Old French Pad Washers (Screws metric or not?)

[wally]

Hi, new to this forum, tried the search and can't seem to find the info I need (though I wouldn't be surprised it is here somewhere....).

I bought an old unplayable but complete closed-hole E.Roche French-made flute on the 'bay as a cadaver to practice my rebuilding skills (poor at the moment). The flute is apparently made of cupronickel, has soldered/beveled tonehole chimneys, and seems to be not too badly made (even has the French pointed key arms). However, the washer/screw arrangement in the pad cups is the reverse of the more common setup around these days, with the screw hard-soldered into the center of the cup and the washers center-tapped to screw down on the pad. The washers are flat on their underside but have some curvature on top.

My problem is that I will probably need to make a couple washers but I can't quite measure the screw-thread pitch. Closest fit I can get is about a 78 TPI on an Imperial gauge, and nothing seems to match with my metric gauge. Maybe a .40 would be close, but still ....

Could it be the flute was made prior to metric standardization? Any comments, advice, bad jokes, cyberbullying, etc. appreciated. I am already flinching over what I expect to hear about E.Roche.....

[JButky]

My problem is that I will probably need to make a couple washers but I can't quite measure the screw-thread pitch. Closest fit I can get is about a 78 TPI on an Imperial gauge, and nothing seems to match with my metric gauge. Maybe a .40 would be close, but still ....

Most of the English threads in this range would be 1-72 or 0-80. The .4 and .35 sizes are probably the closest you are going to find. You could try a tapping a few washers and check them for fit since the old post threads may simply be buggered a bit from the years.

If you can't find anything to match, I would replace the threaded posts with new ones and new washers made to a common size. There are a lot of ways to go about doing that design wise, you can go as simple or as difficult as you want if you want to get this thing to play.

Good luck..

[wally]

Most of the English threads in this range would be 1-72 or 0-80. The .4 and .35 sizes are probably the closest you are going to find. You could try a tapping a few washers and check them for fit since the old post threads may simply be buggered a bit from the years.

If you can't find anything to match, I would replace the threaded posts with new ones and new washers made to a common size. There are a lot of ways to go about doing that design wise, you can go as simple or as difficult as you want if you want to get this thing to play.

Good luck..

Hi Joe, thanks for that. The screw threads are a bit worn but still functional and the washers seem interchangeable. I'll go simple and try making a couple of 0-80 threaded washers (originals are the cupro-n stuff apparently) and see where that takes me. I suppose it was a bit wild to assume French makers would be using metric threading on a mid-20th century flute. Wally Moore