Cook Bros Cranks ?
 

So I bought a couple Kleins the other day and on one there is a set of cranks that I am not sure what exactly they are they have a Cook Brothers shape but they are fluted the whole length of the side of the crank....all they day on them is 170....Any ideas ?

Cook Bros ?
 

Not sure what these are...

If I recall it's Grafton or Topline cranks that look like Cook cranks but have the flutes.

nice ! :beer:

The Topline roads differ with it having 130 BCD......but it seems like they have very similar crank arm design.....

Those look threaded for a triple so maybe a Topline mountain?

Definetly Topline Mountain Micro Drive Crankset
 

Looks just like the Topline cranks that I bought new on my Fat Chance at the end of 1993 which I still have & ride.
There are reports of splitting on these cranks at either the pedal eye or the BB axle end. I heard somewhere they really are for lightweight weight weenies ( 150 lb. rider was one number tossed about). I am still under that number & picked up a spare pair on the Bay about a decade ago. They sure are pretty.

Yes, Topline MTN. cranks but maybe even smaller than usual spider, and with a replacement CNC outer ring:
NOS Topline Mountain Crank Arms: 175mm 110/74, Highly Polished - Bike Recyclery
best for the lightweight and smooth spinner.