i am a novice to sharpening tool bits.(been using HSS inserts). so after a previous thread; the question that i have is. after getting the back rake; what happens after i re-sharpen the bit. i will loose the "center point" on the bit. what do i do. shim the tool bit to the proper height??
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Back rake question
- Thread starter porthos
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If you are using a 4 way tool post that is common as an OEM on import lathes, you might have to shim the tool to bring the cutting edge up to the centerline of the spindle. That was my main reason for going to a QCTP. A small amount of difference is probably still acceptable but definitely if you are grinding top rake into the tool, sharpening the tool will drop the contact point below the centerline. b The old lantern style tool holders built top rake into the toolholder. Not possible with a 4 way.
Re-sharpening usually is just honing a bit, a couple of tenths. If you go to the grinder, yeah, might have to adjust with shims/qctp. I made a little gauge I use to check height with, only takes a few seconds to do a quick check and adjust if needed.
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Or you could buy an insert tool and inserts. They come ready to use.
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If you are using an Aloris tool post and you grind a tool bit you adjust centerline with the wheel that is on the tool holder.
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By far the easiest way to align a resharpened HSS tool is to use a quick-change tool post. You can raise or lower the cutting edge with just a twist of a knob. Being somewhat lazy I use a 6" scale against the work piece to make sure I'm on center.
Here's a quick video showing how it's done:
Here's a quick video showing how it's done:
