Dead Beat Chinese

MuensterMann

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Mar 23, 2008
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I have two clocks with the same movement and same case. The clock is Chinese and a typical large wall case. The movement has a dead beat escapement. Both clock movements were cleaned and were put back in the clock working - but the clock stops at times. I am thinking it is the escapement - since I had to remove it and readjust. It is hard to see the escapement in action to adjust properly.

Does anyone have experience with this movement? It seems like a good movement, but maybe there is something odd about it.

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MuensterMann

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I have been adjusting the dead beat escapement, but I cannot fully see both sides (enter and exit) to gage if I have it perfect. Does a mirror usually work?
 

R. Croswell

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I have been adjusting the dead beat escapement, but I cannot fully see both sides (enter and exit) to gage if I have it perfect. Does a mirror usually work?
I find it hard to work with a mirror. You can get an idea if you are close by working the escapement slowly by hand. Move the crutch very very slowly until a tooth is just released, then watch the escape wheel as you continue moving the crutch in the same direction. Does the escape wheel remain stationary as you move the crutch after the tooth drop? If it does you have the deadbeat action. If the escape wheel recoils (backs up slightly) after the tooth drops then you do not have the proper deadbeat action because the tooth is landing on the impulse face. Move the verge closer to the escape wheel until you get deadbeat action. Check the action at both pallets. Note that some cheap clocks use strip deadbeat verges that do not quite have the correct geometry for absolute deadbeat operation.

RC
 

MuensterMann

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It does have a strip deadbeat verge. One should consider they movement a low quality one??

So, I just need to verify that no recoil is occurring to consider is set properly? Some positions it will stop soon. Other positions a day or two. Would like 30 days!

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shutterbug

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I have never encountered a strip verge in a dead beat Chinese clock. Usually they have a different kind of verge. I would encourage you to look at how to determine the 2 degree lift angle required for that type of pallet and see if yours was made correctly. David LaBounty has an excellent article on how to do it on his web site.
 

MuensterMann

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Looking through literature, is this what they call a half-dead beat?

Anyway, I can get the clock to run without stopping without hands, but when I add the minute hand it stops. There is no binding of the hand in any way. The usual spot of it stopping is on its why up from 6 to 12, usually around 9. I imagine the clock is on the wall between working (enough power) and not working - and the slight extra weight of the hand put it is the non-working category.

I tried to adjust by moving the verge in towards the wheel to bind it, then slowly move out until it works. I do not see any recoil - which is good. I need help!
 

R. Croswell

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A strip deadbeat escapement is less expensive to make and potentially has a smaller impulse face compared to a typical "full size" deadbeat but the operation is essentially the same. Seth Thomas, and others made a lot of decent clocks with strip deadbeat escapements. A half-deadbeat is not quite the same thing but at first blush they may appear to be identical. The geometry of a true deadbeat is such that when the escape wheel tooth drops onto the dead face of the verge the escape wheel remains stationary (dead) during the overswing. If the geometry of the strip verge does not completely conform to the deadbeat specification there will be some recoil at one or both pallets and we call it a "half-deadbeat".

Moving the verge closer until the escapement will not unlock then backing off a little is a method used by some to adjust a recoil escapement. That will not always yield the best result on a deadbeat or half-deadbeat. Each end of the deadbeat strip pallet has an impulse face, and a dead face. There should be a sharp line of demarcation between the two. Sometimes that line (where the angle between the two faces abruptly changes) gets rounded off and the movement will fail to run. You want to adjust the position of the verge such that the escape wheel teeth land on the dead face just a tiny bit across the line of demarcation from the impulse face. That's where it will be most efficient. Continuing to move the verge closer to the escape wheel until just before it hangs can cause the clock to run poorly or not at all. It can be difficult to find the "sweet spot" even when you can see what you are doing. If you attempt to adjust blindly, you will find the sweet spot is when you gradually move the verge closer and get to the point where going further does not cause any further reduction in recoil. If the tooth lands on the impulse face it will recoil, if on the dead face it will not (or be very little).

If yours is running and the weight of the minute hand from 6 to 12 is enough to stop it my guess is that it is just barely running anyway. The most common problems are; the line of demarcation between the impulse and dead faces is rounded off with the EW teeth landing on the rounded off area, the escapement not properly adjusted, accumulated dirt and dried up oil, and wear in the pivot holes & pivots. I like to make sure the escapement is working right first, then look for wear and dirt that are preventing power from getting to the escapement. I seriously doubt that the minute hand is a problem as long as it isn't hitting anything. Get the clock running strong and it should be fine.

RC
 

MuensterMann

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Thank you RC for such a clearly written tutorial on dead beats and my situation! Yes, I have found that being just off the point of locking up is NOT the sweet spot. I am trying everything!

As mentioned I am working on both at the same time. One movement was pristine (never touched) and the issue was not being able to keep running. The movement was cleaned and freshly lubricated. I found the movement to be of reasonable quality and easy to disassemble and reassemble. The mainspring in a barrel was great to deal with for it being a 30 day spring.

The other clock was touched before and it had a broken strike mainspring. I am not sure if it was running properly or not, but the owner wanted that mainspring replaced - and why not get it cleaned and freshly lubed since the plates would be apart. So, cleaned and freshly lubed as well. This one is a little harder to keep running.

Unfortunately to disassemble this movement, the escapement must be removed by taking off the plate holding the bushing on the front side. Thus, re-adjusting the escapement is necessary. It could be that the original position before disassembly what no longer the good position anyway.
 

MuensterMann

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Here is a similar case - but gives you the idea of what the clocks look like that have the Chinese movement of this post.

Similar Case.jpg
 

Willie X

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On the Chinese clock in post #1, the barrels will come out without splitting the plates.

Note, this pattern has been in production since 1964, maybe sooner.

Willie X
 

shutterbug

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I had one of those in the shop several years ago, and am pretty sure it was a recoil escapement. It was a frustrating thing that never did work well. Are you sure yours is dead beat?
 

shutterbug

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Yeah, I was looking more for confirmation of the EW wheel direction of rotation ;)
 

MuensterMann

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Yep, the EW teeth direction coincide with the half dead beat.

As for an Asian-made clock which usually have the long open mainsprings, I was happy that this one had a 116 inch long spring in a barrel.

After taking the movement apart I did realize that the mainspring could be removed with opening the plates. It needs cleaning anyway.

Since 1964? That is good information to have.

Still cannot keep one of the two running!
 

shutterbug

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Read David LaBounty's method of checking the impulse angles. You need right on 2°.
 

MuensterMann

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The 1964 date is an interesting piece of information. The mainspring is 116 inches long, is it an 8-day movement?
 

MuensterMann

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I believe I have found my source of power loss. The time arbor for the hands has a pivot that extends a little bit past the outside of the back plate where a e-clip is used (not sure why a clip is used). When the movement is placed in the case and tightened down, the pivot end makes contact with the case.

The big wheels use e-clips as well, but I believe those are used for the functionality to be able to remove the barrels without opening the plates.
 

Willie X

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30-Day but it's best to wind them every week.

Be sure to de-burr the soft steel click wheels and check your mainsprings for cracks. Willie X

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Addable13

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How old is the clock it self?. I have a Kassel TM that was purchased brand new in box around 2004-ish with the same movement, my uncle bought the same clock around 2010 off walmart.com. Makes me wonder how long those movements were produced.
 

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