wooden clock tooth replacement

Discussion in 'Wood Movement Clocks' started by clockman230@comcast.net, Oct 7, 2014.

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  1. clockman230@comcast.net

    clockman230@comcast.net Registered User

    Jan 30, 2005
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    can some one give advice in replacing several teeth in a wooden work s clock. I tried epoxy with no success.
     
  2. shutterbug

    shutterbug Moderator
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    There are several threads here that discuss that (use search) but you might want to bounce over to the wooden works forum for better exposure. I can transfer this thread if you want.
     
  3. clockman230@comcast.net

    clockman230@comcast.net Registered User

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    yes, please transfer. how do i search this topic ?
     
  4. clockman230@comcast.net

    clockman230@comcast.net Registered User

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    please give me advice. I have used epoxy without success.
     
  5. D Crone

    D Crone Registered User

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    My advice is to have parts movements and gears from which to cut teeth or sections of teeth out. You cut a dovetail out of the gear where the broken teeth were and then glue the tooth or section into place. You have to make it so the teeth are just slightly oversized so you can sand them down to match. This takes a lot of patience and care to do this and have it come out looking good. They say to use "hide glue" as well. Then you file and sand the teeth down to an exact match to your other teeth. I have also seen posts where people use epoxy but they make a mold of the gear teeth out of clay and use the clay to "cast" the new teeth onto the gear. Never tried that.
     
  6. R. Croswell

    R. Croswell Registered User

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    There are several ways to do this but it is a bit more challenging when more than three teeth in a group need to be replaced. It would help to see pictures of the wheels to be repaired. I prefer to just cut out the bad and dovetail in new wood with the grain perpendicular to the wheel. I use epoxy glue. I've seen too many old repairs with hide glue come loose (have one on the bench now). Once the "plug" is faced flush with both sides of the wheel and shaped to the radius of the wheel, then you need to lay out the teeth to be cut. If you are working on a main wheel and the other main wheel is the same size you can place them back to back and trace the teeth. Cut with a jeweler's saw them file and sand to final shape. If no pattern is available you can use a caliper to measure distance between the faces of good teeth and scribe on the "plug" where the tip of each tooth will be. The teeth angle with one face tangent to a circle around the center of the wheel and the other face tangent to a smaller circle. Using the face of a good tooth and a straight edge you can determined the diameter of the circles and trace the face of the new teeth.

    As suggested, make them a bit oversize and file and sand to final size keeping check with a caliper to maintain exact spacing. Yes, you can cut teeth from a spare wheel but is critical that the space at the ends of the replaced section be right.

    RC
     
  7. D Crone

    D Crone Registered User

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    I actually use epoxy as well. I just see lots of people saying to use "hide glue" on your wood work. Never actually tried hide glue.
     
  8. D Crone

    D Crone Registered User

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    R Croswell - what kind of wood do you use?
     
  9. harold bain

    harold bain Registered User
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    Hide glue is fine to use on case joints. Yes it may fail, particularly if the case falls. But it's easier to re-glue the joints than to repair broken wood when the joint doesn't break because the glue was too strong. When a case falls, something has to give.
     
  10. R. Croswell

    R. Croswell Registered User

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    Cherry, but other fine grain hardwood can be used.
     
  11. Jim DuBois

    Jim DuBois Registered User
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    I generally like to use the same wood for replacement teeth as the original wheel. In most cases that is cherry, but examples are known that used lignum vitae, mahogany, maple, oak, birch, and so forth. Pinions are reportedly most often maple or mountain laurel.
     
  12. R. Croswell

    R. Croswell Registered User

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    I place a rather low priority on making replacement parts invisible - if it is a replacement it is not original regardless of what the material is. I know others disagree. If one does require the replaced teeth to color match the original, one thing I have done is cut the new teeth from the center part of a scrap wheel - not using the scrap teeth but using wood from that wheel.

    RC
     
  13. Jim DuBois

    Jim DuBois Registered User
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    Not certain where the "making replacement parts invisible" comes from...I just prefer to use the "right" materials when I can, and yes, IMO repairs need not stick out like a sore thumb.... I have owned / repaired / restored / sold a lot of wood works clocks. I have had them with gears repaired using plastic, epoxy, Masonite, plywood, soft woods like pine, tin, brass, screws, nails, and in one case a master tinsmith had created an entire gear of tin, made like a cookie cutter (great piece of work, I left it in the clock as a part of its history, it worked perfectly).

    The idea of cutting replacement blanks out of old wheels is an excellent idea, my only comments would be most gears fail cross grain and from a repair standpoint it is best to use long grain in repairing a section of failed teeth. Gears/wheels fail as a result of about 4 major things, 1) have shrunk cross grain to the point they bind/butt and then break, 2) the wood has dried out and lost most of its strength cross grain, 3) the wheel has suffered abuse by someone exerting excessive force or weight on it, or something has bound up and efforts to correct it has broken parts, and / or 4) there is excessive wear in the bushings allowing wheels and pinions to separate, bind, and ultimately break. It is not unusual for a wheel to be 1/4" out of round as a result of shrinkage of the wood in our dry central heated homes...
     
  14. R. Croswell

    R. Croswell Registered User

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    I think I pretty much agree with what you are saying although I guess everyone has a somewhat different idea of what "right materials" means. Perhaps I should clarify a bit. In the context of replacing teeth I want the replacements to have the same height, width, and profile as the original. The repair must be neat with well fitted parts. The repair must be strong and durable and of course perform correctly. I to prefer to go "long grain" for strength as opposed to a less visible but weaker matched grain repair. I am not especially concerned with the color or species of wood so long as it is a fine grain hardwood. It doesn't bother me if someone looks at my clock and sees immediately that 5 teeth on a main wheel have been replaced as long as they can also say the replacement was well executed and should last for a long time. Now if the movement is visible in the clock, that's a different story.

    I prefer wood for replacing wooden teeth but have no objection if one can produce a cast tooth of equal strength. I just find it easier to use wood. No way would I ever use bent steel wires, screws, nails, or pegs or the like. I don't have a problem with using some modern materials and adhesives. I ask my self what would a repair person have used 150 years ago if they had what we have available today?

    As an aside, I have read where some restorers of museum pieces actually paint replacement parts a bright color to make it clear that the part IS a replacement and not original. I don't go out of my way to call attention to the repair, but I don't mind if it is noticed as long as it is otherwise well done. And I do appreciate those who's objective it is to make a repair as invisible as possible. It really depends on what one's goal is for the finished product.

    I think perhaps the reason we see so much "junk and hardware" and other "innovative" (for lack of a polite alternative) repairs to these old wooden clocks is that we forget that the ones that have survived went through a period of time when they were just an old clock not worth spending much on for repair. Sort of like a 20 year old car with 200,000 miles - just an old jalopy so OK if some grease monkey working in his back yard can keep it running awhile longer with duct tape and bailing wire. These clocks have also seen more than one depression and hard times, and some were probably given away to the less affluent who may not have been able to afford proper repairs.

    RC
     

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