Bolt head markings: R-H-B

My Super M has a SpeeCo, or Norden aftermarket front end on it.

The bolts holding it to the front bolster do not have the normal tick marks indicating grade, but the letters R-H-B where the normal markings of a Grade 5 bolt.

What do they stand for? Really Hard Bolt, I hope...

Probably grade 2, markings are just manufacturer. They don't
use lines until grade 5 and 8.

The letter are code assigned to different manufacturers. There may be a list online. We had a list from SAE that we used to check whether the bolts in delivered equipment were certified (tested to SAE standards) or counterfeit bolts from some other country or company that does not test and certify their bolts. It is too risky for government agencies to use counterfeit bolts.

There was a flood of counterfeit bolts in the U.S. in the early 90's and some of them may still be in the supply line yet today.

The most extreme example of using counterfeit bolts was the DC10 that crashed several years ago in Sioux City, Iowa. The aircraft industry weren't checking the bolts that they used back then.

If there are no markings on the bolt, you can assume that they are grade 2. If the manufacturers code/initials are not on the certified list, you should assume that the bolts could be weaker than they should be and may be risky to use.

We had one paver come in that 102 counterfeit bolts in the machine that did not meet our specifications. The vendor was given the choice to change the bolts to certified bolts or pay a penalty and take back the machine.

Google Bolts and Nuts.com and they will show a chart of grades of bolts.

(quoted from post at 06:53:11 06/04/12) My Super M has a SpeeCo, or Norden aftermarket front end on it.

The bolts holding it to the front bolster do not have the normal tick marks indicating grade, but the letters R-H-B where the normal markings of a Grade 5 bolt.

What do they stand for? Really Hard Bolt, I hope...

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For what it's worth, Norden and Spee-Co are two seperate companies, or were. Norden no longer exists, and Spee-Co was bought out by Schwartz.

Parts for the Spee-Co and Schwartz are not a problem as they are still in business. Schwartz parts can sometimes be made to fit the Norden with a little imagination and determination.

We had a overhead mounted robot gantry arm, weighing over 2K, fall off, due to crappy bolts. We had to shut the line down, and replace all the mounting bolts, one at a time - something like 1600 1.5 in bolts.

I said the front end was a Norden OR a SpeeCo, not both.

It's definitely not a Schwartz.

I sincerely doubt that the bolts are "counterfeit" as they have probably been in there since the 1960's. If they were from the 90's, they would come out easily.

(quoted from post at 10:36:18 06/07/12) I said the front end was a Norden OR a SpeeCo, not both.

It's definitely not a Schwartz.

I sincerely doubt that the bolts are "counterfeit" as they have probably been in there since the 1960's. If they were from the 90's, they would come out easily.

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R H B would be either the initials of the company that made them, or a special code used by that company for identification purposes. They definitely are grade 5 bolts, and I would bet they are made in the U.S.A.

I've seen other bolts with similar markings but I can't say for sure if I've ever seen RHB.

If you want GOOD, grade 5 replacement bolts, get them from a farm machinery dealer and not at your local farm store or home center.