Required Bolt Grade

[lil_Blue_Ford]

I know the OEM shackle bolts trashed the metal cutoff blades on my sawzall. I had to resort to cut off wheels in order to get the old ones out. So, they are pretty hard.

Yup, even the Milwaukee Torch blades and Diablo carbide tipped metal blades have a hard time chewing OEM shackle bolts. Death wheel is the ticket. Or a torch and make them liquid.

 

[1984RESTOMOD]

Or a torch and make them liquid.

This was my approach when breaking down my frame for sandblast. Made quick work of 80s rivets alongside a punch and sledge.

 

[lil_Blue_Ford]

This was my approach when breaking down my frame for sandblast. Made quick work of 80s rivets alongside a punch and sledge.

Torch is arguably one of my favorite tools…

 

[superj]

Head bolts markings were in effect in 2000 when i went to a&p school. So they had to be before that too as our a&p handbooks were dating prior to my time in school.

I too work from government, or oem, supplied manuals so i don't have to remeber head bolt markings.

And for us, if you knowingly don't follow the manuals, the few times i have read in the pass downs from upper managment, people went to federal prison. There was no loss of life or aircraft but lots of rotor blades had to come off aircraft and be sent back to be overhauled again. Three or four guys got 20 years for falsifying the numbers when testing the blades before sending them out.

 

[rubydist]

When you are as old as I am, 2000 was just a few years back...

 

[alwaysFlOoReD]

To answer the original question...
Grade 8 x 1/2" diameter is what I used on my race truck. BUT... I made sure the unthreaded portion of the shank supported both the frame and bracket and that the holes were drilled to the same size as the bolts... No slop! I used washers where I had to, to take up space so the nut didn't hit the plain shank before tightening. After, I got to thinking of aftermarket bolt on hitches, and they are all grade 5 bolts. Thicker than the ones used in truck frame brackets tho. So I would probably use grade 5 slightly bigger diameter if necessary.

 

[don4331]

My shackle/spring bolts are grade 8 with holes in them and grease zerks. So, they probably are not really grade 8 anymore. Don't remember what the shackle hardware was that came with the hangers. I want to say it was 8.8 which is a tad harder than grade 5.

If your shackle bolts are stamped grade 8, they need have grade 8 strength.

Note: Bolt grade specify the minimum, not the maximum.​

There are steels out there with strength far beyond the 150ksi required for grade 8 - e.g. 8740 at 210 ksi, or L19 at 260 ksi.​

​

So, with your hollow bolt, the mfr. needs to use a better material/heat treatment if he is certifying their strength.

To the OPs - class 8.8 bolts probably exceed the strength of the OEM rivets, so class 10.9 would be fine (Ford allowed grade 5 bolts in their frame repair manual). Then you either need washers or flanged bolts/nuts to distribute load before lock washer/thread locker.

 

[don4331]

To answer the original question...
Grade 8 x 1/2" diameter is what I used on my race truck. BUT... I made sure the unthreaded portion of the shank supported both the frame and bracket and that the holes were drilled to the same size as the bolts... No slop! I used washers where I had to, to take up space so the nut didn't hit the plain shank before tightening. After, I got to thinking of aftermarket bolt on hitches, and they are all grade 5 bolts. Thicker than the ones used in truck frame brackets tho. So I would probably use grade 5 slightly bigger diameter if necessary.

No slop and supported on shank, not threads are critical, but not drilling out such a large hole that there is insufficient material in the bracket to maintain strength is the flip side.

This is one case where the slight differences between metric and imperial is an advantage - e.g. 3/8" is just slightly smaller than 10mm (~0.4mm), so you may ream the hole for the metric bolt to eliminate any slop without having to remove as much material as going to 7/16"​

 

[alwaysFlOoReD]

Rivets work even if the holes aren't aligned.
The rivets I was replacing needed 1/2" holes to properly align. 7/16" left some parts of the hole too big. But yes, I would use the smallest diameter possible.

 

[JoshT]

Head bolts markings were in effect in 2000 when i went to a&p school. So they had to be before that too as our a&p handbooks were dating prior to my time in school.

Dad and I both went to the same A&P school. He started in 2000 and graduated in 2003, I started in late 2003 and finished around 2005. Didn't actually graduate until 2013 because I continued part time for the assaociates degree. Took so long because I had to take classes around work schedule and had to wait for what I needed to drop, since I needed to stay enrolled I tackled a double major with IT as the second.

 

[superj]

Thats great that you stayed and got IT also.

 

[JoshT]

Thats great that you stayed and got IT also.

It would be even greater if I were actually using it. Even so, I think the dual associates helped on my last job interview. Was taking classes to turn that one into a bachelors, one to two classes a semester takes years to complete at the school I was attending. Stopped after summer semester and life has certainly been more enjoyable. Finally getting time to do things I want to do outside of work and actually feel like doing them instead of being worn out from turning wrenches on airplanes all day.

With this job I don't think the B.S. is beneficial any more. I'm guranteed a GS 9 next year with a fairly easy promotion to GS 11 after that. If something in the works actually happens, it will be a non competitive promotion to the 11 in two years. Higher than that in this job gets into management positions like team leads, I'm not sure that I want that.

 

[superj]

I can tell you, previously being a ws10, management in government positions gets very old. Especially at the lower tiers because you get blamed from the employees and from the higher managment.

I was a ws10 for 6 years and finally went back to being a wd06. Same pay, basically, and i only account for myself. 8 more years and i can retire to bike riding and playing in the yard

 

[JoshT]

That's why I'm where I'm at. I was a WG-10 step 5 with 16 or 17 years in. They had several WL slots opens, but that is as high as I wanted to go on that path for the same reason. Didn't get referred for a few. one opened with about 6 slots and I got an interview for it. After getting passed over for a supervisor's buddy with less than 4 years and no knowledge of what he was being promoted to (never worked systems that he got selected for), I said to hell with maintenance. My buddy did get one of those slots, he disserved it and I was happy for him. After seeing how the position was treating him, I'm glad I didn't get it, things would not have gone well.

Less than a year later I got a position in scheduling for a different weapon system where I'd spent a year and a half on load during covid period. It's nice not busting my butt on the air plane all day, even nicer being out of that weapon system. Look forward to the day I actually get to start the scheduling part ofmy job. So far I've been serving as an FLS (parts ordering and management) for several aircraft, the last few have been terrible parts wise and just haven't had time to start the transition.

Wish I only had 8 more years. I've got about 11 to the 30 year mark, then another 7 to retirement age. With the way things are going I'm not sure I'll be able to afford to then. Maybe I can take a deferred retirement after the 30 or 37 years and find a way to use that IT degree. By then everything should be paid for so I should be able to live comfortably off part time work. Now watch me get married and have a kid in the next few years, then have to work until I'm drawing SS to pay for their education. (Doesn't seem too likely.)

 

[sgtsandman]

I'm happy being a WG-10 and will retire as one. I applied for a few GS-9 and 10 positions over the years but in hind sight, it was a blessing that I never got them. I never had an interest in supervision. The negatives of the job just don't seem worth it and you get crap from above for what someone else did because you are in charge of them or you get crap from below because you are doing your job or having to enforce what has come down from above. Lose-lose all the way around.