Sprocket replacement January 1959

I was recently given a stack of Caterpillar Service Reporter Bulletins from 1959 thru 1967.  I found this sprocket replacement on the back of January 1959 thought it was of interest when they would cut and weld on new sprockets, how many pounds of rod would it take for a D8?  Wonder what year cat went to the bolt on tooth segments for the newer models.

Thats what I'm doing on my 17A D7 now but welding bolt on segment rims to the spokes The bolt ones came out around 1961 I believe. 

Warren does a great job in this series of YouTube videos on D4D undercarriage work, including weld on sprockets. They’re still available!

https://youtu.be/BdiyfS8BlG8

it would be easier to make neat cuts by making a plug to fit the centre bore of the sprocket with a centre drill mark, if it was tapered it could fit multiple models. and then you simply use the circle attachment and get a nice round cut that needs minimal clean up.