A Fogless Coolant Sprayer

Cutting metal always works better when you apply cutting fluid (except cast iron, which you cut dry). It lubricates as well as cools the cutting tool. Serious machining usually uses flood coolant, which is very messy. A better solution for the small machine shop is a fogless coolant sprayer.

These basically mix air flow with a trickle of fluid. The better ones pressurize the fluid as well as the air. The design is very simple, 2 holes to let air and fluid into the mixing block, a .040 hole lets fluid into the air stream. As .035 hole in the end of the nozzle and you are done.

A visit to eBay for parts, Home Hardware for a 1/4-18 NPT tap and off to the workshop.


I made a hose barb fitting from some scrap brass to match the one for the coolant intake filter.


The various parts, the block is not finished yet.

Cleaned up and assembled

The block is now cleaned up (edges chamfered to 45°) and 2 mounting holes counter-bored, using a 5/16 end mill.


Video of the unit in action:

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