Printing A Lathe - 3-Jaw Chuck Assembled

First, I can't believe it's been about a month since my last post.  Work and life sure can get in the way of trying to take over the world . . .

Although I haven't worked on the assembly of the full lathe, I did manage to assemble the 3-jaw chuck:

3-Jaw Chuck from Sublime on GitHub

Here is an image of the parts that went into the assembly EXCEPT for 3 springs, 3 washers, and 3 pins (shown below):

Most of the 3-Jaw Chuck Components and Hardware

The 3 pins are the items highlighted in red below in this exploded view of the chuck from SketchUp:

3-Jaw Chuck Exploded View with Pins Highlighted

The assembled 3-jaw chuck is working OK, but the three pins that press against the back of the face of the chuck to lock the jaws in place are not holding well.  The instructions call for these three pins to be cut to length from smooth rod.  Since I had to cut the rod with a band saw (I obviously don't have a lathe or I would have used that), I was concerned that I would not get the three pieces to be the same length.  I knew I could print them to a very exact height, so that's what I did:

Printed Pins for 3-Jaw Chuck

At first, these seemed to be working fine, but I think that after some loads and stress have been applied the three small cylinders are binding in the holes and not imparting sufficient load against the back of the jaw face.  I think I need to go back and replace these with smooth rod.

I had to drill out a few of the holes based on the hardware I ended up using, and what drill size you need and how much of this is required will vary from one person to the next depending on the behavior of your printer and your choice of hardware.

Drilling Holes to Size

I also used a drill bit to clean up some strings and stray traces of plastic where the holes are counterbored on one side of the piece shown below.  When the piece prints these counterbores require basically printing a cone, and it came out messy for a few layers inside the hole.  Not a concern for the overall function of the chuck, however.

Cleaning out Counterbores

If you do not have access to a drill press or just want to make the hole sizes exact, I suggest printing out a small test part for a fit check and then updating the models as needed before slicing and printing the full part.  The nut traps in the jaw pieces were too large for what I needed, so I did something similar there and reprinted the jaws.  No sweat!

On to the rest of the assembly . . .

D