Small-scale milking machines by Steve Shore from the May/June, 2006 issue of Countryside & Small Stock Journal
Small-scale milking machines
By Steve Shore
When I first wanted a milking machine I looked in all the goat supply catalogs and in the back of the American Dairy Goat Association’s directory for the perfect machine. I bought one from one of the supply houses that was “designed just for goats.” I ordered a two-goat machine and was shipped a one-goat machine. The supplier talked me into keeping the one-goat machine. It was usable but the small milk bucket wasn’t quite big enough when used on my most productive doe. The foam from the milk would be sucked into the small vacuum tank and the milk bucket was so light that it tipped over easily. Then after using if for less that a month, the electric pulsator quit. I packed it up and sent it back.
Later I bought a unit from Mick Lawyer. It uses a Gast pump that you can get from W.W. Grainger for about $325, a compressor tank, vacuum gauge and vacuum relief valve. It is so easy and simple I wish I had thought of it. The milk bucket is a surge with two-foot long hoses on the inflations, so the bucket will set on the floor and the inflations will reach the goats on the milk stand. Yes, you can milk two goats at a time.
This unit works very well, but while at a goat show I started talking to an old cow dairyman whose wife has goats. He showed me his “show machine.” Let me tell you this thing was a beauty. He had an air conditioning pump off a car hooked up to a 1/3 hp motor, and his tank was a 12 inch pipe that was capped with a piece of plate. He didn’t bother to trim the edges of the plate off or anything. His welds were ugly and it was leaking vacuum. But the best was the vacuum relief-a piece of plate over a hole in the bottom of the tank with weights hanging on a chain. The only thing that looked decent on this thing was a brand new vacuum gauge.
He explained that the air conditioning pump from a car is actually a vacuum pump. To turn the pump you need a 1/3 hp reversible motor that turns at 1,725 rpm. It needs to be a reversible motor because a car engine runs backwards from a standard electric motor. You have to tack weld the clutch pulley on the vacuum pump so it won’t just spin. Your vacuum tank can be anything that won’t collapse under 11 pounds of vacuum. His pump could even keep up with the vacuum leaks from his poor welds. When asked about his vacuum relief set-up he told me that to regulate the vacuum, you add or take off weight while watching the vacuum gauge. When the vacuum gets more than the weight of the weights hanging on the chain, the plate in the bottom of the tank lifts up causing a leak, and the vacuum is reduced. It’s so simple it’s ridiculous. When I came back home I just had to make my own machine. I had a piece of 4×18 tube laying around from a job I had been on. I capped both ends and ground down the welds, and added some angles on the top to mount the reversible motor on (I had to buy that), picked up a vacuum pump off a friend’s junker, and a couple of pipe fittings. I bought a new vacuum gauge and vacuum relief valve from W.W. Grainger. Now I have another good working milking machine.
Some notes on building your own machine: try to get a pump off a big car or a nine-passenger van-it will be bigger than a small economy car’s pump. You have to weld the pulley to the electric clutch on the pump, or the pulley will just spin. Your motor must be reversed and 1,725 rpm and at least 1/3 hp. Use a good size tank, too, if it’s small you lose vacuum too easily. Buy a new vacuum gauge and watch it. The dairy supply houses sell a vacuum relief valve for over $40; Grainger’s sells one for about $10. Both work on the same principle-a spring that holds tension on the valve to control vacuum. I have both types and have never had trouble with either. While the weight on the chain works (the old surge pumps did use them) it takes up a lot of space-spend the $10. For a milk bucket you can find them on eBay. I would stick with the Surge belly-style, as you can easily get replacement parts.
There was a question about converting a compressor into a vacuum pump. While in theory it should work, it doesn’t work very well at all. Your intake stroke doesn’t have enough vacuum in it to do much good. You can actually run your milk bucket off your car’s intake manifold but once again you need a vacuum gauge and a way to control your vacuum. By the time you pay for the gas in your car, the hose to go to your milk bucket, the gauge and relief valve, you might as well buy an electric motor.
I use the one-piece silicone inflations by Sil-Tec or Marathone. I like the Sil-Tec’s better because they are cheaper. Both brands are clear at the bottom where they attach to the milk hose. I attach the inflations directly on to the hose without any elbows or shut off valves to close off the inflations. I use the plug-it type inflation plugs, this keeps anything from getting inside the inflations. I use a DeLaval bucket with a surge lid. The DeLaval bucket sits higher so my milk lines are flat out to my stanchions, making them shorter. By using the Surge lid and pulsator, I don’t need a claw, and the Surge pulsator is easy to rebuild and your can buy the parts from most dairy supply houses. Put a drain in you vacuum tank. Your vacuum tank will pick up moisture from condensation and milk vapors. When people tell me that their milking machine isn’t working right the first thing I tell them to do is to drain the tank. This usually solves their problem. You see when the tank starts filling up with milk or water, you reduce the volume of vacuum in the tank and you are running just off your pump if you get a leak in vacuum (such as when a goat kicks off an inflation or you are switching inflations from goat to goat) you lose vacuum. If you don’t have enough reserve vacuum in your tank, inflations start falling off or the pulsator stops.
You can make a water trap with an auto drain. Mine is made out of three-inch PVC about 12 inches long, capped on one end with a threaded cap on the other end-this way it can be taken apart for cleaning. On the capped end drill and tap a hole for a 1/2-inch pipe and screw a pipe fitting with a hose barb into the hole. Seal it with Teflon&153; tape so it won’t leak. On the other end drill and tap a hole in the middle of the threaded cap and one in the side of the pipe, down low. Screw another threaded hose barb fitting into the hole in the side of the pipe. You will need to solder a short piece of copper pipe into a male copper adapter for your duckbill to fit onto, then screw it into the hole in the threaded cap. You can hose clamp the whole thing onto your milking machine or your milk stand. Run a hose from your vacuum pump to the top hose barb, and the hose to your bucket to the bottom hose barb. If you suck milk or water into your vacuum lines it will collect in the bottom of your trap and not your tank. When you turn off your pump the water will run out of the duckbill.
If you are milking more than one or two goats you are spending a lot of time moving goats from pens to milk stand and back again, and waiting for them to finish eating. The solution is to make a stanchion that holds more goats. (I was an ironworker, and many times I drove 100 miles one way just to get to the job. In the summer we would start work at dawn to beat the heat, so I had no time to waste waiting for the goats.) I built an eight-goat stanchion and milked two goats at a time. From the time I walked out of the house to the time I walked back in took 35 minutes. This included clean-up of eight goats in the stanchion at one time: wash the first two udders, start milking from the right to the left, wash the other six udders while waiting for the first two to milk out. I teat dip as I go. After the last two are milked out, cut all eight loose at once and run them back to the pen, and dump the milk into waiting jars. I had a two-section sink with soap in one side and bleach in the other. I’d turn the pump on and suck five gallons of soapy water up, dump it and do the same with the rinse, then head for the house. I did a more thorough cleaning when I got home after work and I had the feed in the feed bowls at night and the milking machine all set up.
One last thing. If you are looking at those real cute belly milkers for your goat, please don’t waste your time or money. The Surge belly milkers hung under the cow. The cow could move around and the bucket would move with it. With the goat set up, the bucket is light weight and sets on the milk stand. If your goat is tall, the inflations will pull down on the udder; if the goat is short or has a large udder, the bucket and inflations will be pressed against the udder. If the goat moves the bucket is moved with the goat, sometimes scaring the goat enough to make it starting jumping around. Everyone I have talked to that has a goat belly milker hasn’t liked it. Don’t waste your money.