[John Tribe]

The accuracy of a clock depends only on the length of the pendulum, and if you're interested not the bob weight either. A light bob can give the same accuracy as a heavy one provided neither is under the influence of "drafts" from doors or furnaces etc.

You can scale the gears to any size you wish but I would keep in mind that our ability to be precise is somewhat fixed and a 0.001" deviation is probably as good as we'll ever get in wood. That deviation in a 0.5" pinion is on heck of a lot more critical that the same 0.001" deviation in a 2" pinion.

I will go for the largest gear size that is practical for my application and prefer gears that are in the 8" or less size and that limitation is because my WidgetMaster Midi CNC can only cut an 8.5" item.

When scaling I agree that if you have both the gear and the pinion on the scanner at the same time you'll have a lot less chance of getting different scales. Another thing that I do is to put a 6" circle on a clear plastic overhead and put that on the scanner first then when I scan and go to a program it is easy to tell if I have some distortion or not. I also use this idea when printing if a part needs to be cut on a scroll saw or band saw. Printed copies are nearly always distorted. I correct for distortion in Powerpoint where I can change either the width or the lenght to come back to "round".

If you get to the point where you want to do more on your own designs there are some good computer programs that will produce "perfect" tooth forms in either cycloid or involute design. I always go for involute myself.

John

Hi Steve,

Yes I do have CAD programs. I use BobCad for basic 2D work but I also have Autodesk Inventor and VCarvePro. The point you make about only having to draw half of an arc for a tooth and then using a radial copy and paste type of operation makes sense but I would have to see if BobCad does this. I have done this using Inventor and that will save hours of time. Great suggestion!

I still wonder if you can scale a clock down or up without changing the clocks time keeping accuracy. I really doubt that my scans will be of the exact size as the original paper drawings.

I like the gear making website link but you would obviously need to understand clocks to a much higher level than I do. I figure if I could be successful making a clock from plans then I may have enough confidence to try something like that.

Thanks!
Bill

[BJenkins]

The last few post have really cleared up my questions regarding getting plans into a CAD program and then cleaning them up.

I understand in general your method of checking for proper scale and roundness using a 6" circle but I don't understand what you mean when you mention a clear overhead.

Thanks for answering the question about scale and for going into detail on accuracy issues.

Thanks for sharing.
BillJ

[John Tribe]

Sorry for the confusion - by overhead I am referring to clear plastic sheet that is used on overhead projectors. The reason for this is that you can put the circle on the plastic sheet and then put the plastic sheet on scanner and scan both your drawing and the circle at the same time.

I hope this clears up more than it muddies the water

John

The last few post have really cleared up my questions regarding getting plans into a CAD program and then cleaning them up.

I understand in general your method of checking for proper scale and roundness using a 6" circle but I don't understand what you mean when you mention a clear overhead.

Thanks for answering the question about scale and for going into detail on accuracy issues.

Thanks for sharing.
BillJ

[blackbeard52]

Thought you might like this clock

http://www.scrollsawer.com/issue26/woodengearclock.php

Bob

[BJenkins]

I ordered the plans.

I look forward to giving this a try. I really like the design because it should run for around 30 hours and it does not require massive weight along with the clean look.

Thanks,
BillJ

[John Tribe]

Hi BillJ
I have built a number of Marc's designs and they are really well thought out and tested. The ones from Marc that I have built have all worked really well.
Good Luck
John

I ordered the plans.

I look forward to giving this a try. I really like the design because it should run for around 30 hours and it does not require massive weight along with the clean look.

Thanks,
BillJ

[BJenkins]

Thanks John,

While surfing the web for wooden gear clocks, I ran across your name and I think there was a link to a web site for your clockwork but the link didn't work. Do you have a web site?

BillJ

[John Tribe]

Thanks John,

While surfing the web for wooden gear clocks, I ran across your name and I think there was a link to a web site for your clockwork but the link didn't work. Do you have a web site?

BillJ

Hi Bill,
My site is at :

http://www.jtwoodenclocks.com/

What was the url that didn't work?

[BJenkins]

John,

Here is the link to the site where I found the link. http://www.woodenworksclocks.com/KitsPlans.htm

WOW, your site will take a while to go over. I look forward to searching through it all.

I live in TN; I wish I knew someone in my area that was building these types of clocks. I understand the MLT-13 drawings as far as what needs to be cut out and I’m pretty sure I’ll be able to put it all together. (pretty sure - Ha!)

BillJ

[blackbeard52]

Bill
How ya doin...I built one of the clockworks clocks a few years ago...

Bob

[BJenkins]

Hi Bob,

I would definitely like to hear about your clock building experience. I remember now that you mentioned that you had built a clock.

Thanks for suggesting this clock. If I'm successful with this one, I hope to try some others. I think everyone needs at least one wooden gear clock.

BillJ

[blackbeard52]

Bill

Since I didnt have any experience with clock building I ordered the gears laser cut so the mesh would be more accurate... Glad I did, It took me a month to cut and finish the other pieces...

Bob

[BJenkins]

Here is a 3D CAD simulation of the MLT-13 that I just finished.

[ame="http://www.youtube.com/watch?v=mz_9pTHqjT4"]YouTube- Wooden Gear Clock[/ame]


Also; I found this series of escapement videos interesting.

http://www.youtube.com/user/BenVanDeWaal


Thanks,
Bill

[becikeja]

Thanks for sharing, awsome simulation

[revwarguy]

Not exactly "clock" gears, but wooden gears nonetheless - I am just about to complete an orrery build, like one by John Tribe - see:

www.liming.org/orrery

for some more info and photos.

[Mr.Chips]

Not exactly "clock" gears, but wooden gears nonetheless - I am just about to complete an orrery build, like one by John Tribe - see:

www.liming.org/orrery

for some more info and photos.

And this is for your Daughters 3rd grade science project, right?

Just joking, it is really nice and looking for the YouTube version soon.

Did you CNC cut it?

Hager

[revwarguy]

You bet. I am a complete boob at a scroll saw. Each of the gears are cnc, as well as almost all of the other pieces. (Well, I did route some edges of the top and bottom with a regular router table.) Lots more about it at the web address.

[BJenkins]

Thanks for sharing all the details of the Orrery build. It is a beautiful piece of mechanical design and craftsmanship. I’m sure it will be a super education device and a wonderful addition to a home. I look forward to staying up to date with the project.
Oh yeah, thanks for explaining your method of changing paper drawings to dxf. Also, I’m sure the video will help a lot of people understand how the CNC process works. (Very nice)
Bill

[Gingernut]

The first wooden clock I made I cut out all the cogs with the band saw, the cutting lines were CAD printouts glued on to the ply. But after sanding and adjusting so the cogs did not bind, I had such a great amount of backlash it almost made me weep. This is when I decided I would make my own CNC router, and I have never looked back since. I draw all my clocks in Sketchup and with a DXF exporter plugin I can do everything I need, and for free(good argument for Sketchup). All cutting paths I produce in Cut2D which is more than enough for my needs, simple to use and at a price that can not be beaten. The Router is controlled by EMC2 which runs on linux, so therefore completely free.If you are interested you can take a look at my clocks here
http://www.uhrkunst.com
If anybody has any questions about CNCing wooden clocks please do not hesitate to ask.

[BJenkins]

Those are some pretty clocks!

I wish I could design clocks. I have the CAD skills and a CNC machine. I even have a program to draw gears. Those of you that actually design your own clocks amaze me. Do you have any recommendations on books that explain the basics? Several nice folks have explained different aspects of clock making but I still have way too many questions.

Thanks,
Bill