hi - trying to find a way to size rod bushings. I have a mini mill as well as a van norman. option 1 is to use a marble slab or machinist plate to clamp/index the rod to the van norman and attach a smaller cutter? or use the mill- im not sure what cutter would be able to cut around a 1 inch hole tho, i have the R8 spindle - maybe im better off trying to fab a custom cutter? will be br***/babbit and light cuts- i have thought of using/modifying a mag drill and checking the run out on those- they seem ridgid enough for the task..
maybe im better off buying a sized tapered reamer. I did buy some US made expandable ones but they are really long, too long for my mill.. i will finish hone the last 3 -5 thou, just want to get it close.
Roughing them out is one thing but I’m wondering how you intend to hone and hold the necessary ten-thousandths tolerances the pin bores require. Bite the bullet and pay the price to have then honed on a Sunnen pin home.
You want the pin bore centerline to be parallel to the big end bore centerline. That is part of the definition of a "straight connecting rod." Tolerances for bend and twist are .001" or so at the ends of the wrist pin. https://www.hometownbuick.com/wp-co...5-buick-checking-connecting-rod-alignment.jpg Tobin Arp machines positively reference off the big end bore, and can control the center to center distance within .001" or so, if the pin bushing has enough meat. https://i.ebayimg.com/images/g/hYkAAOSwiT9jB5w1/s-l500.jpg The side faces of the rod big end probably are not a good enough reference for machining.
Sounds about as iffy as surfacing cylinder heads with a 7" grinder. I actually knew a guy who did that once thinking he could make up the unevenness with thicker head gaskets.
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