[msimpson99]

I wanted to do some router bit testing using a bunch of Tulipwood I had on hand. I thought to myself "I'm gunna make a large clock". What a perfect project to test the bits and a few other things along the way..

I wrote a bok called "Building the HANS Electric Gear Clock". The book is written to be built by a woodworker using a router table or scroll saw. I also have a DVD with all the drawing files available for CNC and LASER folk.

I decided to take the drawing files and size them larger to build a Gandfather sized clock. Im doing this project off the cuff. Im going to be using the book and enlarged drawing files. I enlarged the files by a factor of 1.5. This is my first time building this clock this way and I wanted to take you with me on this journey to creating cool clock, or a lot of firewood.

The project will be an on going one and can be found here:
Large Gear Clock


Lets start with Gear #6
[ame="http://www.youtube.com/watch?v=ov5j-y0qcM0"]GearTest - YouTube[/ame]

Kind of boring but it was created in length to compare the SmoothStepper with parallel port.


Here is Gear #7
[ame=http://www.youtube.com/watch?v=j6DlKSIjSnM]Large Clock Gear 7 - YouTube[/ame]

I streamlined it a little.





I will be adding entries to this post as I move forward.

[msimpson99]

Sorry if the link to the project was not working. It should be good now.

One update I will add to the project. It is important that you use extra clamps and use tabs on the milled parts that are large enough to that the stock does not shift.

I am suing a 1/8" cutting pass at 100IPM and that puts a load on the stock. IF you wanted to make a 1/4" cutting pass it would add even more force that would shift the stock or break your part free from the tabs.

On my next gear I will take a more aggressive pass but do a final pass removing .005 from the profile. This should allow me to cut the part very quickly yet still give me a nice part. The key will be how much bit deflection I will get. If its less than .005 then the final pass should compensate.

[msimpson99]

Oh how can I fail, let me count the ways.

First off, I reversed the final pass and the inital pass when I started cutting the teeth. Totaly a rookie mistake. I was able to recover as the bit did not cut into the teeth.


Next, I found the proccess of making aggressive cuts and then doing a final pass worked great on the spokes. However cutting the teeth on the gear prooved to much for the Tulipwood. I got excesive chip out on the teeth when cutting the edge grain.


This shows you can have a nice CNC machine, good stock and accurate drawings and still mess things up in the CAM phase.

Im going to go back and work on the tooling paths abit and give it another try.

Gear 9 Failure
[ame=http://www.youtube.com/watch?v=sVjeZNj-xhI]Gear 9 Milling Failure - YouTube[/ame]

[msimpson99]

On my second attempt on gear 9, I made a scoring shallow cut on the gear teeth. I then kept my cuts to .09 at 100 IPM untill the theeth were cut. I finished up with a single pass removing .005 from the teeth.

This worked out much better and I got no chipping on the teeth.

[ame=http://www.youtube.com/watch?v=24yyh1bzkW8]Gear 9 Success - YouTube[/ame]

The only thing that needs to be changed is to enlarge the tabs. The final pass on the teeth was too much load for the current tabs.

You can see the project here:
http://www.kronosrobotics.com/krmx02...ck/index.shtml

[msimpson99]

I just completed the remaining gears used on the clock. With the experimentation on the smaller gears, I was able to dial in a set of feeds and speed s that worked very well on the Tulip-wood.



Gear 3
[ame=http://www.youtube.com/watch?v=PmTZ04sk0nU]Large Clock Project Gear 3 - YouTube[/ame]

On this one I nested a couple of the smaller gears so I could get them all in one job.

Gears 4, 5, 8
[ame=http://www.youtube.com/watch?v=kDZVgG605o8]Large Clock Project Gear 5 - YouTube[/ame]

This completes the gears and large spacers needed to build the clock. I burnt the tips just a littl when I rounded over the gears. This wont matter much since the gears are going to be dyed a dark brown. Later I need to get a light sanding all the gears. I wont do this until after the first assembly test.

Next I need to cut a set of gear spacers and a bunch of thin spacers. I have to scout around to see what stock I have on hand. I'm thinking 1/4" Tulip-wood if I have any.



Follow the project here:
Large Gear Clock

[robe_uk]

looking good,
Just goes to show the power that these machines have when things go wrong

Rob

[msimpson99]

The final mechanism parts have been cut. These are the thin spacers. They are used in the gear assemblies and also to align the gears so they mesh properly. On this larger clock I cut them all out of 1/4" Tulip-wood using a 1/8" spiral bit.

[ame=http://www.youtube.com/watch?v=Xkr227yep7Q]large Clock Project Thin Spacers - YouTube[/ame]

With all the works of the clock complete (Except for the hands) the right brain processes are complete. I can now start the left brain processes.

