Testing A Raisman Platt Crankshaft In An MS660

[Mastermind]

Thanks for the update Brian.

 

[watsonr]

Good to hear it's still grinding them up.

 

[Mastermind]

Hello Brother Randy.

 

[imagineero]

For those who were wondering, the cause of snapped cranks like this is heat/tension/big bars. I've snapped one too.

If you run your saw and the chain heats right up, especially if blunt, the chain will stretch. Double that if you're using cheap chain. On a large bar (3'+), a small amount of stretch on each link adds up to a huge amount of stretch over the whole chain, leaving the chain flapping in the breeze. So you tension it up, and keep cutting... it heats up more, you tighten it again, even tighter than you should, thinking it will stretch more. You finish up cutting, put your saw away and the chain cools down and tightens up like crazy. Next time you pull your saw out, the chain is so tight it wont even spin. You have to loosen it off just to get the saw running. You might not have broken your crank that way, but you started the crack... especially if done repetitively.

It's far more likely when milling, because guys milling make long continuous cuts. Depending on species, even if you start with a sharp chain, you might not be able to finish a single slab before you get blunt. You might be tempted to just keep cutting if the cut is nearly done, which overheats and stretches the chain...

 

[watsonr]

Hello Brother Randy.

Good morning Sir

 

[Stihlofadeal64]

Good morning Sir

You back on this side of the pond Randy?

 

[watsonr]

Yes. But have been busier than normal. My helper was fired, doing whatever he had plus mine.... makes for long days and more travel. Hopefully, a couple new guys here in the next weeks or so, still need to train them.

 

[whitedogone]

Hey moobs, You ever find time to split any of those broked cranks and piece together working ones?

 

[Mastermind]

I did........but have never bothered to true them. Threw them in a box after pressing them back together......

 

[Trx250r180]

I did........but have never bothered to true them. Threw them in a box after pressing them back together......

That would make a great thread .

 

[whitedogone]

So what would be involved in truing them? Any idea?

 

[Mastermind]

Put them in V blocks with a dial indicator. Bump em around some.

 

[Chris-PA]

It is on my wall now
View attachment 424401

Do you mount the bicycle seat on the full wrap?

 

[huskihl]

Almost 2 years later ,still not broked yet
View attachment 424026 View attachment 424028

Hey. Thanks for your help. We have the same mill. And they work great