Rob711
New member
Can/should this be fixed. Prob won't help I just installed 9t sprocket at the other end.
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Does crack really kill
- Thread starter Rob711
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chancer
ɔ ɥ ɐ u ɔ ǝ ɹ
I would think you could weld that temporarily. Till you can afford an new one.
I mean it has a 1/4" Keyway so it would have to really stretch open before slipping.
It will break though if not welded. But the weld will heat it and Make the steel more brittle along the crack, so anything you do is gonna be NOt long term.
I have another idea. Can you fabricate stuff? If so I would remove the nuts for the set screws.
Then put a sleeve over the whole piece. So it cant open up more or break. weld it on. then drill the sleeve for the set screw holes and put back the nuts on the sleeve.
I mean it has a 1/4" Keyway so it would have to really stretch open before slipping.
It will break though if not welded. But the weld will heat it and Make the steel more brittle along the crack, so anything you do is gonna be NOt long term.
I have another idea. Can you fabricate stuff? If so I would remove the nuts for the set screws.
Then put a sleeve over the whole piece. So it cant open up more or break. weld it on. then drill the sleeve for the set screw holes and put back the nuts on the sleeve.
Rob711
New member
Wow!! That is a fantastic idea!! Can I fabricate stuff? Heck no, I do have a angle grinder, and a cousin who can weld.
There's a industrial steel place near by that diameter hub measures 1.631". Wonder if there's a thick walled tubing that would be able to be pressed on. Thanks again for the idea!
Rob
There's a industrial steel place near by that diameter hub measures 1.631". Wonder if there's a thick walled tubing that would be able to be pressed on. Thanks again for the idea!
Rob
tinamcjittles
ello m8
Great idea with the tubing!
OzFab
Well-known member
I see at least three issues with trying to weld that (besides the reason Chancer mentioned):
1. the crack follows the line of the keyway; welding may distort the keyway (not unfixable but, not desirable either
2. a nut screws down right next to it &
3. it's, most likely, cast meaning welding will be difficult...
Chancers idea is great if you can do it...
1. the crack follows the line of the keyway; welding may distort the keyway (not unfixable but, not desirable either
2. a nut screws down right next to it &
3. it's, most likely, cast meaning welding will be difficult...
Chancers idea is great if you can do it...
Rob711
New member
Thanks everyone, looks like 40$ Shipped for a new one, I'll get it off tomorrow and see what I can find. Really opened up when I tightened the screw not on the key. That's when I cursed a lot!
Do those plastic covers on the axle serve a purpose? Looks like it's going slightly tedious to get to the sprocket off.
Do those plastic covers on the axle serve a purpose? Looks like it's going slightly tedious to get to the sprocket off.
chancer
ɔ ɥ ɐ u ɔ ǝ ɹ
Maybe prevent rust. they are not needed.
It is a job to get the sprocket off. But take your time pay attention and it will be a good learning experience.
It is a job to get the sprocket off. But take your time pay attention and it will be a good learning experience.
welder74
welder74
Heat it up and weld it cold 7018 at 115amps 1/8" rod and wrap it with an insulation blanket so it cools down slow it will be fine.
Go uphill!!
Go uphill!!
KartFab
Active member
Those sleeves don't serve a purpose other than to keep hair etc from getting caught and wrapping around the axle. Kind of pointless imo, but in some cases it has happened.
New sprocket, problem solved.
Another option if you wanted to fix it. Leave the key in place. V (grind, die grinder) that crack right down into the key, even into the weld in the sprocket. Or drill a hole in the crack adjacent to the weld. This will prevent the crack from propogating after welding. It almost always a good idea to preheat. Just the heat from grinding may be sufficient.
If it's cast iron braze welding works well. Better than expensive nickel rod IMHO.
If your not sure what the material is. Hit it with a grinder. Then grind some regular steel. You'll be able to tell the difference by the spark pattern.
Or grind a small area of the part in question. With most cast iron you will be able to feel the free carbon, graphite. It's slippery.
Another way is with a chisel. You can build up a curl with steel. Cast iron only little chips.
Yet one more way. Weld a little bead on the piece. If it's cast iron the weld will pull carbon from the base metal. In effect it becomes quenched, untempered high carbon steel. File hard or harder. You might even see the weld crack and hear it while it cools down.
Another option if you wanted to fix it. Leave the key in place. V (grind, die grinder) that crack right down into the key, even into the weld in the sprocket. Or drill a hole in the crack adjacent to the weld. This will prevent the crack from propogating after welding. It almost always a good idea to preheat. Just the heat from grinding may be sufficient.
If it's cast iron braze welding works well. Better than expensive nickel rod IMHO.
If your not sure what the material is. Hit it with a grinder. Then grind some regular steel. You'll be able to tell the difference by the spark pattern.
Or grind a small area of the part in question. With most cast iron you will be able to feel the free carbon, graphite. It's slippery.
Another way is with a chisel. You can build up a curl with steel. Cast iron only little chips.
Yet one more way. Weld a little bead on the piece. If it's cast iron the weld will pull carbon from the base metal. In effect it becomes quenched, untempered high carbon steel. File hard or harder. You might even see the weld crack and hear it while it cools down.
bob58o
SuckSqueezeBangBlow
Hose clamp.
Jfive
New member
I kinda like brazing rod too, but it probably just do like chancer suggested and use a metal sleeve and drill some holes.
Rob711
New member
New one on its way, along with bearing and brake band, before I gave up and cut the bearing, I used the sprocket like a slide hammer, to no avail! The sprocket broke, that hub that's welded to the sprocket cracked off. I'll get a pic.
Thanks again for the suggestions. Man hoseclamp would have saved me 40$!!
Thanks again for the suggestions. Man hoseclamp would have saved me 40$!!
maknwar
New member
That's what I was thinking.
KartFab
Active member
If you can't spring for the hose clamp (they are pricy, and you need a fancy tool called a screw driver to install them) I think you can just zip tie it together, then sell the used zip tie ends on Craigslist.
Bosch
New member
I know it kind of goes against the DJY spirit, but I agree with replacement. I consider most components on my karts to be disposable. At some point, it's just less hassle to replace vs repair.
OzFab
Well-known member
It certainly does; anyone can change parts, it takes skill to know how to repair them...
Having said that, the most important part of doing anything is knowing when it's best to exchange something as opposed to attempting to repair it; "time is money" as they say; if it will take an hour or more to repair an easily accessible $5 part, obviously, it's best to replace it; likewise, if you can repair a $200 part in 10 minutes, repair it...
Having said that, the most important part of doing anything is knowing when it's best to exchange something as opposed to attempting to repair it; "time is money" as they say; if it will take an hour or more to repair an easily accessible $5 part, obviously, it's best to replace it; likewise, if you can repair a $200 part in 10 minutes, repair it...
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