Shear pin?

[hayden]

Good question! Maybe they restrike the face?

Personally, I think just using grade 2 bolts is the way to go. The rest of the issues are in the noise.

 

[TWINKLE_TOES]

Randy,

This is a text file for SAE and ASTM markings. Not as good as a picture but accurate. If you would like to view this without the indentation all messed up, see FAQ #22 here
Al

-----------------------------------------------------------------------------
ASTM and SAE Grade Markings for Steel Bolts and Screws
-----------------------------------------------------------------------------

Grade Marking Spec. Material
-----------------------------------------------------------------------------
SAE - Grade 1 Low or Medium Carbon Steel
No ASTM - A 307 Low Carbon Steel
Mark SAE - Grade 2 Low or Medium Carbon Steel

-----------------------------------------------------------------------------


-- -- SAE - Grade 3 Medium Carbon Steel


-----------------------------------------------------------------------------
| SAE - Grade 5 Medium Carbon Steel
Quenched and Tempered
ASTM - A 409
/ \
Min Tensile Strength: 105,000 to 120,000 psi
Proof load: 74,000 to 85,000 psi
-----------------------------------------------------------------------------
| SAE - Grade 5.2 Low Carbon Martensite Steel
\ / Quenched and Tempered


-----------------------------------------------------------------------------
|
-- -- SAE - Grade 6 Medium Carbon Steel
| Tempered

-----------------------------------------------------------------------------
| ASTM - A 325 Medium Carbon Steel
Type 1 Quenched and Tempered
A 325 Radial dashes optional
/ \

-----------------------------------------------------------------------------
| ASTM - A 325 Low Carbon Martensite Steel
\ / Type 2 Quenched and Tempered
A 325


-----------------------------------------------------------------------------
ASTM - A 325 Atmospheric Corrosion (Weathering)
Type 3 Steel, Quenched and Tempered
A 325
-----

-----------------------------------------------------------------------------
ASTM - A 354 Alloy Steel,
Grade BC Quenched and Tempered
BC


-----------------------------------------------------------------------------
| SAE - Grade 7 Medium Carbon Alloy Steel
Quenched and Tempered,
-- -- Roll Threaded After Heat
/ \ Treatment
Min Tensile Strength: 133,000 psi
Proof load: 105,000 psi
-----------------------------------------------------------------------------
| SAE - Grade 8 Medium Carbon Alloy Steel
\ / Quenched and Tempered
ASTM - A 354 Alloy Steel,
/ \ Grade BD Quenched and Tempered
| Min Tensile Strength: 150,000 psi
Proof load: 120,000 psi
-----------------------------------------------------------------------------
\/ SAE - Grade 8.2 Low Carbon Martensite Steel
\ / Quenched and Tempered
\ /


-----------------------------------------------------------------------------
ASTM - A 490 Alloy Steel,
Type 1 Quenched and Tempered
A 490


-----------------------------------------------------------------------------
ASTM - A 490 Atmospheric Corrosion (Weathering)
Type 3 Steel, Quenched and Tempered
A 490
-----

 

[TWINKLE_TOES]

Dan,

I would guess, as you, the markings are product of the mold when the bolt is manufactured. I would also guess to downgrade and remark would be a question of economics.

So with two guesses I have to admit I don't know. Guess thats what happens when you quote something you don't fully understand. /w3tcompact/icons/blush.gif

 

[TWINKLE_TOES]

<font color=blue>for those of us who are memory impared - the grade is the number of lines plus 2.</font color=blue>

That would be me Hayden. Now what was I going to post??/w3tcompact/icons/frown.gif Oh, that works for all but SAE grade 3.

 

[dmccarty]

My JD 48 backhoe uses grade 5 bolts. I busted one a few weeks back and I went to get a replacement bolt. What is causeing me to scratch my head is that the bolt head not only had the grade 5 marks but other marks. At first I thought the marks were just brand marks but when I was at the dealer, the bolt is a special order bolt for some reason. Then I checked out another JD 48 they had on the lot and the bolts on it had the same marks that mine did. So I'm worrying that marks mean something.

