Gear Project

get a cheap book, "Gears and gear cutting" by Ivan Law.

Delrin sounds like a good choice here. or maybe move up to brass which is veryeasy to machine for this project.

I would not look for the absolute best material for wear resistance. Anything that is real wear resistant will be a pain to machine. Better to make ten sets of gears out of something that is easy to machine than one set out of a material that has to be ground because it is very hard.

Dan

the headlights of my corvette have a plastic (delrin?) gear that is known for turning to dust in about 10 years or so. the replacement ones available are brass. i'd agree with karl about this.

Ok, so making the gears out of brass is a *step-up* from Delrin. (I'm assuming that that's the best I can do on a mini-lathe).

I do already have the book "Gears and gear cutting" by Ivan Law.

Thanks a lot.

Darren Harris Staten Island, New York.

One does need to consider the use though. I once made a new drive gear for a butcher's meat slicer. The original had been made from plastic and had stripped the teeth so I made the new one of brass. When we assembled the damned thing and tested it sounded like a very large siren Rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr.

It seems that there is more then one reason for selecting gear materials :-)

Yes, I thought about that. I was wondering how loud can brass gears from just turning a yoke between left and right like a steering wheel. Would you be able to hear them at all? (I know you cannot hear the original plastic gears).

Thanks.

Darren Harris Staten Island, New York.

The kit looks to be Delrin, and that is a good choice as plastic gears not having to transmit too much torque go. And given that they are driving pots -- look like the old Allen Bradley ones -- you should not have that much torque, unless the system is missing rotational stops, so it works against the stops in the pots.

If you want them to be metal instead, you really want two different metals -- and especially not aluminum meshing with aluminum. (But aluminum would be easy to machine.) Make the larger ones of aluminum, and the smaller ones of brass and you should be fine. A different grease would likely be called for to lubricate the mesh of the gears. You could make the smaller gears of bronze instead, but harder to machine and more expensive material. I doubt that you will wear a brass/aluminum mesh out in your lifetime just turning pots.

You will need an index head to position it for the cuts, and you will need to know the pitch, and the pressure angle (likely 20 degrees or 14-1/2 degrees, unless it is metric (module) gears.)

Good Luck, DoN.

Do you have a milling machine as well? And an index head? Otherwise, how do you plan to cut the teeth? I feel it unlikely for you to have a hobbing machine -- those are typically large, heavy, and rare.

A good start.

Good Luck, DoN.

I'd stick to insulative material. Delrin is machinable plastic.

Conductive paths can cause unwanted connections.

Mart> I want to undertake a gear making project for practice if not nothing

This was actually one of my favorite games back when. It had a special display with vector graphics, like Asteroids, but in color.

Try looking for appropriate replacement gears from some of the online catalogs like here:

That's not a problem. Anything that needs to be conductive is secured out of the way for obvious reasons.

Darren Harris Staten Island, New York.

Well that would defeat the purpose of me learning how to do this.

Also, In addition to Star Wars, I have two other vector games as well. Asteroids and Star Trek. (All my other ones are raster games).

Darren Harris Staten Island, New York.

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Can you machine a 28 tooth gear with that thing. 360/28=12.857 degrees?

A big reason is the rigidity and power of your machine tools. The gear cutter has to cut the entire periphery of the tooth space at once, which puts a heavy load on the cutter and the indexer supporting the blank.

jsw

I had to cut a one-off steering gear for my tractor when the original was no longer available.

I made a really simple fixture, it was basically an angle plate that the gear blank mounted to and a dowel pin. I cut a tooth, repositioned the blank so the dowel pin was locating the tooth, and repeated.

MikeB

That's a very good idea for a sector gear but not for a full one, as the spacing error accumulates and the tooth width between the first and last cuts is unlikely to be acceptable.

Long ago master index plates were generated a similar way, by stepping around the circle with dividers and attempting to adjust out the closure error.

Cutting a steering sector:

jsw

I remember the sit-down SW game at the local billard hall in the late-seventies. Seemed fascinating, but I was more into pinball at the time.

Jon