I managed to mangle the threads on a crank that I was trying to take off of a square taper BB spindle with a crank extractor. The threads inside the crank are now useless. This is the driveside crank with the chainrings.
Luckily, they are a cheap set of cranks that I was going to take off and throw away anyway. Cheap aluminium, no name brand. So I did a quick search on the "internets". Suggestions which came up: angle grinding or sawing the cranks/spindle off. I will probably hack saw the spindle off (Not interested in the BB either).
SO, what I was interested in, was any other methods that you've used in this situation. Is there any was to get them off without damaging the cranks or BB?
Don't know what I did wrong as the left side crank came off with no problems. Maybe I over-tightened the "nut" ? Any suggestions on crank extractor tool usage would be great.
I managed to mangle the threads on a crank that I was trying to take off of a square taper BB spindle with a crank extractor. The threads inside the crank are now useless. This is the driveside crank with the chainrings.
Luckily, they are a cheap set of cranks that I was going to take off and throw away anyway. Cheap aluminium, no name brand. So I did a quick search on the "internets". Suggestions which came up: angle grinding or sawing the cranks/spindle off. I will probably hack saw the spindle off (Not interested in the BB either).
SO, what I was interested in, was any other methods that you've used in this situation. Is there any was to get them off without damaging the cranks or BB?
Don't know what I did wrong as the left side crank came off with no problems. Maybe I over-tightened the "nut" ? Any suggestions on crank extractor tool usage would be great.
-Andres
Try this link for crank extraction with damaged threads
I managed to mangle the threads on a crank that I was trying to take off of a square taper BB spindle with a crank extractor. The threads inside the crank are now useless. This is the driveside crank with the chainrings.
Luckily, they are a cheap set of cranks that I was going to take off and throw away anyway. Cheap aluminium, no name brand. So I did a quick search on the "internets". Suggestions which came up: angle grinding or sawing the cranks/spindle off. I will probably hack saw the spindle off (Not interested in the BB either).
SO, what I was interested in, was any other methods that you've used in this situation. Is there any was to get them off without damaging the cranks or BB?
Don't know what I did wrong as the left side crank came off with no problems. Maybe I over-tightened the "nut" ? Any suggestions on crank extractor tool usage would be great.
-Andres
Best (and most fun) option is the angle grinder...... you will have to throw the crank away anyway, but the BB will be spared if you do it properly......
I managed to mangle the threads on a crank that I was trying to take off of a square taper BB spindle with a crank extractor
....
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SO, what I was interested in, was any other methods that you've used in this situation. Is there any was to get them off without damaging the cranks or BB?
I've succeeded at this job, when my crank extractor had given up the ghost - I stripped the internal thread in the extractor - by knocking the crank off from the back with a mallet, with the frame supported on blocks of wood. That was a cheap and heavy steel frame though, I don't think I'd be happy applying that much force to a light thin-walled steel or aluminium frame.
I have been involved in hacksawing a crank off a bottom bracket, the crank was destroyed, the bb was undamaged. Remember that the bottom bracket is likely steel and the crank is likely aluminium.
"Andres" <[email hidden]> wrote in message news:[email hidden]...
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I managed to mangle the threads on a crank that I was trying to take off of a square taper BB spindle with a crank extractor. The threads inside the crank are now useless. This is the driveside crank with the chainrings.
Luckily, they are a cheap set of cranks that I was going to take off and throw away anyway. Cheap aluminium, no name brand. So I did a quick search on the "internets". Suggestions which came up: angle grinding or sawing the cranks/spindle off. I will probably hack saw the spindle off (Not interested in the BB either).
SO, what I was interested in, was any other methods that you've used in this situation. Is there any was to get them off without damaging the cranks or BB?
Don't know what I did wrong as the left side crank came off with no problems. Maybe I over-tightened the "nut" ? Any suggestions on crank extractor tool usage would be great.
-Andres
here are a couple of things you can try that have worked for me in the passed. 1. do the crank bolt up finger tight then ride around your yard standing/jumping on the pedals with the cranks horizontal swapping your front foot now and again. with a little luck it will come loose 2. this is easier on the left crank, but you might be able to do it on the right. take two hammers, lay the bike on its side. then with a hammer in each hand hit the sides on the crank near the BB you need to time this just right so both hammers hit at the same time.
SO, what I was interested in, was any other methods that you've used in this situation. Is there any was to get them off without damaging the cranks or BB?
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2. this is easier on the left crank, but you might be able to do it on the right. take two hammers, lay the bike on its side. then with a hammer in each hand hit the sides on the crank near the BB you need to time this just right so both hammers hit at the same time.
A gear puller would make more sense but, as I've never had the problem, what would I know.
"Theo Bekkers" <[email hidden]> wrote in message news:[email hidden]...
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stu said:
"Andres" wrote
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SO, what I was interested in, was any other methods that you've used in this situation. Is there any was to get them off without damaging the cranks or BB?
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2. this is easier on the left crank, but you might be able to do it on the right. take two hammers, lay the bike on its side. then with a hammer in each hand hit the sides on the crank near the BB you need to time this just right so both hammers hit at the same time.
A gear puller would make more sense but, as I've never had the problem,
what
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would I know.
Theo
well sure if you have one handy, but i couln't get mine to fit the right side
"Theo Bekkers" <[email hidden]> wrote in message news:[email hidden]...
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stu said:
"Theo Bekkers" wrote
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A gear puller would make more sense but, as I've never had the problem, what would I know.
