I noticed today that my sheave that is only in action when I am using my 30 ton load block and rigged for a 3 part line, is slopped out, bushing (bearing?) apparently gone. This is a recent issue near as I can tell. Question is: is it worth just rebushing it, or better in the long run to just get a new sheave (NOT through National, I learned my lesson on the parts pricing on my outrigger pad). I know there are gauges for various wire rope sized that will tell you if the sheave groove is worn too much, this one seems OK, not widened out. Kind of a puzzler why the bushing is shot with the very little use I at least have given it. Greased enough, as much as my windshield could stand. 1" bore I think, guess I'll have to pull it to order the correct parts, then put it back together while waiting for them to arrive. My National book has a parts # for just the bushing, and I just checked, $69.00 for the bronze bushing, seems high, as expected, but it is in stock. Buying a complete new sheave from this outfit https://www.isheaves.com/ and putting it on my single line side where I'd use it every day, and putting the one there now on the 3 part line side, is probably the way I'll go.
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Sheave bushing
- Thread starter Natman
- Start date
DMiller
Senior Member
Check the pin for roughed surface wear or chrome lifting, that will in short order destroy a bushing.
crane operator
Senior Member
Do you have steel sheaves or the nylon sheaves?
Steel. My previous boom trucks had nylon, I kind of liked the steel wire rope working against the nylon rather then steel, but what do I know? I do know my airplane's control system uses pulley's that are composite, phenolic I think.
crane operator
Senior Member
In steel, I think I'd just replace the bushing/ bearing. You could make a temporary bushing to take its place while you have it out if you don't want to be down. Nylon I would replace it.
I actually prefer steel, they handle side loading better, and last longer. The real push behind nylon is for weight savings on the head of the boom. 80-90% of the 100 ton and up cranes you see for sale (almost all will have nylon sheaves), will have a sheave or two with pieces broken out. They just aren't very durable.
I actually prefer steel, they handle side loading better, and last longer. The real push behind nylon is for weight savings on the head of the boom. 80-90% of the 100 ton and up cranes you see for sale (almost all will have nylon sheaves), will have a sheave or two with pieces broken out. They just aren't very durable.
I got my sheave off today, no bushing, but a mostly gone roller/needle bearing. All gone actually, but no scoring on the race. No scoring or damage to the shaft/axle, so I shimmed up the space it left, so I could use my usual single part line without any worries of it wandering around in the boom tip, not that I thought it would (the upper boom tip single sheave is free to "wander", depending on how many part lines I'm running. Self aligning. I'll knock the race out tomorrow and take it down to my local bearing shop. I'm pretty sure they will beat my National dealer's price of $69.00, plus sales tax, plus UPS charges. They refused to just stick a bearing they had in stock in a padded envelope anD just mail it to me, 130 miles away, and that just stuck in my craw. Remember, this is the outfit that quoted $1500.00 and a month wait for an outrigger pad, that I ended up getting for about $600.00 in a bit more then a week!
What kinda baffles me is this is the sheave only used in 2 or 3 part line ops. My single line sheave gets much more use, and it's fine. Maybe the previous owner (I'm the second) swapped them around.
What kinda baffles me is this is the sheave only used in 2 or 3 part line ops. My single line sheave gets much more use, and it's fine. Maybe the previous owner (I'm the second) swapped them around.
crane operator
Senior Member
It's okay if the top wanders, the bottom one holds it in line. If the bottom one is loose/ free to align, as you pick and swing anything, the sheave slams from side to side if its free. You needed the shims.
Got the sheave out, a 2 minute job, set up took longer, and after cleaning up all the excess grease, took it by my local Kamen bearing house. $25.00, it'll be here Monday. Versus nearly $100.00 from the National dealer. I'm in the wrong business, I need to sell crane parts.
Flat Thunder Channel
Senior Member
I don't think $69 is too hateful for a needle roller bearing. I am guessing it probably tied up from corrosion and not moving very often. Happy you were able to get it fixed without too much effort. Curious where was your $25 bearing made? I do not have much faith in 'chinesian' bearing quality. Happy Lifting!
Good point, as I was baffled why the sheave I rarely use would be trashed, little use makes sense. That and maybe it was swapped out earlier, who knows. Best bearing house in town, I assume it's USA made, we'll see.
I guess since I was quoted $1500.00 for a outrigger pad by the same National parts supplier, and ended up getting it for around $600.00 direct from the manufacturer, I am predisposed to feel they are going mark up everything 2 or 300%! With UPS charges (they claimed they could not mail it, HAD to go UPS...) nearly 100 bucks, and who's to say their's would be USA made?!
I guess since I was quoted $1500.00 for a outrigger pad by the same National parts supplier, and ended up getting it for around $600.00 direct from the manufacturer, I am predisposed to feel they are going mark up everything 2 or 300%! With UPS charges (they claimed they could not mail it, HAD to go UPS...) nearly 100 bucks, and who's to say their's would be USA made?!
The old race had to be pressed out, after the right sized tool was made. I did it old school for the new one: I put the black sheave out in the sun for a couple hours, on a 90 degree day, and put the new bearing in the freezer. Perfect fit, a few taps with a smallish hammer, and zero slop.
As luck would have it, I got a job today pulling an old ag pump (where the multi HP motor sits on top and a drive shaft goes down to the pump) out of a 24" casing. I was setting trusses nearby already and the guy, a past customer, talked me into making the lift. I told him I was only good for around 15 K with a 2 part line (I always carry my 10" snatch block), but if it was over that my 3 part line setup was out of commission. This was a couple hours before the new bearing was installed! I've pulled a lot of these pumps and these weights are common. Sure enough,, at 15,400 pounds I was done, and it hadn't lifted yet. I gave him my 6' pry bar and told him to try and get a feel for how much more pull was required, and he pretty easily got it to come up a couple inches, telling me that it's probably 16-17K or so, so doable and worth rigging the 3 part big load block I keep in the shed, with my new sheave bearing and coming back in a few days. He's trashing the whole thing, just wants it out of there, it hasn't worked for over 20 years, and he will replace it with a common residential well pump, which I also have set a lot of. I'll make one trip back, out with the old, re rig to a single part line, and set the new pump 60' at a time, using schedule 80 PVC drop pipe.
As luck would have it, I got a job today pulling an old ag pump (where the multi HP motor sits on top and a drive shaft goes down to the pump) out of a 24" casing. I was setting trusses nearby already and the guy, a past customer, talked me into making the lift. I told him I was only good for around 15 K with a 2 part line (I always carry my 10" snatch block), but if it was over that my 3 part line setup was out of commission. This was a couple hours before the new bearing was installed! I've pulled a lot of these pumps and these weights are common. Sure enough,, at 15,400 pounds I was done, and it hadn't lifted yet. I gave him my 6' pry bar and told him to try and get a feel for how much more pull was required, and he pretty easily got it to come up a couple inches, telling me that it's probably 16-17K or so, so doable and worth rigging the 3 part big load block I keep in the shed, with my new sheave bearing and coming back in a few days. He's trashing the whole thing, just wants it out of there, it hasn't worked for over 20 years, and he will replace it with a common residential well pump, which I also have set a lot of. I'll make one trip back, out with the old, re rig to a single part line, and set the new pump 60' at a time, using schedule 80 PVC drop pipe.