Removing a z axis spring

CNC Machines Shapeoko
1

Anyone have to remove a spring when running a makita router?

2

If you did that the z will fall down on the work if you lose power.

3

I’m meant to say one of the springs.

4

The community recommends that you not remove just one spring. Removing just one side makes the forces needed to move the Z axis up and down uneven. If you want to try changing the springs, go to two softer springs of the same ratings.

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5

Removing one spring seems to be a useful test, and doesn’t seem to hinder operation that much — the linear rail system should hold things in alignment.

It’s strange that this continues to be a problem — I suspect that it’s usually belt tension — that said there were some pretty convincing tests done on the other forum. The springs are a commodity part — I wonder what the variability is, or if occasionally the wrong spring gets slipped into the stock somehow.

Contact support@carbide3d.com if you continue to have difficulties.

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6

I did. I was getting that “thump” and recoil at the bottom of the z axis. Took it out and it is working well now. I asked on another forum for a longer replacement spring suggestion but have not heard anything.

Tony

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7

I’m still skipping steps on Z and have adjusted and readjusted belt tension to no avail. Couple things I noticed that were my fault though:

  1. Stiff dust boot bristles sometimes will foul on deep pocket cuts, solution is to pause cut and remove brush after the cut deepens.

  2. Cold belts. I haven’t proven this one yet, but I had a few sub freezing days and noticed I lost Z frequently. The belts are rated just below freezing, but I suspect I was right at the threshold of where they stop working well.

I haven’t looked for a lighter spring, which I suspect would help especially when making deeper cuts. I did notice on the Z carriage though that the holes for the spring studs are not the same distance from top to bottom, wonder if I could flip the carriage over and get a little less spring tension…this may cause springs to become bound at the top of Z travel though, have not tried it yet.

I see the springs as a necessary evil, if they aren’t there the router will drop unpowered, but while they are there if I make an emergency machine stop by cutting power (EStop pins not on latest controllers) then the router springs up and potentially lets loose work go flying (shop teacher always told me if work comes loose on the drill press keep that handle down till after you cut power to the motor or you’ll be sorry!). I’m curious to see what others come up with.

Thanks,

Dan

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8

Try taking one spring off and see if it skips. That’s what I did. You can always put it back on.

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9

I will probably try this first. Also just measured the Z carriage and it is in fact NOT symmetrical top to bottom, so it appears as though it could be flipped over leaving less tension on the springs. Also looks like there MAY be correct mounting holes already in it to mount the router inverted. Has anyone tried this?

Thanks,

Dan

10

Mounting the spindle carriage plate upside down has been done a couple of times by folks accidentally — only notable problem is it makes the Z-axis run backwards.

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11

Then you would need to reverse the wiring to the motor.

12

Or you can change the GRBL config. $23=6
I realize this is an OLD thread, but I wanted to put this comment in case someone else needs this info.
I bought a used machine and the Z axis homed backwards (Z-plate was/is upside down). I just changed the GRBL config $23=1 to $23=6 to fix the issue. Actually, I just realized the plate is upside down, when I started looking for CAD files to mount a custom dust boot. I wondered why it homed backwards. :rofl:

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13

@themillertree You probably don’t want to change the homing direction ($23). You want to invert the axis direction which will involve a change to $3.
Your Z still “thinks” it’s moving down when it homes upward, and you set it to find home at the bottom of your Z.

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14

It may have been $3 that I changed. I’ll have to look tomorrow when I can get to the machine. I just know that I changed a setting instead of reversing the motor. Thanks for pointing that out.