Bushing American Escape Wheel Question

[Swanicyouth]

I always thought you do all things bushings from inside the plates. The movements I’m taking about are regular antique American movements, this one specifically is an 8 day spring driven time only Sessions.

In Temple’s clock restoration book, it says to “bush” from inside of plates. But, specifically I’m bushing an escape wheel on a platform on top of the plates. He has a picture for that & it shows him broaching / filing from outside of plates.

Just double checking, and either side is accessible, do you bush a platform escape from the outside, inside, or does it matter?

 

[Willie X]

Platform escapement?

Are you speaking of the little bridge that supports the outer end of the escape-wheel arbor?

And, what kind of tools will you using to make the hole?

Willie X

 

[Swanicyouth]

Platform escapement?

Are you speaking of the little bridge that supports the outer end of the escape-wheel arbor?

And, what kind of tools will you using to make the hole?

Willie X

Yes. I’m calling it a platform, but it’s as above. When the escape wheel is mounted externally on the plates. Hand tools: files, broaches, & KWM reamer

 

[wow]

View attachment 682788

Yes. I’m calling it a platform, but it’s as above. When the escape wheel is mounted externally on the plates. Hand tools: files, broaches, & KWM reamer

If you are using hand tools it really doesn’t matter. I would use something like feeler gauge leaves to support the bridge and ream from the front side. The bushing can be pressed in with flat jawed pliers.

 

[Swanicyouth]

I can’t recall if KWM bushings have a top & bottom or both ends are the same. Assuming the are the same, I couldn’t see how it would matter much either

 

[wow]

The flat side goes on the bottom and the oil sink on the top.

 

[Willie X]

The main thing is to make sure the finished pivot hole is in line with the opposite hole. To do this, pick a broach that will go across and into the other hole, for the final fitting. Willie X

 

[bruce linde]

kwm's have a flat side and an oil sink side.

i would bush from the inside side, and use a little stepper piece or willie's suggestion.

 

[shutterbug]

If you are using a reamer, you can ream from the front and press it in from the back. That's the best way so it won't wiggle itself out eventually.

 

[bruce linde]

with all due respect for my esteemed colleague, that seems backwards to me. If you are using a tapered reamer the hole is going to be slightly bigger in front… which means that if you press a bushing in from the back it will be tight at first but could then get looser the more you push. I would ream and press from the back, toward the front

 

[Willie X]

I agree The OP is using a broach; that should all be done from the inside the bushing should go in from the inside.

Just to make "one thing perfectly clear"
(President Nixon's voice). In post #7, I was speaking of the very last stage of finishing the already placed bushing and this 'pivot hole alignment thing" can only be done from outside the new bushing. Reason being, the escape wheel bridge is often bent inward and crooked on the plate. This does not matter as long as the pivot hole (on the bridge) is lined up with the one on the other plate.

Willie X

 

[wow]

The OP said he has a KWM reamer. A reamer cuts a straight hole, not tapered like a broach or file. If he uses the reamer it shouldn’t matter which direction the bushing goes in. It just needs to be flush with the back side of the bridge. Is what I think.
Will

 

[bruce linde]

all kwm reamers are tapered... until the very end, where the shaft just fits through the reamed hole. sometimes, though, i stop just as i get to the end, so as to not over-broach the pivot hole. the trick is to create a perfectly round hole that still lets you pressure fit the bushing instead of allowing it to fall through.

since all of my regular smoothing and cutting broaches are tapered, i think it's still a good/best practice to go from inside to out... is what i think. (plus willie's comment)

 

[Willie X]

I ream holes, using "D" cutters, either way, with no problems but I always press in the bushings from the inside.

I had picked up what the OP said as he described someone else using a broach in post #1. Everyone else evidently read post #3 too.

Willie X

 

[Mike Phelan]

I bush from inside and do the final broach from outside.

 

[shutterbug]

Yes, the difference between a broach and a reamer seems to be the issue some are having. If you use a reamer but don't allow it to go through the plate, it would create a slight taper. In that instance, reaming and bushing from the back side would be best.
When a bushing is pushed into a hole that is slightly smaller than it, the end inserted first is more compressed than the other end. That makes it susceptible to being pushed out if it was inserted from the front. It's a gamble.