Are there washers or couplers available for motors with flat shafts?

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Discussion Overview

The discussion revolves around the challenges of connecting a small gearhead motor with a flat section on its shaft to other components. Participants explore potential solutions, including couplers and alternative attachment methods, while sharing their experiences and suggestions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant describes the motor shaft as common, indicating that the flat section is intended for a set-screw to secure a coupling.
  • Another participant notes that many couplings may be more expensive than the motor itself and expresses difficulty finding suitable options for a ~2mm shaft.
  • Several participants discuss the necessity of a D-shaped hole for couplings, with one suggesting that drilling a flat screw through the axle to the shaft is a viable solution.
  • There is a mention of using cotter pins in conjunction with flat shafts, referencing a practice from bicycle pedal cranks.

Areas of Agreement / Disagreement

Participants generally agree on the function of the flat section on the shaft and the use of set-screws, but there are differing opinions on the necessity and practicality of creating D-shaped holes for couplings. The discussion remains unresolved regarding the best attachment methods and the availability of suitable couplers.

Contextual Notes

Some participants express uncertainty about the availability of couplers that fit the specific shaft shape, and there are mentions of varying experiences with attachment methods, indicating a lack of consensus on the optimal approach.

Who May Find This Useful

This discussion may be useful for hobbyists or students working on projects involving small motors, particularly those facing similar challenges with shaft connections and coupler selection.

rafehi
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Hi all,

I bought a small gearhead motor for a uni project, however the shaft is a strange shape. Round for the most part with a flat section. Not sure how I'd connect it to something? I could use glue I guess but would prefer a cleaner solution. Is there washers/couplers for these type of shafts that are easily available? Been searching online for a good hour with no luck.
 
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rafehi said:
Hi all,

I bought a small gearhead motor for a uni project, however the shaft is a strange shape. Round for the most part with a flat section. Not sure how I'd connect it to something? I could use glue I guess but would prefer a cleaner solution. Is there washers/couplers for these type of shafts that are easily available? Been searching online for a good hour with no luck.

That is a very common shaft for a motor. The flat spot is to be used with a set-screw to hold the coupling in place whicle in motion.

You can find a coupling that will work at http://www1.mscdirect.com/CGI/N2DRVSH?SISHNO=14263762&SISRCH=1&SIS0NO=1490332&SIT4NO=92383665".
 
Last edited by a moderator:
Mech_Engineer said:
That is a very common shaft for a motor. The flat spot is to be used with a set-screw to hold the coupling in place whicle in motion.

You can find a coupling that will work at http://www1.mscdirect.com/CGI/N2DRVSH?SISHNO=14263762&SISRCH=1&SIS0NO=1490332&SIT4NO=92383665".

Most of those components are more expensive than the motor...just to clarify, the motor's shaft is only ~2mm. Also, I didn't see any thing there that wasn't fully round.

[PLAIN]http://www.jaycar.com.au/products_uploaded/productLarge_7971.jpg
 
Last edited by a moderator:
Let me ask you this- what are you trying to attach to the motor's shaft? Are you using a coupling? The hole the shaft goes in will not necessarily be D-shaped; as I said the flat spot is for a set-screw in whatever part you're attaching to the motor's shaft.

Good place to look for motor couplings from several companies: http://www.globalspec.com/SpecSearch/Suppliers/Motion_Controls/Power_Transmission_Mechanical/Flexible_Couplings
 
Mech_Engineer said:
Let me ask you this- what are you trying to attach to the motor's shaft? Are you using a coupling? The hole the shaft goes in will not necessarily be D-shaped; as I said the flat spot is for a set-screw in whatever part you're attaching to the motor's shaft.

Good place to look for motor couplings from several companies: http://www.globalspec.com/SpecSearch/Suppliers/Motion_Controls/Power_Transmission_Mechanical/Flexible_Couplings
Trying to attach it to a wooden axle. While I managed to get a D-ish shaped hole, the shaft grinded it round when the load got to heavy. Decided to just drill a flat screw through the axle onto the flat end of the shaft to keep it in place and it seems to be working well enough.
 
rafehi said:
Trying to attach it to a wooden axle. While I managed to get a D-ish shaped hole, the shaft grinded it round when the load got to heavy. Decided to just drill a flat screw through the axle onto the flat end of the shaft to keep it in place and it seems to be working well enough.

That's working because that's how it's supposed to be used. Making a D-shaped hole is expensive and unnecessary.
 
Mech_Engineer said:
That's working because that's how it's supposed to be used. Making a D-shaped hole is expensive and unnecessary.

Now I get what you were trying to say! So those small holes on the side of the couplers are for set (flat) screws?

Thanks for the help.
 
rafehi said:
Now I get what you were trying to say! So those small holes on the side of the couplers are for set (flat) screws?

Thanks for the help.

Excactly!
 
Flats on shafts can also be used in conjunction with 'Cotter Pins' like we used to have on all bicycle pedal cranks.
 

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