Measuring the Force to Shear a Pin

Wait. What are you designing?

Build a replica of the shafts and measure the torque required to shear the pin.

This looks like a torque wrench and a mock-up to me.

Size the pin accordingly, or limit the torque peaks to be below the failure point of the shear pin.

If you have no way to measure the torque peaks of the system, you're doomed.

Torque Sensor - Transducer Techniques

TORQUE TRANSDUCER | Honeywell

Torque Transducers - S. Himmelstein and Company

Link

Did you use spell check??????????????????????????????????????

This LMGTFY has no spell checker!

Is this an attempt to figure out if you can use say a grade 5 bolt as a shear pin, in order to avoid buying the Manufacturer replacement which is ridiculously overpriced ?

I can't think of another reason they would not give you the shear specification.

They are an OEM supplier from Japan. The pins they use are over rated and significant damage is caused when the pin fails to shear. The OEM then sells lots of parts but leaves the service agent to fight the battle of why its over rated pin failed to shear.

The current pins are machined 4140(not heat treated) which I believe is not ideal, and depending on where in the cycle the jam occurs, may or maynot Shear. I am trialing a Pneumatic Detent Slip Clutch on a machine with success. But again I'm not the designer

Common Greed is the main motivator for not revealing the data I feel.

4140?

Wow, try cold rolled steel pins.

Of course, not knowing any force numbers limits ones choices.

Break out the torque wrench.

Maybe one of these KrisDel "shearomatic" light duty shear pins would work better. Guaranteed to shear

Del

In your position I would go to an outboard motor company, as they have the best and longest experience with shear pins on outboard props....your local boat dealer is the place to start.

Whether or not they have one as a direct replacement for yours I cannot say as you haven't told us the diameter or length of yours! Nor that of your shear pin either!!

Certainly, I suspect that they will be able to help you further....

Companies that keep such secrets do not deserve you as a customer...find another source as quickly as possible.

You may want to think of a different system, like that in a torque wrench for example, nothing actually breaks, and it is resettable....

Even a ball bearing, forced out by adjustable spring pressure, into a dip in the opposite part may be enough.....

A good source for shear pins and data is a snow blower company. To them, a shear pin is the mechanical equivalent of a fuse. They are inexpensive and reliable.

If you're not shearing and the equipment is sustaining damage, I would look at that as an opportunity to experiment.

Begin cutting your own pins notching the shearing location at different depths.

Shoot low to start, and find where you're comfortable by decreasing the depth of the cut.

Not having the cost of the parts that need replaced in one of these events would be worth the trouble at least a few times.

The worst problem you would have is replacing the pin a number of times until you found the dimensions on the shear pin that will keep you in production and save your equipment when it jams.

This is just looking at what you want, not what they will offer.

Don't beat me up too bad if this seems too simplistic.

When you mentioned a grade eight bolt it sounded like a substantial system where a small existing pin may not already exist off the shelf.

I would guess that true shear pins are "over" hardened, so that they do not try to stretch and bend, which could cause a disaster...they must simply "shear"....yours sound like they are not made properly, or of the wrong metal......cast iron might work....

Heating good steel up to red heat and throwing it in water, will make it almost like a piece of glass, no bending allowed, it will just snap....though I have never made a shear pin, only bought them!!

I learnt this when making my own lock picking tools and hardening is part of the deal, then bluing to stop them snapping....lock picking is a fun hobby!! Legally of course!!!

When asked by the owner of a property for example, though some modern anti pick and anti bump locks, make this hobby one with little future at least in the area of quality cylinders.

But I can snap the cylinder if needed with special tools from my locksmith days if I get beaten.....many do not know this!!! They are shocked when they see me break a cylinder in place and open a door, otherwise undamaged!!!

Few cylinders can stay in one piece with that tool, only the MOST expensive ones....I have never ever been beaten one way or the other!!!

The other way to open someones eyes wide is to use a card to open a door. One where is a key still in the other side and blocking a key from the outside (very cheap locks!!), I can usually open them in under 30 seconds, even sometimes under 10 seconds, with NO noise and NO damage to anything. Even the police will find no picking scratches in or on the lock either...

That is also not difficult when you know how and have the right tools.....and if you watch YouTube!!!

Andy, if you are ever passing and we're out. Just let yourself in and make yourself at home

Del

Address please and holiday dates?

Seriously though, there are several sorts of burglary prevention that work really well, its a well proven list given out by the UK police some years go....I only remember the first few, but alarms with outside sirens etc., just tell burglars where to go!!!!

The first few in order of effectiveness, believe it or not are:-

1) Signs on each window and door with the picture of a big dog and a warning that he does not like strangers.

2) A dog that barks at the slightest thing, big or small.....maybe even an "electronic" dog activated by the doorbell as most daylight burglars ring first to see if anyone is at home....night ones generally don't - creepy!!!

A friend was burgled in spite of his dog, but he told me his wife had shut the dog in the kitchen, not let it have the run of the ground floor and basement as it needs to.....wife was 'shore pissed on her return!!! Crap on the sofa in the living room was one "problem" the burglars left......and I do mean CRAP!!!

3) One of those special alarms that reacts to both changes in volume of air in a house and changes in air pressure. But not those that are made in the far east, too many false alarms they only react to one or the other - badly.

I have all three, but even though 3) allows pets and people to move around inside the house with no problems, it is only switched on when we are all away. I have both 1) and 2) or course........

With regard to 3)The only good one is made in Germany, is cheaper than installing a PROPER conventional alarm, but not cheap (but no redecorating or radio links), is fully patented (which is why the Chinese cannot sell their versions here!!) and is mostly portable too!!!

If you need more details on it just ask me and I will post some YouTube videos...Though I am not sure if the good ones are sold are sold in the USA or Canada, simply no idea.....I do not sell them anymore I hasten to add!!

Do remember though that nothing is perfect, that we have not ever been broken into is one thing, but I cannot see into the future. All I can say is that over the years many houses around here have been broken into, but not ours, yet!!