Wooden Clock - Trial & Error

[KtownScroller]

I am building a John Randle, WC5, wooden geared clock. The plans can be obtained here: CLOCKS BY JOHN - A Gallery of Clock Designs from Randle Design, LLC John offers a couple of other wooden clock versions as well.

Being as I am building a wooden geared clock for the first time I thought it might be nice to log my trials and tribulations here, so that it might serve as a tutorial for others who might be trying such a project for the first time.

[KtownScroller]

I have been thinking about doing this clock for quite some time. What always stops me is the shear precision of the project. Actually the precision part is not so scary. It is the barbaric tools that I will have to use to create this project! My biggest concern is T.I.R (total indicator runout). In this case, T.I.R. is the relationship between the root of the gear tooth and the center hole of the gear blank. Typically on precision gears this is less than .001 of an inch (1/1000). On wooden gears I would think a T.I.R. of 1/64" ( .015625) might be reasonable. At least that is my original goal.

I posed a question in another similar thread on how to drill a hole in the exact center of the pattern. I was given the following advice:

Originally Posted by lucky788scroller

One thing you might consider trying is a relatively simple trick similar to what I have seen used quite a bit by Gary MacKay on a lot of his inlay things. drill a teeny hole in the center of your piece of wood you intend to cut the gear from.By teeny, I mean certainly no bigger than 1/16th inch, smaller would be better. On your gear pattern, I assume the center of the hole is marked with a + , poke a pin through that center point. Squirt on your spray glue on the pattern, and line that pin up in that teeny hole you drilled, and stick your pattern down. Now, your pattern should be fairly accurately attached. Since sometimes a larger drillbit can grap and rip a pattern, you can flip the wood over, and drill through that teeny hole from the backside, but be sure to have a piece backing it for the bit exiting, or you might cuss a little bit. Making the teeth all uniform seems to me like that would be the hardest part for me to do, I have never tried doing gears, yet.

And...

Originally Posted by weiner9696

What I have done is to glue the pattern on the wood, then use a punch to mark the true center. I drilled the hole with a 1/16 bit then drilled the hole out with the proper size. Worked great for me.

[KtownScroller]

I am starting this project with some practice parts. I do not want to spend hours creating gears only to find that I went about it the wrong way. I am starting with two gears that will mesh together. My goal is to discover potential problems and to troubleshoot these problems with my own ideas and the ideas of members of this forum. Together we can figure this project out and possibly construct a nice tutorial along the way.

I understand that building a wooden geared clock is not mainstream. I do think that if relatively simple methods are obtained in cutting this clock pattern, other people might take the plunge and build a clock for themselves. Can you imagine how proud you would be to display such a masterpiece in your home?

Here we go...

I have cut two prototype wooden gears. I drilled up a quick assembly plate to test the run out. Although the run out isn't too bad, I think I need to find a better way to get the gear holes drilled exactly in the middle of the gear blanks.

I used a combination of ideas to drill the center hole. I attached the pattern to the 1/4" oak wood blank and drilled a 1/16" hole directly in the center. I noticed that even with a small drill it is possible to miss the exact center. The next practice piece I drill will be done in the following order: pin prick the center hole on the cross-hairs, drill a 1/16" pilot hole, finishing with a 3/8" forstner bit hole.

I have attached two pictures to show the gear train assembly. I do not like the brass pin drive! It is far too easy to get those pins out of alignment. The pins don't necessarily want to stand perfectly straight after insertion in the hole. I think I am going to circumvent this problem by designing a small pinion to take the place of the drive pins. It will require a little effort, but I think it may be well worth it.

[scrollpup]

Rick,I checked out the clock.This is definitely not for the faint of heart (lol)!Good luck on your project and I will enjoy watching your progress on this.

Jerry C

[Wood Dog]

I'm ready for the ride......good luck. Love WIP's.

[KtownScroller]

I designed a pinion to replace the brass drive pin assembly. The fit between the gear and the pinion were satisfactory. Today I am going to redesign the pinion leaving more material at the root of the tooth. This will make the pinion stronger without affecting the movement between the pinion and the 2nd gear.

I included photos of the prototype pinion and the temporary gear assembly. Notice how the the pinion teeth and the brass drive pin holes that were drilled into the 1st gear do not line up. This is a major problem that I am trying to work around. Evidently I drilled the brass pin holes slightly out of position. If I were to use the gear with the brass drive pins it would never work. The pins would bind up with the 2nd gear because of the poor positioning.

I intend to fix the compound gear together with two pins and glue. This will insure the proper position between the smaller and larger gear, which forms one of the compound gears in the project.

After redesigning the new pinion, I want to cutout and drill a test fixture that will approximate the clock housing. With that fixture/jig I will be able to test fit all the gears in the prototype, before fabricating the actual pieces.

[dragyn]

Thansk for taking the 'TIME' to take us on this trip with you KT!

I know, I know, but I just couldn't resist the pun!

[wood-n-things]

Well,
Now you 've gone daffy. I am with ya brother in spirit. Good luck.. I'd never have the patience for this one. Looking forward to the journey with you though.

[KtownScroller]

I just cut the new pinion. It looks good and solid. It works well too.

My next step is to fabricate the fixture/jig that I will test the whole clock assembly on.

I was at Woodcraft yesterday looking at hardwood, plywood and scroll saw blades. I bought a couple packs of some very fine toothed Olson blades. I am hoping that they will work out well when I cut the finished gears. I checked the baltic birch plywood selection and found it to be a disaster. The boards were severely warped and unusable. There was a second section containing better quality baltic birch plywood that was fairly flat, but the price was out of this world! They wanted $26.00 for a 24" x 32" sheet of 1/4" plywood. Needless to say I didn't buy any of the plywood. I did pick up some decent 1/4" Kiaat and some 1/8" Hard Maple. I was thinking about cutting gears from that wood, but I am having second thoughts. I might use that wood for something else. I am considering making the gears out of baltic birch (maybe Michaels has a better plywood selection) and MAYBE covering them with a exotic hardwood. Just a thought.

[wood-n-things]

Looking good so far. hang in there.
I had never heard of "Kiaat" before looked it up via google sounds like a nice wood. However did find this:
Strength
Owing to the varying grain, even in the same log, its strength is generally lower on average than the values for padauk, being about 30 percent inferior in stiffness, but it is about 20 percent more resistant to shock loads, and about equal in bending strength.