motor spindles

Most of the electric motors that I've come across have smooth spindles. This seems really strange - as I can't think of any decent
way to attach them to anything (a few do have the spindle flattened on one side - which helps... though I can't think of anything that would attach to it.)
As you will have guessed, I'm a 'newbie', and I'd appreciate any advice!
many thanks! Joel
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The smooth spindles are the most common type. A set screw in the coupler, gear, or whatever else you're mounting on the spindle is the most common method for attachment. The spindles with one or both sides flattened will provide a better connection for high-torque applications, but the couplers, gears, etc for these type of spindles are less common (and usually more expensive).
It's possible to file or grind flat two sides on the spindles but it's VERY hard to get the flat sides parallel and generally not worth the effort.
Regards, Bill

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
W.E.Cole wrote:

I'm not sure why you'd want two parallel flat sides, but it's a good idea to file or grind one flat so that when the set screw deforms the shaft there is clearance to allow the mounted item to slide off easily from the shaft when you want to remove it.
Mitch
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
It might be desireable to have two flat sides if the motor is being used as part of a drive system. The the spindle can be inserted into a slotted coupler or gear in a high torque drive system without fear of it slipping if the set screw doesn't hold.

to
is
when
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

"Great minds think alike..."
I haven`t come across anything which can be attached to these spindles either without slipping round!
----------------------------------------------------------------------- Ashley Clarke -------------------------------------------------------
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

If I never make anything, this stuff is just nice to fiddle with; If the spindle turns only one way, some wire wrapped around it won`t slip... until the spindle turns the other way.
----------------------------------------------------------------------- Ashley Clarke -------------------------------------------------------
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I think the round smooth shaft motor shafts are intended to be used with press on gears or pulleys. Plus these are typically lower torque or smaller motors too. Usually you can locate press on gears, sprockets or pulleys for these but they tend to cost more. Sprockets would probably be easier to attach as you can get sprockets with enough of a shoulder to drill and tap a few holes for set screws. Another trick is to "knurl" the shaft using a knurling tool, but this can be pretty tricky in some cases. You can also carefully file in a small flat on the shaft. Another way is to use a keyway cutter to cut in a narrow keyway on the shaft, and then cut a keyway in the gear, sprocket or pulley, but on small motors this may not be possible. Larger more powerful motors appear to always have a flat on one or two sides of the shaft, or even a threaded keyed shaft. Getting a set of broaches and a tall press for making "D" holes in a gear or pulley or sprocket is very expensive. www.didel.com has small tiny gears for small motors like pager motors. http://www.smallparts.com and http://www.sdp-si.com both have a rich selection of gears, sprockets and pulleys to use. Your local RC model hobby shop usually has a good selection of gears and stuff for RC cars and airplanes. Most of these work for the Mabuchi RS550 type of motors, but they have a lot to choose from. Surplus dealers and stores have gears, sprockets and pulleys that can be used too, but you may have trouble getting the ones you want or need. You sort of have to be lucky.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
thank you all for your help. I feel I know a little more about how to tackle this problem now! wishing you all the best, Joel
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
What shaft diameter and torque are we talking about here?
Shafts around 1mm with small torques can be attached to gears and such with adhesives. "Threadlocker" will work. So will press fits.
Small metal gears with close tolerances can be heated, slipped on the shaft, and allowed to cool. In some cases, boiling water is hot enough for this.
For more serious torques, you mill a keyway. For really serious torques, like an automotive driveshaft, you need a full spline.
                John Nagle
Joel wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.