Easy way to tension the Z belt

[CastIrony]

While rebuilding my Z axis carriage, I decided to do a better job of tensioning the Z belt, since it was always much looser than the other belts on my machine. After a bunch of pulling, lifting, fastening, and unfastening, I had a really good idea.

Just loosen the Z motor bolts, and shove a wooden door shim in between the motors from both sides:

IMG_2595 2.jpg (166.89 KiB) Viewed 4275 times

Then tighten the Z motor bolts, and remove the shims. I had to use a hammer to get them out, but you might be able to just wiggle them free.

These shims are cheap and easy to find, I think my hardware store sells a pack of a dozen for $2.

[WillAdams]

Yeah, I had to use a small pry bar on mine, and I worried about bending the motor shaft.

Added to the wiki.

[twforeman]

This is how I tension mine too. Works a treet.

[LTEPM]

I use wedges to tighten my X axis as well, leave them in place, then tension the Z axis motor the same way.

[hatallica]

Major kudos, CastIrony! This saved me tons of grief on Friday. In the middle of running a few projects, the Z axis just gave up and barely skimmed the surface. Thankfully, I still had a few shims in my tool closet (my wife - God bless her soul - used most of them as paint stirrers).

Ten minutes later, I was back to making a pile of oak chips. Cheers!

[KAScnc]

Some reason my belt was already tight with the stepper in the lowest position. I had to loosen the two 15mm spacers to gain enough slack to get the belt over the top pulley. Once everything was routed correctly, I tightened those two spacers which tensioned the belt without having to raise the stepper.

[CastIrony]

Some reason my belt was already tight with the stepper in the lowest position. I had to loosen the two 15mm spacers to gain enough slack to get the belt over the top pulley. Once everything was routed correctly, I tightened those two spacers which tensioned the belt without having to raise the stepper.

Do you have the old or new style Z carriage plate? The old one was a little bit more adjustable, which might explain that.

[KAScnc]

Some reason my belt was already tight with the stepper in the lowest position. I had to loosen the two 15mm spacers to gain enough slack to get the belt over the top pulley. Once everything was routed correctly, I tightened those two spacers which tensioned the belt without having to raise the stepper.

Do you have the old or new style Z carriage plate? The old one was a little bit more adjustable, which might explain that.

Hmm, I'll assume it was the original style. It was the spark fun edition purchased Dec 2015. I just got the upgraded (front) Z-Plate few days ago.





What I don't have is that adjustment screw on the back plate that puts tension on the z-belt pictured here.

[WillAdams]

Pick up a stainless steel SHCS at your local hardware store.

[KAScnc]

Pick up a stainless steel SHCS at your local hardware store.

That would be sort of obvious if the plate had an adjustable slot for the bottom guide pulley and a threaded bung welded to the plate for that steel SHCS tension screw.

Maybe this is a Sparkfun thing?