Give your metalwork a gleaming texture
that makes light dance. By Brian Dereu
Engine turning, or jeweling, is a striking, prism-like
finish that’s applied to metal surfaces. Traditionally
used on pocketwatch cases and rifle bolts, it can be
applied to tools, lighters, or any other area of metal.
And although it is labor intensive, it’s not difficult
to accomplish. All you need are a drill press, valve
grinding compound (Clover brand or similar), and
some miscellaneous items found in the shop.
The pattern is accomplished by applying the
abrasive, lowering a spinning tool onto the work
for a few seconds, then raising it, moving the work
piece over, and repeating until the entire surface is
worked. A moveable, indexable table is ideal for this
type of project, but you can produce results just as
good by using a scale and a few spacers.
Although jeweling will hide surface imperfections,
it’s best to start with a nice finish. Here’s how to
give a mirror finish to softer nonferrous metals like
copper, brass, and aluminum.
As in woodworking, work through progressively
finer grits of sandpaper, up to 600. After using 600
grit, you can see reflections in the metal, though
they will be foggy. Rub a small amount of metal
polishing compound on the backside of a sheet of
sandpaper, and then run the metal surface across
it, back and forth. Soon a mirror-polished finish will
jump out and the metal is ready to jewel.
To apply the pattern, use a short piece of wooden
dowel, about 3" long and 7"– 2" in diameter.
Chuck up the dowel in a drill press. Set up the drill
press table so that your work piece can slide along
next to a scale that’s been fixed to the table. Super
glue works well for this, and can be scraped off later.
Set the drill press to around 1,000rpm and apply
a good amount of grinding compound to the work.
A medium-grit (200 to 300) compound works well.
Start by lowering the dowel in the far corner, and
apply 3lbs–5lbs of pressure for 3–5 seconds. Raise
the dowel, move the work the desired distance,
and continue, until the first row is complete. It’s
important to maintain the same spacing throughout the entire surface, in both the x and y axes. The
dowel should be changed intermittently to prevent
128 Make: Volume 19
it from mushrooming out at the work end, which
will increase the size of the burnish.
After the first row is complete, add a spacer
between the work and the scale that’s the same
thickness as the distance between each burnish.
Graph paper can also be used as a spacing grid.
The sample shown above has spacings of ¼" in
both the x and y axes.
Small circular wire brushes are also used instead
of dowels, usually on harder metals like carbon steel
and stainless steel. Bridle the brush by wrapping its
wires with a few turns of electrical tape down most
of its length, to keep it from flaring. There are also
round, rubberized abrasive sticks (such as Cratex
brand) that can be used as jeweling tools. Cratex
sticks don’t require the use of grinding compound,
but they’re not very aggressive, and can be used
only on a super-polished surface.
After the entire surface has been finished, gently
rinse away the remaining grinding compound. Some
of the compounds are oil soluble, and must be
rinsed away with paint thinner, acetone, or a similar
solvent. Don’t rub off the compound with a rag, or
it will scratch. When all the compound is rinsed off,
wash the work piece in soap and water, and dry it.
Most metals will oxidize over time. To keep the
surface looking new, protect it with a clear coat,
such as a spray lacquer. Don’t delay on this step, as
visible oxidation can take place in a very short time.
Photograph by Brian Dereu
Brian Dereu is a self-employed manufacturer who enjoys
gadgets, fishing, and family.