Z axis creep, had to remove a spring to get it to cut right


(Ivan Nix) #1

So I spent months trying to figure out why my machine was cutting along and every time it moved to another cut, the Z would creep up. My .75 cut would be a .69 cut by the end.

I research all the forums, make sure your belts are tight, make sure your pully set screws are in on the flat spot, level your table, skim your waste board. Been there done that. Then for some reason some one hinted at removing a spring from one side. Oh my gosh it was like heaven just opened up and it started cutting great.

So I have emailed Carbide and got a few answer but not on this issue about the spring. I wanted to bring it to every body attention to save you the pain I was having.

*Yes make sure your belts are tight,
*Yes make sure your pulley set screws are in with lock tight on the flat end of the motor. By the way I received mine with set screws falling out.
*Yes make sure your roller wheels are not spinning and giving good tension on the rails
*Yes have a good sharp bit, If you don’t and use an old one you may get some creep

So Question is:
I am using 1 spring at the moment, is the a problem using 1 spring?
Is there a solution from Carbite about this?

All I can think is the new spring coming with the Shapeoko are too strong and they need to get a lighter spring.

So I am opening the discussion up to the public. This about drove me made because of the Z creep. I was about to buy another CNC machine because this was driving me crazy.

Hopefully Carbide will see this and make comments.

Oh yea, I did a simple circle test, with 2 springs and 1 spring, let the picture speak for it self


(Jim Amos) #2

Ivan -

Interesting to say the least… the difference with 1 vs. 2 is quite dramatic. Even if you ran these samples on different locations of your bed which may introduce some Z depth variance, the disparity is still huge.

Also, are your numbers representative of the relative stock thickness at your N/S/E/W locations?


(Matt Freivald) #3

My springs are way too strong on my XXL unless there is an 3/4 inch spoilboard on top of the included wasteboard.


(Ivan Nix) #4

I use a 3/4 mdf board ontop of my existing board that came with it. I cut groves for hold down clamps. I was getting the creep no matter what I did.

Yea I think these springs are too heavy. like to hear what Carbide has to say about it. Maybe they can get us some other springs that don’t have that much tension.


(Jeff Hillyer) #5

I have also had the z axis creep on me on a brand new xxl. First job it creeped on three different runs at different locations. I removed 1 spring and my next project ran as it should.


(Henry Ellingsen) #6

It would be important to know which router is being used here. The Makita is about 1/4lb lighter than the DeWALT, so if these current springs are too strong this will be more problematic on the Makita installs I would think. I’m currently assembling the SO3 XL and already have my Makita ready to go when completed so I’m anxious to see how this issue plays out.


(Jeff Hillyer) #7

I have a Dewalt on my xxl.


(Ivan Nix) #8

I have a dewalt with a kent cnc dust boot. https://www.kentcnc.net/nc The kent cnc dust boot was recommended when I called Carbide to ask about the machine. I believe they use this at carbide.


(Ivan Nix) #9

Sorry haven’t updated this lately. So I contacted support and come to find out that, some units were shipped with the wrong springs. So Carbide was gracious enough to send me the correct springs. I compared them and the one I currently are the same length but there is a difference in the diameter of the wire.

So did it work you may ask. Well I put the new springs on that were sent and I got the same result, I still had the Z creep.

So I am back to just using 1 spring. I elected to use the 1 spring I originally got with the machine because it was a little bit heavier then what was suppose to be on it.

I am at a loss to why it keeps doing it.

I even ordered the repair kit, changed the wheels and the z axis belt, still same result.


(Richard Cournoyer) #10

And you sufficient tension on your V-Wheels?


(Ivan Nix) #11

Yeap have good tension on belt and the adjustable wheels are making good contact.

I know if I run 2 springs I loose Z and when i run 1 spring it’s really close to what I am cutting setting are.


(mark robinson) #12

What would happen if you tightened the Z v-wheels with even more tension?..worth a shot at this point id say.


(Richard Cournoyer) #13

Let me add, there is about 0.030" of play in the square nuts inside the Z rails, to you can bring them closer OR farther apart, and at that point (apart) I don’t think you can get enough tension on the adjustment nuts. Just an FYI

PS The Z motor provides about 20 pounds of UP and Downforce, so there is is no way in hell should it be losing Z. So sometihng is not right!


(mark robinson) #14

Good call on the Z rails @RichCournoyer ,I was trying to think what else it could be aswell.


