With some simple, inexpensive techniques, you can avoid rust on small machine tools, cutting bits, and machining parts. Furthermore, these tips can also help you organize your shop and can prevent chipping due to metal parts smashing together (especially those brittle carbide end mills and tiny delicate PCB drill bits).
Unless you’re fortunate enough to have a climate controlled work area for your home machine shop, then your tools are likely either in your garage or basement. Depending on the season and your region, your expensive tools can be exposed to high humidity, which causes rust on exposed steel tooling.
Most machinists know to apply a thin coating of protective oil before they put away a tool. A classic technique is for a soft oil-impregnated cloth to be placed both under and over a drawer full of tools, not only to reduce rust, but also to prevent the tools from banging against one another.
Year ago, drills and end mills were supplied in cardboard tubes. Upon becoming exposed to cutting fluids or oils, the tubes were marginally successful at keeping out water vapor.
Left: High-speed steel countersink in a labeled plastic resealable bag. Right: Taps and HSS drill bits in a sealed Ziploc container.
Nowadays, inexpensive drills are often supplied in press-to-close plastic bags. Also called zip-press or zipper sealable bags, they are a cheap way to protect the tools from moist air, and it provides a conveniently large surface for labeling the part number and tool characteristics.
If you lose a bag, you can always buy freezer bags from the grocery or hardware store to enclose any loose tools. Unfortunately, a pile of bags takes up a lot of space, tends to slide around, and makes it a hassle to access tools quickly.
Instead, I like to put groups of small bits into sealable plastic containers, such as a Ziploc sandwich container (I also like to put robots in them). If all of the tools in a single storage container are related (like the metal taps and drills for #4-40 screws), then it isn’t a hassle to open the plastic tub and leave it open while that aspect of the project is being worked on.
You can find a variety of plastic container sizes and qualities for different needs. Many thin disposable containers fit perfectly in tool chest drawers. Thicker, higher-quality storage containers, like Rubbermaid or Tupperware products, are rugged and strong enough to be stacked on shelves. For example, my associated sizes of steel step blocks for milling are in several heavy-duty plastic containers on my workbench.
Although a sturdy sealable container keeps out most of the moisture, it doesn’t prevent the tools inside from banging around. Nowadays, high-end drills and mills come in individual plastic tubes to protect the cutting edges (and your fingers). However, hardware-store blister packs and bulk purchases from eBay can leave you wishing you could make your own tubes.
Top-Left: The manufacturer’s tube protects this Niagara Cutter Solid Carbide End Mill. Middle and Bottom: Individually cut plastic tubes protect drills, taps, and end mills. Cut-to-length plastic tubing and caps are available to make your own custom protective tubes of any length.
I recently discovered that McMaster-Carr has cut-to-length semirigid polyethylene tubing in a range of diameters from about 1/4-inch up to 2.55 inches. And, McMaster-Carr also sells matching flexible PVC end caps in either red or black. This allows you to make your own custom cases for resistance against humidity and collision.
The plastic tubing and covers come in round or square. I prefer square, as it doesn’t roll off the workbench or table, and square is easier to label and stack. Since they don’t roll as much in a drawer, square tubes help keep my cutting bits organized.
I would have thought that plastic tubes would be located in the McMaster catalog near the individual drills or other bits. But, they’re located in the section with cardboard tubes and plastic bags. Search for part #2044T61 online at McMaster Carr to find the correct catalog page with the full selection of cut-to-length tubing and caps.
When I first purchased the cut-to-length tubing, I tried cutting it with a Dremel rotary tool with a cut-off blade. While that worked, it left the tube interior full of plastic dust and particles, which immediately adhered to any freshly-oiled tool that I inserted.
Craftsman Accu-Cut razor-blade utility shears are good for cutting polyethylene tubing.
When I bothered reading the catalog description of the cut-to-length tubing, I found that cutting was quick, clean, and fast with heavy-duty scissors or flat-jaw utility shears. (Flat-jaw utility shears are also called “razor-blade scissors” or “flat anvil-style jaw shears”. See part number 3095A13 for an example.)
I’ve had less luck with tin snips and wire cutters and tube cutters. The thin plastic tubing tends to bend and stress, rather than cut.
With individually-sealed plastic tubes inside of group containers, my end mills, drills, metal taps, Dremel cutting bits, and other small metal bits are well protected from the environment and breakage.
Although my medium-size machining accessories (like my Sherline rotary table, step blocks, jigs, tool vises, and drill chucks) are stored in thicker storage containers, I still worry that there is enough air in the plastic box to result in minor rust. There is some additional rust protection you can add for free...