I modeled the gear clock in AutoCAD which I needed to do for two reasons:

1. I need an idea of how long the arbors need to be, and I needed to calculate the distance between the two clock plates. The HANS book gives you all this information, but since I changed the thickness of the gears and spacers I need to recalculate.

2. I wanted to start looking at the design of the clock.

The design I am going with will look something like the one shown here:


I still have to work out my motor mount and a way to hide the cord. There are a couple ways of doing it.

[Lee DeRaud]

...and a way to hide the cord.

Speaking of which, are there any battery-powered alternatives to that 1RPM synchronous motor you use? I'd really like to wall-mount one of these things...

(I seem to recall you talking about some sort of pulsed-stepper setup on another forum, but that sounded like it needed more DC power than batteries would provide.)

[msimpson99]

I have been looking for some. They would have to have some sort of timing control.

The AC 1RPM motors I am using, use the 60 cycles to control the RPM. Very accurate and will outperform Quartz movements for accuracy.

[msimpson99]

I have completed the design for the most part and its time to cut the clock plates. Before getting started I want to show you what happens when you dont properly referance you Z axis. This happens more than I want to admit.

[ame=http://www.youtube.com/watch?v=MiZFbqqZ_Jk]Bad Z - YouTube[/ame]

The funny thing is I knew something was wring the second it came in contact with the stock. It took my brain a few seconds to react and hit the EStop.

I ended up with a nice gouge in my aluminum top as the bit went through my waster board as well. Its not that big of a deal since a single 3" section can be flipped over or replaced.

The Clock Plates

Since this is the first time with this clock design, I decided to do the rest of the clock in MDF. This way I dont have to waste any of my solid wood for design errors.

Cutting the upper sides and clock plates:
[ame=http://www.youtube.com/watch?v=9cVKOQJgiuk]Large Clock Project Clock Plates - YouTube[/ame]

I am glad I did them in MDF as I did find a couple tweaks I will make when I do the final wood cutouts.

All in all they went together like a glove. With the plates spaced out I was able to calculate the lengths of my arbors.

As always you can find the whole project here:
Large Gear Clock

[CarveOne]

You can repair the damage by taping the gouged area to make dams, then fill it with JB Weld, JB Kwik, or Lab Metal. When fully cured sand it flush with the aluminum.

Wooden clocks are on my future list of things to make.

[msimpson99]

Do they stick to the aluminum ok?

[Falcon69]

Need to be careful about that. I have built many handmade wood projects. I have used the JB weld, JB KWIK, Lab Metal, and even other stuff including Bondo.

The problem with this stuff, is that it does not expand or contract at the same rate that the wood does. That creates a problem in areas where there is any type of temperature change. Wherever the stuff was applied, that cascaded through the paint and or veneer and you can see it as a bump in the shape of the applied area. Really makes it look bad.

The only thing I can actually suggest which seems to work the best is....take some of the saw dust of the same wood (different wood also contract s and expands differently than other wood) and mic it with some good glue, like Tightbond. Then apply that, wait 30 minutes, then sand.

This is just my experience. I've built cabinets and custom furniture for the last 20+ years.

[Falcon69]

Sorry, didn't realize you were trying to fix an aluminum spot. If you got a welder, (tig welder, whatever), just fill the gouge and grind flat, otherwise, try using the JB stuff. Not sure if it will have the same affect like it does with wood. It might just work fine.

[msimpson99]

Thing is, I know I will do it again. Its like the first scratch on a new car. I have three CNC machines and the other two have gouges or holes. Its that its the firs on this machine. The top is a series of 80/20 1030 stock. At some point I will remove the gouged ones, flip them over and replace.

Im just glad I didnt break the bit.

[CarveOne]

Do they stick to the aluminum ok?

If you rough up the gouged area with a Dremel tool and a diamond bit to give the epoxy something to get a toe hold into it will work fine. When putting it on a nearly polished aluminum surface it won't stick well.

[Falcon69]

I'd even go as far as drill small, shallow holes sideways in the gouge and force the epoxy into it when applying it. Just for added assurance

[CarveOne]

I'd even go as far as drill small, shallow holes sideways in the gouge and force the epoxy into it when applying it. Just for added assurance

Agreed. Anything that gives it a good toe hold. Clean with acetone before filling the cut area also.

[msimpson99]

I finished the prototype stand today. I need to make a couple design changes but overall it went together well.

[ame=http://www.youtube.com/watch?v=X4jdFYpuzjY]Large GearClock Project: Stand - YouTube[/ame]

I still have to tweak a few things and have to figure out how to rout my power cord.

You can view the whole project here:
Large Gear Clock

[CarveOne]

That's a nice looking clock design. Will there be a clock face made for it? Lexan, so that the parts are not hidden, or a ring style?

How about a kerf in the back edge of the parts that the power cable can be pressed into to hide it?

What is the total height of the clock now?