[DeTomaso] Stainless steel hardware and aluminum complications

Sat Jul 27 19:13:40 EDT 2024

 To all,

Electrical discharge Machining will remove stainless steel from aluminum without damage to threads. I worked in field service on semiconductor environmental handling equipment for about 10 years. There was mechanical movement inside a chamber that had to operate through a temperature range from -55 °C to +125 °C. The mechanism was anodized aluminum and all hardware used was stainless steel to prevent rusting. I took many parts to a machine shop for removal of stainless steel from aluminum. Largest thread size was 8-32. But not often enough to make me think the cause was not human related.

Bud 3400 Drive like there will be no tomorrow, for there may not be.

     On Saturday, July 27, 2024 at 03:16:59 PM CDT, Charles Engles <cengles at cox.net> wrote:  

 Dear Ken,

              ARP's engineering and technical staff know much more than I do, but I would never use stainless steel bolts in an aluminum crank pulley.    :-)

                            Warmest regards, Chuck Engles

-----Original Message-----
From: Ken Green [mailto:kenn_green at yahoo.com] 
Sent: Saturday, July 27, 2024 11:47 AM
To: detomaso at server.detomasolist.com; Charles Engles
Cc: 'B Hower'; Asa Jay Laughton
Subject: Re: Stainless steel hardware and aluminum complications

ARP says to use an anti-seize on the stainless fasteners, do you think that resolves the issues?

On Saturday, July 27, 2024 at 06:26:41 AM PDT, Charles Engles <cengles at cox.net> wrote: 

Dear Ken,

            Your comment about using stainless steel studs and hardware on the ZF, reminded me of a lesson I learned from another Pantera owner and a very experienced Ford Motorsports and Rousch Industries engineer.  After my friend’s Pantera began making troubling noises, it was determined that the culprit was the aluminum crank pulley secured with stainless steel bolts.  Ultimately, it required major mechanical efforts to remove the cold-welded stainless steel-aluminum from the balancer.  The pro told me to never use stainless steel in aluminum because of the tendency to galling and worst case scenario---cold welding.  I had *no* idea.

          Just yesterday I was working on a Windsor engine with an aluminum intake manifold.  My brother told me that on its previous iteration, the front nose (?) piece on the intake manifold coolant snout was very problematic to get watertight.  Short story: I found that the two *stainless steel* bolts did not completely thread down.  Each was blocked at a different depth.  A thread chaser was a big improvement, but I re-tapped both and finally got both bolts to seat properly.  Then, it dawned on me that the snout-intake had been assembled, at least, two or three times before I got it.  The problem was the stainless steel bolts galling the bolts holes.  I also replaced the SS bolts with common steel bolts.

          In addition to the SS-aluminum galling propensity, there is also a potential for electrolytic reaction of SS-alum to produce “tea staining” of the *stainless*steel fasteners.

          Information links:

              Galling:  https://www.pencomsf.com/articles-updates/galling-of-stainless-steel-fasteners/

              Staining:  https://www.marshfasteners.com/can-stainless-steel-and-aluminum-be-used-together/#:~:text=When%20using%20stainless%20steel%20fasteners,also%20called%20'tea%20staining'.

                      Metallurgically yours,  Chuck Engles 

-------------- next part --------------
    To all,
   Electrical discharge Machining will remove stainless steel from
   aluminum without damage to threads. I worked in field service on
   semiconductor environmental handling equipment for about 10 years.
   There was mechanical movement inside a chamber that had to operate
   through a temperature range from -55 ADEGC to +125 ADEGC. The mechanism
   was anodized aluminum and all hardware used was stainless steel to
   prevent rusting. I took many parts to a machine shop for removal of
   stainless steel from aluminum. Largest thread size was 8-32. But not
   often enough to make me think the cause was not human related.
   Bud 3400 Drive like there will be no tomorrow, for there may not be.

   On Saturday, July 27, 2024 at 03:16:59 PM CDT, Charles Engles
   <cengles at cox.net> wrote:
   Dear Ken,
                 ARP's engineering and technical staff know much more than
   I do, but I would never use stainless steel bolts in an aluminum crank
   pulley.    :-)
                               Warmest regards, Chuck Engles
   -----Original Message-----
   From: Ken Green [mailto:kenn_green at yahoo.com]
   Sent: Saturday, July 27, 2024 11:47 AM
   To: detomaso at server.detomasolist.com; Charles Engles
   Cc: 'B Hower'; Asa Jay Laughton
   Subject: Re: Stainless steel hardware and aluminum complications
   ARP says to use an anti-seize on the stainless fasteners, do you think
   that resolves the issues?
   On Saturday, July 27, 2024 at 06:26:41 AM PDT, Charles Engles
   <[1]cengles at cox.net> wrote:
   Dear Ken,
               Your comment about using stainless steel studs and hardware
   on the ZF, reminded me of a lesson I learned from another Pantera owner
   and a very experienced Ford Motorsports and Rousch Industries
   engineer.  After my friendas Pantera began making troubling noises, it
   was determined that the culprit was the aluminum crank pulley secured
   with stainless steel bolts.  Ultimately, it required major mechanical
   efforts to remove the cold-welded stainless steel-aluminum from the
   balancer.  The pro told me to never use stainless steel in aluminum
   because of the tendency to galling and worst case scenario---cold
   welding.  I had *no* idea.
             Just yesterday I was working on a Windsor engine with an
   aluminum intake manifold.  My brother told me that on its previous
   iteration, the front nose (?) piece on the intake manifold coolant
   snout was very problematic to get watertight.  Short story: I found
   that the two *stainless steel* bolts did not completely thread down.
   Each was blocked at a different depth.  A thread chaser was a big
   improvement, but I re-tapped both and finally got both bolts to seat
   properly.  Then, it dawned on me that the snout-intake had been
   assembled, at least, two or three times before I got it.  The problem
   was the stainless steel bolts galling the bolts holes.  I also replaced
   the SS bolts with common steel bolts.
             In addition to the SS-aluminum galling propensity, there is
   also a potential for electrolytic reaction of SS-alum to produce atea
   staininga of the *stainless*steel fasteners.
             Information links:
                 Galling:
   [2]https://www.pencomsf.com/articles-updates/galling-of-stainless-steel
   -fasteners/
                 Staining:
   https://www.marshfasteners.com/can-stainless-steel-and-aluminum-be-used
   -together/#:~:text=When%20using%20stainless%20steel%20fasteners,also%20
   called%20'tea%20staining'.
                         Metallurgically yours,  Chuck Engles

References

   1. mailto:cengles at cox.net
   2. https://www.pencomsf.com/articles-updates/galling-of-stainless-steel-fasteners/