Models for grinding HSS Lathe Tools

[WobblyHand]

@Janderso page 10, post #104 gives you the directions you need. @mikey's write up is amazing. He has great pictures, and clear instructions. This thread has greatly increased in size since that time, so you may have missed it. As stated very early in this thread, practice with cheap keystock. I know it helped me a lot to get the basic shapes right. Wish the honing was easier for me, but, I'm still working on that. Need to build a nice low speed grinder like yours!

 

[Janderso]

Jeff, your tool has good relief angles and decent side rake but zero back rake. See how the edge is horizontal in pic 5 above?

Have you ever seen the model tools we have been sending out? If not, PM @Z2V and have him send you a set so you can see what the tools look like. Take a break until you get them, maybe?

A properly ground HSS tool will more than keep up with a carbide tool. In fact, my tools will take a deeper roughing cut than my carbide tools will and will easily take a micro-cut that no insert will take. Try dialing in a 0.0001" deep cut with an insert and see what happens to your accuracy.

I know it isn't easy to grind tools in the beginning but it gets better, much better, if you stay the course and learn the skill.

Yeah I noticed that. The strange thing is I started out with a side rake. I must have allowed it to go neutral.

 

[Janderso]

I spent the morning going through this thread. I then added some back rake to my new attempt.
Same ****ty results.
After spending 4-5 hours on this subject, I think it’s time to try try again some other time.
I understand the basics, I think I have a fair cutting tool but the results are not adequate.
It’s probably not sharp/honed properly.

 

[WobblyHand]

@Janderso you are getting the basic shape much better, so that's an improvement. To help further, you need a better focus on your first two pictures. When they are blown up they are out of focus. A trick I use for phone cameras is to put something very close to the part you want to focus on, like a piece of paper. This fools phone camera autofocus and makes the edges and faces in focus. The third picture is in focus and I can see on the back edge (and front edge) a black ridge of metal extending above the top face. This means they are not honed right. You need to hone the top as well. There should be no crud visible on these edges.

I find getting this right hard. It certainly tests my patience. But when it is right, the tool cuts very well. It's very worthwhile to keep on plugging at it.

 

[mikey]

It can be frustrating grinding and not getting the results you want. This is why I highly recommend you start learning to grind tools using mild steel keystock until you have the process down. It takes a bit of practice learning how to move your hands and keystock is cheaper and easier to grind than HSS.

Jeff, please buy some keystock at the hardware store in your desired size. Cut it into tool bit size chunks. Read this article and try to duplicate the steps shown until you can grind the desired angles into the tool. Switch to HSS when you can grind keystock accurately.

If I can, then you can.

 

[Janderso]

It can be frustrating grinding and not getting the results you want. This is why I highly recommend you start learning to grind tools using mild steel keystock until you have the process down. It takes a bit of practice learning how to move your hands and keystock is cheaper and easier to grind than HSS.

Jeff, please buy some keystock at the hardware store in your desired size. Cut it into tool bit size chunks. Read this article and try to duplicate the steps shown until you can grind the desired angles into the tool. Switch to HSS when you can grind keystock accurately.

If I can, then you can.

Thank you for your time and attention.
I stock, key stock.
I have a full range of McMaster key stock.
That is a great idea!
Learning the process this way makes sense.

 

[mikey]

Thank you for your time and attention.
I stock, key stock.
I have a full range of McMaster key stock.
That is a great idea!
Learning the process this way makes sense.

Brother, I said I will stay with you until you get it. I meant that.

 

[devils4ever]

I bought some finer belts for my grinder (320, 600, and 1200) to use in place of the diamond hones since I was having trouble keeping the hones flat on the faces. Here's the results. It's hard to tell from the pics, but the surfaces appear fairly well polished. What do you think?

 

[mikey]

Looks pretty good to me. Can't tell how the intersections are but as long as they don't reflect light then it should work. I think I would still at least put a light hone on each face, though. Proof is in the pudding; if it cuts well then it's good enough!

 

[devils4ever]

I did my best to hone the faces. I think they look pretty good.

I was able to take 0.040" deep cuts in 3/4" 12L14 steel without issue. I didn't try any deeper. Here's the results. What do you think? This was a 0.010" deep pass at 675 RPM with 0.004" feed rate.