Stainless or steel 1/2 or 9/16

[hooken203]

What bolts are you using to mount your jackplate/engine? Have read posts about going to 9/16 bolts and a few about using grade 8 or 9 bolts. I have been using 1/2 fine thread SS and brass nyloc nuts forever and have never seen a problem.

 

[catfish123]

Subscribed................I do not believe SS hardware is recommended for this application, but I'll wait for someone to post who knows the answer for sure...........LOL

 

[GotMyAlly]

Stainless and brass is what I've always used.

 

[Myron]

9/16 bolts thru the transom, grade 8 fine thread double bolted at the tops for the jackplate to setback and for jackplate to motor

 

[racerx]

Now call Allison for two bolts 60 bucks...I couldn't fine one anywhere when I needed them..

 

[hooken203]

Theres plenty of places to get SS bolts and brass nyloc nut. Quality can be a problem some times.

 

[racerx]

9/16 fine thread is a my mom to find probally 6 inches long..

 

[h2oskiier30]

http://www.mcmaster.com/#91257a788/=qb78w6

Grade 8 Alloy Steel Hex Head Cap Screw
Zinc Yellow-Plated, 9/16"-18 Thread, 6" Length
In stock
$3.50 per pack of 1
91257A788

 

[catfish123]

This type of bolt, Grade 8 was what I thought was recommended, not SS?

 

[Bobalouie]

I don't know if grade 8 is the best choice due to its poor performance when subjected to cyclic loads in shear. Grade 8 is great when it is loaded in tension, but a bolt holding a motor on a transom or jackplate is shear loading. A good SS bolt is about the same as a grade 5, which, in my opinion is a better choice due to being less brittle and therefore less prone to catastophic failure when subjected to cyclic shear loading.

A good example of this is RAs trailer tounge bolt. If I remember correctly, he replaced it with grade 8 hoping it would solve the problem, but it didnt. Its a classic example of a very strong but brittle fastener being used in an application where it is subjected to cyclic shear loads.

 

[hooken203]

Bobalouie thats what my thoughts were on this also. I have seen other situations where a harder bolt was not the better way to go.

 

[SLOmofo]

Another, Stainless on stainless will gall big time! Then you get to cut it off.

 

[ssv1761982]

Another, Stainless on stainless will gall big time! Then you get to cut it off.

Just a little lube will prevent the galling.

 

[SLOmofo]

Most of the time, yes. Then there's that other time! BTDT.

 

[loop]

17-4 or 15-5 if you need strong stainless bolts. wont find em at home depot but they are available online

 

[ziemer]

I think I paid Allison $100 for the set of bolts for my GS (9/16" top, 1/2" bottom). Since all mine are behind the gas tank they have flat tabs welded on. I guess welding tabs on those fancy bolts is expensive... :banghead :beer:

 

[boat doctor]

Buy a CATERPILLAR ones .............:wink

 

[fasterbass]

On stainless bolts use antisieze, the silver looking kind.my can is unreadable or I would give you the brand..it smears and makes a mess and you can't hardly get it off of yourself but I have never gallded a lugnut or jackplate bolt and I use stainless bolts and nuts and stainless flat washers