3d Printing, Making, Taz

Building a 3d printer – Taz-5, Part 7: Thread and guide rails for the Z-axis

It’s been a couple of weeks since I posted an update on this – I needed to get out to the garage to do some work on this and it’s been kind of cold so I’ve been avoiding going out there. But today was starting to warm up a bit so I decided to get out and do something.

The Taz-5 has a very precise threaded rod – called a ball screw rod – to allow the printer mechanism to run up and down the Z-axis. These are pretty expensive and take a long time to arrive from China (I can’t find them available anywhere else in the world), so I decided to try this with a regular M8 threaded rod which is cheaper and immediately available locally. I was able to buy some of this from Screwfix for under £10.


I also needed to insert guide rails into the frame – I purchased some 10mm x 600mm steel rods from eBay for this.I fitted the rods into the frame of the printer so far, and used some electrical tape to mark where I needed to cut them.


I used a regular hacksaw to cut these to size, filed the sharp edges down, and placed them back into the frame.


I repeated this for both sides of the X/Z-axis frame, so I now have rails and threaded rod completed for one axis.

I decided to follow up on a few smaller things that needed to be done – one was to get a small “thumbscrew” to allow me to adjust when the Z-axis limit switch is triggered. The photos below show the thumbscrews I purchased from eBay, and where one of them fits into the frame so far.

Finally for this time, I needed to connect the stepper motor (which has a shaft of 5mm diameter) and the M8 rod (which is 8mm in diameter). Obviously there’s a difference in diameter, but fortunately there are custom connectors which are widely available, and are known as Flexible Shaft Couplers, or Beam Couplers. I purchased a couple of these, and inserted them into the frame as shown below.

These couplers can be very securely attached to the shafts of the stepper motor and the threaded rods using pre-fitted grub screws- however, I didn’t tighten the nuts in these couplers yet because I’ll need to remove the rods for the next step.

The photo below shows where I am in the project so far.


Next time, I’ll start creating the X-axis which holds the printer unit.