So I have this crank that needs the end fixed on it. I remember seeing a thread a long time ago about someone on here who fixed one that was broke the same way. I can't remember what he did, who it was, or what the thread was about, just the picture of a very nice little bead on the end that was then milled back to shape. So is this a job for a mig or tig? I have a small mig at home and large one at work I could use, but have never tried to weld anything so small. Most of my welding expierence has been with tube and plate steel. Any advice on fixing this would be welcome.
welding advice needed
- Thread starter marti384
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So I have this crank that needs the end fixed on it. I remember seeing a thread a long time ago about someone on here who fixed one that was broke the same way. I can't remember what he did, who it was, or what the thread was about, just the picture of a very nice little bead on the end that was then milled back to shape. So is this a job for a mig or tig? I have a small mig at home and large one at work I could use, but have never tried to weld anything so small. Most of my welding expierence has been with tube and plate steel. Any advice on fixing this would be welcome.
Is that the snap ring grove on the end? If so, take careful measurements before you start welding. Tig is going to be the best. Build up material around it, then machine down on a metal lathe. What is the crank out of? If it's a common crank it may well be just as easy to get another one vs. the time and money to get this one right.
If its a common crank it will be cheaper to just replace it unless you can do all the work to it yourself. If you can do the welding and machining then its doable, done it myself more than once.
griff154
ArboristSite Operative
Tig all the way.
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Big_Wood
westcoast dweller
here's the thread by the member you were talking about. 2 bad pictures are gone 
http://www.arboristsite.com/community/threads/044-broken-crank-tig-weld-repair-pic.217108/
http://www.arboristsite.com/community/threads/044-broken-crank-tig-weld-repair-pic.217108/
Twisted Priorities
ArboristSite Operative
Draw a sketch with all dimensions need to re machine. Acquire proper tig rod for material ( go to local welding shop ). Clean material (no rust/oxidation ), pre heat area to be welded with brazing tip of torch, tig weld in layers not a big puddle. Post heat area to anneal weld. Machine on lathe.
Projects like these may take a bit of practice. If there is a local machine / welding shop ask for a quote, might be cheaper to have them weld it.
Projects like these may take a bit of practice. If there is a local machine / welding shop ask for a quote, might be cheaper to have them weld it.
I read through that thread and found this to quote
"I Tig weld little gun parts, all day, every day......"
If it is just for a snap ring why not make a half circle copper thing like a washer cut in half and weld with that where no metal is wanted. Perhaps nickel rod wouldn't have to get quite as hot. There is a point the carbon content gets high enough special tactics or not welding are in order.
Can we turn this into an inboard clutch vs outboard clutch discussion?
"I Tig weld little gun parts, all day, every day......"
If it is just for a snap ring why not make a half circle copper thing like a washer cut in half and weld with that where no metal is wanted. Perhaps nickel rod wouldn't have to get quite as hot. There is a point the carbon content gets high enough special tactics or not welding are in order.
Can we turn this into an inboard clutch vs outboard clutch discussion?
Oh yes, let's.
The crank is from a husky 385. I have a 385 with a bent crank, and had this broken one laying around, was just wondering what it would take to fix it and use it instead of the bent one. I know I can get a aftermarket from watsonr for about $80, but didn't really want to put that much into the saw after the other money I already put into before I found out the crank was bad. I had contacted some machine shops about straightening the bent one and everyone sounded real leary about that. I would have to get a quote on someone to TIG it, but I bet that it wouldn't be cheap.
Big_Wood
westcoast dweller
my buddy tigged one for me a few years ago. he has been welding since he was 10 and is now 45 though. he made it look easy. i expected to be at his shop for a few hours but he was done the crank in 20min. we just drank beer for the rest of the evening 
I wish I would know a guy that could fix it.
It seems like that might result in thread derailment. And really, who likes to argue about stuff like that.
Karl Robbers
ArboristSite Operative
Tig would be the best choice, but MIG or stick would also be quite workable and produce the desired results.
I know several old farmers and mechanics that could and would weld that, grind it back and cut the groove with a hacksaw if needs be. They used what they had and desperation was a marvellous motivator.
I know several old farmers and mechanics that could and would weld that, grind it back and cut the groove with a hacksaw if needs be. They used what they had and desperation was a marvellous motivator.
machinisttx
Addicted to ArboristSite
I see a lot of rigged junk like that come in at work to be fixed right since the initial "repair" didn't last. It takes longer and costs more to fix it correctly than it would if they had just brought it in to start with.
if I were to tackle that job this is how I would do it....I tig weld but not a pro. I would first in a lathe machine the broken area to a nice round register. I would make a washer that fit that register and weld the washer to the end of the crank to minimize having to machine the groove for the c-clip. I the crank material is soft enough I might consider drilling and threading the end for a short 6x1.00 mm bolt and washer to retain the clutch drum.....but the real farm repair....put it all together and fit a washer where the c-clip goes and just put a small weld there and grid it off is you need to replace the drive sprocket!
ha!
sap can
ha!
sap can
DanTheCanadian
Weekend Warrior
If you wanna attempt it first with a mig I suggest a piece of copper that you can wrap in the groove, get in there and weld it, clean it up real pretty, and see if it did it. I know it's not ideal, ideal it getting a new crank, but if you wanna save some money that is one option. Tig is better than mig by a lot IMO, but if you have a mig it might just as easy, you'll NVR no unless you try. BTW, aluminum might work in place of copper but beware of contamination.
Well, you have all given me a lot to think about. I have another junk crank with a bad big end bearing I could practice on with the mig, and depending on how poorly that goes, try to find someone with a tig to use. The idea of threading the end and using a bolt and washer (and locktite) to hold the sprocket on is interesting, but might make selling it at some point in the future a problem.
I guess we can start discussing the pro's of outboard clutches now.
I guess we can start discussing the pro's of outboard clutches now.
814hammer
arboristSite member
Yes a tig would work best but a mig will work if thats all you have use that and do it yourself to save some money turn heat up bump it let cool bump again and repeat and if you don't have lathe I don't see why you couldn't use a dremel the grind back in shape
