I know this sounds cheap but has anyone made a coolant mister? If so how? They cost $50 to $70 to buy. Seems like a lot of money for what they are.
drill a hole through a piece
tap a small cross hole (at a slight angle) for liquid line
add air (flow control optional)
add liquid (flow control optional)
it's a mister
it's a lot easier if you keep coolant (coffee can) above mister
then you don't have to maintain siphone
add a little valve to control flow
get as sophisticated with control as
the budget allows
Or....go to your friendly local HF store and buy an $8 engine cleaner wand....
Or cheaper yet, get an air brush kit from HF, on sale for $4.99:
Oh course any of the cheap suction designs will eventually sputter, and sometimes even clog completely. More reliable are pressure type spray mist such as those made by Bijur.
But then if "50 to $70" sounds like a lot (sounds like a meal for three at Outback steak house to me :rolleyes: ), then you may run screaming thru the night when you find out how much the Bijur's cost new !
But they probably show up used on eBay cheap enough...
If you want to build your own head over to http://www.metalworking.com/ and check the drop box. Down in the 2002 retired files there are some notes and pics on how to build a "zero fog" misting unit. The secret is to pressurize the coolant as much or more than the air flow. I have seen them built out of water filter canisters and some parts, probably for less than a meal for three at the western sizzler.
So, how do the Bijur or more particularly the Trico MicroDrop systems work? From the sketchy descriptions, they (1) pressurize the fluid directly rather than relying on an aspirating venturi and (2) the nozzles are designed not to fog. Anybody know the details? E.g. where, relative to the tip, is the fluid introduced? How is it introduced? How is the fluid metered?
I have a couple of the Trico Microdrop. Yes, I believe it does pressurize the bulk oil cannister. Other than that, the rest of the secret seems to lie in the nozzle, which is nothing fancy, just a tiny hole.
It has an air line and an oil line running to each nozzle unit, the latter which is comprised of a few inches of locline affixed to a magnet. IIRC, only the oil tube itself is snaked through the inside of the locline to attach to the nozzle.
There are fine flow adjustments on the main dispenser housing, one for air, one for oil.
The nozzle uses a brass fitting pressed into a locline nozzle. The brass fitting is made from hex stock, so there are 6 slight airgaps all around, because it fits into a round hole in the nozzle. The pressured air flows through these gaps, and induces oil flow out of the tiny hole in the nozzle.
Although I was loath at that time to spend the five or six hundred on such a unit, it does work well for light duty use on a job where just a trace of lube is required (like aluminum ), and a light (but not noisy) air flow keeps the chips out of the cut zone.
For deep cavity milling in aluminum, its actually much better than machining in a 'lake' of coolant that traps the chips in the pocket.
However, for milling steel, I would not recommend it for roughing unless you have smoke removal equipment. I guess the little bit of lube won't harm carbides that cut best in 'dry state', but it will smoke up like crazy. Most likely there is not enough air flow to move heavy steel chips. But for finishing steel, it would be fine.
Glad to see this thread. I have been using a mister on my mill. The fog is a little annoying and I get a sputter/clog now and then. I didn't realize that there were different designs till this thread.
I checked out the URL. That one looks neat on paper. Have you or anyone else built one like that? I am thinking about building one similar to Mr. Townsend's plan. Mine probably won't look like his but I will use his basic dimensions and orifice sizes. No since in experimenting if his design works as good as he says.
From the ideas submitted, this is what I came up with. Bought some small brass tubing from Menards today. Then took a 360 brass block
1/2 x 1 x 1 1/2, drilled and tapped 10-32 for air lines and soldered to tubing to the block. One line for coolant and the other for air. A
2" x 18" pipe nipple is the coolant tank. An air pressure regulator pushes coolant out the bottom of the tank. A flow control regulates the volume of air. It looks like it works but need to try it on the mill. I'll use it to apply Wd40 to aluminum milling.
The brass block and tubing soldered into an assembly.
The tank and regulator. Only about 5 lbs PSI in tank. The SMC flow control for the air is in the upper right of pic.
Drip coolant working. Coolant comes out on top and air propels the coolant to the work.
Now what am I going to do with the coolant mister bought on Ebay last night?
Thanks for the ideas,
The plans at metalworking.com that jkilroy mentioned above looked pretty good. Here are the beginnings of my nozzle. I used the same orifice openings as the plan shows but tapped my inlet valves directly into the block to eliminate some soldering.
I cut an extra brass block to practice my soldering a little before messing up my final part. I figured that the little 1/8" OD copper would be tricky with the bulky brass. I was right.I am not having much luck with getting the brass to take solder or even brazing rod! That block of brass is a real heat sink! If I hadn't already drilled a 1/8 hole in the block I would thread the tube. Too late now unless I start all over.
Also I question the author's reasoning for using 20 psi on the coolant line and 5 psi on the air line. I would think that equal pressures would suffice. I'll let you know after I try it.
SCOTT (fabricator - wanabee machinist)
Forgot all about this thread.
Scott, I really like what you have done there with the single output line. Let us know how it works. I'm already thinking of copying what you have done.
Here is a pic of mine working.
While it works well I'm not fond of the dual output lines. It really saves compressed air, coolant and no fog in the shop. The coolant is turned on and off as needed controlled with the CNC control.
I ended up with a flow control valve on both the coolant and air lines. The air pressure was increased for better response time.
It seems that a couple of posts to this thread were lost in the changeover. Maybe they will show back up.
Does anyone know where a copy of the HenchForth Fog Buster patent can be found? I tried emailing Karl Townsend to discuss his interpretation of the plan but the mail was undeliverable.
From one of the missing posts we learned that Hench used equal sized orifices (.093) for both air and coolant supplies. He also used equal pressure on each line.
Karl claims superior performance by using .093 on the air supply and .040 on the coolant. He is using 20 psi on the coolant and 5 psi on the air. He also places emphasis on the air ventura size for correct velocity.
With all due respect could Karl's design be a little "over engineered"? This is no longer a siphon system. Since we are now injecting coolant I would think that orifice size is not as critical as volume control. We basically have two needle valves controlling our mixture ratio with a simple nozzle providing the spray. Not unlike the plastic straw supplied with a can of WD40. Could Karl's need for a higher coolant pressure just be to compensate for the reduced orifice size? The end result (at the nozzle) may be the same for each design. ?????????
My prototype is built almost exactly to Karl's specs however I am going to try equal pressure (saves buying 2 regulators). If it doesn't perform up to snuff I can always drill my coolant orifice up to (.093)
Well---I guess I better put together a tank so I can try this puppy out.
I see I'm a bit late to the party.
Thanks for the kind words about my <copied> design of the Hench Fog Buster
I made my own mister or dribbler more like it a bit different to the ones others have mentioned due to parts on hand. Anyway here goes Air solenoid which can be switched off operates when the spindle is running, this feeds through a flow control (very common item in pneumatics) to a pipe which runs down the centre of the segmented plastic coolant pipe almost to the nozzle end. A dosing pump which is also controlled by spindle power and which can be turned off seperately from the air draws coolant from a tank. The discharge of the dosing pump goes into the coolant pipe around the outside of the air pipe. I can have air and coolant in whatever proportion is required. Yes it works well, there is a slight pulsation in flow from the dosing pump but the hold up in the segmented coolant pipe seems to dampen a lot of this..
The system worked so well on the mill I will make one for the lathe but using the coolant pump to supply coolant. Air is great for keeping the chips out of boring jobs of which I do guite a few.