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ropesfish
08-24-2009, 02:06 PM
Hi folks.
I need to ask the community for a bit of help in locating something. I have spent many hours looking to no avail...so HELP!!! <please>
I am looking for a source for DC motors with a LONG shaft: the shaft must be 1.5+ inches in length and .125"-.250" in diameter with a round cross-section (no flats, keyways or any other non-round features). Stainless steel would be nice but not absolutely needed.
and these general specs:
12-24V
brushed permanent magnet
OD: 1.25-2.0 inches
OAL: 1.75 - 4 inches
RPM 2K -5K
Amp draw: <5A
Cost: under 30 USD.a
Surplus motors will work if and only if there is a huge supply of them. I hope to need several hundred over time, but right now I just need 6 or so for prototyping. I've lookedinto some overseas suppliers but their minimum order is a bit too much for the present.
Thanks in advance for any assistance.
Bill Black
Roseland, FL
Blue Ocean Eng.

CogswellCogs
08-24-2009, 03:17 PM
This one doesn't meet all your requirements. It's a little fatter and the shaft is a little thicker. Not a bad fit, though.
http://www.surpluscenter.com/item.asp?UID=2009082415041485&item=10-2221&catname=electric

I love Surplus Center. It's the official R/C Tank Combat superstore.

jes1510
08-24-2009, 09:54 PM
If you can dedicate to a few hundred then sure one of the suppliers can give you a few samples.

ropesfish
08-25-2009, 11:46 AM
This one doesn't meet all your requirements. It's a little fatter and the shaft is a little thicker. Not a bad fit, though.
http://www.surpluscenter.com/item.asp?UID=2009082415041485&item=10-2221&catname=electric

I love Surplus Center. It's the official R/C Tank Combat superstore.
>>>>>>>>>>>>>>.
Thanks, but that one won't do it.
The application is for a small underwater thruster (think trolling motor for Lilliputians). The motor has to fit inside a PVC housing and I need to keep the diameter as small as possible-maximum of 2 inch ID and the weight is also a concern.
The issue with buying surplus is this: once the drawings are done, the prototypes are made and tested and the design finalized, if the source for the motor used in the original design dries up you get to start all over again. While Surplus Center has 812 of them today, they could have 17 tomorrow.
I, too, like Surplus Center. Great stuff, but not for production. Hell...I may not sell more than 17 of these things, but I have to plan to sell hundreds..maybe thousands!
A chicken in every pot and a chicken sized trolling motor to stir the pot with!!!!
Ahhh...the stuff entrepreneurial dreams are made of.
:veryhappy:

ropesfish
08-25-2009, 11:52 AM
If you can dedicate to a few hundred then sure one of the suppliers can give you a few samples.
====================
Thanks for the reply!
I'd love to buy a few hundred, but my "college student budget" has more control than my "small business owner spending". I'd hate to be some guy on E-Bay selling 319 DC motors one at a time.

lnxfergy
08-25-2009, 12:28 PM
====================
Thanks for the reply!
I'd love to buy a few hundred, but my "college student budget" has more control than my "small business owner spending". I'd hate to be some guy on E-Bay selling 319 DC motors one at a time.


Typically, if the request is furnished by a corporate R&D, getting a few samples to evaluate, or design around, a component is not difficult (and usually free).

-Fergs

ropesfish
12-13-2009, 03:38 PM
Just a note to reveal my amazingly cheap and fully functional solution. Sorry it's been so long coming, but for some reason the last year of college seems to be the hardest... :)
Solution: Superglue.
The shaft needed for this project is .250 inches in diameter.
The motor shaft on a Mabuchi 555 is +.125 inches.
Chuck the larger shaft in a lathe and drill a slightly oversize hole in the center of said shaft. Depth needs to be less than the length of the motor shaft by some amount. put a big drop of Superglue in the drilled hole and carefully slide the shaft down over the motor shaft. You want a fillet of glue around the motor shaft, but be careful not to drill too deep. You will end up glueing the new shaft to the motor casing. That is a bad thing.
I made a fixture to hold the whole thing straight while it dried.
Results- no failures to date, but I am driving a propeller, not a wheel. In testing I could induce no failures by making it run off center, trying to break the shaft loose by topping the running motor with Vise Grips, etc. In a cold environment one might have to use a different adhesive. Watercraft, whether surface or sub-surface, seldom encounter truly cold temps...an ice borer might see some issues though.
Locktite Stud and Bearing Mount may be stronger, but Superglue works for this application.
Thanks for the replies and suggestions.