Grinding HSS Lathe Tools – Part 1: Grinding a RH Tool

Hi, Barry Young here and today we are going
to grind some tool bits for your lathe out of high-speed blanks. This is actually a high-speed
tool bit. It’s 1″ square. You probably won’t be using anything this big but it really makes
it easy for you to see what I’m doing. I’m actually going to grind a smaller one because
this takes forever to grind and I know your time is valuable. So, I’ve labeled the faces
of this tool: face 1; face 2; and face 3.  Face 1 is the end of the tool bit and it’s
a compound angle. Face 2 is a regular angle, that’s the side rake. The top rake, face 3,
is also a regular angle. So let’s knock that compound angle out first. Step to the side
and start the grinder, because it’s dangerous. Just in case. Now, first thing I’m going to
do is turn the tool flat on the tool rest and just grind this away. Now, I’m going to
turn this blue because I’m grinding it way to fast. When you do this in your workshop
you’re going to want to grind with less pressure and more dunking. Ok, we’ve got a 5 to 7 degree
angle on the end of this tool bit. Now this is mild steel so it ground a little easier
than what you’re going to grind. And I’m also using the fine wheel on my grinder which is
on the left side. Course are almost always on the right. And I’m using this mild steel
so it will go quicker. Now, we’ve got the end angle, but it’s not a compound angle.
It’s just flat right now. I’m going to lower the shank, the end in my right hand, and raise
the tip a little bit, like this, to grind that compound angle. No you’ll notice how
I went straight into the wheel to match the angle that I had ground before, and then raised
the tip. So, again this is turning colors because I’m grinding it way to fast to save
some time on this video so that you can get back to the football game… As soon as the
sparks start coming of the top of the tool instead of going underneath it I know I’ve
reached the top. And sure enough ,I have. Right here this grind has gone all the way
to the top of the tool. And it got rather warm! For the second face, face 2, the side
rake, I’m going to turn the tool 90 degrees and then I’m going to rotate it back towards
me about 3 degrees, which is in the beginning pretty tough to accomplish. But you’ll get
used to it the more tools you grind. I like to grind back just about 1.5 times as far
as the thickness of the tool. Just go straight in. Don’t forget to dunk! Now, if you look
right here, one of your goals is to make that grind parallel, the top of that grind should
be parallel with the top of the tool. Easier said than done. Practice practice practice!
Once again, we are going to grind until sparks come off the top of the tool. Which means
the angle we are grinding has reached the top of the tool. Some of these tool bits have
a slight radius on them, the older ones. The newer ones tend to be ground all over and
don’t, so they are easier to grind. I’m starting to see sparks, so I am all the way. Now, one
thing we want to do is try to make one solid continuous grind from top to bottom. This
particular one has got two facets. We are going to keep grinding until those facets
go away. Try and hold the bit steady as long as you can without burning yourself and that
will make it one continuous grind. You can feel when the tool flattens itself on the
wheel. That means that you’ve matched all the cuts you’ve made before. And now we have
one continuous grind from top to bottom. Beautiful! The last grind that we need to do is on the
top of the tool, called the top rake. To do that we go on the other side of the wheel.
Ninety degrees, tilt it back, and plunge. This is going to be a 2 to 4 degree angle
because I’m cutting a really hard material today, 4140, and I need as much cutter left
as I can get. Once again, let’s take a peek right here. Notice how the distance from my
grind to the side of the tool is greater at the root than it is at the tip. That means
that I had this end elevated a bit and I need to straighten it back out and get it truly
horizontal. Which I will do right now. And, there we are. One continuous grind all the
way without digging into the tool. This leading edge is the cutting edge and we now have a
good tool except for a few little touch-ups, burrs that I have to get off. And the radius.
How in the heck do we get a radius on there? What I do is I look at the side and I match
the angle on the front of the tool to the angle of the wheel and then I walk it around
the corner of the wheel. Just like that. And the goal is to get the width of this radius
equal on the top and the bottom. You’ll notice that mine is just a little bit narrow at the
bottom. So I’m going to go back in until it hits flat and then I’m going to lower the
shank just a little bit. And that should make my radius equal in width from top to bottom.
And that’s definitely good enough. This tool will cut after I get the burrs removed.
Which I can do very easily by a super light grind on each face that I did before. Now,
before I use this I would hit it with an EZE-Lap diamond hone to remove any little tiny burrs
that I can’t see. And that’s how we make a right hand turning tool. Just change the angles
exactly opposite of these angles to make a left hand turning tool. Thank you!

82 thoughts on “Grinding HSS Lathe Tools – Part 1: Grinding a RH Tool

  1. Barry,

    Can tell You are from the Old (Older) school as I NEVER heard You say: "You Know" one time! I absolutely DETEST those words, plus are a STUPID thing to say. IF I KNEW I probably would not be watching, would I? Oh, Quit apologizing about Time, I THANK YOU for giving US – Yours!!!




