Drilling lubrication

They sell a water soluble oil just for this purpose. The oil prevents rusting of the iron, and the water cools better than straight oil. Some systems use compresses air to mist the solution other systems flood cool and circulate the fluid.

Interesting. "Water-soluble oil" sounds almost an oxymoron. Do you have any trade names? Also, a supplementary question: Is there any benefit in keeping the cooling fluid as cool as possible? By that I mean for instance dropping ice cubes into the container prior to starting drilling?

Rustlick WS-5050 is what I use. MSC et al sell it in one gallon containers, and one gallon makes 15 or 20 gallons of emulsion.

The key is detergent. That's what allows the oil to emulsify into water.

The cooling is to keep the metal at the cutting point from achieving welding temperatures, so any reasonable fluid will do (compared to air). Oil is traditional, but messy. Water has a particularly high heat capacity, even before it boils. The combination works very well.

So don't bother with the ice cubes.

Joe Gwinn

Yeah. Whyn't keep a 100 lb. block of ice next to the vise on your drill press table. You could drill into it to cool those bits off nicely.

I use as little as I can get away with to avoid cleanup. This afternoon the channel iron drilled nicely dry, the welded hot-rolled steel under it wanted oil and the tap received fancy tapping fluid. The rest of the holes all got the tapping fluid for drilling as well. The job is a sheet metal brake and cutting oil might get onto the window flashing I'm making.

When I write that a tool 'wanted' something it means experience shows how well it is cutting. I got that experience by starting dry, then adding oil, then tapping fluid and observing the differences in chips, handle pressure, machine sounds, bit & work heating, how fast it dulled, and so on. Put a little oil on the bit and watch for subtle changes when it's gone. If you are drilling a few holes at a moderate spindle speed, cutting oil or coolant isn't really necessary.

Jim Wilkins

You are kidding, right? How am I gonna keep the beer cool if the block is melting all over the shop floor? That would not do at all! I suppose one could save up all the drilling for Saturdays and use the left-over ice sculpture from all the gay weddings...

Second that Jim. You are working at the craftsman level. It is interesting and very informative to experiment with various techniques as you indicate. Most of the things we read about cutting lubes, etc. are written for a production environment, not a home shop. Generally speaking, with a little experience under your belt (experimentation strongly recommended) the job will usually let you know if lubricant is required.

Bob (if its hot cool it, if it squeals lube it) Swinney