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HSS & cast iron

animal12

Hot Rolled
Joined
Apr 9, 2009
Location
CA USA
it sweems that all the sharpening guides I find for HSS for cast iron is for the old lantern tool holders , what am I lookin for for tool grinding for a straight QCTP tool holder
thanks
animal
 
it sweems that all the sharpening guides I find for HSS for cast iron is for the old lantern tool holders , what am I lookin for for tool grinding for a straight QCTP tool holder
thanks
animal

jrr_toolbit.jpg
 
thanks for that . I have my first back plate all resized & lost a lot of over hang in the process . using back gear was part of the trick I think . so on to my next question . How do you get a good finish when turning cast iron ? I'm down to .0015 runout but I know i can get it better with a nice finish , any input is greatly appreciated
tks
animal
 
Cast iron is very abrasive, so the edge on HSS will not last very long, but it will last about 4 hrs. assuming correct speed and feed.. You should use cobalt alloy HSS for that reason. The tool relief angles should be 7 degrees. I find that works best. It is adequate to reduce tool load and yet provide plenty of edge support. It is also very important to have plenty of back clearance to prevent the chips from getting trapped between the tool and the work piece. This is a common cause of poor finish. Also you should use a nose radius of at least 1,5 times the feed rate per revolution for a good finish.
 
Jim posted a great cartoon but forgot to include any angles??? Attached you’ll find generic single point angles. Try the cast iron recipe based on material strength condition & then salt to taste.

Once you’re happy with a recipe take some crayon’s & mark up the nifty cutter detail for future reference. When you get things right, a 3/64” nose radius & .006-.008” feedrate should get you near 64 micro inch finish & polish after that if you want better.

Good luck,
Matt
 

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