Where to purchase Flexible Shaft Couplings

[AdamHeard]

Originally Posted by ferrari77

This is actually for another project I am working on in college
I have access to a machine shop to drill them out but our long term plan is having something easily available to the public that wouldnt require them to machine anything.

If the McMaster price is normal then we are just going to go with the extra long shipping from China and deal with it.

I will be going to Lonestar though, I look forward to seeing 57 there, Kevin

Thanks for your help guys

Mcmaster prices for such things are a little high, but closer enough to normal to know you're not getting a quality made in america coupler for $10.

The cheaper couplers are made with lower tolerances and worse materials, which will show up as a problem in high speed and/or high torque applications. This may be a nonissue for your application though. My hunch is you're linking an encoder to a CIM shaft, so the speed might be a tad high for a poor quality coupler.

[ferrari77]

I am actually hooking a Versaplanetary 10:1 with a CIM output to a 1/4 inch lead screw to move a sweeper across a Replicator 2 build plate to remove the parts.

The motor runs at about 1600rpm and the lower quality ones were rated to at least 3000 rpm

[Kevin Sevcik]

Is there any reason you're going with a flexible beam coupling, then? Unless you're counting on the coupling as support for one end of the leadscrew*, there's a number of other coupling options available to you. You could buy a mis-matched set of Lovejoy or Oldham couplings and have your 1/4 to 8mm adapter that way. For instance, you could buy an 8mm Oldham and a 1/4" Oldham from SDP-SI for $24 each and have two of your 8mm to 1/4" couplings. Alternatively, if you want to use your Versa as support for one end of the shaft, I'd recommend finding a rigid inch-metric coupling instead of a flexible one. Or even easier, get a 1/2" output shaft for your Versa, and find a 1/4" to 1/2" coupling.

*You should only do this under light loads and low speeds. Those beam couplings are intended to be used between a rigidly mounted motor and a rigidly mounted shaft that aren't perfectly aligned. They're designed to transmit torque, not bear axial loads. If your wiper catches on anything, you're liable to permanently rip your coupling apart.

[ferrari77]

I saw those but the reason i didnt go with those is because the McMaster flexible coupling is around $40 so i'm trying to find a lower price.
I am using a flexible beam coupling so that any mis alignment between the motor axle and the lead screw casued by mounting it slightly off.

Good idea on the 1/2 to 1/4 coupling
I didnt realize those would be easier to find than the 8mm to 1/4 coupling
I found one from Michigan that is only $13
http://www.cadcamcadcam.com/shaftcoupling-2-1.aspx

[Kevin Sevcik]

Originally Posted by ferrari77

I saw those but the reason i didnt go with those is because the McMaster flexible coupling is around $40 so i'm trying to find a lower price.
I am using a flexible beam coupling so that any mis alignment between the motor axle and the lead screw casued by mounting it slightly off.

Good idea on the 1/2 to 1/4 coupling
I didnt realize those would be easier to find than the 8mm to 1/4 coupling
I found one from Michigan that is only $13
http://www.cadcamcadcam.com/shaftcoupling-2-1.aspx

Yeah, but there's lots of misalignment coupling options. I'm curious why you picked the flexible beam option specifically over something like an Oldham or Lovejoy or something. Beam couplings are typically more expensive and less robust than Lovejoys, for instance. If you're using the beam coupling because it's like a flexible version of a rigid coupling, that's no necessarily the best idea for the reasons I outlined above.

[ferrari77]

Looking at those, they seem to fit our purpose as well
I dont think there is any reason we didnt use it other than the fact that we used to use a helical beam coupling and so we continued to use it because the project team is familiar with them'.

I'll keep those in mind though for future iterations.

[BBray_T1296]

I have seen people use surgical tubing stretched around the shaft to connect some shaft to an encoder in a very short length (or a long length with a wooden dowel inside) for a misaligned/basically free shaft coupler in a low (ish) load application. It would give you the benefit of allowing some slack in case the sweeper gets stuck but the motor keeps turning a few.

[Chowmaster4695]

Originally Posted by AdamHeard

Mcmaster prices for such things are a little high, but closer enough to normal to know you're not getting a quality made in america coupler for $10.

I agree with your statement that you will not find a quality coupler made in the US for cheap . This is why we always buy our couplers and other small goods in France where the quality is good but the price is not too high. Just make sure to insure your shipments. Our season has been negatively affected by the outbreak of piracy in the surrounding waters so we air ship when we can.I will look to see if we can get the couplers in a reasonable time.