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I'm filing/sanding my end effector carriage. As far as side-to-side play, I can barely get a .002" feeler gauge in between the plastic and aluminum before I put the screw in that holds the halves together. Without the screw, it passes the "flick" test. With the screw, it's slightly (I mean, barely just barely) draggy. The feeler gauge doesn't fit. Is this acceptable? I expect the parts to 'wear in' slightly over time...

On a side note, aren't these areas supposed to be pre-machined on newer kits? The perfectionism is fun and all, but I'd rather be printing than sanding, ya know?

-Doc

OK, so I got a little crazy with the cheeze-wiz doing the fitting for the U-joints. Here' what I ended up doing to get silky smooth, slop-free movement at the end effector:

For the plastic, use normal procedure of file/scrape with scalpel/sand with 400 and then 600 grit sanding block to match dimension of aluminum part. This puts you at 0.000 clearance, which binds.

Here's the interesting part - I used toothpaste as a lapping compound to polish the aluminum face where it touches the plastic. I don't know what the SMCNC guys are using for tooling, feed rates, and spindle speeds but those faces are (were) pretty rough. There was also a noticeable low spot around the through-hole for the axle. I put two aluminum parts on an axle, put the paste between them and spun one with the air compressor while holding the other one. Rinse, flip the parts to the other face, repeat. They now have a beautiful, smooth circular finish that glides over the plastic with NO slop. I'm kinda proud, even though no one will ever see it.

Makes me wonder why I didn't just get the magnetic arms to begin with, but it's done now.

This U joint business has kicked my butt for the night. Sheesh.

-Doc

I'm simply overwhelmed by the response! 666 views though...hmmm must change that.

doctorgonzo wrote:I'm simply overwhelmed by the response! 666 views though...hmmm must change that.

Here's a message just for you so that you can be extremely overwhelmed.