  2. Dude, what kind of grinder are you using? I have a crappy little bench grinder about 1/2" thick at best. I want the one you use! Thanks for your vids, they help alot…

  3. I'm learning the lathe right now. I want to make a tool for cutting a 30 degree interior chamfer. The chamfer only has to be about .150 deep into a 2.25 inch diameter aluminum tube so I'm pretty confident that I can do it. I can't figure out why the person who is teaching me insists that we use such an elaborate setup for a simple cut. He just gets mad if I ask so I'm going to figure it out on my own. I think the tips in your video will help a lot. Thanks!

  4. this is the same way the tought me at trade school, use mild steel until we got it and then we got some hss ground a few different tools wrong on purpose so we could see what would happen if used one the lathe. great video and well presented thanks.

  5. I have looked for and watched a lot of videos for making lathe tools and this is by far the best! Thanks so much for passing on the skill to others.

  6. Kinda crud with his finishing, no stones used or mentioned other than a diamond lap that is not the best for a steel bit.  lets ignore the mild steel vs HSS as Barry did.

  7. Thank you so much for sharing your skill and knowledge. My husband and I have been working on a project  today and I believe with your video tomorrow will go more smoothly.

  8. Thanks so much for the upload, I have a lot of trouble with the grinder and making tools. This helped to explain a lot.

  9. Barry, allow me to share a snippet of wisdom with you drawing on my many years of working in big industry.  As an instructor you should already know this, nonetheless, long sleeves and rotating equipment is deadly!  Wedding rings, watches, long hair (you're ok there) also just as deadly.  Please, as a good example and in the interest of sharing best work and safety practices, roll up your sleeves and keep your limbs for future use.  These rules and policies are written in blood.  Quite literally.  Thank you for the information but there are no exceptions when it comes to safety.  Were you working for me you, despite your level of knowledge and skill, would be fired for the safety violation.  Good luck to you.

  10. in my precision machining class we had to do this the second day of class before we were aloud to get on any machines then we had to sharpen drill bits

  11. GRat video and thank you! But what a pain in the neck! Isn't there a jig where I can set the tool in it and it gives me all those angles? Who's got time for this?

  12. What's up with wanting to get back to the football game?  I find your instruction more useful and interesting than watching a bunch of multi-millionaire homos wrestling around with each other in their pajamas.

  13. This video was incredibly helpful in grinding my first two tools!

    The brazed carbide tools, because of the slow speeds and feed rates, I could only achieve 15~25 thou cuts, but I was able to push my machine (a local equivalent of a G0602) to .125" with my first RH tool!

    Thanks! 🙂

  14. respected sir please upload parting tool hss sharpening i m having difficulty in that. i m cutting 34 mm roud solid bar with hss tool

  15. Thank you that was a very good video and you made it easy to understand the geometry of the angles and how to achieve them. Thank you once again John Tasmania Australia

  16. Very well demonstrated. It is good to see this basic tool can be accomplished on the be bench grinder without a complicated support system. My Dad and Grandfather were both journeymen tool and die men and your video brought back memories of Dad showing me how to use a bench grinder. Your video brought the process back, now I need to practice. Thanks.

  17. Great video ,thanks, I bookmarked it and have already watched it 3 times,also will recommend it to whoever is looking to learn how to grind lathe cutting tools the easy way.

  18. You might want to take off your long sleeve. That's just waiting for a spinning object to grab and drag you in with it…

  19. A comment and a question.
    You didn't explain the rake well on the top of the bit as you were sharpening. Did I miss that?
    Question; You were sharpening 4140 and spoke as if you were actually going to cut with it. Do you use 4140 for aluminum or plastic only cutting? Do you harden it first?

  20. I love this lathe.>>>    I purchased this over a year ago, and it is still running strong. It does all the smaller jobs you need to do without skipping a beat. The variable speed on this machine is hands down the best feature you could ask for…(especially for the price!!!) Id recommend this to everyone looking for a quality, and affordable lathe.

  21. A true Machinist is able to grind his own tools. I was always told to look in the toolbox of an old timer and see his HSS tools… and that will show you a level of experience

  22. great, if need turn a concave as in tube firmer dye, using a tool that pivots, what will by tool shape be, as the tools pivots in an arc , both ways? rgds

  23. I hate these videos that show you how to grind the tool but they never tell the purpose of the tool what's it to be used for what position do you put it I'm totally lost here I know it's not a facing tool I know it's not a parting to but what exactly is it to be used for, help,

  24. That’s going to take practice but I will achieve my goal. Thank you and I’ll be watching your videos because I just got my great great uncles 1937 south bend 9”C

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