Grinding HSS Lathe Tools | Beginner Tutorial

G'day everyone,

I've recently bought some new HSS tool blanks for the lathe. My intention is to grind them into lathe tools for various types of cuts and materials. Since I was already going to grind the tools, I thought it might be useful to film the process of how I decide how to grind the tools for different types of turning operations and materials.

In this video I will go over some basic tool geometries (rake angles and clearance angles) and tool shapes that I have ground over the past 6 years. This video is intended as a beginning introduction to tool grinding and will allow beginners to understand the reasons why tools are shaped the way they are. I will be using by bench grinder to grind the tools into shape.

I hope you enjoy the video, cheers.

Timestamps
Intro - 0:00
High Speed Steel - 1:03
Grinding A Brass Tool - 3:27
Grinding A Positive Rake Tool - 8:02
Aluminum Chip Breaker - 10:25
Steel Chip Breaker - 11:41
Back Rake Angle - 13:01
Right Hand Tool - 14:08
Left Hand Tool - 15:34
Form Tool - 16:10
Boring Bars - 17:30

Lathe: Sieg c3 7x14 mini lathe
Mill: Sieg x2.7l

#machining #DIY #lathe

[spevakdesigns]

I bought a used Kennedy machinist toolbox a few years ago and one of the drawers was filled with hundreds of HSS tools. Most already ground, with plenty of life left and dozens upon dozens of blanks to work with as well. A lifetime's worth of tooling. It's allowed me to study the grind on the existing tools and plenty of material to better learn to grind my own.

[cameronmccreary]

Years ago when I was doing a lot more custom tool-making; I was using high-speed steel to make Precision Form Tools.
Now since I work a lot with diamond tools, I make "All my form tools from Tungsten Carbide." I use fine grain tungsten carbide and they rarely break when in use and a form tool will last for years. Geometry is "King" when making any tool.

[kwaaaa]

After watching so many videos, some people are just gifted at explaining and teaching. Thanks yet again for another clear and concise video on such a murky subject. I kid you not, I just watched 5 videos that defined each geometry but no explanation why they are there.

[MPH]

Grinding the tools brings back memories....
Can't remember how many times I had to re-grind because my teacher found a flaw. If you finally got his approval you needed to use it on the lathe for a test cut.
After handing in the work and tool he would mess it up so no-one could re-use it.
We learned to do a quick switch after turning and before handing in the work. We needed to hand him the tool as far from his desk as possible (that's where his glasses were). He didn't checked the tool, he just picked up an airgrinder
We had to make 6 or 7 different tools so with 7 classmates we all made just one. This trick saved many hours of re-grinding.

[asressaraia]

Thank you for your exclusively lucid/clear and highly appreciable contributions - please keep it up.

[j.hankinson]

Thanks for posting. I dwell more in the Woodturning world where we sharpen HSS a lot. Many of us move quickly past the crap grey wheels on to the blue wheels, then white, finally ending up at a CBN wheel. As you probably know these are designed for HSS and are better than diamond. No silica dust, they don’t wear out for a long time, easier on the steel, and maintain a 8” diameter always. I find a 80 grit for shaping and a 200 grit for sharpening are a great combination. I’ve found your content to be interesting and educational. Thanks again.

[davidspin]

I bought a South Bend 9" C lathe from an old guy who retired and it had probably 10 lbs of this HSS, now I need to practice making these.

[sparkiekosten]

Whilst I know what needs to be done to create a HSS cutting tool seeing it explained in this way without all the "Math" involved makes me more confident in having a go!
I have ground custom cutting tools for jobs but mostly they are used once and then reground for something else.
My go to tool however is and will always be my diamond tool holder. Expensive to buy but more than paid for itself in usage.
Keep up the good work!

[keithslayback]

Thank you finally someone showing and explaining in a way I understand I have been struggling with grinding bits and this video and how you're explaining it is so very helpful thank you so much

[fredford]

I've been at this game for many years, thanks to this video, I have learned quite a bit. Thank you!

[GavinFreedomLover]

Beginner here, this video was exactly what I was looking for subbd, love from England :)

[haggis]

I'm really old school.... I still grind everything by eye. It's been working for over 40 years so I reckon I'm going to stick with it.
Maybe my angles are not optimal but I probably have 500 + different HSS cutting tools for every possible machine lathe operation in various sizes. If it ain't broke.. yada yada.
Nice video though. Well done, you!
Edit... I do all my drills by eye too... if it ain't broke. I see new fangled jigs to maintain angles but it seems to work no better than my eye and requires setup.
Oh... new sub here. Soothing to watch.

[machinistmikethetinkerer]

Been doing this a long long time, as my father and grandfather before me. I think I have two almost three tool drawerfulls of tool bits and drill bits and countless more around the shop. I grind and sharpen all by site sound and spark as I was taught. It's a dying art and I have to admit inserts are the go-to now. But I still use my HSS now and then. Great vid.

[gp]

Great video one suggestion if I may when chopping the tool to amore proper size if you cut the blank at 10-degree instead of straight with the cut off tool you will save time and steel because both blanks will have a 10-degree clearance built in so is less material to grind
Thanks for the time you take to explain other how to!

[wolw]

Extremely helpful and interesting. I'm getting blanks and just the odd carbide bit holder for threading. Thanks !

[geoffcrumblin]

Good explanation. The dremel mini tool can improve the cutting edge with a chipbreaker.
Also a set of diamond files can smooth out the cutting edge into a radius, to improve surface finish

[lloydrmc]

Even more informative than usual, which is saying something in your case. Bravo!

[andreasoberg]

Very nice and comprehensive tutorial. I thoght for sure that the hardening would be ruined and just assumed ju had to have som sort of cooling fluid when grinding. Looks easy now when you show it. Thanks!😊

[metalmanglingmariner]

Always been worried about grinding my own tools but now I feel a lot better about giving it a try.
Thanks and a happy new year to you.

[AndrewMoizer]

Thanks for this. Clear and simple. Just the refresher I needed.