Models for grinding HSS Lathe Tools

[Aaron_W]

On another note, and maybe this has been discussed buried somewhere in this thread, but does anybody use a leather strop block along with or in place of diamond honing stones?

I started dabbling with wood carving (ok, being honest, buying chisels, knives and paraphernalia to do wood carving... haven't got much carving done yet) and a leather strop is the preferred honing method. I bought a bag of leather scraps to make some honing blocks, and thought I might make an extra block to try on the lathe tooling.

 

[Jimsehr]

Those tool shapes were the standard in about the year 1890. But you will not see any modern shops using them today. Tool material is MUCH better today.

 

[Downunder Bob]

Your tool looks pretty good but I can't see the rake angles. A shot from the front of the tool will help. Also, you need to put a small nose rdius on your tool and hone all three faces. Otherwise, you did a fine job. For more detail on how to grind this tool, search for "How to grind a HSS lathe tool".

I've had extensive experience grinding tools with both a bench grinder and a belt sander and in my opinion you cannot beat a good belt sander for grinding lathe tools (and many other tasks). Ideally, you want a 2" wide belt and the sander must allow access to the right side of the platen. Search for "belt sanders tool grinding" and read up.

I don't expect anyone to read this whole thread. It is a monster at this point. However, if you wish to really understand how lathe tools work and how they are used then you might consider taking a deeper dive. I've read comments that the various tool angles on a turning tool are not important. I have ground more than 300 experimental tools and I KNOW that a tool ground with a specific tool geometry/angles can double or even triple the performance of a tool ground with stock or haphazard angles. I have a little Sherline lathe that will take a 0.060" deep cut in mild steel (0.120" off the diameter), then turn around and cut off 0.0001". Try that on any other lathe with only 0.08HP and you'll understand why I think tool geometry matters.

Hi Mikey, I can understand why you consider sharp tools with correct angles are very important, and with that little lathe of yours it makes sense.

With my 12x16 LD I find it rarely matters I don't have a belt sander, I would if I had the room. and generally use a 60 grit wheel. With which I can get very good results, I have even used an angle grinder (60 grit wheel) when in a hurry, and my grinder is not set up.

During my apprenticeship 1961 to 1966 in a toolroom for a large manufacturing business we always used a 60 grit wheel for sharpening HSS usually 3/8 square, and got very good results, we also very rarely hand dressed a tool. We were taught that a correctly dressed grinding wheel was the most important factor.

 

[Z2V]

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It requires searching through this thread but there are a couple of posts interspersed throughout that summarize the various tools discussed to that point.


Making a 2" belt sander is on my to do list, but while it is not perfect, my 8" bench grinder has not left me feeling inadequate. Seems to me a lot of the guys who own a nice belt sander still resort to a bench grinder for certain aspects of tool grinding. I've been quite happy with my Rikon 1hp low speed 8" grinder. When I finally wear out the white stones I'm thinking I will replace them with CBN wheels. It seems like this grinder will always continue to find a use as a dedicated tool grinder even after I finally get my belt sander built. I also do some woodworking so it does double duty sharpening some of those tools as well.

If you go the DIY route on a 2 x 72 belt grinder keep your eye on Craigslist for a cheap or FREE treadmill. You have your motor and control board right there.

 

[finsruskw]

Lots of t/mills around here, $50 & up.
Any make or model better than another?
HP?
I had junked one out years ago before I got into this hobby, and still have the motor but all the rest is long gone.
Has anyone authored a thread on building one from scratch or a kit?

 

[ttabbal]

Lots of t/mills around here, $50 & up.
Any make or model better than another?
HP?
I had junked one out years ago before I got into this hobby, and still have the motor but all the rest is long gone.
Has anyone authored a thread on building one from scratch or a kit?

Outside of the commercial level units having better motors and such, the treadmills are about the same. If you have the motor, you can probably find a DC motor controller reasonably priced. If you want to go higher end than that for whatever reason, 3 phase TEFC is nice to not have to be concerned about grinding dust getting into it. I pulled a treadmill apart, then got a deal on a motor so I ended up using that for the grinder and the treadmill motor to drive a die filer. I've seen a lot of people recommend 2HP for belt grinders. I've never come close to stalling mine using 2HP 3 phase. I think you would slip or break the belt before that would happen even with a weaker motor. If you are near even a suburb, you can likely get lots of free treadmills in spring.

There are some build threads here, and a number of free plans online to build from. If you can weld, it's a pretty basic build. My booger welds hold up, so I think even a poor weld will hold it fine.

 

[mikey]

Hi Mikey, I can understand why you consider sharp tools with correct angles are very important, and with that little lathe of yours it makes sense.

With my 12x16 LD I find it rarely matters I don't have a belt sander, I would if I had the room. and generally use a 60 grit wheel. With which I can get very good results, I have even used an angle grinder (60 grit wheel) when in a hurry, and my grinder is not set up.

During my apprenticeship 1961 to 1966 in a toolroom for a large manufacturing business we always used a 60 grit wheel for sharpening HSS usually 3/8 square, and got very good results, we also very rarely hand dressed a tool. We were taught that a correctly dressed grinding wheel was the most important factor.

Hey, Bob.

Yes, tool geometry matters a lot, and the smaller and lighter the lathe the more important it becomes. However, the benefits of improved tool geometry transfer directly to larger lathes, too. It allows my 11" Emco Super 11 to cut better than many lathes much larger, simply because the tool is more efficient.

Insofar as which is a better tool grinder, I think whichever you are most comfortabe with is the right tool for you. I used a bench grinder exclusively for over a decade and I know they work. I just find a good belt sander to be vastly supeior fo tool grinding, at least in my opinion. We use what works, right?

Most of my turning tools are over a decade old and have only been honed, not reground. They perform like new so I think honing tools works. We all have our own way of doing things. I was not taught; I figured out what worked for me and stuck with it. Doesn't mean I'm right.

 

[mikey]

Thanks for your comments.

Here's a pic looking at the front of the tool.

I did try honing a radius with a stone, but it's woefully small. I suspect that a hone is not sufficient and the radius needs grinding (the section of the thread that I used didn't have any radius instructions). I did find a .stl for a tool in the thread and printed one. I think I can duplicate that radius on the HSS cutter with my sanding disk.

The side rake on your tool is sloping in the wrong direction. This will make it difficult for the tool to cut as it should. Look at the pics in the article on how to grind a HSS turning tool and try to duplicate that.

Insofar as grinding the nose radius, I find it much harder to control when doing it under power. A simple diamond card is faster and controllable but use what works for you. The nose radius is tiny. Look at a 1/32" drill. That is the profile you're trying to emulate.

 

[mikey]

On another note, and maybe this has been discussed buried somewhere in this thread, but does anybody use a leather strop block along with or in place of diamond honing stones?

I started dabbling with wood carving (ok, being honest, buying chisels, knives and paraphernalia to do wood carving... haven't got much carving done yet) and a leather strop is the preferred honing method. I bought a bag of leather scraps to make some honing blocks, and thought I might make an extra block to try on the lathe tooling.

I tried it once, many years ago. I found that it rounded my edges but maybe my technique sucked. What works better for when I need a polished edge is a Translucent Arkansas stone. Amazing how well that works.

 

[Shiseiji]

‘

If you go the DIY route on a 2 x 72 belt grinder keep your eye on Craigslist for a cheap or FREE treadmill. You have your motor and control board right there.

Minor caution. On the fancier treadmills the controller is on a huge multi-function board. New stand alone controllers are available, but last time I looked at them the price made me think twice. They also often have some nice SS bar stock, but my experience with the frame is that the material is so thin walled it's tough to weld. YMMV.