hardware compatibility question

[Justin_NSA]

I was finishing up my propshaft coupling installation and had a problem with the pinch bolts. I sent the question on to the place I bought the new Buck Algonquin split coupling from. Maybe I can get a quicker answer here:

I purchased a split coupling from you, part number 400YS. I was installing and torquing the 2 pinch bolts to 60lbs, because there were no instructions on how much. I ended up twisting the first bolt in half. I noticed they are cheap steel. Do you see any metal compatibility issues with using stainless steel bolts with the iron coupling? How much should they be torqued to?

Do you see an electrolysis issue using stainless pinch bolts with a ductile iron coupling? Any idea how much 3/8" bolts should be torqued to? These are the 2 pinch bolts, not the 4 that bolt to the transmission flange.

 

[lillia28]

I was told that stainless is not preferred for shaft couplings as it is more brittle and prone to cracking. I don't know if it is true, but I use mild steel bolts and lots of anti seize. Attached is only a guide, but closer to 30 ft/lbs for a 3/8 bolt.

http://www.portlandbolt.com/technical/bolt-torque-chart/#bolt-torque-a449

 

[Justin_NSA]

Thanks for the guide. Maybe I should go back with the same steel and torque to 30#. The important thing is that they be even tightness so as not to distort the flange.

 

[Justin_NSA]

Thanks for the help. I got new bolts and torqued them appropriately (evenly). All I have left on the shaft seal project is to add a jumper ground wire from the transmission shaft. over the shaft saver, to the coupling. There's not enough room for the old ground strap to ride on the shaft anymore with the longer LasDrop shaft seal. I feel better after replacing the old plastic stuffing box. Rudder is back on and the hull is waxed. I am sooo close to splashing her!

 

[lillia28]

That is a nice set up! I am trying to come up with a ground around the flex disc myself.

 

[Justin_NSA]

That is a nice set up! I am trying to come up with a ground around the flex disc myself.

Thanks! My plan is to use ring terminals on the bolts with a wire between. I've heard of thin copper ribbon strips being used but I don't have any.

 

[lillia28]

Wire and ring terminals is where I am ending up too. I've seen copper ribbon/mesh, but I am not comfortable drilling holes in it. Any ground straps are way too long for what I need, about 3 inches..

 

[jibes138]

I used ring terminals with wire between the bolts. Works well but a little unnerving having that wire whipping around , make sure nothing is nearby to snag on it. A flat copper strip fit tightly to the diameter of the flex coupling will be ideal but corrosion of the copper might be a concern. The tinned ring terminals and heat shrunk adhesive lined tubing takes care of most of the corrosion concerns using the wire method. Unprotected copper turns green pretty quick.