Bolts

[John C.]

Sometime ago there was a topic talking about bolt markings and strength and such. I ran across this YouTube channel awhile back and saw this. It will answer any questions about the markings mean and how they measure out as far and strength and hardness go.

 

[Coaldust]

I really dig these guys. Awesome content.

 

[8V71]

I cringe any time I see anything less than grade 8/ 10.9 (hardware store bolts) on any machine.

 

[digger doug]

I cringe any time I see anything less than grade 8/ 10.9 (hardware store bolts) on any machine.

Some times a grade 5 is better when you don't want it to fail with a bang.

 

[Birken Vogt]

Use the grade and material that the application calls for.

 

[John C.]

I like the grade 5 for sheet metal and non load carrying stuff. It's easier to drill and easy out.

 

[Spud_Monkey]

Grade 2 for shear bolts.

 

[Simon C]

Watched the entire video, and was what I previously read in a book written by Bouwman bolt makers about 30 years ago. Good amount of detail, and well made video. Glad you shared it.
Simon C

 

[mitch504]

I personally use a lot of gr 5 for general applications, gr 8 for anything critical, gr 2 for shear bolts, or if I need a lot of bolts to hold wood together. Otherwise, if I find a gr 2 or 307a bolt around my shop, I throw it away. This is mostly an old habit from the days when I had lots of employees.

What I learned from this video the first time I saw it was about the stainless bolts. Since I work with fertilizer so much, I use a LOT of 18-8 bolts. If a gr 8 bolt is going to lose 50% of it's diameter in a year, it's definitely not stronger. You also won't unbolt it next week. I always thought the 18-8 was about the same as gr 2, so I tried to upsize it where I could. This video showed them to be about the same as a gr 5, which matched my experience, so I relaxed about them somewhat.

Also, I have noticed a few of those Bouwman bolts over the years, but I didn't really know what they were.

 

[Welder Dave]

Some people refer to the Bowmalloy type bolts as grade 12 but that's not an official grade. The bolts sometimes referred to as grade 9 isn't an official grade either. There was a discussion about that quite a while ago. I think Cat bolts are in this category but referred to as exceeding grade 8. For things like a temporary tooth pin grade 5 are better because they bend instead of snapping. I was good friends with the manager of Bowman in Edmonton. He retired after 47 years and Bowman didn't really do much or give him anything for his many years of service. He started in the warehouse packing customers orders and worked his way to the top. Super nice guy. Bowman was a little pricey but very high quality stuff. I went to see him once on a Friday and it was past closing when a customer knocked on the door looking for a HD battery cable crimper for his Cats. Instead of turning the customer away, he went in the back and got the crimper and connectors the guy needed and put it on the customer's account. I know a lot places would have just said we're closed and to come back on Monday when we're open. He offered to send out news letters for the MX club no charge and Bowman had a postage machine to make it easy. He covered the cost of the postage. Figured it was a small way to help the non profit club.
I haven't spoken to him in about 12 years but just looked his name up and am saddened to see he passed away from pancreatic cancer at 74. Rip Jim. His wife raised and showed sheltie's and had the top sheltie in Canada. It got hit by a car when with someone else. She had another top sheltie she sold for $14,000!

 

[Coaldust]

The Bowman Fastener Facts book from 1989, that Simon mentioned, is an awesome resource. It was updated a couple of times, then it disappeared.

I adopted it as a text book when I was teaching. There are pdf copies available on the interwebs.

 

[Tyler d4c]

Grade 2 for shear bolts.

On a lot of new farm machinery there using a smaller bolt of higher grade so that it snaps cleaner and doesn't smash its self to the point of being difficult to remove

 

[colson04]

On a lot of new farm machinery there using a smaller bolt of higher grade so that it snaps cleaner and doesn't smash its self to the point of being difficult to remove

Our unloading auger at the farm is this way. Its a pto driven, 60 ft long, 10" auger with a truck unloading hopper attached. 100hp tractor to run it, a single grade 5, ⅜" bolt for shear protection. When it pops, its a nice clean break. Clean enough that I'm usually able to find both halfs laying on the ground underneath the pto shift area which let's me reuse the lock nut. I think we went through 5 shear bolts this year, but the same lock nut every time. It's a special shaped lock nut so its worth finding as a nylock won't fit in the slot it has to set in.

 

[John C.]

I saw a sales rep for Bowman make a big presentation at the maintenance conference at the University of Washington back in the eighties. He did a similar thing with a hydraulic machine and a torque wrench to demonstrate the yield strength of various bolts in a small size. The Bowman bolts were very good but didn't make any sense in the heavy equipment industry. The unit cost was way out of proportion when compared with a simple grade 8 bolt. It was a great presentation more in line for people working in the aerospace industry, meaning Boeing. The majority of the people attending the conference at that time were about two steps out of being blacksmiths.

 

[Birken Vogt]

If any equipment repeatedly breaks bolts, there is a problem with the equipment, or the operator. Hard to imagine a situation that would be solved by installing exotic super strong bolts.

 

[John C.]

The Bowman guy said that. Another statement was that a properly torqued bolt in a properly designed application will not come loose therefore all lock washers should be sold and never used. When I started in this industry there were a lot of single very large fasteners requiring huge sockets and wrenches. Now everything is held together with lots of small bolts.

 

[Willie B]

Thank you for posting this.

 

[92U 3406]

The Bowman guy said that. Another statement was that a properly torqued bolt in a properly designed application will not come loose therefore all lock washers should be sold and never used. When I started in this industry there were a lot of single very large fasteners requiring huge sockets and wrenches. Now everything is held together with lots of small bolts.

I tend to agree in most applications. When vibration and/or flex is involved is where I find bolts and regular nuts tend to come loose. I try and use stovers or nylocks as much as possible. I'm not a fan of split lockwashers. I find they distort and spread apart often, usually when you have to hit the nut with the impact wrench due to lack of access to the bolt head.

Nordlocks are becoming a favourite of mine. Kind of a PITA to bust the fastners loose, many times I have to use a breaker bar as the impact just doesn't quite have enough jam to get it over the first set of ramps on the washers.

 

[Birken Vogt]

Another statement was that a properly torqued bolt in a properly designed application will not come loose therefore all lock washers should be sold and never used

Agree in principle but I still use split washers over flat washers and they do seem to add something to the stack. If they start to come loose there is still some tension being added by them.

 

[Tyler d4c]

This brings to mind dad talking about the bolts holding the backhoe on there international backhoe they had it would even break supertanium bolts.