(Bill Smith) #15

I’ve been cutting with only one spring for about a month now. I don’t even bother to put the spring back on anymore.

I have a DeWalt 611. I have a 3/4" MDF waste board on top of the original waste board. I’ve had to raise the height of the router within the bracket a bit to avoid “soft/hard limit” errors as as the gantry raises the initial 20mm to begin a job.

With both springs on the machine I would invariably hear the snap sound of the Z-Axis skipping a tread on the belt at least once sometimes more during a cut. Each snap means about a 2mm loss of depth on remaining paths.

My Z Belt is about as taut as I can get it. The two adjustable V Wheels are tight.

I’ve reduced the Plunge rate by 10 and didn’t see any difference.

I’m not sure I know exactly what is meant by “creep”. My only problem is with depth of cut.

I’ve just gotten used to the idea that this his how I have to work unless someone can give me a suggestion.

Guess I’ll drop a note to Support to see if I can get a new pair of springs.

Thanks for the post.


(Roger Newmon) #16

I had the DW 611 to begin with then I switched to the Makita. The Makita is a little lighter and quiet, but the lighter part caused my machine issues with the Z axis as well. That is when I decided to stretch the springs a bit. I used a screwdriver on each side of the springs and pulled then both at the same time across my chest as if I was working out but slowly. I did this a few times until I could just visibly see light through all of the coils. After re-installing the loosened springs all the issues went away. It doesn’t quite make it all the way to the top when the power goes off, but the stepper has more power to push down without the spring fighting it so it cuts great now.

This method may not be the best method, but it worked for me. What would be neat is if someone comes up with an air cylinder or something that will spring the motor up when the power turns off thus eliminating the springs all together?!?!


(Ivan Nix) #17

Roger great idea about the springs. I just hat messing with it and trying this and trying that. I thought about weight and wondered if the dewalt was heavier then the makita.

You know what would be cool if Carbide 3d created a screw driven Z axis. I think there is too many problems with springs and belts especially on the Z axis. My X and Y are great but Z is the zombie.

I am trying to cut out part consistently but ever time I mess with my machine it just make all my parts not fit.

Bill Smith, I would contact support and ask for new springs. They didn’t do much for me but it can’t hurt. I had my Z belt really tight. I backed the z tention off a little. I also changed out the wheels on the z travel plate. I think I had a dead spot on one of the wheels.

I am like you on the Z, I am thinking it is the best I am going to get with one spring. I might try pulling on the other set of springs and see what I get though.

Z screw driven axis My vote


(William Adams) #18

We used screws on the SO1 and 2. There are tradeoffs.

Belt advantages:

  • faster
  • more common parts, reduced cost, ease of assembly
  • simpler configuration
  • machine not likely to damage itself in a crash

Back in the SO1/2 days, upgrading from the M8 threaded rod to an Acme screw was a popular upgrade — https://www.shapeoko.com/wiki/index.php/ACME_Z-axis

I actually did a sketch and started on a B.O.M. for changing my SO3 over to an Acme screw: https://www.shapeoko.com/wiki/index.php/User:Willadams#Acme_screw — but never got any farther. It seemed straightforward enough if one were willing to mod one’s plates.

Hoping to assemble a test bed machine out of spare parts now that I’ve given away my SO1 and Ordbot — that’s one of the things I’m hoping to experiment with.


(Ivan Nix) #19

So I took my old springs and tweeked them a little bit and I was cutting a little better. Tweeked meaning stretched them out a little.

For contect, the original springs I got with my S3 was the wrong ones sent I found out. They were a lot stronger then the original springs. I tweeked those and it got alot better in the, when I add both of them to the z axis. When I took off 1 of the springs, man I was cutting really good, a .25 cut was cutting .253 or so. With the 2 springs I was cutting .24xx.

Now the right springs when Carbide3d sent me were a little light, I stretched them and I over stretched them, really easy to do. So those don’t even fit the machine any more.

So I am back to running 1 spring with a little a little stretch but the cut is tollerable and decent. When turning off the machine it does go to the waste board, which the springs is holding it up very well.

So the weight of the Dewalt I have is definitely a factor. I don’t want to get a makita but I might one day. Well it is working so better but I still don’t like having to tweek it.

So if you have the Z creep, try pulling on your springs, but do it in moderations and see what you get.


(Jerry Gray) #20

Same here. I do most of my work down low, so I just took one off, and haven’t looked back.