how come the counterweight has so many balance holes? is it to save money over using a lathe to get it closer before balancing?
The crank was factory balanced for 2300 gram bobweight,actual bobweight was much lighter.
We used a 440 callies crank in a 400 block and had to make 3 trips from balancer to lathe but ended up with only one tiny balancing hole. Had to cut the counterwghts about .250. Of course that would be cost prohibative if you had to pay for the extra trips I suppose.
Yes cutting CW's down in a lathe or in a grinder is cost & time prohibitive...... Does it do a "nicer job" than just machining holes (usually done right in the balancer, if you've got a "good" one) absolutely.... but is is a necessity? Absolutely not.
As an example.... if I was doing your Callies crank, I would have charged you a flat $175 balancing fee to internally balance it, that would have included drilling any potential lightning holes.... If you wanted .250" ground off all CW's & then drilled with small holes.... would be minimum $200-$250 to take .250" off CW's so cost more than doubled. I know alot of crank shops like to talk about "hole-less balancing" but it gets pricey....
Now in instances where we have needed to do like a string of 4 or 5 1" lightning holes all to a fairly deep depth, to do a balance job.... then yes we will cut CW's to reduce drilling amt. (so we're not swiss cheesing the crank) & charge accordingly. That's just a deal where if you have a bobweight, that much lighter than target bob on the CW's you have to expect to pay to play sort of deal....Usually only happens on aluminum rod stuff.....
But a pair of 1" holes, an inch or 1.5" deep is not a big deal.
