NEMA coupling questions...

[adam_m]

What are the differences between - Lovejoy - Oldham - Helical - etc. couplers are any better than the other, any I should avoid?

Thanks,

Adam

[RicknBeachcrest]

Good question.

Also I see that the Lovejoy coupling comes in a couple different varieties.

[cheetahcnc]

The amount of backlash and misalignment compensation. Lovejoy type use various durometer rubber "spiders" between their hubs, and relieve axial and radial misalignment. Less backlash is achieved through the Oldham type with the tight tolerance plastic part which slides side to side to compensate for radial misalignment, not so much axial. The helical, whether bellows or spring type compensate both the best with no backlash, the shaft clamping being better than the set screw type.

Jim

[adam_m]

OK, thanks for the breakdown.

Then the Helical is the preferred connection type since it would have the least amount of backlash, if I read that correctly

Adam,

[Al_The_Man]

Lovejoy is a manufacturer, not a type, although prevalent usage has attributed spider couplings to them.
Personally If you are using helical, I would use stainless, the aluminum does not take stress over time.
I only use aluminum for encoder coupling.
Suppliers such as Misumi, stock all types with the spider type coming with many different filler material.
Their high torque servo disc couplers have zero backlash also.
Al.

[awerby]

Is how they connect to the shaft. I've had bad luck with set-screw connections on couplers - and much better luck with the clamping type. They cost a little more, but save a lot in pulled-out hair...

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

[adam_m]

Like CNCRouter parts as far as a clamping type?

CNCRouterParts

Adam,

[RicknBeachcrest]

Does any one have a source for Helical couplings (1/4" on one end and 3/8" on the other end)?

Thanks.

[Al_The_Man]

They can often be ordered that way, see if there is a Helical supplier in your area?
Standard Coupling Guide
Al.

[awerby]

Originally Posted by adam_m Like CNCRouter parts as far as a clamping type? CNCRouterParts Adam,

I agree about the stainless vs. aluminum helicals - I've broken a few aluminum ones, always at just the wrong time...

It's difficult to find them with different size bores at each end, especially when one is metric and the other one is Imperial. That's when you have to look more seriously at the Oldham type, which can be ordered as separate halves, or get boring...

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

[adam_m]

Originally Posted by Al_The_Man They can often be ordered that way, see if there is a Helical supplier in your area? Standard Coupling Guide Al.

Which application from Helical for home CNC's?

[Al_The_Man]

If you pick the required Torque range in the stainless models, and click further in it will allow further selection and give you minor and major bore dia, which can be ordered in Inch and mm combined bores and clamp screw types etc.
http://heli-cal.com/cm/Products/Flex...MC-Series.html
Al.