Saturday, October 15, 2016

First Try at Milling

Welp, I had a few minutes to spend out in the shop, so I thought I'd finish the milling attachment.  I went through the old "L. C. Mason" article that was posted to Vintage Projects (  The original plans were for a 7" to 8" lathe, but my South Bend Junior is a 9".  The instructions do mention "scaling it up" for a 9" to 10" lathe, so I thought I'd take a whack at it :

Of course, with the 3MT spindle taper and a short lathe bed, I needed some end mill collets that would fit the taper inside, without using a collet chuck.  I found a set of 3MT collets that used a 3/8-16 threaded rod, so I ordered those and some end mills.  I ran to Home Depot and bought a two-foot chunk of threaded rod to match.  However, I needed a way to hold it on the other end (gear end of the spindle).  I had a chunk of 1" round stock sitting from the build for the milling attachment project.  I chucked that up in the 4-jaw chuck, drilled a tight hole through the center (for the threaded rod), and put a bevel (a 45 degree bevel) on one end, just long enough to self-center in the spindle through hole.  I turned it round, and then I cut it off flat.  It was PERFECT for holding those collets into that taper :

There is one issue, though - it likes to come loose.  I think I need to put a burr on that threaded rod to prevent the nut from releasing.

Next, I started to finish the milling attachment by milling the face of the table.  I got the two bottom surfaces complete before I ran into an issue :

The issue here is that it wouldn't go low enough to mill all of the surfaces.  Also, I had built the face all the way up, without realizing I'd never be able to mill that high.  The efforts were pretty pointless for that.  The scaling was basically done wrong.

If I were to do it over, I'd only scale the bottom surface (where the milling surface is stacked) - leave the top angle stuff alone.  Then, you simply lengthen the threaded feed screw (on the bottom side), and the ways you build (in the guide, parts F, G, H, and J).  I'd also do it myself, as the t-slots didn't line up right - but the neighborhood kids are now interested in making things (3D printers and metal work), so my job there is done.

Wednesday, October 5, 2016

Addictions Run Deep

Within a week of having my first "machine tool" up and running, I've learned quite a bit (my wife would probably want to see me sometime).

  • Facing
  • Center-drilling
  • Turning between centers
  •  How NOT to orient a tool for the best finish
  • The tool is also critical  (larger tools means stable cuts)
Unfortunately, I didm't have the 4-jaw ready to try learning the technique of parting off.  Instead, I used a hacksaw while the piece was turning.  Silly me.

Once I had experienced facing, I decided it was time to prepare the backplate for the second chuck (I started out with a 3-jaw scroll, and wanted a 4-jaw independent).  That was completed today - the chuck and back plate have been permanently joined.

While I was at it, I needed a better way to store my #2 armstrong tool holders.

I realized that a 3/4" PVC pipe coupling was about the right size, except for a small shoulder inside.  That lead me to salvage a stainless steel printer rod.  I grabbed one of my collets for this and an end-mill, and milled a flat end on the rod (3/8", so nothing I'd readily bore steel with), drilled a hole across it, and turned it into a simple boring bar.

I then chucked a PVC coupling into the old 3-jaw, bored out the shoulder inside the PVC couplings, drilled a cross hole, and screwed them to my wall.  They worked perfectly!

So, I now know I can easily make a good boring bar if I ever have to.  I have two chucks (self-centering/scroll 3-jaw [came with the lathe] and a 4-jaw independent), and I'm half way to having made a milling attachment table (not one of those key-way cutting "attachments", this would be a much more solid attachment).  Forgive the crudeness of the attachment, it was intended to be squared up with the collets and end mills, so I wasn't trying to be completely accurate in setting it up and laying it out.  I'll use side mills for the slots, and I still need to pick up some slot cutters, but at this point, it is somewhat useable.

The next things on my list