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| Harden a locking pin |
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| Manxmodder:
--- Quote from: awemawson on May 14, 2015, 04:01:26 PM ---So why don't you take a larger 'grade 7' and turn it down to a snug fit and use that? --- End quote --- That sounds like a sensible solution to me.......OZ. |
| vtsteam:
--- Quote from: petertheterrible on May 15, 2015, 01:08:19 PM ---Splined shafts do not have shear pins, only pins that hold the parts together. What would be the point of using a shear pin if it won't afford any protection to the system when it breaks? --- End quote --- Yes, forgot about that. The shear pin on my bush hog is located down at the mower head connection, The spline pin up at the PTO itself is spring loaded and built into the pto shaft universal joint housing, and crosses a recess on the side of the shaft, rather than running through a hole in it. That isn't a shear type of arrangement. It prevents the splined shaft from uncoupling axially, the splines themselves prevent rotation so you can't possibly shear it by hitting something with the blades unless the splines ar broken off. It is subjected to axial forces so if the mower hits something in line and somehow the 3 point fails to prevent over-extension, I guess it could break. The other possibility is there isn't enough length in the PTO shaft so it's banging when raised or lowered. In fact PTO shafts are telescoping, up to a limit to avoid putting any axial stress on that pin. True you want to replace it with something the right size instead of a pin too small, and also if you make it yourself it should be properly strong and hardened, but a lot of the confusion here surrounds the idea that it was a shear pin being asked about, and why a shear pin would be highly hardened since the point of it is to shear. Many shear pins in fact are made of materials with a notch machined into them or have a reduced waist to encourage breakage, or made of softer materials than steel even so that they will shear. |
| PekkaNF:
I have used whole loat of PTO shafts with overload clutches and some with oneway cluch action too, because our tractor had a brake integragted to PTO and some high inertia machines would kill PTO shaft when slammed. Pekka |
| vtsteam:
Yup, mine has a one way (over-running) clutch, too. |
| vtsteam:
I just had to go down to the barn and check out the PTO shaft and bush hog -- hadn't used it yet this year, and I couldn't even picture the pin on the splined shaft. Nope, what I have doesn't even remotely apply. No pin on the PTO housing knuckle. It's 3 balls that retract to lock it in place in recesses near the splines. The bush hog has a plain shaft with a bolt shear pin. No splines. So nothing I have applies to your situation, Anthony. And I'm going to end by saying I just don't know what your situation is. You should have a pin to fit, in any case, which is what you enquired about making in the first place. But with no experience of what you have, I just don't know about the hardness issue. |
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