Chilly807
Elite Member
An interesting thread to say the least... I overextended my first cylinder because the cylinder was the wrong size, and the original design didn't permit the rod to fully extend without bending it, as MWB thought. It didn't quite get to the kingpin, but it was darn close. I simply wasn't paying attention as I extended the cylinder, and it bent like a banana. Re-positioning the mounts cured that, as did the right length cylinder.
The re-design thread is here:
http://www.tractorbynet.com/forums/hydraulics/192127-cylinder-travel-limiter-3.html
It gets into the re-design phase during the second page, I got some good ideas from the guys here.
After the re-design, I haven't had any problems at all. I decided to use the larger cylinder (3x10) while I was at it anyway. LD1 and MWB are correct in their thoughts that the smaller cylinders may cause a burst problem if the blade end hooks solidly into "something".
The larger piston diameter gives you more of a safety margin, and the larger diameter rod (new one is 1.5 inch compared to 1.25 for the 2 inch cylinder I had originally) is more resistant to bending under compression load.
I often use the very edge of the blade to wing back the edges of snowbanks on the driveways I plow, so it's a valid concern. The blade has considerable leverage over the cylinder, as we've discussed.
Mark, you mentioned you were going to attach the rod end to the kingpin plate I think. I'd encourage you to re-think that a bit. The farther out along the blade you go, the less leverage the blade has. My attachment point is 10 inches from the kingpin center, which is as far as I could go and still have something solid to weld the post to on the bottom. 12 or 14 inches would have been better, but I would have had to angle both ends and still try to get the pin holes to line up.
The previous owner had welded the rod pivot to the top of the blade, which then bent like spaghetti. I eliminated that and then added a stiffener gusset from the post to the kingpin top plate.
3/8 plate is heavy enough for the cylinder mounts, I drilled my pin holes with a bi-metal hole saw. Cut through like butter, although I did use a drill press. A large slow-turning hand drill would have worked too. If the holes were slightly oversize to allow for a bit of misalignment it wouldn't hurt anything either. You might get away with simply using a standard cross-tube cylinder if you can get the alignment a bit closer. I think my 3x10 was about $110 IIRC.
I looked into adding the crossover relief valve, it would have worked except that the volume is different on each side of the piston. They are better employed on two same-size cylinders (usually single acting, like angle plow cylinders), in my opinion.
We can all suggest different ways of doing this, it's human nature.
Sean
The re-design thread is here:
http://www.tractorbynet.com/forums/hydraulics/192127-cylinder-travel-limiter-3.html
It gets into the re-design phase during the second page, I got some good ideas from the guys here.
After the re-design, I haven't had any problems at all. I decided to use the larger cylinder (3x10) while I was at it anyway. LD1 and MWB are correct in their thoughts that the smaller cylinders may cause a burst problem if the blade end hooks solidly into "something".
The larger piston diameter gives you more of a safety margin, and the larger diameter rod (new one is 1.5 inch compared to 1.25 for the 2 inch cylinder I had originally) is more resistant to bending under compression load.
I often use the very edge of the blade to wing back the edges of snowbanks on the driveways I plow, so it's a valid concern. The blade has considerable leverage over the cylinder, as we've discussed.
Mark, you mentioned you were going to attach the rod end to the kingpin plate I think. I'd encourage you to re-think that a bit. The farther out along the blade you go, the less leverage the blade has. My attachment point is 10 inches from the kingpin center, which is as far as I could go and still have something solid to weld the post to on the bottom. 12 or 14 inches would have been better, but I would have had to angle both ends and still try to get the pin holes to line up.
The previous owner had welded the rod pivot to the top of the blade, which then bent like spaghetti. I eliminated that and then added a stiffener gusset from the post to the kingpin top plate.
3/8 plate is heavy enough for the cylinder mounts, I drilled my pin holes with a bi-metal hole saw. Cut through like butter, although I did use a drill press. A large slow-turning hand drill would have worked too. If the holes were slightly oversize to allow for a bit of misalignment it wouldn't hurt anything either. You might get away with simply using a standard cross-tube cylinder if you can get the alignment a bit closer. I think my 3x10 was about $110 IIRC.
I looked into adding the crossover relief valve, it would have worked except that the volume is different on each side of the piston. They are better employed on two same-size cylinders (usually single acting, like angle plow cylinders), in my opinion.
We can all suggest different ways of doing this, it's human nature.
Sean
