Can we help Ito (Stepper screw coupling issues)

[ynneb]

Today I recieved this PM.

Desperated newbe -------------------------------------------------------------------------------- Hello Benny: Well, i don´t know more what to do.... I started 3 CNCs, but always stucked by same thing: how to fix screw and stepper together... something is not centered... ALWAYS, in all my 16 motors! I´m trying to make it with NYLON, i made a hole with 6mm full (crossing the nylon) then i remake the hole with 9.5 or 9mm to put the 10mm screw using a homemade tool to make the screw line into the nylon (maybe could br on this time i´m doing wrong) Please help me, i bet all my extra money on the projects and now i have 3 machines and one command box (controlers etc...) but no CNC working... Sorry about my english, i´m from Brazil. Please help, i have not who to ask heare and no much more money to use on it... It became an obsecion, i worked 3 days full time (16 hours a day) trying to solve, making other machine, trying to solve, etc etc... all the time i stoped by the same problem: fix motor and screw. thanks anyway ! Ito.

I have suggested that he use two pulleys and a timing belt, or the hose coupling method. Does anyone else have some further suggestions?

Thanks

[ynneb]

Ito, I just found this in the photo gallery.

EDIT: all of a sudden it has been removed from the phot gallery. I wonder why?

[Ito-Brazil]

Could work:

If i make a homemade "lovejoy" ? i will use 20mm diam NYLON and some floppy disk parts.

see the pics.

What do you think?

Ito.

[Ito-Brazil]

Opps, one more picture...

[pminmo]

Ito,
Try taking a short piece piece of rubber hose the size of the motor shaft or the scre shaft. Automotive gas or vacuum line will work. The on the other side make a nylon piece the size of the other shaft. Use automotive hose clamps to secure.

Phil

[chuckknigh]

What you just drew is a homemade U-Joint, like the one in your socket wrench set. It'll probably work, but you might want to mock it up and see how much flex is present in it.

I think the hose coupling is a much better, and definitely simpler method for shafts of even remotely similar size.

-- Chuck Knight

[vladdy]

The rubber hose idea may sound crude, but in practice it works rather well, especially for a lighter hobby use table..
I did this one as a 'temporary' joint, and haven't found any reason to upgrade it yet..
the red rubber hose is from an auto air conditioning recycling unit, just under 1/4" , and is fairly well reinforced with virtually no twist, easy to cut, and the clamps are single use crimp clamps, again designed for air conditioning ewuipment, and just crimp tight with a pair of end cutters..
the stepper ouput shaft is 1/4" and the all thread rod is 1/4x20tpi, at least the rod is one step above 'cheap' grade...

sorry about the poor photo..

[Ito-Brazil]

Is that the correct type? It is used on air pressured...

Thanks a lot!
The entusiasm came with full power!

[JFettig]

I would suggest turning the ends to a diameter such as 1/4" and getting some real couplers from mcmaster, I use the helical beam couplers for my cnc kits, I got a couple spider couplers, those have a small amount of play but will work just fine unless your using absolutely zero backlash screws.

Jon

[Ito-Brazil]

Well, i wish i have money to get real stuffs to my machine...

As you know, heare in 3rd world thing are so much more expensive. Multiply by 3 or 4 the costs.

I bought today the rubber hose. I worked 4 hours on the new coupling system. It seems to be OK !
Tomorrow i will make a test, but moving by the fingers i can see the rubber hose work, really amazing. I should made this at first time...

The mounting stoped as the pictures show.

Thanks guys, you are good guys !!!!!

[pminmo]

Way to go ITO !

Phil

[ynneb]

I an happy for you mate, you have made a great effort of your machine
Thanks for posting the pictures