The bolts were something like 90 cents from JD. I ordered three of them but I have not had time to pick them up yet. Three dollars is cheap insurance at this point. The parts guys did not know what the stamping meant or if there was any difference at all.

My question is, do bolts have different markings other than the slashes? When this happened I searched the web and found some of the bolt standards but I did not get an answer to my question.

The back hoe has four or so different bolt markings. The bolt I have to replace was a grade 5 with RR on the head. Another was a 5 with a pyramid stamp. A plain old grade 5. And another grade 5 with a JH or JC stamp.

Does anyone know what these markings mean?

Thanks...
Dan McCarty

 

[RJohnson]

The marking are manufacturer identification marks. They may or may not be present depending upon the specification the bolt was manufactured to. SAE J429 does require the grade identification along with the manufacturer's identification symbol. The symbol may be raised or depressed. But it has generally been industry practice to raise the stamping as this has to be added to the head stamping die and depressed markings could be added after the bolt was made and therfore can be construed to be a fake. Counterfitting of bolts was a big issue a few years back. The only publication that I am aware of that addresses head marking is published by the Fastener Technology International Magazine http://www.fastenertech.com/. You can order it for $25 on their website, I haven't bought one in years and mine is 10 years old and doesn't have the head markings you described.
But to get back to the issue of shear pins, the shear pin is a designed weak link in the system and anytime you change the strength of the weak link the load will be transferred to the next weak link and something else can now break instead of a cheap pin. And it could also kill or injure you in the process. I would not use any grade of bolt stronger than the manufacturers recommendation. IMHO.

Randy

 

[TWINKLE_TOES]

Randy and Dan,

Dan good question, I hope you don't have any more, they keep gettin harder./w3tcompact/icons/smile.gif

I agree with Randy, the markings are manufacturer identification marks.

Military Handbook 57B (Mil-HDBK-57B)also registers manufactuer symbols.

I was able to identify RR and JH but not JC. There are many hundreds of symbols identified and not necessarily related to the manufacteurs name.

RR is: Rassini International, Inc.
617 East Huron Street
Ann, Arbor Mi. 48104

JH is: (The J and H share the vertical portion, like a stock brand)
Hassall John, Inc
P.O. Box 698
Cantiagui Rock Rd.
Westbury, NY 11590

Other marks are placed on the bolts, for example six dots in a circular pattern are used to identify locking features.

Al

 

[DFB]

Here is a link to the register of current fastener insignias. http://www.uspto.gov/web/offices/tac/fqa/fqa.htm

Also a printable online grade mark chart can be found here. americanfastener.com/techref/grade

DFB

 

[gerard]

My post hole digger uses grade 2 and I just buy them by the handful. cheaper insurance you can't get. If I remember right at the local farm store the grade 2 are silver, 5 are red and grade 8 are dyed blue. (This inaddition to the head markings) Probably not universal but a nice touch when they use it?
Von - re WD40 on clutch plates - I would think that since WD40 is so volatile it tends to evaporate off pretty quickly as it would do on a clutch plate. That's why it's really not good as a long term lubricant like heavy oil or grease. I thinks it's probably closer to a solvent than a lubricant?

 

[dmccarty]

Thanks Randy, DFB, and Mr. TToes! /w3tcompact/icons/smile.gif

There was a discussion on the head markings a few months ago and I thought I remembered that the markings were the company's brand. What made me scratch my head was that the RR bolt was in the same place on my JD 48 as well as the one on the dealers lot. That and the special order on the bolt me get a bit cautious. /w3tcompact/icons/smile.gif

I still have not picked up the bolts I ordered and I'm very curious if they have RR on the bolt.

Thanks again....
Dan McCarty