Check your alignment

A friend of mine hadn't checked his alignment and this is a good example of what happens:



Luckily he found the problem before the shaft went aft (no safety collar in 70) hitting the rudder. For those who aren't familiar with the problem, misalignment between the prop shaft and trans coupling causes movement at the interference fit between the two. This causes fretting to the point were only the key and safety set screws are transmitting the power to the shaft and holding the two together. A black smut around the shaft at the coupling bore is a good indicator of fretting.

Check your alignment!

phatsat67 wrote: Don't fret Pete. My alignment is perfect.

My only fretting is when Ken works me over!!

So Pete, are you going to use your ability and knowledge and make that shaft into a double taper shaft and save your friend some cash or let him go buy a complete new assembly? BTW don't forget to lap the new one in.

Better check the tranny rear bearing too.

If I can help out just holler

Gary S wrote: Hope he orders a safety collar too Pete,McMaster Carr has them After seeing what happened to Dave Gwinn's Southwind I put them on anything that didn't have one.

The collar has been discussed but there's not much room between the trans coupling and the shaft gland packing nut on the 1st gen Cuda. In fact, the last Cuda up here that got the ARE, the socket to draw the shaft into the coupling taper had to be ground down in length!

This is what I used on the Mustang

splt collar

or better price

Charlie's back home in St. Paul so UPS dropped off his new shaft at my house and I'm impressed. In another thread, it was discussed that ARE shafts have been breaking at the woodruff key at the trans end taper. I understand they made a design change which hopefully will fix the problem. Anyway, I mentioned this to Charlie so he decided to get in touch with General Propeller regarding their double taper system. First, it's not an "off the shelf" shaft and coupling. GP requested lots of measuring especially at the trans end where clearance between the coupling and packing gland nut is limited. GP then selects a coupling to suit giving them as much taper length as possible. The ARE's have a rather short and steep taper which from an engineering standpoint has always been a concern of mine. GP also uses a 1/4" square key minimizing material needed to be removed out of the shaft compared to a woodruff key that goes deeper. I assume going to a 1/4" key is what ARE has done with their engineering change??

The General Propeller double taper shaft and coupling

Good info Pete, I may be in need of it before long. Visually checking my alignment a couple weeks ago after noticing your post, I discovered a slight wobble in the prop shaft. I'll be taking it apart this weekend and seeing if it is a misalignment or a bent shaft. Hopefully just an alignment issue since there's already several other items on my list to repair and/ or replace.

Yes, I caught the link in a previous post and watched it that night. Mostly very logical stuff, but if you've never done it before the video is a great tool to make sure you don't forget anything. Lots of great tips though