Tensile Strength Stainless lugs and hub plange bolts

[ScottT]

Anyone know the grade or tensile strength of the 3/8 BSF bolts that hold the flange to the hub? I am looking at getting some in stainless and want to be sure they are strong enough.
Anyone have any experience with the Stainless lugs for Wrington Engineering?

Thanks
Scott

[109 Pretender]

Scott,
I don't think you want to use S/S for your drive flange bolts. S/S is generally Grade 1/2 - OK for trim H/W or body bolts. Stainless also galls much more than steel alloy bolts. You would want at least a good quality Grade 5 min. or a Grade 8 if you want that extra strength. Also the drive flange bolts don't experience much 'tension' loading (function of your torque specs. for the bolt). The bolts are loaded in 'shear' much more and a high quality grade 5 or better should suffice (not Ace H/W stuff). I don't think regular S/S has enough reserve strength. Stainless BSF would probably be vhard to find in USA as well.

cheers

[109 Pretender]

Here's a link that gives some decent general bolt info about material types and grading.

http://www.boltdepot.com/Fastener-Information/Materials-and-Grades/Materials.aspx

Happy wrenching!

[Mercedesrover]

What he said.

Stainless isn't what you want for this application. It galls up, doesn't take torque well and won't take being removed more than once or twice. Stick wit the stock bolts.

Those bolts are 3/8 x 16 and not easy to find. If you find a source for studs and nuts, let me know.

[Terrys]

The only stainless alloys whose tensile strength and ductility are equal to, or better than high strength carbon steel, are the martensitic alloys. I have never heard of fasteners being made in these alloys (409, 410, CA6NM, etc)
Fasteners are almost always Austenitic alloys containing 18% Chrome, 8% nickel, and those also with Molybdenum. They are great for corrosion resistance, but inferior for tensile strength. They do, however have great ductility (stretch like taffy) As mentioned above, you are primarily interested in shear resistance (measured by Charpy impact testing, in ftlbs)
Good quality Grade 8 bolts are what you want here. Grade 5 are not strong enough for this application.

[greenmeanie]

It could be the answer to the well known bane of series ownership - the snapping half shaft. Choose the right material and your drive flanges will break loose before the halfshaft goes. I can see our hosts doing a run on these with a predrilled hole down the middle and matching easy out.:D

[jp-]

It could be the answer to the well known bane of series ownership - the snapping half shaft. Choose the right material and your drive flanges will break loose before the halfshaft goes. I can see our hosts doing a run on these with a predrilled hole down the middle and matching easy out.:D

Actually, that might be doable.

[Mercedesrover]

It could be the answer to the well known bane of series ownership - the snapping half shaft. Choose the right material and your drive flanges will break loose before the halfshaft goes. I can see our hosts doing a run on these with a predrilled hole down the middle and matching easy out.:D

I know a better solution......

:)

[ScottT]

If anyone is interested in stainless lugs PM me. They get cheaper with quantity.

[jp-]

If anyone is interested in stainless lugs PM me. They get cheaper with quantity.

Didn't we just agree that this was a bad idea?

[Terrys]

Those bolts are 3/8 x 16 and not easy to find. If you find a source for studs and nuts, let me know.

? I think you're kidding. 3/8-16 is standard USS, 3/8-24 is USF. MacMaster-Carr has grade 8 studs

[ScottT]

I thought the studs for the flange plate were the issue, the BSF 3/8 and I have since decided against those. Did I miss something on the lugs? I may have I was checking the board on my preps today.


Didn't we just agree that this was a bad idea?

[Daurie]

I've stripped out a 3/8 x 16 stainless bolt with a 3/8 battery operated impact. :(

[ScottT]

Does anyone see an issue with stainless steel lugs 1 1/16 in 316 Marine Grade Stainless.
Thanks

[Mercedesrover]

? I think you're kidding. 3/8-16 is standard USS, 3/8-24 is USF. MacMaster-Carr has grade 8 studs

Doh! My bad. If I remember right these drive flange bolts are 3/8 x 18. Is that right? It's been a while since I've been down that road trying to find an alternative.

[jp-]

Mercedes you are not wrong. There is a 3/8 x 16 UNC and a 3/8 x 16 BSC. The thread count is the same, but the pitches are different, 60 deg vs 55 deg for the BSC. You should not mix and match these as you will lose some strength by doing so.

UNF and BSF will not go together, so no chance of getting these two mixed up.

BSC and BSF are available from several online suppliers.

[Daurie]

Does anyone see an issue with stainless steel lugs 1 1/16 in 316 Marine Grade Stainless.
Thanks

Stainless fastners, by reputation, just don't stand up to repeated use. Try out the 1 1/16 lugs and let us know how it goes. :thumb-up:

[jp-]

Does anyone see an issue with stainless steel lugs 1 1/16 in 316 Marine Grade Stainless.
Thanks

There is a reason that most lug nuts that are stainless are only clad in stainless (outer shell is stainless). The base metal is grade 8 steel.

[Mercedesrover]

Just went out and pulled a bolt out of a spare diff housing. That thread is 3/8" x 20. I knew it was something funky. If anyone finds 3/8" x 20 studs and nuts I'd love to have some myself.

[Terrys]

Doh! My bad. If I remember right these drive flange bolts are 3/8 x 18. Is that right? It's been a while since I've been down that road trying to find an alternative.

Don't make me go out there again Jim. I just did the same thing, but you have more energy than I. I pulled a front drive flange bolt. It's 3/8 BSF (which I thought was 18tpi. If memory serves, which is hit or miss lately, isn't 3/8 BSF the same as 5/16 Whitworth?

[Mercedesrover]

3/8" BSF is 20tpi. 5/16 BSW is 18tpi and 3/8" BSW is 16tpi.
Is 3/8 BSF the same bolt size as 5/16 BSW?