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August 1, 2012 at 8:50 am #48348
Hello, not feeling too smart today, I have this Seth Thomas 89 E movement and I am a little confused about the verge pallets and escape wheel interaction. the clock wasnt running when I got it. Is this a half dead beat???? I cant seem to grasp what is going on with it the way it is. I used David Labountys lift angle process but the angle on the exit side was really steep. I was thinking of spreading the verge to capture a greater distance within the same amount of tooth spread (8 now, but barely) and reshaping the angles for the pallets impulse. if that is true then should I be at a 45 degree angle with that???? Thanks guys, today is a weird day for me William
August 1, 2012 at 9:22 pm #52121
Yes that’s a half deadbeat. From what I can tell from the pics (good pics by the way) it looks pretty good. These escapements are great timekeepers but are more temperamental than the recoil. They don’t hold up well to power loss in the train due to dirt, pivot hole wear, worn pivots, tired or wrong mainspring etc. as compared to the recoil escapement and are more susceptible to stopping when out of beat. Also this escapement won’t perform well when over powered so they are designed to have just enough power to run the clock plus a tiny bit more to overcome slight wear and dirt where as the recoil escapement can be over powered and as a result is very forgiving when it comes to the movement being out of beat, dirty, and worn out! You won’t have much drop with your half dead beat and very little over swing from the pendulum after lock which keeps the recoil way down resulting in a much more accurate escapement. So… your problem may simply be that the movement is losing power somewhere and just doesn’t have enough left to keep the escapement going.
If the drop on both pallets is equal and the lock is correct (not dropping onto the impulse face but locking on the locking face of the pallet) then my guess is that the escapement is fine and under delivery of power is the problem. Again from what I can tell from the photos things look pretty good but my eyes might be playing tricks on me so please let us know how the drop and lock look when testing the escapement action.
BobAugust 2, 2012 at 7:14 am #52122
Thank you Bob, yes pivots polished/ burnished and new bushings, all cleaned up, you hit it on the head when you said @Bob Tascione wrote:
If the drop on both pallets is equal and the lock is correct (not dropping onto the impulse face but locking on the locking face of the pallet)
that is my fault for not having that in the post, that was what is confusing me, the escape wheel teeth ARE hitting on the impulse faces, I put this into a depthing tool and saw no way to get it to lock properly and still function, some one had worked on this in a previous life so I checked the angles of the impulse as I mentioned with Labountys method, adjusted a little and it still just did not seem right. I did put the time side together to see the action under slight power and it did run but hitting impulse faces, then sliding up, then back down over the impulse face again..With how the pallets looked when i first seen it this is how it has run in the past!!! . Bob, did I check the angles correctly????? should a half dead beat have a impulse face on the exit pallet only???? am I going crazy??? 😯 can you have a verge span 7 teeth and get the same results if you span the same clock 8 teeth???? I did find a Seth Thomas works with the same set up and will tear it down to see how it is supposed to be, already I see the verge being a different size (its longer). I may be able to figure this out by another works or by getting different parts ect….. BUT I would rather learn how to see the issue if I didnt have that avenue, HEY, have a fantastic day. WilliamAugust 2, 2012 at 1:55 pm #52123
You’re not going crazy!
The term “Half Dead Beat” is used for two totally different escapements. The one that you ask about where the entry pallet is used for locking only and impulse given only on exit is also referred to as a half dead beat. These are not seen too often. The much more common half dead beat where impulse is given on both entry and exit pallets is the one that you have and is seen on many American clocks. Some people feel that the term should only be used on the one that has impulse on exit only to avoid confusion but that to me seems like it would just cause more confusion as I think most of us in the U.S. relate the term to the type that you have. So whether correct or not I’ll call it a half dead beat and will just continue to dodge bullets from those who feel I’m wrong.
You may be right about spanning 8 teeth William or at least moving the pallets a little further apart to allow for a little more drop and lock. The most agreed upon number for obtaining maximum efficiency for a “dead beat” with an escape wheel of around 30 teeth is 7 1/2 teeth (I think) and it looks like your clock may have around 40 teeth so I would think that a span of 8 1/2 teeth would be quite possible. If it is meant to be 7 1/2 teeth then changing it to 8 1/2 would decrease the pendulum arc as the distance from the escape wheel center to the verge pivot center would need to be increased. So I think the answer to your question “can you have a verge span 7 teeth and get the same results if you span the same clock 8 teeth?” is… almost. If the same clock is changed from 7 to 8 and maximum efficiency is maintain by adjusting the escape wheel to anchor center distances and pallet lift angles to get as close as possible to the max efficiency of 50% then the pendulum swing arc will be smaller. In practice 50% isn’t possible as a little bit of fudging needs to be done to get enough drop and lock for the escapement to function properly but you can get close.
