Gear creating software

[tuck]

Brady - I googled "synchronous timing motors" and they look amazingly similar to the microwave turntable motors I've been yacking about, and for roughly the same price. They also have the same tiny drive shafts, most even smaller in diameter (1/8" vs 1/4") and that presents a problem for securing the motor shaft to the drive gear.

http://www.hansen-motor.com/ac-synchronous-motors.php

If one wants an AC motor for continuous power on a larger display, finding a slow-turning motor with an adaptable (larger, longer) shaft is most of the battle and at least half of the frustration of building a nice one that will run quietly for hours on end. I liked Jack's idea about a rotisserie motor, but where on earth to find them? If ya gotta buy a whole new rotisserie just to get the motor, you're not doing it right!

[Brady Watson]

Mark,
Yeah...the shafts are a bit stubby, but I don't think it would be hard to machine a pocket into a drive gear to mate it up perfectly - then just tag it to the shaft with a grub screw.

McMaster has some here


-B

[myxpykalix]

Brady (or anyone),

I'm wanting to make some gears and do a sculpture and have read what all are saying but what would someone need to know about motor size depending on the amount of gears you want to run?

What i mean is lets say i want to make a simple gear set of 4 gears at 6" diameter, that would take less torque or power to turn then say a set of 8 gears at 9" diameter. How do i determine what size/type motor i might need depending on the size or complexity of the sculpture? How would i measure the amount of torque needed to run one? Is it as simple as buying a motor that would handle the biggest thing you might make and not worry about it? Since i have not made one yet am I just overthinking it?

[tuck]

Jack, I think you are over-thinking it to a degree. If you watch the first youtube link I posted in this thread of the gear set I did last year, the center drive gear is 19" in diameter, and the shell they are all mounted to is 24" x 48". The gears are cut from 3/4" pvc and have some weight, but the little microwave turntable motor drives them just fine. The bigger problems stem from mounting the motor to the drive gear (tiny shaft), and mounting all of the rest of the gears on their own shafts so that they will spin freely and all mesh correctly. I used 1/4" bolts but they have threads that the gears can tighten themselves down on and lock up the whole works. An extra nut on the back helped that problem, but didn't cure it entirely. The problem is that you want all the gears to look tight (not flopping around), but to spin freely with little or no resistance. It can get very tricky.

Brett Dickens in Australia uses wooden dowel rods for his shafts and while he hasn't been clear to me on how he attaches everything (obviously the gears can't spin off the shafts), he seems to have it down to a science.

To me, it's all a fascinating mix of math, engineering and design that I have yet to master like Brett has. He sells his displays and does well. If he is a graduate of "gear college", I'm still in elementary school. I haven't completed another set since the one last year and I won't try another one until I have better ideas for motors and mounting. Finished displays should work perfectly with little or no maintenance. Mine is relatively simple but when I flip the switch, my friends can hardly take their eyes off of it. Everybody likes to see things go "round and round".

Edit to say, you can buy rotisserie motors, both AC and DC, but they come with no shaft, just a pocket for a shaft. Now ya gotta find the shaft, haha! http://www.4thegrill.com/rotisserie-...isserie-motor/

If you google "rotisserie motor", you can find a wide variety and they are not pricey and most are ready to "plug and play".

[mark_stief]

Get shoulder bolts made just for what you are trying to do the shoulder of the bolt is smooth and bigger around than the threads so you can tighten it to what ever you're mounting to and tighten it up and not bind on the gear I hope I explained that right

[myxpykalix]

Mark,
I watched that video before (where do you think i got my interest in making a gear sculpture?, that is so f'ing COOL!).

"The problem is that you want all the gears to look tight (not flopping around), but to spin freely with little or no resistance. It can get very tricky."

Again with overthinking it, but so as not to run into the issues you mention here and not having the program it would seem that when you make a set of gears you would set it up within a project framework, then your holes could be drilled exactly based on the shaft placement according to the gear array you create, am I on the right track?

[shoeshine]

OK wow, a bunch of things to respond to.

As far as the framework goes, this is one of the biggest advantages of Gearotic IMHO. When using the output module you can save a dxf of the framework calculated by the prog. Gives you all the center points of all the gears in your system. I have just then modifed this in Rhino/PW to create a housing for my gears. I generaly just mark my drill points with a Vbit and then drill to the dia. of my shafts with an accurate bit on the press.

...and yes, shoulder bolts (right on Mark, didn't think to mention) are perfect for this. I am now cutting my framework in sheet aluminum and then drilling/tapping holes for the bolts. (near perfect gear meshing for my tolerences)

@Jack:
In gearotic there is a program settings icon on the top bar to the right (a little green sphere with a chain link) Heres where you can toggle metric or SAE for your projects. The interface is not really intuitive but I have been able to get what I need via changing the D pitch and wheel teeth # to get the gear I want. Just watch the relationships to get a sense of how they interact. The actual mechanical theory is more complicated but for this purpose it has been sufficient. Getting meshing gears is a breeze as they are calculated by the prog. Nice feature is that in the spur gear panel, it gives you the minimum bit dia. to cut the involute "flat on the table".

@Dana:
As I posted earlier, the motor I have does have an info plate, but unfortunately with little helpful information. (no hits on product #) It does however say 120v 60Hz so it is clearly an AC motor. As it is from a breadmaker I will guess it has 2 speeds with different voltage ( prob. mixing and dough kneading as Edward suggested) Ill go ahead an hook it up to a 12v supply as you suggested to test. I'll report back.

@Brady:
As for safety, I am a contractor by training, not an engineer, so mains power is something I am both comfortable with and respectful of. My electronic geek friends get really annoyed by me as I still tend to "lock-out/tag-out" even for LV situations. Trust me, I am well away when power is applied (5' away with a covered switch wired w/ romex into a handy box screwed to my work table, motor housing held in a ramussen clamp). I might fry something, but no threat to life and limb.

Also these motors are damn near free. ( I paid all of $1.75 for the motor in question) A good learning situation for me, and if I get it to work? bonus.

@Mark:
one of the other scores was a george foreman JR rotisserie. I pulled the motor/gearbox... and wow. 120v, 2 lead, AC with a 12mm "D" shaft. Incredibly quiet, approx. 3RPM, and I cannot stall it with my fingers. No idea how it compares in torque to the aftermarket rotisserie motors, but it seems perfect for my purposes. The price was right ;-) and I am keeping an eye out for similar items on craigslist, freecycle, etc...

Side note: I also pulled apart a paper shredder and electric can opener from a yard sale. Nice torque and easy wiring, but damn... the noise. Give em a pass for kinetic sculpture.

Anyway,
Thanks for all the feedback.

This is a great forum.

Chris

[Bob Eustace]

Heres a bunch of stuff along similar lines and all Botable!


http://www.youtube.com/watch?v=dehXi...e_gdata_player

[myxpykalix]

Bob,
I've seen that before and that is so amazing

[steve_g]

http://www.mpja.com/1-RPM-120VAC-Timer-Motor/productinfo/17843+MA/

Is this cheap enough?

Steve