I Need Some Coupling Suggestions.

[ljoe1969]

HI

I NEED SOME SUGGESTIONS ON COUPLING MY ACME LEAD SCREW TO MY STEPPER MOTORS MY MOTORS HAVE .25 SHAFTS AND I TURNED MY LEAD SCREW DOWN TO MATCH.

I WOULD PREFER NOT TO USE A RIGID STEEL COUPLER SO ANY SUGGESTIONS WOULD BE APPRECIATED.

[Al_The_Man]

Depending on the load you may get away with stainless helical couplings, if you intend to use solid coupling the alignment has to be perfect, I have found some of the best no-backlash couplings to be made by Lovejoy, In particular I like their 'U' type which is constructed like to 2 coil springs tightly wound one inside the other wound in opposing directions, they are very compact, no backlash and can take alot of load.
Al

[kong]

There are a load of different types over here for you to browse. I quite like the look of the Oldham style couplings which have a "torque disc" in the centre of the coupling which will move with your alignment. The discs can be replaced should they ever wear out.

[ljoe1969]

DO YOU HAVE A LINK FOR THE LOVEJOY COUPLINGS?

[jgro]

I got mine from here: http://www.meci.com/
MECI Part Number: 170-1226

[Al_The_Man]

Lovejoy at www.lovejoy-inc.com
Al

[pack rat]

There are some on fle-bayhttp://search-desc.ebay.com/ws/search/SaleSearch?catref=C0&basicsearch=&ht=1&sospellrecommendation=1&sosortproperty=1&satitle=stepper+motor+coupling&sotextsearched=2&from=R10

[lurch]

Try www.mscdirect.com Part no. 35407006 1/4in bore $2.11 ea. Part no. 35407022 1/2in bore $2.11 ea. The pieces are interchangable so, I plan to use the 1/4in ends on my stepper motor shafts, and the 1/2 in ends on my drive rod acme 1/2-10 thread. These should do the job! I'll let you know when I get the chace to work on them after holidays.

[bobs bots]

Hi Joe
Depending on your accuracy requirements, you may be able to use something as simple as a short piece of 1/4" fuel hose (rubber type with fabric reinforcement) , this is best secured with those one piece clamps you get for free with every automotive fuel filter, as this provides uniform clamping around the circumference, (worm clamps will distort the tube a bit), (and you usually get two bits of suitable tube with the fuel filter).
The fabric in this hose is laid at 45degrees to provide high torsional stiffness, but still be soft in bending.
The inherent friction in leadscrews will cause an offset depending on the direction you are going (due to deflection in the rubber), but this can be accommodated with the backlash correction in most software.
If you are prepared to accept the loss of accuracy due to leadscrew backlash, then the additional error of the rubber deflection will be small in comparison.
Cheers, BobT.