I’ve got to run into town for a bit and will take a look at LaBounty’s description when I get back. I think if you are following the standard way of checking to see if the pallet angles are correct (I think that’s what he was showing) then yes I believe you are right on target.
I’ll be back home in a couple of hours or so and will check it out better. I just fired this stuff off so please don’t take what I’ve posted above as fact until I can verify it by going through some books etc. when I get back as I’m going from memory which usually isn’t too accurate! At this point it’s just some food for thought.
Back in a while,
BobAugust 2, 2012 at 10:52 pm #52124
Got sidetracked and couldn’t get back to this until late tonight. I just took a look at LaBounty’s pdf and it’s the one I was thinking of. It’s been a long and busy day so I’ll dig a little deeper into this in the morning when my brain’s working better.
Adios for now
BobAugust 3, 2012 at 5:29 am #52125
Hi Bob, thank you for all you do,you are guiding me to a better place I got busy until late also, I was going coo-coo 😯 with some clocks if you know what I mean…let me also do some more research and post my findings first then you can tell me if I have figured it out or not and correct my findings if wrong, would be the best way for me to learn dont you think??? If it gets past this evening then my head exploded.. WilliamAugust 5, 2012 at 9:52 am #52126
Hi everyone, here is what I have come up with , please do not quote my findings until approved, also please interject with any comments. I want to thank you Bob and David Labounty for putting sooooo much effort in your work so that guys like me can really benefit from your knowledge, <u>BUT it is possible I have misunderstood</u>, it would not be your teaching that is at any fault. I would like these concepts to not be tainted with my limited knowledge, I feel they are very important to a proper restoration of our historical timepieces. If I have grasped the concept let me know, if I have not then please correct me, thank you.
I made a actual size drawing of my escape wheel with the pallet center pivot point, by using the drawing techniques discussed by Mr. LaBountys teaching, (by the way going thru his process of drawing really helped in understanding how this all works) In my findings I noticed at first the entrance pallet would lock but the exit pallet would not, by putting these in the depthing tool there was no way to adjust for it to work properly, something definitely wrong. After doing a true to scale drawing of the escapement I realized the verge from this works must have been shortened and reconfigured by a previous smith, also the angles of impulse were not at 45degrees to the intersecting lines from the pallet center tangent from the escape wheel radius and the escape wheel center 90 degrees from that line. It all worked out that the radii lines from the escape wheel center were 80 /100 degree segments which I wonder if this was the design to account for any recoil?????? Also the pallet itself was configured that one side from the pallet center to 1/2 the entrance pallet thickness measured 13.69mm and the exit pallet side measured 10.29mm This is what I am thinking, Increase the size of the verge from a spread at the entrance pallet let off point of 19.5mm to 22.15mm and center it on the arbor to mimic my drawing. pallet impulse faces at 45 degrees angle to the 90 degree intersecting lines from the escape wheel center to the pallet center tangent radius lines and still have the ability to lock properly ending up with a 8.5 tooth spread, WHY, because the smaller sized verge would not give a locking surface on the exit pallet with room for proper movement. This would be my brief overview, if you want I have 7 pages of notes ect… I could confuse everyone with my ramblings 😆 Thanks again, WilliamAugust 5, 2012 at 2:51 pm #52127
I admire your desire to grasp a full understanding of why something works rather than just accepting that it does. I think your curiosity will pay off big time as you move deeper into your restoration work!
I wouldn’t worry that the anchor pivot point distance between pallets is not equal. This may have easily been adjusted for by changing the impulse angle or length of an impulse face by grinding a little metal off of the back of the pallet to allow for the difference.
I looked at your pics again and I think I’m seeing 8 teeth between the pallets! Am I losing it?
If that’s correct then I would think that the verge may be the correct one and opening the space just a little more might do the trick for gaining some extra drop. You could then check the lift angles by using the method that LaBounty describes. If the impulse angles were never changed by grinding down then you may be able to open the gap slightly, checking how it lines up on the tangent line each time until the lift angle looks good. You mentioned in your first post that the angle on the exit pallet looked really deep. If you open the gap from the exit side then that angle will be reduced. If the angle on the entry seems shallow then you could open from that side.
You may already be aware of this but just in case…since the distance to the pallets from the anchor pivot point is un-even you will need to measure each side and divide EACH side in half before drawing your circles! Dividing the distance in half will give you around a 2 degree lift angle which sounds about right for these American half dead beat escapements.
Using this method to obtain the lift angle should get you more than close enough to then make few adjustments to get minimum drop and still have sufficient lock.
