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I am leveling key cups on my bench anvil and want to know what to do when you hammer too hard denting the cup.What is process to fix this ?
 

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I usually take a mushroom dent ball, or a rounded burnisher, are re-shape the dented area from the underside of the cup back 'out', by tapping with a mallet. Do you have anything like that ?
 

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I usually take a mushroom dent ball, or a rounded burnisher, are re-shape the dented area from the underside of the cup back 'out', by tapping with a mallet. Do you have anything like that ?
Yes I have a rawhide mallet,I suppose I hold cup in my hand and tap till back where it should be.


thanks.
 

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I think an equally important question is how to flatten a key cup without putting dings or dents into the surface. I use my jewler's block (bench anvil) at eye level to see which areas of the key cup are higher than the rest. Then I position the key cup on the block so that the high portion hangs over the edge of the block. Then I tap just the outer edge of the key cup with a medium plastic mallet. I go around to tap down all of the high areas, and when the key cup is close to being level, I set it on the block and give a couple of firm taps to the center rib or spine of the key.

I would be interested to hear how others flatten key cups. To me "leveling" the key cup more accurately describes bending the "flat" key cup so that it is perfectly parallel with the tone hole.
 

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I don't do it that way... but I like the idea, because you can get a better 'swing' with the hammer tap if it is overhanging the anvil edge, and hit only the edge corned of the cup and not the top surface itself. I usually just tap it down with entire keycup within the borders of the anvil.

Doorknob.....that's a good one.....

(BTW, JustTheSax...I was saying use the dent ball or burnisher as an intermediary between the keycup and the mallet. So you are actually tapping the ball or the burnisher, as it's pressed against the cup).
 

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My door handles are a twisted wrought Iron design. Should make an interesting design when hammered into a pad cup :)

I use a technique similar to JBT and Matt. Really bad pad cups get a cusom made pad cup mandrel made on my lathe out of hardwood. This is extreeme case though. Plastic or rawhide to do most of the forming. Metal hammer will tend to leave peen marks in the metal.


One can usually find a cabinet door knob that has the right shape.
 

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I place the cup like JBT but I use a plastic anvil (delrin, nylon, teflon) and a small hammer that has 2 sides, a brass side and a plastic side. I replaced the brass side with lead and the plastic with an old drumstick turned to fit in the screw in cap. I try not to hammer on the rib because you can get the cup out of shape (put a dent where the rib's soldered to the cup) and if needed I go little taps at a time.

Also if previous repairers have bent the cup in a way where there's sectors of the cup way misalingned, I try to bring the low spots up from the underside (pad side) tapping the edge of the cup with the lead side of the hammer against my palm.
 

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I use a few methods, some similar to others. I put the key cup on a steel anvil and rock it and look at it (sometimes direct it more to the light) to see if and where the rim is not level. If it's clearly very warped, I tap with a rawhide and/or plastic hammer (different weight) on the high areas, with all the circumference of the key cup supported by the anvil. If the warp is smaller then this doesn't always work, so I move the key cup to stick out in the same way jbtsax described. I rounded the edge of the anvil because a sharp edge can easily dig into the key cup rim.

Then I check the key cup with a short and completely flat and level steel rod. This checks that the back of key cup is level. This is the more important part since it is the part supporting the pad. Sometimes leveling the rim will also level the back. Sometimes not. If I find the back is level but the rim isn't then I don't level the rim because the back is more important. This situation generally means the rim isn't the same height all around.
 

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My door handles are a twisted wrought Iron design. Should make an interesting design when hammered into a pad cup :)

I use a technique similar to JBT and Matt. Really bad pad cups get a cusom made pad cup mandrel made on my lathe out of hardwood. This is extreeme case though. Plastic or rawhide to do most of the forming. Metal hammer will tend to leave peen marks in the metal.
Sure, but for the player/occasional self-repad tech, without a lathe, in a pinch, a door knob of the correct shape can often do the trick.
 

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Sure, but for the player/occasional self-repad tech, without a lathe, in a pinch, a door knob of the correct shape can often do the trick.
you mean there's people out there whom tries to do things without lathes, milling machines and such? Oh noooo! :tsk::faceinpalm:

:mrgreen:
 

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For removing dents in key cups I use a sand-filled leather bag - but you can do much the same with a small, firm cushion (the arm of the sofa will do).
To avoid knocking yet more dents into the cup you'll need a wide, rounded 'punch' - this can be made up from a stick of wood and all you need do is file and sand a dome on it (it helps if the stick is round, but it's not essential). As a rule of thumb the diameter of the punch should be about half that of the key cup...unless you're dealing with a very small dent.

Place the upturned cup on the cushion, position the punch over the dented area and tap the punch with a mallet. Bear in mind that there's a risk you'll knock a bigger dent in the cup if you overdo it, and that you'll probably need to level the cup again anyway.
I should stress that the cushion needs to be firm...if it's too soft you run the risk of completely buckling the cup.
If all else fails you can use your own leg. No need to take it off...just sit upright in a chair and place the cup just above your knee.

Regards,
 

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you mean there's people out there whom tries to do things without lathes, milling machines and such? Oh noooo! :tsk::faceinpalm::mrgreen:
From what I understand these are luxuries for repairers as well

Taking dents out of keys, I use a sand bag, to level keys I use a flat 10mm steel plate and rawhide hammer
 

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If all else fails you can use your own leg. No need to take it off...just sit upright in a chair and place the cup just above your knee.
How do you undo your leg to take it off? I can't seem to find the screws that hold it in place.

The tough leather sandbag is the best bet as it will conform to the shape you want it to and give the correct resistance and support behind the pad cup when you tap it from the inside - decorative metalwork suppliers should stock these. I just rebuilt an old Selmer Adolphe where the RH3 pad cup and arm was really bent and curled up in all manner of strange shapes, but used my leg (the bit just above the knee) as a makeshift sandbag and checked it on a surface plate to be sure it was flat.

To uncurl the pad cup arm I used an adjustable spanner to open it up (do this with a rod screw in the key barrel to prevent the barrel getting flattened) as that held it and applied the pressure to where I wanted it so I could get the set right so it wasn't wide open at the back.
 

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but used my leg (the bit just above the knee) as a makeshift sandbag and checked it on a surface plate to be sure it was flat.
Useful to know how to check your leg is flat without taking it off...
 

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I should stress that the cushion needs to be firm ...If all else fails you can use your own leg. No need to take it off...just...
Use your heel instead. :) It's firmer.
 

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Just to be clear, I did say that the lathe came into play when the pad cup was badly damaged. I don't think I would define a lathe as a luxury in the repair shop. While you may be able to take minor dents out using sand bags, your leg, and door knobs, it is fairly difficult to economically fabricate parts without the use of machine tools (as you already know). My first lathe cost about double the price of a bench motor, which I then made for myself on my lathe. I do repairs that those without machine tools cannot do. It also makes certain minor repairs that people do by hand easier.
Matt


From what I understand these are luxuries for repairers as well

Taking dents out of keys, I use a sand bag, to level keys I use a flat 10mm steel plate and rawhide hammer
 
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