If you want to stop the other crank moving, get it just offset from the chainstay and stick a big bar of something between the two (and some padding between said bar and chainstay, you don't want a dented frame). This should give you moar leverage, you may run out of hands/ heavy things to hold things in place though.
If you want to stop the other crank moving, get it just offset from the chainstay and stick a big bar of something between the two (and some padding between said bar and chainstay, you don't want a dented frame). This should give you moar leverage, you may run out of hands/ heavy things to hold things in place though.