I asked a friend of mine who was driving from Los Angeles down to his boat in La Paz to grab my boxes of American movements and drop them off here at the house on the way down. He left Saturday morning so should get here sometime today. I’m sure I have some Seth Thomas and other make movements with half deadbeat escapements. I’ll take a look at one as soon as he gets here.
BobAugust 5, 2012 at 5:58 pm #52128
Thank you Bob, that is what confused me in a previous thread, I do think I have a better handle on it now and will continue to think it thru. if I am catching you right, if the 2 distances from the anchor pivot point to the pallets are different then I would draw 2 separate size circles for the LaBounty method, that makes sense now. I was a little confused when he said “divide that value in half”, I added the 2 measurements then divided by 2 for a average then divided in half 🙄 I also see how bending outward will reduce the exit pallet impulse face size a little, same with the entry side. I think it will be alot easier to adjust with much better accuracy now by drawing what I need. If I were to make new verges would I use a carbon steel??? I think I can buy blank verges from one of the supply houses.. One more thing at this time, I may keep bugging you but I am sure it will end soon and you will be free I just miss bugging Paul!!!!…….since we are talking about a 1/2 deadbeat verge then we really do not have to worry about the lock being at 90 degrees. the true dead beat being configured by the radius of the pallet center traveling 90 degrees from the travel of the tooth, creating a dead stop at impact. our 1/2 deadbeat will recoil slightly because of the pallet radius being tighter, entry and exit, and we dont really worry about the 90 degree rule, just as long as we get all the power we can by having the impulse faces at 45 degrees to the tooth travel, right?????? O.K. now my brain just did a flip flop 😯 I’ll post this, yall can have a laugh and Ill get back to the drawing board. Thanks, WilliamDecember 10, 2016 at 11:30 am #52129
Hello, I just found this post because I’m having verge issues. It seems that verge issues are very common and not talked about much. Maybe I just don’t know how to search for topics or something. Maybe I’m not using the right keywords.
I’m working on a clock of my own. It’s a Seth Thomas with an 89 in it. As you can see from the pictures the verge is in pretty bad shape. It needs to be filed smooth.
After I smooth the impulse faces will I have to check the angles and set it back to an efficient drop? I’m not sure how to do that . I’m hoping this post from William and Bob will shed some light on it.
Will someone direct me to the best explanation you know of on this topic? A book or a video or forum. I just can’t seem to find anything I can grasp.
Maybe I just don’t understand what is right so I keep thinking things are wrong when there not.
December 11, 2016 at 12:44 pm #52130
Hey, Ya’ll. I think I am catching on now! Seeing it on paper is a huge help. I can see why it works this way now. I hope! Take a look at these pics and let me know if I’m on the right track. I found David LaBounty’s www. and from what I learned about it from Bob and William I think I get the idea.
Please look at these and let me know, will you?
So, my question is, If I file the wear out of this verge and then bring it back to these specs it should work. If in fact, it worked in the past which I am going to verify before I so anything else.
Thanks for all your help, Danny
December 13, 2016 at 7:49 am #52131
- This reply was modified 1 year ago by Tamas Richard.
Danny, it appears your on the right track…. @disciple_dan wrote:
So, my question is, If I file the wear out of this verge and then bring it back to these specs it should work
Possibly….like you said, if it was working before? …there are several other things that would have to be looked at between the escape wheel and the verge, escape wheel teeth, pivot holes, lock and drop. On the road today so I better get going for now. Keep up the study…by the way, filing will help get the groove out of the pallet faces but you will also want to get them as smooth and polished as possible. I use stones ending with hard Arkansas then polishing and burnishing.December 13, 2016 at 3:46 pm #52132
Hey, William, thanks for the encouragement, I have always been mechanically minded so I know it will come in time.
I am still having trouble with the drop. I’m just not sure what right is. Can you point me to the best explanation of it? I understand what it is, I just don’t understand what correct is. What can I study to help with why it works that way?
I got the 89 back together and it works great. The teeth all look good. I had to bush almost every hole. Someone before me had punched up several holes, it was pretty nasty. I bushed both EW holes.
As I was looking at the wear on the anchor while it was running, I noticed the teeth were not landing on the wear but off to one side. I’m not sure how that could have happened. The only thing I can think of is the repairer moved the wheel and pinion on the arbor. I don’t know but it seems like it is running on a fresh track. Is that something you have seen before?
The gear below it is still on the 3rd part of the pinion closest to the wheel. You could probably get another 20 years out of it. Is that the wrong way to look at it? Anyway, I’m going to file it down and fix it. It will be a good learning experience.
Okay, thanks again for the help. If you know of somewhere to get a better understanding of the drop and lock thing please let me know.
God bless, take care, Danny
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