Project: Clockwork

[DonT-FeaR]

ohh yay gear trains they can be your best friend or your worst good luck

[blueonblack]

ohh yay gear trains they can be your best friend or your worst good luck

Thanks. Out of that pile of gears I've found 22 that will work in sequence, if properly oriented. That should be enough, with leftovers for other places on the case. Got 2 more nights to work then I'll have a couple to work on it.

[The boy 4rm oz]

Awesome. I am looking forward to seeing how that turns out.

[DonT-FeaR]

oh ok i shall look forward to it also

[mittelmeier]

Can't wait to see the gear set up you are working on.

[blueonblack]

Well, I am sorry to say that, due to family, work, and life in general, this project is going to have to be shelved for a while. I will pick it back up where I left off when I have some things caught up and squared away.

Keep up the great work, people.

[DonT-FeaR]

ok pitty to see it put away but we understand...

get everything all good again and come back when your ready

[blueonblack]

Ok, so this project had been shelved for a while due to other intrusions. I think those are straightened out for the time being so back to work I go.

Like most computers, the left side panel on this one is designed to remove for access. As my computer sits on my desk on my right, I decided to put the motorized geartrain on this panel. I am glad to say it's done. All of the gears are in place and ready to turn. I still have to figure out a way to mount the motor so that it is adjustable for tension, but that's child's play compared to this.

I recall when I had this idea I said "Hmmmm, I know. I'll get a bunch of gears together, sort out some that will turn together and I'll put them in a train on a computer!" Well, that's what I did, but let me tell you, I had no idea. I set myself up for a very complicated puzzle in three dimensions. With pieces from five different puzzle boxes, so to speak. Forgive me if this post is long, but there were a lot of problems to overcome, and I want to share my methods, in case anyone else can use them. These were all pretty much poor man's solutions to problems that any machine shop could have solved in ten minutes.

First off, every gear shaft had to be perfectly perpendicular to the side panel. If it was crooked at all, the gear would wobble and the teeth wouldn't mesh. So far, so good, I have a drill press, problem solved.

That's about the only easy part. The gear shaft also had to turn freely to allow the torque from the motor to pass through the whole train. BUT it couldn't wobble. That was a joy to fix, kicked my brain for a while. Oh! And the shafts on clock gears are not fractional sizes. Or metric. They're wire gauge, or close enough that wire gauge drills do the job. I own a set of those now.

So I couldn't just drill holes in the side panel for the shafts, either the bearing didn't spin freely enough or it wobbled. I thought of nylon bushings, sleeve bearings, ball bearings, name it. I dare you to find ball bearings with the inside diameter measured in wire gauge. In the end I did end up using ball bearings. Thirty-eight of them. I bought bearings that were 3/8" inside diameter and 5/8" outside diameter. Then I cut a 3/8" oak dowel rod down to 1/2" lengths (the panel is 1/2" thick).

These would go inside the bearings to act as a shaft. Then I had to figure out how to drill holes for the gear shafts *exactly* in the center of the dowels. Off even a hair and the gear would wobble, and the teeth would slip on one gear and bind on the gear on the other side.

Banged my head for a while on that. I ended up clamping a piece of 3/4" scrap MDF to the table and drilling a 3/8" hole in it with the drill press:

Now, as long as the board or the drill press table don't move, no matter what size drill bit I put in the drill press it is EXACTLY centered on that hole. Used the drill press to press the little shaft into the hole:

And bingo. Sort out which drill bit to use for each gearshaft (one size small so it's a press fit into it) and drill the hole. Dead center. When it's done I put a bolt on top of it and pressed it out the bottom of the table:

So now the hole is drilled, here's what they look like with two bearings on them, and a gear mounted:

Cool, all the gears are turning freely and will stay perpendicular. The fit is tight enough that the pressure will also control the distance of each gear from the side panel, which *also* had to be perfect. Even a millimeter too close or too far away and they slip. Picky little things.

Another puzzle was how to measure how far apart every hole would be from the next. Again, very tight tolerances. I cut two boards and drilled 5/8" holes in the ends of them:

Then put the two gears in question in the holes and got a rough measurement from shaft to shaft with calipers:

Ok, that's rough, I could only get so precise eyeballing two shafts from the top. I needed a way to drill some holes and adjust that distance closer or further by trial and error until I got it right. This is called a dowel center:

It's a little brass cap that fits over a dowel and it has a spike inside it dead in the center. I slid it over a couple of left-over bare shafts and hit it with a hammer, leaving a small dent in the center of the shaft. Then I mounted two bearings on each of them:

I used these "dummy shafts" as markers for measuring. I drilled another 5/8" hole in another piece of scrap, put the first dummy shaft inside it, then transfered the measurement from the calipers, using the center divot on the dummy shaft to make a mark on the scrap. Drill a hole at that mark and set the two gears in the two holes. Too close or too far away, adjust the measurement and do it again. (Just be sure to cross out the hole you're not going to use!)

I wound up with two pieces of scrap with a LOT of holes in them:

These are the finished measurements for all 19 gears, each marked one to the other. Now how in the world am I going to transfer these exactly to the panel I'm working with?

I made a pivot by stacking six bearings on a longer piece of dowel:

Drilled the first hole for the primary drive gear (since it could be about anywhere). Put the measurement board on top of it so that the right numbered hole was over that hole and slid the pivot through both of them. This held the measurement board onto the panel but let it turn.

I put that assembly on the drill press and put the bit into the hole beside the one with the pivot in it and drill through the panel. Since the hole in the measurement stick was the same size as the drill bit the measurement transferred perfectly.

That pretty much got the gears where I needed them, with a few mistakes while learning along the way. I decided to make this build look kind of retro/antique/psuedo-steampunk, so I didn't want my gears to be nice and shiny. It's amazing what brass will do when subjected to a few seconds of a mapp gas torch.

Enough's enough, here's what it came out to:

I have to stain the panel (and the rest of the thing), plan on painting the fan ring you see there and making a custom grill that I think you'll like.

That's where we stand now, and I'll tell you the rest of this build should be a breeze compared to this! (I don't like gears quite as much as I did two months ago...)

[The boy 4rm oz]

wow you have been busy. The gear train looks fantastic. Excellent work.

[SXRguyinMA]

looks awesome! +rep