TAZ4 bed not flat?

Hi folks
I’m slowly fixing up a TAZ4, having finally got it all operational with a new hot end I decided to start looking at calibration.

Im noticing that the bed is higher in the middle than it is at the 4 corners. I’ve tried adjusting all the corners but that only changed the tilt, doesn’t change the fact that the Z calibration is bang on in the middle but terrible as it gets closer to the corners.

Any pointers?

The toolhead actually twists the X smooth rods when it is in the center, causing the nozzle to be closer to the bed. The Taz 6 corrected this with larger smooth rods.

Just get the corners to an acceptable level of squish and live with extra squish in the middle. You can arrive at a happy middle ground that works.

Swapping the toolhead for a Titan or Titan Aero unit reduces the problem by reducing toolhead weight.

I’ve already got an aerostruder on it. Are the TAZ6 rods a direct drop in or is there more to it than that?

With an Aerostruder in place, you should be good to go. That is if everything else is in good shape/factory specs. Does it have a stock heat bed and glass?

You would need new X end parts to accommodate the larger diameter smooth rods from Taz 6. I am sure it could be done but if you are going that far, just install piercet’s openbuilds X and Y and live a happy life. That is the best mod around for the earlier Taz models.

I had similar issues with my Kittaz. I printed the Taz 6 parts and bought new 12mm rods and bearings to upgrade. The only addition you need is a replacement way to zero the z axis. I used a inductive sensor in a custom printed bracket on the x carriage.