Z Axis wrong amount of travel when switching directions

If I step in one direction only, let’s say going down, the Z is pretty close to accurately traveling the specified distance. I can use 102 and correct that I’m sure with some patience, but the real problem is when I switch directions. If I’m going down for example .01 in, then try to go up .01 in, it only goes .0075. If I go up again .01 in, it goes the right distance (or close or enough for now). So only when switching directions does it travel three fourths the distance it’s supposed to. I have tightened and loosened and tightened again the Z axis belt with no luck. Any help would be greatly appreciated because I have no idea how to fix this or if it’s possible

What you’re describing is called backlash. Basically when you change directions, your gear/pulley on the motor moves a bit before the teeth re-engage with the belt. Think about if you back pedal on a bicycle and then pedal forward…there’s that moment where the chain is slack even though you’re applying force. (Sorry if my analogy is bad…it makes sense in my head)

Or is it traveling .0025" less? If you go 2" one direction does it only go back 1.5"?

Check your V-wheels. Too tight, and it will make the problem worse.

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That sounds right. When I go .1 in it goes about 90% of that when switching directions. Once going in the opposite direction it’s pretty close to spot on. I only have a 1 inch dial indicator so I’m not how much for sure but my guess is that it would go 1.99 of 2 inches. I just did a cut with stock 19mm deep and what was left over was paper thin enough that painters tape stuck to the bottom ripped part of the left over stock. That was probably the amount over top of the stock I set the Z zero too. It’s probably close enough but I can mess with the V wheels to make sure they’re not too tight anyway

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