Models for grinding HSS Lathe Tools

I just finished restoring a Sherline lathe and the owner used it for the very first time today. I let him try my old square tool that needs regrinding; must be at least 10-12 years old and has lost most of its back rake to honing. He was cutting 12L14 and it blew his mind when he took a 0.050" depth of cut (0.100" off the diameter) at 1200 rpm; cut like butter! Pretty sure we could have gone much deeper but he wanted to try lighter cuts. Then he took off a thou, and then he interpolated and took a 0.0001" depth of cut to produce a steel wool ball made of angel hair that just about floated into the trash bin. He is now convinced that the right tool really does make a difference.

I've said it before. A good tool will take as big a cut as your lathe can handle, then turn around and take a micro cut to bring you in dead on size without you even noticing it. Trust me, guys; this tool grinding thing is a skill well worth learning!
 
Yes Mikey I agree, the skill of hand grinding lathe tools and drill bits Is probably the most important skill any machinist can learn

I does't matter how well you learn the many other skills required, without the ability to grind good cutting tools the rest is all but lost.
 
I've probably missed it somewhere along the line. What's the preferred belt for grinding bits?
 
Same here. Orange ceramic
 
we never used belts, only 60 or 80 grit aluminium oxide wheels, Usually 6"Dia.
 
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Aaron W I use a combination square to set the angle of tool bit.

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X2 on ceramic. I don't have a ceramic belt yet. Still using 80 grit aluminum oxide. That's all my local Ace Hardware had. When they wear out I will get some ceramic belts.
 
I'm amazed that the 80 grit belts are producing such fine work. Fine as in not striated. :)
 
36 grit ceramic will chew through HSS faster than you would believe, and it does so with much less heat than Aluminum Oxide. 80 grit smooths out the coarse shaping marks and you can step up to as fine as you wish. If you step up to 600, you'll have a mirror finish.
 
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