Earl's makes conical seals for 37° AN fittings. They are a soft silver metal cone that fits exactly over the fittings tapered cone . They are so thin and soft that they come in little plastic boxes to keep them from getting misshapened. They come in different sizes and are available individually or in assortments. Not shown in paper catalog but still available on line. I incountered them when working on M1 turbine engines. They came with the different fuel componet kits. Lots of SS and you don't want a nineteen year old with large wrenches tightening those fittings. And you don't want leaks. I used them almost everywhere
oil lines, fuel connections, anywhere I used AN fittings. I think it was Summit but it may have been Jeg's.