterbug

    shutterbug Moderator
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    #3 shutterbug, Mar 18, 2014
    Last edited: Mar 18, 2014
    How are you reaming them? They need to go in straight, and with a couple hundreds difference in size, any wobble from reaming by hand or with a drill, etc will really amplify. A bushing machine would be a good investment, or at least a very tight drill press.

    (I see I was typing as hookster was)
     
  4. emhitch

    emhitch Registered User
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    Andrea, I experienced this issue some time ago myself. Although you did not state you use any type of chamfering tool to remove the burrs on the new bushing holes as a result of the reaming operation, my problem was related to removing too much brass with my chamfering tool thereby reducing the available "land" in which the bushing fits. I use the Bergeon double ended, wheel countersinks for this application. If you are using some type of chamfering tool, remove only the burrs and no more, as I found this is critical in achieving a solid bushing in the plate.
     
  5. shimmystep

    shimmystep Registered User

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    It does sound as though, as shuts suggests, that the required tolerance for a tight bushing is being compromised somewhere. Are you using the reamers in a hand tool, or drill press, or bushing tool? If by hand you have to be real light fingered as you approach the right hole size, ensuring 90degs tool position to the clock plate. Ream, try for size, ream, try for size...repeat, taking minute fractions of material off.
    As mentioned a bushing tool, or good drill press will eliminate any sideways factor when turning the reamer. It is definitely something that you get a feel for, getting used to the process and your tools.
     
  6. hookster

    hookster Registered User
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    I agree with what shimmystep just posted (the part I have bolded below). As for buying a bushing machine, they cost about $850 and are hard to justify unless you are doing a lot of clocks. Once you get the 'feel' of doing it manually, it is not that difficult to do it accurately and securely. As the old saying goes 'practice makes perfect'.
     
  7. Kevin W.

    Kevin W. Registered User
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    Maybe the smoothing broach you mention is making the hole oversize and not a tight fit for the bushing. Is this what you did, ream and then use a smoothing broach.
    Very important always square to the plate.
     
  8. hookster

    hookster Registered User
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    #8 hookster, Mar 18, 2014
    Last edited: Mar 18, 2014
    I think what he means, Kevin, is that, once the bushing is in place, it pops back out when he is finishing the hole with his smoothing broach. One hint here is to make sure you don't get impatient with the smoothing broach and get it stuck in the bushing hole. If this happens, the bushing will almost always pop out as you wiggle the broach and try to get it unstuck.
     
  9. David S

    David S Registered User
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    I think it is difficult to explain how to use a smoothing broach properly. If you snug it in like a cutting broach then it invariably locks up tight and then the bushing comes out. I don't snug them into the hole but rather try and roll the broach around the ID of the bushing without getting it stuck.
     
  10. harold bain

    harold bain Registered User
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    All you need to tighten up a loose bushing is a round headed punch.
     
  11. shimmystep

    shimmystep Registered User

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    When using the smoothing broach, avoid getting it in there tight, you're more likely to make the surface worse. Have it in there kinda loose and wallow it about in the pivot hole as you rotate the broach. I remember reading, think it might be Lab, that the oil you use on the smoothing broach should be the same as the oil used to lube when assembled, to avoid impregnating the brass with a potential oil contaminant. I've popped a few bushings when it's got too tight, when that starts squeaking while yer turning it could be trouble :)
     
  12. Bruce Alexander

    Bruce Alexander Registered User
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    As Harold has posted elsewhere:

    ..use a round head punch to set suspect loose bushings. Support the back of the plate on an anvil, and one hit on the punch locks in the bushing. It's a relatively large punch, about 1/4 inch round head. If you have a bushing tool (Bergeon, for sure), it fits in the spindle shaft with the spindle removed. This helps keep it from deforming the bushing by keeping it centered.

    He was asked if you might use a ball bearing instead of a punch:

    Yes, I recall others have suggested that in past posts. I suppose one the size of a BB would work on smaller bushings, and since they can be had in many sizes, you could match the bearing to the bushing. But you would have to strike it at as close to straight as you can to keep it from being deformed

    Tolerances on bushings do vary. I had a "batch" of bronze KWM bushings that were just plain loose in properly reamed holes. My regular brass bushings did fine in the same holes. Harold's technique works well. As far as the loose bushings which you've already cut, if you don't have the tools, you can use Loctite Retaining Adhesives (not the same as their thread adhesives), but my advice would be to get the tools necessary to tighten suspect bushings properly because you will encounter this issue again due to no fault of your own. Also, if you use your smooth broaches to burnish the inner diameter of your bushings you'll need them to be set very tightly in the plate.
     
  13. shutterbug

    shutterbug Moderator
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    I'll just mention that in those rare cases when the bushing needs to be expanded, I do it outside the plate. I'm not sure if the others do it inside or not :)
     
  14. bkerr

    bkerr Registered User
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    FYI I have found out that a dull cutter will cut oversize and create the same issue too. I use both a KWM and Bergeon systems, most of the time I go to the KWM.

    Yes, they are not giving them away but, good tools last and the demand as you will see on the BAY is always high
     
  15. harold bain

    harold bain Registered User
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    Thanks for digging, Bruce. Yes, keep your cutters sharp. Removing a small amount of material when sharpening will give you a smaller hole, and a better fit bushing. SB, I tighten them after installing them. Give it a hit from the front (punch in the oil sink), and the expansion is even, and the bushing won't come out. The back of the bushing is against an anvil to keep it where it should be.
    A staking tool set has many different sizes of round head punches that also would work well for this.
     
  16. shutterbug

    shutterbug Moderator
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    I'll give that a try next time :)
     
  17. harold bain

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    Yeah, the object is to lock in the bushing. You can only do this with the bushing already installed.
     
  18. orso

    orso Registered User

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    Hi, thanks to you all. I thought I had already posted an answer, but it's not here. It was just to say that I'll keep in mind your advice. The press drill will be my choice; not going to invest too much into my new hobby although I like it very much.

    Andrea
     
  19. shutterbug

    shutterbug Moderator
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    I think it works both ways. As long as the bushing is a little larger than the hole, you can push it in. Or you can lock it in, as you described. I've never tried it your way, but will next time I get an 'oops'.
     
  20. shimmystep

    shimmystep Registered User

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    Agree, I use the staking tool to do this with French Bouchons, the area around the pivot hole on the inside of French plates are often a little recessed. So a small stump needs to be used or an upturned flat ended punch in the staking tool to fit in the recess or the bouchon will pop out when its locked from the outside. It can be a bit of pain though, in that the pivot holes are very small on the french bouchon and locking them can easily close the pivot hole up, which can be a bit fiddly. Higher up the train for the last two wheels(or and fly) if the bouchons have gone in as a real good tight fit with no gap seen on the outside plate under mag, I'll not lock it; it's going no where with that small amount of power on those.
     
  21. MARK A. BUTTERWORTH

    MARK A. BUTTERWORTH Registered User
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    free handing tends to produce looser results and not always straight. Personally I would suggest a table top drill press. I have a very short rough video on YouTube.com showing how easy it is to use the drill press. Look up "bushing using a Drill press" You only need n adapter for your reamers.
     
  22. orso

    orso Registered User

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    Thanks, Mark for your link.
     

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