Lead Screws?

I've been considering upgrading my standard zinc 5mm threaded rods for lead screws on my prusa i3. I've made quite a few upgrade over teh past few months and I feel my z-axis is holding me back. I assume it is merely printing new a new x axis, adding new couplers and changing steps per mm Does anyone have any experience with moving to lead screw?. Where to get one of necessary for a good price and what improvements/drawbacks should one expect.

Regards,
Kevin

Leadscrews are awesome, especially compared to threaded rod.

Threaded rod is imprecise, not very straight, and literally designed to bind under force. These are not design flaws, they are design: threaded rod is supposed to be used to fix things together, not as a linear actuator.

Leadscrews are the opposite. Like a good toaster, they simply take themselves out of the equation, because they work so well that you never have to worry about them.

As for where to get one, just search eBay for "t8 leadscrew." Many come with couplers and brass nuts. It should run you about $15 USD.

Good luck!

Any source for single-start lead screws? Everything on ebay is 8mm lead (4-starts).

4 starts is fine. Why would you want single start?

I've done tr8 leadscrews on an i3 and they are a big improvement. The 8mm lead does mean far lower z steps per mm, whether this really reduces effective printing resolution I don't know. It's more than made up for by the improved precision.

I have seen 2mm lead being offered which might offer higher resolution. The alignment of the mountings has to be very precise. Mine weren't that precise until my pla top bearing holders softened in my enclosure and aligned themselves. Runs super smooth now. I'm using flex couplers at motor end and bearings at the top.

Next project is to fit a pillow bearing at the base of one screw, ditch one motor and couple the two screws at the top with pulleys and a belt. For this I'll need a closed belt custom made to size with a little slack and a tensioner. I don't know if one motor will drive it but I'm hopeful.

Thinking of buying a pair of (Chinese £50 each) ballscrews for another printer, see how they compare. More just curiosity really the only advantage is longevity and low torque required to drive it, which I probably don't need as the carriage I'm planning to lift is no heavier than an i3 x carriage with a fairly loaded print head.

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The alignment of the mountings has to be very precise.

Yes, I struggled (and swore) for quite a while with that.

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I don't know if one motor will drive it but I'm hopeful.

One motor is fine, that's how mine is set up.