Squaring Z-Axis

Assembly questions and answers for the Shapeoko 3 CNC Mill
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GurneyHalleck
Posts: 22
Joined: Tue Mar 12, 2019 1:24 am
Location: Chicago - Southwest Suburbs

Squaring Z-Axis

Post by GurneyHalleck » Sat Aug 17, 2019 5:18 pm

I’m in the midst of milling and assembling a Clayton Boyer clock. As I was spinning one of the larger gears on its shaft, I noticed a definite wobble when viewed from the side. A quick check with a drafting triangle showed that the z-axis was not perpendicular with the x-y plane by about 1 degree. If the z-axis could move 12 inches, the tool would be almost 1/4" off of position. The direction that the test rod tilted was parallel to the x-axis, so it appeared that the spindle mounting block was rotated slightly.
Before.jpg
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I thought I was going to need to loosen the belt and slide the z-axis assembly from the rails to be able to access the spindle mounting block screws. It turns out that while lowering the z-axis, just as the lower wheels are about to come off of the rails, the mounting screws are accessible through two holes on the x-axis plate, visible from the back side.
SpindleMountAccess.jpg
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I un-hooked the springs and rested the spindle mount on scrap wood at the appropriate height for access. I then clamped the hex wrench into a vise grip and cracked the screws loose. I snugged the screws up a bit so I could adjust the position of the spindle mounting block and not have it slip back. With the spindle over-hanging the table, I clamped a 12 inch long 3/16” brass rod (using my new 3/16” Colette) into the spindle. I tied a c-clamp to a long piece of string to make a plumb bob and looped the string over the spindle nut. I verified that the rod was at an angle to the string and that I could somewhat measure the error. I then put a thickness of cloth into the jaws of my channel-lock pliers, grabbed the spindle mounting block with it, and with trial-and-error, rotated the spindle mount until the rod was parallel to the string. Lastly, I tightened the mounting screws and ran another test hole. Success.
After.jpg
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Just purchased a Shapeoko 3. :)

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