Quote:
Originally Posted by 1930artdeco
Hi Tod,
This is a just curious machining question. How long do the cores, and boring machine bits last? Do they have to be replaced every 100 blocks or so? Just curious.
Mike
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Cores are part of the foundry/casting process, and are good for one casting. Every casting requires a fresh set of cores and mold halves to make it.
As for machining tooling, tool life is a variable depending on optimal cutting conditions and variance from it. I use as many carbide tipped drills as I can, and most cutting is done with indexable tooling, which means carbide inserts for the specific metal are used (perishable) and their lives are dependent on cutting conditions. The primary cause for insert wear in my shop is interrupted cutting, where the inserts are not able to be in their engineered environment, which is engaged in metal removal. When an insert is moving from metal to air and back to metal again there is an amount of 'slamming' going on that cannot be avoided. Drills can be resharpened to extend life and I am pretty good at resharpening carbide inserts but that is only allowable where tolerances will nor be effected by the small change in either diameter or tool length. The edges I have learned to put on inserts are usually better than the OEM but I cannot coat them so I usually get only one or two resharpens out of each corner.
I have rarely had tools last for 100 pieces of anything except maybe drills for heads. I have to constantly listen to every sound in the shop as, say, 4 machines are running. I listen for sounds of tool wear or breakage which is evident in the sound of the tool engaging the part and even the sound of the spindle motor.
Taps are probably the worst. If you don't stay ahead of breakage you will get one busted off in a casting, which is a possible way of scrapping an otherwise good part. When you have a 1000 dollar engine block casting (like my Cleveland blocks) you listen VERY intently to every sound!
Tod