Bolts and powder coating the frame?? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Estanley · 06-12-2002, 09:34 AM

It will take 2 or 3 extra months to make up the cost difference but I have decided the have my frame and suspension components powder coated. I hope I can have every bracket that bolts to the frame done as well. My question is about the bolts. I am assuming the bolts that attach the front crossmember and the trans x-member are hardened. I am considering using all stainless bolts, nuts and washers. Can I get hardened bolts in stainless? Has anyone done this?

JimKshortstep4x4 · 06-12-2002, 10:32 AM

I would be hesitant to use stainless bolts in a structural situation because they will stretch under loading.

Jim

chaptr2 · 06-12-2002, 12:35 PM

Why don't you have the heads of the bolts and the nuts powder coated too?

I took the u-bolts and nuts for my trailing arms and powder coated them. Then I had to use the impact to tighten them up. The powder coat held up really well with minor chipping (not enough to tell unless you put your nose up to it).

It will make the hardened bolts look a lot better and last longer if that is what you are looking for.

tom hand · 06-12-2002, 01:45 PM

Do not put stainless bolts on anything structural. They are weak compared to medium grade hardware store bolts. The only reason to use them is corrosion. If you must have shiny bolts, have good 8 grade ones chromed, but keep in mind that even that weakens them.

Slammed67 · 06-12-2002, 02:27 PM

I used stainless steel bolts on mine. I understand the concern for structural strength with stainless fasteners, but how much stress is there really on a trans crossmember? The thing sits inside the "C" channel of the frame. As far as I can see, those bolts only hold it in place..... no stress on them. As for the front cross memeber, same thing. It sits under the frame, so all the force is upwards..... The only downward force is the partial weight of the engine. And since it straddles the frame, it isn't going anywhere side to side either. Maybe I just live life one the edge, but I wouldn't worry about it. My $0.02.

70 Jimmy · 06-12-2002, 03:44 PM

The stress on the crossmembers is more than you think. The transmission twists under heavy acceleration and the suspension takes multiple side loads too. Think about when you hit a bump.

Estanley · 06-12-2002, 04:18 PM

Just found out that regular stainless bolts are a grade 2. What grade bolts are in the crossmembers?

tom hand · 06-12-2002, 04:40 PM

Every bolt you put on your truck should be grade 5 for minor stuff and grade 8 for anything important. I wouldn't put grade 2 on a kids tricycle.

Chad · 06-12-2002, 04:48 PM

My dad did a Rockwell Hardness test on the original rivets that came from my blazers frame. They were all suprisingly soft. I am using grade 8 equivilent stainless on everything. I don't remember the grading scale for stainless. Yes, Stainless has a different grading scale. Just make sure you don't get the run of the mill stainless stuff. Spend the extra to get grade 8 equivilent.

Later,
Chad

06-12-2002, 09:34 AM	#1
Estanley Registered User Join Date: Nov 2001 Location: Eatonton, GA, USA Posts: 191	Bolts and powder coating the frame?? It will take 2 or 3 extra months to make up the cost difference but I have decided the have my frame and suspension components powder coated. I hope I can have every bracket that bolts to the frame done as well. My question is about the bolts. I am assuming the bolts that attach the front crossmember and the trans x-member are hardened. I am considering using all stainless bolts, nuts and washers. Can I get hardened bolts in stainless? Has anyone done this?

06-12-2002, 12:35 PM	#3
chaptr2 Registered User Join Date: Mar 2000 Location: Olalla, WA Posts: 705	Why don't you have the heads of the bolts and the nuts powder coated too? I took the u-bolts and nuts for my trailing arms and powder coated them. Then I had to use the impact to tighten them up. The powder coat held up really well with minor chipping (not enough to tell unless you put your nose up to it). It will make the hardened bolts look a lot better and last longer if that is what you are looking for. __________________ This is only my opinion and it is subject to change. 70 GMC Short box stepside Blown 388 Stroker 72 K/5 Blazer 350/SM465/205

06-12-2002, 01:45 PM	#4
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	Do not put stainless bolts on anything structural. They are weak compared to medium grade hardware store bolts. The only reason to use them is corrosion. If you must have shiny bolts, have good 8 grade ones chromed, but keep in mind that even that weakens them. __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS Last edited by tom hand; 06-12-2002 at 02:37 PM.

06-12-2002, 02:27 PM	#5
Slammed67 Progress = 0% Join Date: Nov 2001 Location: Kansas City, MO Posts: 2,108	I used stainless steel bolts on mine. I understand the concern for structural strength with stainless fasteners, but how much stress is there really on a trans crossmember? The thing sits inside the "C" channel of the frame. As far as I can see, those bolts only hold it in place..... no stress on them. As for the front cross memeber, same thing. It sits under the frame, so all the force is upwards..... The only downward force is the partial weight of the engine. And since it straddles the frame, it isn't going anywhere side to side either. Maybe I just live life one the edge, but I wouldn't worry about it. My $0.02. __________________ Jason - '67 GMC swb \| '57 Bel-Air 4dr hardtop \| '56 210 4dr Wagon \| 2000 GMC Sierra

06-12-2002, 03:44 PM	#6
70 Jimmy aka Crusher, Crushergmc Join Date: Mar 2000 Location: Oregon Posts: 1,834	The stress on the crossmembers is more than you think. The transmission twists under heavy acceleration and the suspension takes multiple side loads too. Think about when you hit a bump. __________________ "KEEP IT DOWN!" 70 Jimmy 454 2wd 56 GMC Big Window "It's funny till someone gets hurt, then it's freakin' hilarious"

06-12-2002, 10:32 AM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	I would be hesitant to use stainless bolts in a structural situation because they will stretch under loading. Jim

06-12-2002, 04:18 PM	#7
Estanley Registered User Join Date: Nov 2001 Location: Eatonton, GA, USA Posts: 191	Just found out that regular stainless bolts are a grade 2. What grade bolts are in the crossmembers?

06-12-2002, 04:40 PM	#8
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	Every bolt you put on your truck should be grade 5 for minor stuff and grade 8 for anything important. I wouldn't put grade 2 on a kids tricycle. __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

06-12-2002, 04:48 PM	#9
Chad Registered User Join Date: Oct 2000 Location: Midlothian, Tx Posts: 199	My dad did a Rockwell Hardness test on the original rivets that came from my blazers frame. They were all suprisingly soft. I am using grade 8 equivilent stainless on everything. I don't remember the grading scale for stainless. Yes, Stainless has a different grading scale. Just make sure you don't get the run of the mill stainless stuff. Spend the extra to get grade 8 equivilent. Later, Chad __________________ Chad ------------------ 69 Short Fleetside 72 2wd Blazer 70 4x4 Blazer 67 Chevy(big window) Just a cab for now 64 Chevelle SS (2dr Ht)



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