|I have a later steel guard and struts Emerson 19666 with a cast hub 6 wing blade that I have been to h ell an back restoring. I called an AFCA member I have had many PM exchanges with, and asked him if he wanted it. he was seeking a big motor 6 wing Emerson at a reasonable price. I called him in recent past and offered him the 19666 I have spent much time with restoring at a very fair price. I advised him that the fan had a cast hub blade that was factory drilled and threaded just a tad off center. I had previously aligned the wings with strobe and used a Dubro balancer to check for a heavy wing or wings. Despite all my efforts and time messing with this blade I witnessed the hub cast wobble upon start up and gaining momentum just enough to raise h ell and cause a mild, yet significant enough unsettling overall vibration. I tested the fan for a couple hour run to let it warm up and noticed a mild motor chatter. The conclusion was I was going to have to call the AFCA member and cancel the sale as the balance issue with this blade was going to eventually cause premature bearing failure.
I called Jerry Bravi and asked him if he had any approach to helping or solving this problem? I was up against a rock and a hard place as this blade hub issue blade to rotor alignment was due to factory machining error. To be honest, I thought I was screwed. Buying another 12" 6 wing cast hub blade to remedy the problem would put me in the hole upon sale time.
Jerry gave me a game plan. He told me to spin the blade and locate the highest point the hub reaches upward when spinning. He then told me one the highest point is determined, shave or file the hub rear surface area that snugs the leather washer on the rotor shoulder slightly creating a indentation. What this does is when you snug the blade hub to the leather washer, the shaved rear hub surface will draw in somewhat thus reducing the blade hub wobble to a more reasonable alignment. I questioned Jerry's logic at first, but found out he has his ducks all in a row. It worked! I can now sell the fan with a clear conscience. It is not 100% better, but improved enough it is! Thanks again, Jerry!
The top single black mark on the rear cast blade hub is the highest point the blade hub would reach, the two black marks on the sides of the blade hub were to mark the half way point for me to shave cast iron from the bottom of the back of the hub upwards.
This is the first time I have ever come across an Emerson blade hub bore and threading off enter in a blade hub.
I used my brother's Hornady bullet casing neck wall casing thickness gauge to locate a more precise cast hub high point while rotating the blade.
Last edited on Sat Oct 9th, 2021 05:58 am by Russ Huber