Brewster & Ingrahams Drop Length

[Daniel Judge]

I have a Brewster & Ingrahams 8 day movement--its the earlier flat plate type and not one with the raised rib--it was the type that B&I's made after having made the Kirke type movement--the escapement bridge comes from the right side of the front plate. The movement is out of a steeple clock and it has 46 teeth on the escapement wheel--the verge embraces 9 teeth. Here's the problem--I cannot get the movement to run slow enough--I've lowered the suspension to the bottom of the case and it still runs a few minutes fast every hour. What could the problem be--how can I get it to run slower?

[harold bain]

Hi, Daniel, and welcome to the message board. Tran's Ingraham book shows a few different movements for their steeple clocks. Are you sure yours is original? You might be able to weight the bob at the bottom to change the center of gravity, or use a longer crutch.

[Steven Thornberry]

I have a B&I steeple whose movement wants to run fast, though not so fast as yours. I'm able to get good time keeping with the bob nearly at the bottom of the hanger. Have you checked whether the EW is skipping due to wrong depthing or a short tooth or two?

[Daniel Judge]

I have the movement out of the case and have run it in a movement stand. Both the escapement wheel and the verge appear to be original. All the teeth on the escapement are fine and the verge engages them all correctly. I believe that the bob is correct as well--its a bigger one and I have the suspension spring as long as I can make it--with the bob at the bottom of its hanger.
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I have several Brewster and Ingrahams clocks--including some with the same movement--although none are the just a regular steeple clock--one is a beehive, one is a 4 post beehive, a 4 post steeple. Does the crutch wire effect its speed? The loop end of the crutch on this movement only comes to the bottom of the front plate's horizontal section. Does how many teeth the verge embraces change the speed of the movement?

[Scottie-TX]

My experience has been that crutch length has little affect on operation - especially regulation. Others will disagree. One can reckon that a shorter crutch will need more power to push the pendulum the same no. of degrees from a higher position and conversely. But we're not facing a power problem here.
The number of teeth embraced by the pallet span will not change regulation. Few will disagree. At this point I'd shoot for bottom weighting the bob if that is possible.

[harold bain]

Daniel, since you have the same movement in other clocks, you can compare the pendulum length and the crutch length in these clocks to the problem one. The number of teeth the anchor spans won't have any affect on regulation, as there is only one tooth released at a time. The crutch length does affect regulation to some extent, but not likely enough to account for a few minutes every hour. The longer the crutch, the further the pendulum has to swing to work the escapement, which slows the clock. Also provides more power to the pendulum, giving a longer swing. A short pendulum swing will make a clock run faster.

[tom427cid]

Hi,
How about changing the thickness of the suspension spring(feather)?A thicker one even by .001 will have a noticeable affect.
tom

[Kim St.Dennis Sr.]

Is this a time & strike movement or time only. I know that it is sometime possible to accidentally swap wheels from the strike train to the time train. There is a later Gilbert movement where the 2nd wheels "look" exactly the same and I swapped them once. When I put it on the test stand it ran great, but gained about 2 to 3 minutes an hour.

[shutterbug]

Is this a time & strike movement or time only. I know that it is sometime possible to accidentally swap wheels from the strike train to the time train. There is a later Gilbert movement where the 2nd wheels "look" exactly the same and I swapped them once. When I put it on the test stand it ran great, but gained about 2 to 3 minutes an hour.

Hmmm. It would be an easy matter to count the teeth on each to see if there's a difference.