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1909 Maxwell Oiler threads

Steve Rinaldo

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I am trying to get the oiling system in my 1909 Maxwell to work correctly. The oil reservoir tank on the firewall uses two different sizes of a tapered flared fittings and I can't seem to find anything like this. All of the fittings I can find have straight threads no taper. Does anyone have an idea what these might be. I was  thinking possibly British BPST. Any thoughts or  suggestions would be appreciated. Thanks, Steve

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The first step would be to measure them...you'll need a micrometer to get the OD of the male part and a thread gauge. 60-degree thread gauges are cheap and, when working on pre-WWI cars, are essential as this pre-dates the adoption of most of the threads we think of as standard today. An odd tapered thread flare nut is going to be almost impossible to find today and they would not be an easy thing to make as the tap needed will be even more rare than the nut. What sort of fitting does the nut attach to? It may well have a 1/8 NPT thread on one side and the thread for the flare nut on the other side. In that case, I'd replace both the nut and the fitting with modern ones.


That said, oilers were virtually always supplied by specialist makers. They were used on all sorts of industrial equipment other than cars and are still made for the purpose today. If you can identify the maker you may be able to find another with some of the nuts still attached. If there is no name on it, post a picture as it may be recognizable.


Tapered threads on a flare nut doesn't make sense. If the threads engaged the nut tightly before the flare was crushed the union would leak. It may be that the thread on the fitting is slightly tapered but the thread in the nut isn't. This would allow it to start easily while the seal is made by pushing the flare of the tubing against the fitting.

Edited by JV Puleo (see edit history)
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