Lathe tool holder for my southbend 9

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refinery mike
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Lathe tool holder for my southbend 9

Post by refinery mike » Sat Jul 09, 2011 8:52 am

Help me out here, i am thinking about making a tool holder set for my southbend 9. maybe its been done before but i have never seen it. The plan is to make solid steel holders that automaticaly set the tool to center, and hold the bit at the proper angle so that the top of the bit is left flat. that way all i have to do is set the grinder to one angle and grind the profile and the bit is ready to go. The block is machined so all i have to do is put a straight edge on the top and adjust the tip of the tool to that, and that will be centered and ready to go. and the slot is machined at a double angle for side relief and top relief.
What do you think am i missing something, improvements. And feel free to laugh at me if this is old or stupid idea. I am always looking for a better way to do things. Maybe you have tried this and can give me some pointers.
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Inspector
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Re: Lathe tool holder for my southbend 9

Post by Inspector » Sat Jul 09, 2011 10:08 am

Looks interesting, but from what I can see of your cutter, you have to put 2 compound angles on the end of your tool bit. If you can do that then there is, in my mind anyway, no reason to grind bits to fit a standard holder. Have a look at tangental tool holders if you want to simplify grinding of the tools. As the more experienced will point out, your tool as designed isn't allowing for a chip breaker. When you have to grind one in it will defeat your original intent of having a flat top.

Pete

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refinery mike
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Re: Lathe tool holder for my southbend 9

Post by refinery mike » Sat Jul 09, 2011 12:53 pm

I forgot to say that the bit is sharpened while still in the tool holder. I set the grinder for the appropriate angle and then grind all the way around the profile. that leaves a hollow ground effect. then i hand hone the edge with diamond stones.

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Re: Lathe tool holder for my southbend 9

Post by Harold_V » Sat Jul 09, 2011 4:30 pm

In a perfect world, that may be an acceptable idea, but that's not where we live.

It is my opinion you would be far better served to hone your skills in grinding tools offhand. There's going to be times when you may need the tool location in a different position, so you'll have already lost the height control feature. The issue with chip breakers is also a consideration, although, with care, you could still grind them. In that regard, if your skills are good enough to do that, there's no real need for making holders as you recommended, for you can tailor the tools as required.

There was a comment on rake. Needless to say, if you alter the way the tool is held, rake is a function that comes automatically, and it will be consistent. It may or may not serve your needs for a given material, but you will have rake, both side and back. a function of the design. If, by chance, you choose to machine brass or other materials that are overly sensitive to positive rake, and your machine is not robust, once again, you will have created a holder that won't serve your needs well.

I would still recommend you concentrating your efforts on offhand grinding.

Harold
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Re: Lathe tool holder for my southbend 9

Post by Harold_V » Sat Jul 09, 2011 4:31 pm

refinery mike wrote:I forgot to say that the bit is sharpened while still in the tool holder. I set the grinder for the appropriate angle and then grind all the way around the profile. that leaves a hollow ground effect. then i hand hone the edge with diamond stones.
If you alter the tool while it's in the holder, you lose center.

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.

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refinery mike
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Re: Lathe tool holder for my southbend 9

Post by refinery mike » Sat Jul 09, 2011 6:40 pm

Thanks for your input, you are right i would have to have to make several styles of holders and i would loose some versatility. It is not that i can not successfully grind a bit to any shape i want, i guess i am just lazy. But laziness is the mother of invention. I think that is the way that goes isnt it.

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