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How To Grind A Hss Turning Tool
- Thread starter mikey
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- Jun 7, 2013
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Another way to go about it is to grind a semi circular or step chip breaker on the top of the tool parallel to the cutting edge with the corner of the grinding wheel; this will curl up the chips rather than having them come off stringy; this we were taught in machine shop class back in the early 1960s by our teacher who taught apprentice classes at our local navy yard after having served apprenticeship there himself. When the feed is increased enough the chips will break in short curls rather than coiling like a spring. These tools were used in Armstrong holders with the built in 15 degree back rake, but also work well in parallel holders.
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- Dec 20, 2012
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You need some additional support under the bit. You might consider making an auxiliary table that drops onto the main table with a support ear on that right side. Once you have the support, all your issues will resolve.
Otherwise, the bit looks good! I can't see well but the cutting tip looks a bit sharp - did you stone a nose radius on it? If you do, the finish will improve.
You did an awesome job, Duane, especially for a first tool bit!
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- Jun 7, 2013
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Yes, that would help immensely!
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- Dec 20, 2012
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Maybe make the nose radius a bit larger - it helps.
The belt to table distance should be about 1/16" or so. Your table should allow front-to-back adjustment. If it doesn't, make it so. This is a safety thing so an object you're grinding cannot tilt up and jam between the table and the belt; if it does, it will happen in an instant, before you can react.
If you make a new table, make it with a protractor slot in it for when you need to grind an angle. Also make a drop on table with a support ear on the right side and a piece of stock underneath that fits the protractor slot. It takes only a second to lift such a table off and allows you to change belts without moving anything else.
It does move forward and back. But as soon as you tilt the table down it touches the belt so you pull it back towards you. I'd say more like an eight or 3/16" from the belt. This photo is not to good in showing that.
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- Dec 20, 2012
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- 9,422
You might have to push the table into the belt and grind a bit of the bottom edge off to get the top of the table closer to the belt. At minimum, you want about 1/8", no more.
I like that idea.