Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I have a new Honda HS928TCD blower.  Apparently a change was made in the past for the shear pins for the HS928 so now there are two types available, depending on the frame serial number. The older style pins have a P/N of  95701-06016-00 and the newer style is 92101-06016-0A. Since I have a bunch of the older style shear pins, I am wondering what the nature of the change was and if the older type of shear pins will work for the newer model.  If the old style is used on the new frame type, is there a danger to the gearcase because the shearing point is different?  See  http://www.boats.net/parts/search/Honda/Snow%20Blower/0/HS928%20WAS%20SNOW%20BLOWER%2C%20JPN%2C%20VIN%23%20SZAS-1100001%20TO%20SZAS-1129999/AUGER/parts.html for the illustrations.  Any ideas out there?

Is there such thing as a "metric" grading system for bolts that is different from a non-metric "grading system" for bolts.

Or is a grade "8" all there is.  I am not familiar with the grading system for bolts.  "8" sounds pretty hard (or strong) to me.

I would think that we would be looking for a softer bolt to protect our auger gear box.

There are grading systems for bolt strength in both SAE and metric. SAE are tested in PSI, metric in MPa.

Unmarked: minimum yield strength is 57,000 PSI, metric unmarked is 640 MPa. Minimum tensile strength for these are 74,000 psi or 800 MPa.

Unmarked bolts are untreated low or medium carbon steel. Grade 5 and metric 8.8 are medium carbon steel, heat treated and tempered. Grade 8 and metric 10.9 and 12.9 are heat treated and tempered alloy steel.

The higher the grade, the stronger the bolt. You want shear pins to be weak. They're supposed to break. The stronger they are, the more stress you apply to parts that are not designed for it.  Repeated stresses will cause failure.

Its easy for me to find unmarked metric bolts.  They are cheap too.  Based on the information outlined here I'm understanding that an unmarked metric bolt would be easier to shear than a bolt marked 8.8.   Does this logic seem misguided?  Sometimes ingorance carries a price.

Could be, misguided that is.  I have seen comments where the "unmarked" bolts are simply rejects from lots of higher grades that didn't meet specs.  If so, then they could be anything.  Dunno if this is so or not.  One would think that if it is, they would have to grind off the markings on the cap to make them unmarked,  unless they put those markings on after they make and test the bolts.  Or maybe they make the bolt stock first, test it before completing the bolt making process. and just make the stock that doesn't meet specs into unmarked bolts.

Underdog wrote:
Correct.

Dr_Woof wrote: Not the common hardware-store-grade ones. Not every bolt is tested, as the test itself destroys the bolt. The same logic that applies to fuses is used here, they're never tested, rather a select amount from each lot are. If a lot does not meet specs, it's usually recycled.
During the manufacture of common bolts, the markings are stamped in when the heads are formed. It's based on knowing the type of steel that is being used - and there are hundreds of types - and the heat-treating process that will be followed. This must be done before treatment while the steel is still (relatively) soft.

Sorry to digress but speaking of a fuse - the thermal fuse on my Kitchenaid dishwashwer went last night - it was an easy fix once you figure out it is a fuse issue.  Dodged another bullet this week as my gas dryer was giving me a burning smell a week before.  These forums are great for narrowing down issues. 

As far as I am concerned, I don't have any issue using 8.8 Metric grade shear bolts on my Honda if I ever have to replace it or them.

Dr_Woof wrote:
Hmmmm, I might be more likely to listen to AC / DC !!!!

I will have my son play  "Back in Black" on his Yamaha piano.  It is an interesting thought although AD/DC's motif is consistent and so similar.

MN_Runner wrote:
The bolts (shear pins) I bought on Ebay for my Honda HS928 arrived today.  The  OE replacements that came with the Honda are exactly like that shown by Mn_runner on the Right.  The Ebay bolts are marked P  M  and 8.8, similar to the ones on the Left.  Thet are slightly longer than the OE bolts from Honda.  They are supplied with Nyloc locking nuts.

The bolts pictured by the seller on Ebay appear to be the same as the ones he sent.  But the picture there is somewhat misleading as it shows them in a plastic bag with the Honda part number and "made in Japan" on the bag.  Ones he shipped were just in a plastic bag with no markings.

Checking on Google, looks like a metric 8.8 bolt is equivalent to an SAE grade 5 bolt.  Don't know what the "P  M" refers to - perhaps the manufacturer?  MN_runner's bolts appear to be grade 8.8 but I can't quite make out the top letters.  Looks like these will probably work as shear pins for the Honda.  Been blowing lots of snow lately - old hard stuff on a gravel drive - and haven't had to repalce a shear pin yet.