Joined: Jan 2010
Posts: 9,782
Likes: 1,751
From: Northern California
Bikes: Cheltenham-Pedersen racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.
If you will be using French pedals, has the threaded hole perhaps been threaded out to 9/16"?
That would leave less metal engaging the threads.
I had a Shimano LX crankset with stripped pedal threads, though I could get about one full turn of engagement with good thread deep in the hole using a certain clipless pedal with no washer.
I cleaned the threads well and saturated the threading of pedal and crankarm with LockTite Red, then slowly threaded in the pedal and tightened.
I have been riding the bike now for a couple of years, offroad, no problems. I did nce remove the pedal in order to service the bearings, but I was able to remove it without application of heat and it went back together just like the first time. I suspect you have a lot more threading to work with than I did!
I have long wondered if a crankarm having been tapped out from French to English threading could again be used with
French pedals, if it would still take full tightening torque. I will do an experiment one day with a discarded French crankarm and French pedal to find out.