# Cast iron milk bottle



## JohnN (Dec 17, 2012)

I thought I remember someone posting something about a cast iron milk bottle on this forum before. I'm not sure if people knew what they were used for or not, so I decided I will post this. 





> We get a lot of questions about this cast iron milk bottle and there are some wild explanations for it on the web.  It had nothing to do with milk or milk delivery.  This bottle is cast iron and is embossed USE TO REPLACE GLASS BOTTLE IF BROKEN on one side and 3781 on the other side.  It is the size of a half pint milk bottle.  Avery Tractors used a half pint glass milk bottle mounted upside down as a sight glass for the oil system.  The oil pump would pump the oil through the milk bottle and then on to the bearings in the engine.  By glancing at the oil inside the milk bottle, the driver could tell if the oil pump was pumping oil.  However if the glass milk bottle broke in the field, the oil would leak out of the engine and the engine would be damaged.  As a back up, Avery tractors came with this cast iron milk bottle that could be kept in the tool box for just such an emergency.  Since this bottle was cast iron it could withstand being bounced around inside the tool box in rough fields.  The cast iron milk bottle was only a temporary patch since the operator could no longer see if the oil was flowing, but at least it would allow one to drive back to the house to get another glass milk bottle.  An extra glass milk bottle in the tool box would have just broke.  The number 3781 was the Avery part number.


 At the bottom, with picture


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## LC (Dec 17, 2012)

Never heard of anything like it , quite interesting . Who would have thought it had to do with a tractor . Great post .


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## sandchip (Dec 18, 2012)

Now, that's cool!  Thanks for teaching us a thing or two.


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## cowseatmaize (Dec 18, 2012)

One mystery is the thread. That was a $1,000,000 offer for a cast iron case (not the tractor) which I think was determined spam and deleted.
 The second mystery appears to be solved.
 Thanks John for posting and especially to Doug and Linda for the site!! That sure clears up a lot.


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## Oldihtractor (Dec 18, 2012)

John deere also used the  glass milk bottles on thier waterloo boy tractors and thier overtime tractor the export version  for the same reason..    

    The Avery tractor cast one is a fact  I have the parts book to back it up..


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## epackage (Dec 18, 2012)

John do you have any sort of pick or drawing on exactly how they looked when in use? This is really interesting to me and I find it amazing that the replacement was a metal piece in the exact form of a milk bottle, very cool...


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