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stan kern
10-07-2013, 10:06 PM
started doing research into cutting clock gears ,with this simple gear arrangement for testing


http://www.youtube.com/watch?v=6aYNMlKSuqw&feature=share&list=UU_PEoeKZVkgYpHbnwePe1Eg

Michael Hunter
10-08-2013, 5:46 AM
Gears are easy - but can you do escapements?

Joe Hillmann
10-08-2013, 11:00 AM
Here is an escapement for when you get to that point.

http://www.sawmillcreek.org/showthread.php?176459-Clock-escapement-file&highlight=clock

Joe Hillmann
10-08-2013, 11:10 AM
If you are actually planning to build a clock you need the gears to mesh and spin with NO binding. The only way I was able to get gears to spin from my escapement was to use brass axles and bushings made from thin wall telescoping brass tubing. I also had to have the axles supported behind and in front of the gears to prevent flexing. And everything had to be lined up PERFECTLY before tightening up the bolts that held everything together.

Michael Hunter
10-08-2013, 11:53 AM
Hey - that's my clock!

Joe - your escapement is good, but I never did figure out how to scale it for my clock.
(Perhaps I'm just not persistent enough).


On the subject of axles and bearings -

Model shops sell brass tubing where each size smaller fits nicely into the previous size.
They also sell piano wire in "matching" sizes.
Great for making bearings etc. and easy to make the three concentric shaft arrangement (hours/minutes/seconds).


Traditionally the clockmaker would make the gears he needed and then use a gauge to work out how far the axles needed to be apart so that the gears meshed correctly.
The gauge measurements would then be scribed onto the brass plates - the chassis of the clock.
This explains why very old handmade clocks appear to have the axles at random points on the plates, rather than being in neat lines.

I could not operate this way and so worked out a family of gears which mesh accurately in whole numbers of millimetres - this way the bearing holes in the plates can be placed beforehand.

If anyone is interested, I could dig out the gear drawings and post them.

Sotos Patistas
10-08-2013, 2:48 PM
Hey - that's my clock!


If anyone is interested, I could dig out the gear drawings and post them.

I'm very interested and would very much appreciate your gear drawings. I'm at about the same point as Stan, just starting to cut a few gears, made a prototype pendulum just today. I've been reading about escapements for the past week, quite a lot to digest.

I especially like this fellow's designs also:

http://www.woodentimes.com/

Some very helpful videos as well.

stan kern
10-08-2013, 7:34 PM
i am having quite a time of it ,might not be an easy venture ,but i would like something basic and then go from there .
Cut all the parts today and that went well ,the shafts are going to be a big deal...might end being a static model

Sotos Patistas
10-08-2013, 7:53 PM
Stan, what are you using for shafts? Is it the alignment that's the problem?

I decided to pull the trigger on plans and cad files for this one: http://www.woodentimes.com/primus.html . I like the way he suspends his pendulumsand the deadbeat escapement looks well configured as well. I think I'll try CNC routing the gears as my laser doesn't have enough umph to cut thicker ply. I'll post on my progress if there's interest, waiting on the plans to arrive as I type.

stan kern
10-08-2013, 10:20 PM
so far i am just experimenting with wood shafts just finding it difficult not cutting the gears but assembly and shafts
When you get youtr plans how will you get it in the format to cut.
This is what i am working on (photo attached)
managed to get it apart and cut all the gears but thats it for now as i need to assemble and look at shafts

stan


http://youtu.be/ooGjn6z3Q30 i am coming along but slowly this was the easy stuff ,the shafts are a problem as i shop around for brass tubing

stan kern
10-09-2013, 12:28 AM
interested too!
stan

Michael Hunter
10-09-2013, 6:34 AM
Just tried to upload a selection of gears, but the file was too big (by a lot!)

Too busy to sort it now, but will split the drawing up into smaller selections and post them next week.

Sotos Patistas
10-09-2013, 9:16 AM
Stan: Plans for the Primus by David Atkinson include PDF as well as dxf files and a 35 page pdf instruction book. Instructions seem straight forward and let you know what measurements (given in metric as well as inches) you need to adjust if you use different thickness wood. My workflow will be dxf's to Autocad to Corel to VCarve Pro. I'm better at drawing in Corel, but Corel seems to have a problem with much of the text in the drawings, converting it to some sort of Asian characters regardless of what font I specify. Autocad seems to read it in cleanly, so no worries.

Your design looks to have great appeal, but after thinking for several weeks that I'd like to try my own design, I caved after days of reading about the evolution of the escapement and decided to go with a proven design for my first build. The plans were a bit pricey, but the design seems very reachable, so hopefully that will increase my chances of success the first go around.

Michael: Appreciate your efforts, so whenever you can manage is great.

stan kern
10-09-2013, 9:25 AM
these files sometimes are difficult to handle ,possibly look at drop box dot com ,its free, a login type thing, but does allow 1.0 gig free to start

stan kern
10-09-2013, 8:40 PM
thanks to joe hillman for the file ,i have cut out all the parts on his example and a temporary assemble,no gluing yet

http://youtu.be/D19npXNjguU

Joe Hillmann
10-09-2013, 11:02 PM
thanks to joe hillman for the file ,i have cut out all the parts on his example and a temporary assemble,no gluing yet

http://youtu.be/D19npXNjguU


The spacers on the outer corners between the two plates need to be thicker than the gears, I would suggest cutting 4 more spacers out of thin card stock and put that in there as well to give the extra thickness needed. I would also suggest replacing the wooden dowels with brass tube epoxied into the plates and a brass shaft epoxied to the moving parts. It will run as is with the dowels but once you add a gear train to it the dowels will cause too much friction.

You need to make the pendulum longer and put the weight about three feet from the pivot. Make sure the pendulum rod is fairly stiff. If you have the pendulum too short it will swing way to fast and the clock will damage itself.

Also when it comes time to add the rest of the gear train keep in mind that wheel is 45 full beats per revolution. If you plan on one revolution to be a minute you need to time the pendulum to do a full swing every 1 1/3 seconds. If you want your swing to be one second you need to gear the escapement down 79.8/1 instead of 60/1 for the hour

Joe Hillmann
10-09-2013, 11:20 PM
Several other things, when you are trying to keep it running keep the weight that is wrapped around dowel on the gear fairly light, maybe a pound or so. Once you get it to run then you can add more weight. If it is too heavy it will bust the pallets off the escapement.

You may want to harden the tips of the pallets by putting a drop of some type of thinned out varnish or super glue to prevent the tips from breaking off. A few thousandths of wear on them can cause problems if your weight is to heavy.

If you try and run it with the wood dowels you need to make the one the gear is on thinner where you plan to wrap the string for the weight on it otherwise it will use up 3/4" per turn and wont run long. Once you get a gear train attached you would make the weight heavier and attach it on the hour shaft or the shaft between this and the hour so you can get a decent run time out of it.

It has to be aligned very carefully to run without skipping teeth.

If you have a wide kerf on your laser you may need to make the pallets a couple thousandths larger and make the gear 4 or 5 thousandths larger.

stan kern
10-10-2013, 8:14 AM
thanks will look for the 2 brass tubes and i will increase the card stock

stan

Michael Hunter
10-11-2013, 6:51 AM
Here is a selection of gears in Corel X3 format.

They were imported directly from the CAD program and have huge numbers of nodes on each tooth, which may or may not cause problems when you try to cut them.
(Some simplification may be necessary).

Have fun!