Welding a crank

[wack 63]

What would be the best way to TIG weld a crank to stop it distorting ,I was thinking wedges and clamps? But would like some feedback from someone in the know. cheers

[red ghost]

More info?

Why,When,Where..because..

[wack 63]

Anyone?

[dapper]

I know feck all, but would have thought that once trued, a shallow hole drilled where the pin meets the web about an eighth of an inch deep and then migged or tigged would be sufficient. There wouldn't be enough time or heat to distort due to the thickness of the metals. Grind the weld flush with the pin/web. (awaits derision from adults )

[lifes a drag]

have a look on here

everything2stroke.com

if you google , 2 stroke crank shaft tig welding, you should find something to help you
theres loads of 2 stroke sites you can look on for info, they dont have to be scooter only ones.

if you see the state of some of the barrels and pistons you will see where not the only one,s that blow them up

[tarmac tickler]

i have welded a few cranks now, i am not a welder by trade and by my own addmission i am crap at welding,, but good at grinding,, if i was you i would take the drilling option,, the benefits being you wont have to split the crank if you dont have the facilities to split/repress/balance it.!

you do the drilling and take it to a competent welder,, ie someone who makes gates/railings will gladly take a tenner from you for a job well done,,,, but i would make/cobble together a couple of bits of tube to slip over the collar for the bearing and one for the other side where the crank is pulled into the drive side bearing to avoid splatter damage


this way there is less heat going into the thing,, it wont distort the webs but it may shag the bearing ,,, then your fooked boy

as i have previous stated i am not a welder but have done a few cranks that are still rattelling around somewhere

hope this helps

[Diablo]

I've seen Harry Barlow do this many times and its not as simple as it seems if you ever want to split the crank again or don't want it to distort.
He usually fuses the pin to the web with a tig welder. No filler wire is used. Unbelieveably the crank can still be trued after welding which is both handy but also crucial if the engine ever siezes.
If you've spent a bit on a crank take it to an expert. I've learn't to my cost that its not as easy as it looks.

[mark]

That's how cs engineering does it as well al, it can also still be split to change big end as well if done right

[Muttley McLadd]

Do you already have a crank? Could be worth buying one from a good shop that'll weld it for you before sending it out.
I've got one that Jerry (Readspeed) welded. It's well welded.

[paul213]

I wouldn't drill the crank at the thinnest point this will reduce the strength of the hole make it more likely to spread under load and then place a lot more strain on the weld .better to do as suggested and leave intact and just fuse the pin to the web