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Z axis couplings

Pretengineer

Z axis couplings
March 03, 2013 12:23PM

Registered: 11 years ago
Posts: 6

Hi all,

I've just started building a Prusa i2 but I'm a little stuck on the z-axis couplings. The printed pieces that screw together are just too loose on the motor shaft. How do I secure them? Do I line them with some sort of tubing, or should I source some metal couplings?

Thanks,
Pretengineer

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Spk64

Re: Z axis couplings
March 03, 2013 12:35PM

Registered: 11 years ago
Posts: 79

Yes, need to add small piece of tubing.

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nophead

Re: Z axis couplings
March 03, 2013 01:32PM

Admin
Registered: 17 years ago
Posts: 7,879

See [hydraraptor.blogspot.co.uk]

[www.hydraraptor.blogspot.com]

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Pretengineer

Re: Z axis couplings
March 03, 2013 03:13PM

Registered: 11 years ago
Posts: 6

Thanks for the responses.

Is there a particular type of tubing to get? I asked a in a plumbing shop about the vinyl tubing mentioned in the parts list but they had no idea what I was talking about.

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KDog

Re: Z axis couplings
March 03, 2013 05:41PM

Registered: 11 years ago
Posts: 98

The clear tubing you can get at ACE Hardware by the foot works. Can't remember if they have the proper diameters available though. My kit came with a few inches of it so I didn't have to buy any separately.

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nophead

Re: Z axis couplings
March 03, 2013 06:58PM

Admin
Registered: 17 years ago
Posts: 7,879

I use aquarium tubing, ID 4 OD 6mm.

[www.hydraraptor.blogspot.com]

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David2

Re: Z axis couplings
March 04, 2013 04:51AM

You can use rubber bands, just try and wrap them as regularly as possible. Lumps will tend to put the rods out of alignment.

Plastic tubing is better, but rubber bands might do in the meantime

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jbernardis

Re: Z axis couplings
March 04, 2013 10:12AM

Registered: 11 years ago
Posts: 1,320

I used 2 or 3 layers of heat shrink tubing. It's what I had on hand.

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xclusive585

Re: Z axis couplings
March 04, 2013 11:24AM

Registered: 11 years ago
Posts: 374

nophead Wrote:
-------------------------------------------------------
> I use aquarium tubing, ID 4 OD 6mm.

+1. Go to a pet shop if you can't find it elsewhere.

(also, what kind of hardware shop doesn't know what vinyl tubing is!? They should have it, though in sizes too big for what we need.)

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DRepBRo

Re: Z axis couplings
March 04, 2013 07:10PM

Registered: 11 years ago
Posts: 10

I don't intend to hijack the thread, but I have a question about z-couplings: I have m5 z threaded rods and m5-to-m8 couplings. So I had to make m5 fit into m8; I screwed a pair of nyloc nuts and machined them to make them fit into the m8 coupling hole; it's not precise and my z rods wobble. Is there a better solution ? How can I fit that together well ?

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Pretengineer

Re: Z axis couplings
March 05, 2013 09:55AM

Registered: 11 years ago
Posts: 6

Aquarium air tubing is perfect, my local pet shop didn't even bother to charge me for so little.

@xclusive585: I don't think vinyl is used much as a term in Ireland, I also asked for pvc under the assumption that it was the same thing but no joy.

Thanks for the advice.