Joined the Gear crowd

[Norm W]

This crowd is getting bigger. It wasn't a lathe gear that needed to be built, a garage door opener had eaten a worm wheel gear. I don't have a hob so a fly cutter had to serve. Instead of making an index wheel I just used the old gear. The gear teeth are angled so the old gear allowed me to match the angle for the blank. The old gear was some sort of plastic, the new one is aluminum. The fly cutter was ground to match the worm thread. This maybe should have been in machining, but I had to fab the jig to machine it. I sure it would have been cheaper to buy a new gear, but the challenge was there.

[Tom Zachman]

Yeah, and damnit!! Some Chineese (how do i spell it) worker makes 4 bucks a day making this part while the rest of the world 'rests'

[CEC]

I like the way you used the old gear for the indexing.
For the angle you pivoted the jig?
How are you going to machine the concave for the worm?

[cutter]

Looks like it must have been a Chamberlain (Sears).

You might want to check the spring tension on your door, Norm. Too much weight is a prime cause of gear failure, along with lack of lube.
They like to sell those repair kits.

[Norm W]

It's not my door. The fellow that owned it already bought a new opener. The "Repair Kit" goes for $25-35 depending on where you get it. SWMBO said, "Get a new one!" so he did. Before it was installed I adjusted the door. The door weight at waist height is now neutral. I had to take up about 9" on the lift springs. The top brackets were too tight, so every time the door started up it took a chunk out of the header. Goes up and down slick now. The concave on the circumference was done "Old School" with a half round file. Yes the jig tilts for the lead angle on the worm wheel. Cutter, sounds like you have tangled with Mr. Chamberlain before. My doors have always had Armstrong openers. I may try to use it for my garage door. The only problem is, it's a 12' door and it goes side ways.

[platypus20]

That poor Atlas!!, thats tantamount to lathe abuse!! Its good to see the lathe being used. Are you machining that just as you show, or are you using a live center to hold the end of the boring bar, while you cut, to stop flexing??


jack



CEC,

In this set up, wouldn't the arc of the cutter, cut the concave in the gear?? (just thinking out loud)

[Lu47Dan]

Originally Posted by Norm W

Cutter, sounds like you have tangled with Mr. Chamberlain before. My doors have always had Armstrong openers. I may try to use it for my garage door. The only problem is, it's a 12' door and it goes side ways.

Norm, I saw a garage door opener used on a sliding door, the traveler was attached to the door with a bracket and the opener itself was mounted above the door opening on the wall. It worked pretty slick.
Interesting fix, Norm.
Dan.

[Floptop]

Seeing these different setups to build things sure opens the eyes of the clueless like me. Thanks for showing it.

[milomilo]

Originally Posted by Norm W

I sure it would have been cheaper to buy a new gear, but the challenge was there.

Those cahllenges are what makes it so much fun. I have a hard time passing a challenge, even though it is cheaper to buy new. I guess it is the rewarding feeling fixing stuff that keeps me in the game.

[Norm W]

Jack, If I had been cutting steel instead of aluminum I would have supported the end of the bar. As it was light cuts and didn't bend anything. I also didn't tighten the belt so it was a Q&D torque limiter. As far as the cutter making the concave, it probably would have if I had ground the bit correctly. By the time I realized what I needed, it was too late, so I made do with what I had.

The door is 11'6" and the track is 8'. I'll have to find, or make, another section of "T" to add on. The door next to the one I want to move is basically the same, however I don't have much room against the wall for the unit and I can't extend into the door space of the other door. I may end up mounting the unit in the rafters. With enough chain, pulleys and levers, one can move almost anything.