shear bolt revisited!!!!!!!

[Deerlope]

At the being of winter my new blower sheared the bolt that drives the auger, so I called my dealer and he said to use just a standard GR 5 bolt so I did. Today I picked up a piece of treated 2x2 and the bolt did not shear. Instead I bent my auger to the point where it was hitting the housing. The 12 lb. sledge has made it usable at least for the rest of the winter. So I had the dealer order the correct shear bolts from my parts list and I told him that we are going to compare them,his suggested bolt and the correct bolt. I think he already knows that I am suggesting that he pay for the replacment auger. But I have not came right out and asked that he do so. My point is this a shear bolt is a shear bolt and be sure to use them. Even a dealer can be wrong.By the way a new auger is $475.00.

 

[KiotiJohn]

<font color="#FF641A">I think shear bolts are usually #3 grade aren't they? Much softer than a 5. Even at that sometimes they will just bend up and not shear completely. I feel for you about the auger, money that should not have to be respent. I would certainly say "outright" to the dealer, that you owe me for the auger because you don't know what you're doing. Good luck, John</font>
CK20Action

 

[greg_g]

I use grade 2 on my rotary cutter PTO shaft. But since that's a different application than a snowblower auger, I did a little checking. Before you get too rough on the dealer, maybe you should read http://www.buhler.com/sitefiles/manuals/740_840_sblower/sblower2.htm

//greg//

 

[Deerlope]

Thanks for the link Greg. I did read it but I don't have to agree with them. I can atest that a GR 5 does not make a good shear bolt. I feel that I am lucky in one sense cause I did not break the gear box. I did not mean for my post to sound that I was going to get rough with the dealer. He suggested that they bring the unit in and try to straighten the auger in their shop.

 

[nomad]

Still same problem of "Shear Bolt"?

You can make high tech. equipments, but you haven't sold the simple problems yet.

By the way, have you ever seen dealers, distributors or manufacturers ever refunded your money? If there are any, they are very rare like this nomad.

 

[GrayBeard]

Now you've got me curious.
I just got a used P620 Pronovost. It came with 2 grade 5 shear bolts and states in the manual to use only grade 5.
There are 2 different sizes on the Pronovost ; 1 - 6mm / pto and 1 - 1/4" on the auger.
The previous owner said he never broke a bolt and the spares came with the machine when new.
GrayBeard

 

[Henro]

Deerlope,

Couple questions popped into my mind this morning...

Do you know what grade the original shear bolt was that broke and which you replaced with the grade five bolt?

Does you manual state what grade shear bolt should be used? I remember a past thread [snow blower or rotary cutter, can't remember] where the manual had a misprint and the wrong grade was listed. Naturally, it was a harder bolt that was listed...

In the end, if a snow blower is damaged by picking up something other than snow, and it the correct shear pin/bolt is installed, whose problem should it be during the warrenty period? Would this just be considered a hazard of ownership? I would tend to think so, but don't know what the normal practice is.

Now if I were the dealer and told you to put the wrong grade bolt in, I would feel pretty bad about the situation.

Hope things work out for you... /forums/images/graemlins/smile.gif

 

[Deerlope]

Henro: this is how the shear bolt is listed in my parts manual
Bolt hex. 5/16"NCx 1 3/4", PTD & stover nut 5/16",PTD Gr 5

what the PTD stands for I do not know& stover nut I am assuming to be a self locking type. A freind has the same blower so I am going to look at his.

 

[Henro]

I wonder if PTD could refer to this company?

Precision Taps & Dyes Pvt Ltd
294/3 Vidyanagri Marg
Kalina, Bombay 400-098

Seems like more and more stuff comes here from off shore.

Their web site states: We also manufacture, Bolts, Foundation Bolts, Anchor Bolts, Screws and Nuts...

Wouldn't surprise me...

 

[kevinj]

The shear bolt for my BX1500 blower auger is listed as a grade 5 bolt too, but if you look at a Kubota bolt it has two gooves machined into it to control the break point of the bolt. You may want to pull the bolt from the other auger and look at it.

 

[Deerlope]

Yes, I planned on pulling the bolt frm my freinds auger. But I do remember that when the orginal bolt sheared all that I could find was the hex head and it had the gr 5 hash marks. I will be axnious to see what the bolts look like that I had the dealer order from my parts list. I am sure that they will be grouved.

 

[KiotiJohn]

<font color="#FF641A">I'm really surprised to learn a shear bolt would be a #5, so I did a little looking and found that some grade 5s can have different strengths. Check this out:
http://www.engineersedge.com/hex_bolt_identification.htm
Notice the different tensile strengths noted. John </font>
CK20Action

 

[SacandagaBrad]

</font><font color="blue" class="small">( I remember a past thread [snow blower or rotary cutter, can't remember] where the manual had a misprint and the wrong grade was listed. Naturally, it was a harder bolt that was listed.. )</font>

Henro,

That was me. It was a Woods SS52 snowblower that came with a Gr 8 in the drive shaft and the misprint called for a Gr 8. I'm running Gr 2 now and have only used the blower once since we can't seem to get any more that 4 inches of snow at a time /forums/images/graemlins/frown.gif

I did use it once to cut back the banks and hit a stone just like the one that stopped the tractor dead in its tracks with the Gr 8, the Gr2 sheared like a charm, 2 minutes later had another in its place and back to work.

