That’s not a genuine Tohatsu/Mariner shear pin - they break fairly easily. You’ll probably find this has been replaced with a “universal” pin from a chandlery or marine supplier.
I would generally buy OEM with that assumption. I'm going to try brass on the basis that it'll be easier to remove on the water if it rounds off and some rounding off seems inevitable due to the countersinking. Contemplating tig welding the top of the holes and redrilling to get rid of that countersink but worried in case I deform the shaft. Could try putting a heat sink on it... but I don't know the exact metal its made from to match the rods. What a bloody faff. I can't believe this really but its a huge problem as I use this on the sea not just for a tender in a river.
It also warms your hands at the end of the day.Don't you just love a Seagull. ?
Starting cord, Spanner, couple of plugs spare spring,pliers, split pin
Oh & a pair of oars to row the dinghy to & from the boat
To be honest, I’d just replace with an OEM pin. I’ve seen brass pins shear under very light impact, and just from someone putting it in reverse at higher revs than it should be.
I didn't hit anything or slam it into gear ,guess fatigue? Was a long row back against the wind and tide. Decided oem was far to weak so made a stainless one.
I made a mistake using the dremel and bur to get the bent pin metal off from around the hole. I should have used the lowest tech thing that I can easily carry first. A folding jab saw with a sawzall blade might have done it. One of these Milwaukee 48220305 Folding Jab saw (sgs-engineering.com) Trouble is though that damn countersunk recess makes it hard to get off all the metal thats bigger than the pin hole diameter. The more remaining the bigger the hammer I need to carry. Without the countersunk part if it was all proud of the surface as you say I could cut across the hole with a flat blade and pull out from the other side. Honestly with that recess full of metal like a countersunk screws head it wasn't pushing through the hole with ease.
I'm not sure your 'shearing' experiments give a true indication of the brass bars performance really. Might be better to drill a hole through two steel blocks, fit a sample pin and hold one block in a vice while drifting the other block........you could even replicate the chamfer! If all else were equal then the brass/alloy pin would be easier to punch out for a variety of reasons. If you have welding access then making a small vee block type clamp with a screw down 'drift' to suit the shaft hole would be good so you don't need to keep beating the unsupported shaft...!
It could well be different in a hole where it has nowhere to go in terms of place to bend into but with a plastic prop thats just what happened as you can see. I was thinking that part of what makes a pin specific for the task was brittleness not softness so I expected it wouldn't cut and bend like it did but snap and for that the test I did would have given a reasonable idea woudn't it as it showed no brittleness at all. But are these supposed to be brittle?
I do and thats a great idea thanks. Though I doubt even that would have gotten this pin out without first removing the metal that was outside the hole diameter, that it was rounded over wouldn't have helped as the drift would slide away from the right alignment. Will give that some thought though
As I wrote a long time ago I am pretty sure the correct item is manufactured by sintering (powdered metal) to give it the desired low ductility fracture characteristics.
What a little known serious menace are the fake ones made of regular stainless! I realise the primary purpose is to protect the other components which it did other than chewing up the inside of the plastic prop, but aren't we all working with the assumption its easy to pop another pin in and carry on? It could have seriously messed up my day if it had happened earlier.
