# Aluminum Pulley On Steel Shaft



## Gerry Sweetland (Mar 28, 2009)

Hi all,
Should I apply some type of anti-seize compound (or oil) to the tapered shaft on the quill shaft before I install the alum. pulley? Or should it be a dry fit?
Also, how tight should the large nut that retains this pulley be tightened?
Thanks,
Gerry


----------



## jmshep (Apr 3, 2009)

Gerry
In the absence of any other reply I will give you my views for what they are worth.

You are right to consider a potential problem with the two dissimilar metals. Rocol for one make anti seize products that may be suitable but I have not experienced a problem assembling dry for use in the workshop.

I would certainly not use oil or grease. 

As far as tightness of the retaining nut is concerned, it depends if the pulley is keyed onto the shaft or not. If it is keyed, just tight enough will do and it my be prudent to use the appropriate Locktite on the thread. If  the nut is the sole fixing then a couple of large washers and just tight enough for the job in hand.


Hope that helps


----------



## rake60 (Apr 3, 2009)

I can't pretend to know why, but the manufactures recommend
a zinc anti seize for aluminum to steel assemblies.

This link tells more about that:
http://www.sacskyranch.com/antiseize.htm

Rick


----------



## deere_x475guy (Apr 3, 2009)

When I a few semi trucks running the road (way back when) I always used anti seize when replacing parts. The suspension components need replacing from time to time and they were cast aluminum mated with steel parts.


----------



## Kermit (Apr 3, 2009)

I remember grandpa "Baba" used a bar of white Ivory soap to coat the threads of the bolts when he worked on the lawnmower or any of the other gardening equipment. Seems I remember those things being cast aluminum mostly and the bolts were standard shiny zinc coated steel.  

Funny what a random story will cause you dredge up from your memory,
Kermit


----------



## Maryak (Apr 3, 2009)

Hi All,

A very brief explanation of why Zinc Anti Seize Compound is recommended for Aluminium mating to Steel.

From the Galvanic Series the metals involved are:

Most Anodic.  Zinc
Next       Aluminium
Most Cathodic Steel


Without the anti seize compound the aluminium will begin to oxidise in the presence of an electrolyte such as moisture from the air, (It is sacrificing itself to preserve the steel - Cathodic Protection), commonly referred to as the pulley growing on the shaft.

When the two are separated the hole in the Aluminium pulley will be bigger and on replacement will locate further up the taper and be out of line from its' previous location.

As the Zinc in the anti seize compound is the most Anodic of the 3 metals it will oxidise protecting both the Aluminium and the Steel.

After approximately 1 year the Zinc will be completely oxidised and will require replacement for the protection of both the Aluminium and Steel to continue.

Hope this helps. ???

Best Regards
Bob


----------



## Gerry Sweetland (Apr 4, 2009)

Thanks for the input fellas.
I ended up using a Locktite product for installing spark plugs into aluminum heads. I'll check to see if it lists what type, zink, graphite, etc. 
Gerry


----------