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well sure if you have one handy, but i couln't get mine to fit the right side
I thought everybody had at least one but I haven't used mine since, umm, Saturday. That was to get the flywheel off my neighbour's mower.
Theo
funny you should say that, it was a mower mechanic that showed me the two hammer trick(for the flange on the tappered shaft at the blade end of the crankshaft) the magneto end i have always managed to gently lever off with a couple of screwdrivers lol ssssh
I thought everybody had at least one but I haven't used mine since, umm, Saturday. That was to get the flywheel off my neighbour's mower.
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funny you should say that, it was a mower mechanic that showed me the two hammer trick(for the flange on the tapered shaft at the blade end of the crankshaft)
Let me know where his shop is so I don't go there accidentally.
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the magneto end i have always managed to gently lever off with a couple of screwdrivers lol ssssh
There was no way this was going to come off with a couple of screwdrivers, believe me. It was also not your urban mower but a ride on with a 14 hp B&S ohv 4-stroke motor. Not the kind of thing you can turn upside down and hit with a hammer. We all live on 2 ha blocks out here and an 2-smoke Victa pushie wouldn't last long and be too much work.
"Theo Bekkers" <[email hidden]> wrote in message news:[email hidden]...
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stu said:
"Theo Bekkers" wrote
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I thought everybody had at least one but I haven't used mine since, umm, Saturday. That was to get the flywheel off my neighbour's mower.
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funny you should say that, it was a mower mechanic that showed me the two hammer trick(for the flange on the tapered shaft at the blade end of the crankshaft)
Let me know where his shop is so I don't go there accidentally.
Well he is retired now so you don't need to worry about him, but they may all do it that way, I couldn't say, but its certainly quick. I'm not sure what damage you think it would do.
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the magneto end i have always managed to gently lever off with a couple of screwdrivers lol ssssh
There was no way this was going to come off with a couple of screwdrivers, believe me. It was also not your urban mower but a ride on with a 14 hp
B&S
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ohv 4-stroke motor. Not the kind of thing you can turn upside down and hit with a hammer. We all live on 2 ha blocks out here and an 2-smoke Victa pushie wouldn't last long and be too much work.
but it would be a great work-out 😉
I cant imagine that you could lever off a taped shaft with a couple of screwdrivers either, the magneto end has a keyed straight shaft so it just wiggles off(of course there would be times that only a puller would do)
Let me know where his shop is so I don't go there accidentally.
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Well he is retired now so you don't need to worry about him, but they may all do it that way, I couldn't say, but its certainly quick. I'm not sure what damage you think it would do.
It's amazingly easy to bend the crankshaft, damage the bearings, or put a pressed big-end out of alignment.
"Theo Bekkers" <[email hidden]> wrote in message news:[email hidden]...
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stu said:
"Theo Bekkers" wrote
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Let me know where his shop is so I don't go there accidentally.
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Well he is retired now so you don't need to worry about him, but they may all do it that way, I couldn't say, but its certainly quick. I'm not sure what damage you think it would do.
It's amazingly easy to bend the crankshaft, damage the bearings, or put a pressed big-end out of alignment.
Theo
as i remember it cast doesn't bend.(sure if you hit it with one hammer hard enough you will break it) you arent going to dint the bearings how is it going to effect the big end?(you mean main bearing?)
"stu" <[email hidden]> wrote in message news:[email hidden]...
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"Theo Bekkers" <[email hidden]> wrote in message news:[email hidden]...
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stu said:
"Theo Bekkers" wrote
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> Let me know where his shop is so I don't go there accidentally.
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Well he is retired now so you don't need to worry about him, but they may all do it that way, I couldn't say, but its certainly quick. I'm not sure what damage you think it would do.
It's amazingly easy to bend the crankshaft, damage the bearings, or put
a
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pressed big-end out of alignment.
Theo
as i remember it cast doesn't bend.(sure if you hit it with one hammer
hard
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enough you will break it) you arent going to dint the bearings how is it going to effect the big end?(you mean main bearing?)
I should add the price of failure also comes into it, what I would do to a 5 year old victa or a stripped crank, I wouldn't necessarily do to a $8000 ride-on mower
It's amazingly easy to bend the crankshaft, damage the bearings, or put a pressed big-end out of alignment.
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as i remember it cast doesn't bend.
Crankshafts are mostly not cast but forged.
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you arent going to dint the bearings
You are putting a serious sideload on the main bearings they are not designed to take. You may move a main bearing partly out of it's housing increasing side play in the crankshaft.
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how is it going to effect the big end?(you mean main bearing?)
No, big end. A lot of small motors (and some really expensive ones) have a built-up crankshaft, particularly two-strokes. The big end is pressed into the two crank halves. Hit one end hard with a hammer, especially away from the centre, and expect consequences.
I should add the price of failure also comes into it, what I would do to a 5 year old victa or a stripped crank, I wouldn't necessarily do to a $8000 ride-on mower
Understood. My mower and my neighbour's are the same, about $4K.
"] I've succeeded at this job, when my crank extractor had given up the ghost - I stripped the internal thread in the extractor - by knocking the crank off from the back with a mallet, with the frame supported on blocks of wood. That was a cheap and heavy steel frame though, I don't think I'd be happy applying that much force to a light thin-walled steel or aluminium frame.
Before I stripped the internal thread in my extractor I applied the gas torch to the cranks hoping to expand them and release them from the BB spindle
Much to my surprise there was lots of bubbling - obviously the bloke at my LBS who installed my sealed BB unit had used epoxy or some other adhesive when assembling. After the glue had melted the cranks came off no worries.
