(Updated 04/21/2001)

Figure 1

Here is a picture of my "new" Clausing 8520 mill (ala 3/2001).

 Figure 2

  Here are more shots of the mill.  It had been used in an unheated garage, and most of the unprotected surfaces are rusty.  Luckily the rust is fine surface rust, and not much pitting is evidenced.

Figure 3                                                                                            Figure 4

    The only critical areas that have rust are the last inch or so of the Y-axis slide nearest the column, and the tubular part of the headstock assembly.  The headstock is designed to slide back and forth in the Y-axis.  At some point in the past, the head was locked about halfway out, and left in this position.  With the head position, the table will pass completely under the spindle, with about an inch of travel left on the Y-axis. Hence the rust there. Note that what appears to be heavy rust on the knee slide is actually a heavy coat of dark grease.

Figure 5

    The rust on the head and slide is not too bad, and this rust as well as the other rusted surfaces will be cleaned using electrolysis (at least this is the plan right now, I'm running some experiments).  This will remove the rust without affecting the good metal below it.  Most mechanical or chemical rust removal techniques also remove some of the good metal.

    The mill was fairly complete, except for the quill feed handles (fine and course feed).  It even had the factory optional belt guard (not shown in the pictures)!  It also came with a handful of MT2 collets (also rusty) and a vise.  The table is a little small 6 X 24, but big enough for what I need.  I was really looking for a knee mill as opposed to the standard mill/drill type.  With the mill/drill if you have to raise the head (on a tube column), you lose your positioning in relation to the workpiece, and have to redial-in the head.  With a knee mill, you just adjust the table height, and the head stays in the same relative position to the workpiece.  I was delighted to stumble across this Clausing mill!!

    The only "fault" is that the spindle is set-up with a MT2, rather than the now popular R-8.  There is plenty of MT2 tooling available, so this is not much of a fault.

Figure 6 - Head Sans Handles                            Figure 7 - Collets

 Figure 8 - Vise

    The mill has nice big dials on the X and Y-axis feeds (see picture above).  The knee dial is a little smaller but still big enough for my old eyes to read.  It even has a separate small graduated dial at the top of the quill position indicator that you can use for precise down feeds.  This is separate from the course and fine feeds.  You turn the dial to raise or lower the quill.  The dial is shown at the top of the indicator, just above the tumb-wheel that locks it in place when not used.  To the left of the indicator is the handle of the spindle brake.

Figure 9

    The photo below shows the surface rust prevalent on this mill.  Most of it is, however, the smooth surfaced type of rust found on worn spots on a handle, and therefore effects mostly the appearance of the mill.  This rust will also be removed by electrolysis, during cleaning, simply to improve the mills appearance.

Figure 10

    All in all a nicely featured machine that I can't wait to finish cleaning it up and start using it!

 Cleaning and Repainting:

    To clean the grease and grime off the mill, I used a couple different solutions.  First I sprayed it down with "Simple Green" full strength, let it soak and wiped it off.  This worked great and was much cheaper than starting with the solvent based cleaners.  If the part was heavily covered, I would repeat this until I was satisfied.  The part was then sprayed with electrical parts cleaner (zero residue) to remove the simple green (and its' water base), that remained.  The part was then either taken to the rust removal stage, or painted (or coated with oil).

  After cleaning, rust removal (with a rust converting spray, see Rust Removal), and repainting, the column and the housing for the Y feedscrew are shown in Figures 11 and 12.  So far (as of 04/21/01) I have also repainted and installed the X/Y slide. and cleaned several other smaller parts.

Figure 11                                                            Figure 12

    The next task is to clean up the table.  I will be using electrolysis to remove the rust, as I did for many of the other parts.  The size of the table dictated a larger container than the 5 gallon bucket I've been using, so I stopped at the store and picked up a rectangular plastic one for about $9.00.

    The cylindrical part of the headstock needed a bit more care, as the rust was on the sliding surface, so I took it to a shop with a cylindrical grinder and had a couple thousandths taken off the diameter.  The machined part is shown in Figure 13 (coming soon).

INDEX

Moving the Mill - One pickup and an engine hoist

Rust Removal - The different ways I removed the rust and the results. (Added 04/21/2001)

Mill Speed Chart - Scan of the chart on my mill  (Added 04/21/2001)

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