Bolt Question

Wed Apr 14, 2004 8:25 pm

I'm rebuilding 49-1 and am using stainless hardware. I think the contrast between the RED and the stainless looks great.

My question is, the bolts that couple the tractor together I believe are grade 8 (150,000 psi tensile strength) The stainless I want to use is 70,000 psi tensile strength or about half. I am leaning on using the grade 8 (they were put there for a reason).

What do you experts say :?: :?: :?:

Wed Apr 14, 2004 8:30 pm

My personal opinion is that this isn't the place to skimp. I'd go with the grade 8.

Wed Apr 14, 2004 8:33 pm

I think I would go with the stronger 8s or original strength bolts. The center of the Cub takes more stress on rough bumpy ground. (Just my personal opinion).

Wed Apr 14, 2004 10:23 pm

The 70,000 psi stainless is probably 300 series (non-magnetic). You can get stainless bolts at 150,000 psi or better if it is 400 series stainless (slightly magnetic). 300 series with it's high nickle content (308, 309, 311, 316, etc) is better for corrosion resistance, but 400 series is much stronger and can be heat treated due to the carbon content (knife blades, etc). It's been a while since I messed with this stuff, but a metallurgist can confirm the above. Bottom line, go with the grade 8 in the head so your bolts don't stretch............

Thu Apr 15, 2004 12:40 pm


If I have it right the 400 series is Monel which is a Nickel Copper Alloy. It is only slightly stronger than the 300 series. An increase from 70,000 psi for the 300 series to 80,000 psi for the 400 or Monel.

I think I'll stick to the Grade 8. Wouldn't want the tractor to come apart. :shock: :shock: :lol: :lol: :lol:

If the tractor was just going to sit then the 300 series would be fine. Merry wouldn't like it if I spend all this money just to have the tractor sitting and not earning it's keep. :wink: :wink: