Author Topic: The Grasshopper Escapement revealed  (Read 60668 times)

Offline jrbeall

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The Grasshopper Escapement revealed
« on: September 04, 2005, 08:42:46 AM »
OK,  now it is available.  Here is the place to go to get everything you need to know about designing your very own grasshopper escapement.  This monoghaph is 18 pages of PDF file.  I scanned it in yesterday and uploaded it to my server.  http://www.bealltool.com/pdfs/Grasshopper0001.pdf

This paper was given to me many years ago by John Economacky of Bridge City Tools.  It has served me well.  I don't know when it was written but I do know that Mr Aydlett is no longer living.  I hope you will find it as useful as I have.

JayRay_Hughes

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« Reply #1 on: September 04, 2005, 06:59:29 PM »
Downloaded it, read it. Need to read it again, but that definitely will simplify the process for me. Answered some questions I hadn’t asked yet and I think some I had. I need to sit down and do some CAD work and see if it all works out. Also, CAD work helps me get it.

I will see if I can get the math stuff in Excel, and post for everybody to use. This may take me a little bit.

Offline rabbit

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Where were you when I needed you?
« Reply #2 on: September 24, 2005, 01:27:53 PM »
Where were you when I needed you?
I designed and built my first grasshopper several years ago. (It and five subsequent g'hoppers are running flawlessly still.)
I had looked EVERYWHERE for information and found pitifully litle useful technical data with which to design an escape mechanism. So, knowing how it worked, and from photograhs of existing examples, I "reverse engineered" my own adaptation. Miraculously, it worked quite well. (I know now how forgiving even a poorly-designed grasshopper is!) My second and subsequent models were further refinements, based on what I'd learned.
This article is excellent! It would have saved me years of trial-and-error. To my surprise, I've gone back and analyzed my previous designs, and by #2 I'd arrived at the correct geometry!
One funny point is the need for the long pallet nibs as a safety against accidental run-down. I experienced this fate on the first model when rewinding about the second time. After destroying an escape wheel, I improvised my own version of a "safety", and by #3 arrived at the long nib solution.
So my advice to anyone wanting/willing to tackle this design: this article is the way to go. There are a lot of subtle variations and techniques that can be derived from other examples, but the explanations and calculations for the geometry are right-on.
- rabbit

Helmut Reinhardt

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The Grasshopper escapement
« Reply #3 on: November 08, 2005, 12:36:52 PM »
I thought I died and gone to heaven when I saw your Bow 2 operate. It took me back to 1994 when I saw Jim Borden's works on display at the NAWCC HQ in Columbia, PA. Function and beauty taken to their highest level. After reading about John (Longitude) Harrison in the late 1970's, I joined NAWCC in 1980, hoping to find a dimensioned drawing of the Grasshopper somewhere in the literature. I soon found the April 1972 issue of the NAWCC BULLETIN (Whole Number 157) which contains the entire article of Guy D. Aydlett's article, "The Anatomy of the Grasshopper". In all the intervening years, I tried to build a working model, but my skills as an amateur wood-crafter so far have failed me. I keep trying.
In NAWCC Bn. #161, Dec. 1972, Aydlett gave some info on other clocks he was building, and in NAWCC Bn. 196, Oct 1978, he wrote about  "A Wooden Works Month Clock", giving tooth counts and other vital dimensions.

Dave

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The Grasshopper Escapement revealed
« Reply #4 on: June 03, 2007, 05:00:00 PM »
I have made a smaller version using brass and steel with the info provided, i had great issues with trying to fit a gravity tail on the exit pallet, there was just not enough space, i resorted to fitting a dog leg extension which cured the problem. I have since found that the 90deg layout did not work with my clock, i must have made a mistake with the maths, i cured it by rotating the yoke counter clockwise one tooth space and reset the controller arms, the clock works fine now, Dave

Rick from Manchester

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The Grasshopper escapement
« Reply #5 on: June 05, 2007, 02:15:58 PM »
Here's a Grasshopper Escapement video I found http://www.youtube.com/watch?v=rluQpoV8638

And...

