Shapeoko 3 Z-axis stuck problem

Assembly questions and answers for the Shapeoko 3 CNC Mill
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chillaxe
Posts: 3
Joined: Fri Dec 23, 2016 3:26 am

Shapeoko 3 Z-axis stuck problem

Post by chillaxe » Fri Dec 23, 2016 6:16 am

I finished assembling the machine but found that one of the screws was touching another. This is preventing the z axis from travelling all the way from top to bottom. I marked the screws as A and B in the images below and also included a video to show what I mean.

I've been over the instructions over and over and every diagram in the steps look exactly like what I have assembled. The nuts and screws are in the correct direction. The only thing I can think of right now is filing the crap out of the side of each screw so that they clear each other but allow me to unscrew them if necessary.

Note that as I push and pull the carriage and all the plates, there is no "play". Everything seems to be tight enough so that it glides easily but doesn't wobble.

I'm at a loss. Any help will be greatly appreciated.

https://youtu.be/Q2Qpws0qNQQ

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WillAdams
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Location: Pennsylvania --- south of the Turnpike, East of US-15
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Re: Shapeoko 3 Z-axis stuck problem

Post by WillAdams » Fri Dec 23, 2016 9:46 am

Which machine do you have?

Which style Z-axis carriage plate?

There should be a washer between the Z-axis carriage plate and the Delrin V-wheel --- make sure that's there for each wheel --- if all are accounted for, my inclination (if the additional troubleshooting below falls through) would be to get some additional M5 washers, and if you have a caliper or micrometers, measure pairs of them until you can find four pairs which are the same thickness, then install them. Newer machines used precision spacers for this --- it might be worth disassembling things to re-use one each per V-wheel.

When you disassemble things, dismantle the V-wheels (use a bolt for the leverage to remove the first bearing for each) check the thickness of the inner race.

The other possibility is an out of spec bearing --- perhaps one is missing a face or somehow narrower than it ought to be?

Should you puzzle out that a part is needed, contact support@carbide3d.com and we'll set it straight. If you're not comfortable doing the above troubleshooting, let us know and we'll work something out.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

chillaxe
Posts: 3
Joined: Fri Dec 23, 2016 3:26 am

Re: Shapeoko 3 Z-axis stuck problem

Post by chillaxe » Fri Dec 23, 2016 5:54 pm

WillAdams, thanks for the prompt response! Here are my answers:
Which machine do you have?
I have Sparkfun's Deluxe version of the Shapeoko 3.
Which style Z-axis carriage plate?
I don't know. If you point me to a diagram or tell me how to tell them apart I'll get you more information.
There should be a washer between the Z-axis carriage plate and the Delrin V-wheel --- make sure that's there for each wheel --- if all are accounted for, my inclination (if the additional troubleshooting below falls through) would be to get some additional M5 washers, and if you have a caliper or micrometers, measure pairs of them until you can find four pairs which are the same thickness, then install them. Newer machines used precision spacers for this --- it might be worth disassembling things to re-use one each per V-wheel.
OK, all the washers are accounted for and I do have some extras. I also have calipers which I can use to measure these. One question though, supposing all the washers are on spec, would it be OK if I used two washers instead of one? That might solve the problem and it would be a lot faster than checking the inner race of each bearing. At least so that I can get up and running until I get some precision spacers.

I'm off to disassemble the plate. I'll post my findings later.

chillaxe
Posts: 3
Joined: Fri Dec 23, 2016 3:26 am

Re: Shapeoko 3 Z-axis stuck problem

Post by chillaxe » Fri Dec 23, 2016 8:53 pm

OK, thanks to your suggestions I found the answer. I'll post my findings just in case anyone else has this problem in the future.

First, using two washers is not an option as the bolt is not long enough.
Second, I decided to pull everything apart and make a spreadsheet of the measurements.

There are basically four components relevant to this problem (from the plate outwards): washer A (the one between the plate and the bearing), first bearing, washer B which is sandwiched against the two bearings, and the other bearing. If you measure this stack, you should get 0.4720". Those were my measurements for both group of components on the right side (if you look at the plate from where the spindle should be). The top left side was 0.001" under that and the bottom left side was 0.001" over that.
I re-arranged all the pieces (and swapped a couple washers with spare ones) to make sure the "stacks" were even, and as I put everything together... it worked!

On a sad note, since I was there, I decided to re-tighten the Y axis motors (the little black hex screw that secures the pulley to the shaft). Aaaannnd.. I broke the tip of the allen key and now one of my Y axis motors is jammed with the tip of my allen key. But screw it, I'm going to ignore it until it becomes a problem.

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