In Deerlope's case, the wood has a lot more give to it than a rock (all those years of geology school finally paying off /forums/images/graemlins/wink.gif). Maybe the shock absorbing tendency of the wood prevented the bolt from shearing, just like using a wooden mallet rather than a steel hammer. If it is easy to replace or you just don't often shear a bolt, try the Gr 2 or 3, they're cheap enough to try a few to see if they work for you without the risk of damage. I hope the dealer comes through for you.

Brad

 

[kfgriffi]

At the being of winter my new blower sheared the bolt that drives the auger, so I called my dealer and he said to use just a standard GR 5 bolt so I did. Today I picked up a piece of treated 2x2 and the bolt did not shear. Instead I bent my auger to the point where it was hitting the housing. The 12 lb. sledge has made it usable at least for the rest of the winter. So I had the dealer order the correct shear bolts from my parts list and I told him that we are going to compare them,his suggested bolt and the correct bolt. I think he already knows that I am suggesting that he pay for the replacment auger. But I have not came right out and asked that he do so. My point is this a shear bolt is a shear bolt and be sure to use them. Even a dealer can be wrong.By the way a new auger is $475.00.

When I bought my snowblower I also sheared the bolt that was providing power to the auger from the drive shaft. I did not have any grade bolts and quickly when through all the small bolts that I had. As a result I investigated what I needed to replace the bolt that sheared because I got so many different answers about what was need. I posted all the information I found in this forum and it can be found by following this link (you may have to cut/past): enter this forum url (tractorbynet.com/forums) and then append the following:

/parts-repairs/350222-everything-you-need-know-about.html#post4329972

BTW: A grade 5 bolt that is NOT threaded will require an additional 1,000lbs before failing...

 

[CDN24]

After passing ? 200 lbs of gravel through my brand new 54" snow blower, I picked up a chunk of ice. The shear bolt snapped like a tooth pick. A bag of 4 came with it. I've cheated on shear bolts before; deerlope's thread tuned me up. Shear Bolts R' Us !

 

[RPW]

Shear bolts are grade 2. You can get them at your local hardware store and they're cheaper. If your shearing bolts you need to investigate why it's happening. In some cases it might be as simple as feeding to much material at a time. If you have the room you could add a slip clutch then you could replace the grade 2 bolts for grade 5. Good luck.

 

[Rock knocker]

BTW: A grade 5 bolt that is NOT threaded will require an additional 1,000lbs before failing...

Source and context?

 

[kfgriffi]

Source and context?

Please see my note it has the reference link described. I could not post the link directly because apparently you need to have a certain number of posts before you can put a link in directly. So I had to split it up into two parts. Put both parts together and enter that into the URL location bar and you will be brought to the page in this forum with all the details and references.

If you want quick data:

Size Size Surface area: Shear Tensil Shear Non Flange
(diam): (len): (Pi * r2) capability strength: Failure thread size
in ksi (lbs): len: (inch):


Grade 8
not threaded 0.25 1.25 0.049087385 90,000 150,000 4,418 0.3615

Grade 5
not threaded 0.25 1.25 0.049087385 72,000 120,000 3,534

Grade 2
not threaded 0.25 1.25 0.049087385 44,400 74,000 2,179

Grade 8
threaded 0.212 1.25 0.035298935 90,000 150,000 3,177 0.326

Grade 5
threaded 0.212 1.25 0.035298935 72,000 120,000 2,542 0.654

Grade 2
threaded 0.212 1.25 0.035298935 44,400 74,000 1,567

ksi = kilopound per square inch
1 ksi = 1000 psi (pounds per square inch)

Grade 5 not threaded - Grade 8 threaded: 357lbs.
(i.e. Grade 5 not threaded is stronger than Grade 8 threaded)

Shear capability is 60% of tensil strength.
Shear failure is shear capability x surface area.

 

[kfgriffi]

Shear bolts are grade 2. You can get them at your local hardware store and they're cheaper. If your shearing bolts you need to investigate why it's happening. In some cases it might be as simple as feeding to much material at a time. If you have the room you could add a slip clutch then you could replace the grade 2 bolts for grade 5. Good luck.

Not all circumstances will use a grade 2 bolt for shear protection. In addition if you use a non-threaded grade 2 vs. a threaded grade 2 there is over 500lbs of difference. The specification for my Kubota snowblower calls for a grade 8 threaded bolt in the flange that connects the augers to the drive shaft. The difference from a grade 2 threaded to a grade 8 threaded is over 1,500lbs.

Bottom line is to check with the manufacturer of your equipment to identify what the requirements are for the bolt needed for shear protection.

 

[RPW]

kfgriffi- you are correct in your statement but for me I haven't met a piece of equipment that uses anything other than grade 2. Then again I also rarely see any snow let alone have to shovel any.