Harrison inspired sea clock with dual balance grasshopper - if you don't mind Meccano http://www.youtube.com/watch?v=z-Gl66PoShE  Someone needs to do this in wood!

Dave

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Re: The Grasshopper escapement
« Reply #6 on: June 06, 2007, 01:57:08 PM »
Quote from: "Rick from Manchester"
Here's a Grasshopper Escapement video I found http://www.youtube.com/watch?v=rluQpoV8638

And...

Harrison inspired sea clock with dual balance grasshopper - if you don't mind Meccano http://www.youtube.com/watch?v=z-Gl66PoShE  Someone needs to do this in wood!

Hi Rick, i hope to post 2 vids of my grasshoppers on youtube in the coming weeks, just have to wait while my son finds some time to work his camera. I plan to post my experimental clock as well, warts and all, its rough cut at the moment but the whole clock is just an experiment to see if the maths work, as stated earlier, i got the maths wrong but pulled the project back because i have over 20 years with this escapement and could correct the faults on a practical level. These sort of problems only strengthen my admiration for Harrison who made this escapement from scratch, how he came up with the idea will never be known, Dave

Rick from Manchester

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The Grasshopper escapement
« Reply #7 on: June 07, 2007, 04:22:24 PM »
Dave,

Excellent! We can't wait to see your clocks in motion, please let us know the moment you get them up there.  Video opens up a whole new dimension.

Rick.

Dave

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The Grasshopper Escapement revealed
« Reply #8 on: June 11, 2007, 01:42:35 PM »
Hi Rick, well i have tried 4 times to upload to youtube without success, i tried this morning and was told that the forum was processing the information or something like that, i decided tonight to delete the vid and was told that there was nothing to delete!!! I have tried again and will see what happens, computers, you just have to love them, Dave

Dave

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The Grasshopper Escapement revealed
« Reply #9 on: June 13, 2007, 02:54:43 AM »
Its up and running on youtube, not the best clip in the world but will do for now, its not as loud in person though otherwise it would be moved to the hallway, type in grasshopper escapement to view, Dave

Offline jrbeall

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The Grasshopper Escapement revealed
« Reply #10 on: June 13, 2007, 10:04:05 AM »
One of those grasshopper escapement, with a double escape wheel is from Smiths plans.  He has a shop manual for building that clock which is very good.  Looks like a lot of people are interested in grasshoppers.

Dave

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The Grasshopper Escapement revealed
« Reply #11 on: June 13, 2007, 12:47:11 PM »
I used to have one of Bill Smiths designed grasshoppers in my shop window in the mid 80s, always a crowd puller. I have found over the years that his escapement design is excellent and will run a first try if made to the specs, it also lends itself to scalling up or down on the calculator which is good news for a designer. I have placed my experimental clock on youtube which uses the information given on this forum by Mr Beall, many thanks, Dave

Rick from Manchester

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The Grasshopper escapement
« Reply #12 on: June 14, 2007, 02:14:23 PM »
Dave,

WOW -- Your grasshopper is extraordinary delicate - beautiful work.

Seeing your videos http://www.youtube.com/watch?v=lDJvzg3J1mM has made my day -- well worth the wait!

I think I remember seeing still photos of your regulator few years back (2003? -- don't remember which site), while it was still under construction.

Keep up the good work.

Rick.

Dave

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The Grasshopper Escapement revealed
« Reply #13 on: June 15, 2007, 12:44:23 PM »
Hi Rick, thanks for the kind words, much appreciated, i used my own camera for these but hope to post better/clearer images with my sons camera, my first try at the experimental clock clip was a laugh, an ice cream van started blaring out music in the next street so had to be deleted, the next one has the resident blackbird in full song. You might have seen the pics of my clock on my own website, i had to give it up due to health probs but i still manage to potter around the workshop some days, regards Dave

Dave

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Re: The Grasshopper Escapement revealed
« Reply #14 on: July 18, 2007, 01:25:49 PM »
Hi Rick, just thought you might like to know, my experimental H1 clock is now on youtube, i am no good with links so type in experimental H1 will take you there. You will see the rough treatment that i give to the clock and it still runs, after all Harrison designed this for sea use, regards Dave