Venturing into insert tooling

[ShawnR]

I have finally ventured into the world of insert tooling. For years, I was determined to continue to use my cemented carbide bits, which I have a lot of, and HSS bits But despite watching numerous videos on sharpening, I don't think I ever got it. I finally caved and bought this. I figured it would be a good test to see if it makes a difference. A cheap set but this was kind of an experiment. I figure if I like it, then the bits could be upgraded or even the holders.

It does. I was able to find a speed and feed today to give me a really nice finish on some shop stock, probably just some hot rolled stuff. Mostly what I have. So I guess I can quit blaming the material and accept that maybe insert tooling is the way to go...

The photo does not make it look too good, probably too close. But there were some better finishes too. I just never seemed to get the finish I wanted with what I was usually using, material or tool bit. I did have some hydraulic shafting in a couple of times and it was like that stuff could not yield a poor finish. But other than that, the finish was seldom what I wanted.

So, I think I have been converted....

 

[Brent H]

Oh you have ventured (inserted yourself) down the rabbit hole of carbide........mooohooohahahahahahaha !

speed and feed are your friends - heavier cuts etc - be sure to write down the insert information so you can get replacements efficiently. It really suck trying to find inserts for yard sale pick ups that have no insert in them....ugh!

 

[ShawnR]

Yea @Brent H , you and I talked about the need for more aggressive cuts with carbide. I was experimenting last week with the cemented ones I have but did not see a huge difference. Maybe I did not go extreme enough.

So what do you do when you get close and want to make a very light or few light cuts as you sneak up on a specific size? Do you switch to HSS? I will be playing with the tools more tomorrow so hopefully can answer my own questions. For such a ridiculously cheap set, nothing lost if they were crap. Time will tell. Nice that they all take the same cutters, although only 2 cutting points each.

 

[DavidR8]

One of the best investments I made when dipping my toes into carbide tooling was this book:

Amazon.com

 

[Darren]

Shawn, I use mostly insert tooling these days too, but often find that HSS is neccesary when you don't have the right insert for a thin circlip groove etc. HSS is cheap and you can make the shape you need. On some metals you need a sharper tool. Aluminum and brass cuts great with HSS, and i find a better finish with HSS. Most carbide is not sharp, instead relies on tool pressure, which on a light machine can pose some issues. Sharp HSS often cuts even 4140 with less heat as well, making tolerances easier to hit. Don't write it off just yet.

 

[DavidR8]

My first experience with a truly sharp, well-ground HSS tool was a total eye-opener. I was able to cut deeper and more easily than I ever thought possible on my South Bend 10K. It is definitely the mainstay in my shop.

 

[Darren]

Most people these days don't realize how good HSS can be. Too many youtube videos maybe. The old guys years ago were cutting hardened gun parts with HSS with no safety glasses while smoking a stogie. When they got dull, they sharpened them on a grinder with no guards.

 

[DavidR8]

I'm also a member of Hobby Machinist. One of the admins there wrote an excellent guide to grinding HSS bits. They even have a program where they grind models of the three most useful tools into 3/8" keystock and send them to you for reference. You get them, duplicate them on keystock and send them to the next person.
I grind my tools on a belt grinder as I find that I get more consistent results than a wheel.

Models for grinding HSS Lathe Tools

In a recent thread by @Darkbluesky, http://www.hobby-machinist.com/threads/lathe-accessories-tools-ideas-of-what-to-buy.62043/#post-511618, @ttabbal joked about sending me blanks to be ground into lathe tools ... he was joking! But it got me to thinking ... yeah, I know it's not a good thing...

www.hobby-machinist.com

 

[Darren]

I was lucky I guess. When I took machine shop in high school back in 88-93, there wasn't a carbide tool in the building. My teacher, Roy Stokes, taught us how to grind them by hand. He did the entire class in front of the grinder and the SM lathes. He showed us the grind, and what the chips looked like when it was done properly. Those of us that paid attention got to learn about rake and clearance, the other kids experimented with what happens when you leave the key in the chuck,

I made a set of punches and chisels from tool steel that Mr Stokes let me have. I heat treated and tempered them. They were all cut with HSS on the lathe and shaper.

 

[PeterT]

One of the best investments I made when dipping my toes into carbide tooling was this book:

Oh that's interesting. I know him from the other forum, we have chatted a few times. That's neat he is getting into boutique publishing.
His overclocked PM lathe & mill projects are over the top.

 

[DavidR8]

Oh that's interesting. I know him from the other forum, we have chatted a few times. That's neat he is getting into boutique publishing.
His overclocked PM lathe & mill projects are over the top.

He does amazing work. His lathe bench is a thing of beauty!

 

[Darren]

I'm also a member of Hobby Machinist. One of the admins there wrote an excellent guide to grinding HSS bits. They even have a program where they grind models of the three most useful tools into 3/8" keystock and send them to you for reference. You get them, duplicate them on keystock and send them to the next person.
I grind my tools on a belt grinder as I find that I get more consistent results than a wheel.

Models for grinding HSS Lathe Tools

In a recent thread by @Darkbluesky, http://www.hobby-machinist.com/threads/lathe-accessories-tools-ideas-of-what-to-buy.62043/#post-511618, @ttabbal joked about sending me blanks to be ground into lathe tools ... he was joking! But it got me to thinking ... yeah, I know it's not a good thing...

www.hobby-machinist.com

I went and looked,and thats actually a great idea. Having learned in high school, I guess Ive always thought that most other guys would have done the same. However, without actually seeing a cutting tool that has been ground from a blank, most people wouldn't know where to begin. Maybe one of us could toss a few pics together in a new thread.

 

[DavidR8]

I went and looked,and thats actually a great idea. Having learned in high school, I guess Ive always thought that most other guys would have done the same. However, without actually seeing a cutting tool that has been ground from a blank, most people wouldn't know where to begin. Maybe one of us could toss a few pics together in a new thread.

I'll shoot some pics of my tools and start a thread.

 

[Susquatch]

I like carbide inserts as much as anyone does. But when the cutting gets tough, nothing beats a custom ground hss bit.

So what do you do when you get close and want to make a very light or few light cuts as you sneak up on a specific size? Do you switch to HSS?

Nobody answered this that I saw....... For my part, I switch to hss. That's prolly not the right answer, but I could never get indexable carbide to cut as clean as hss at very shallow (a thou or so) cutting depths.

Maybe someday when I am older with more patience......

 

[ShawnR]

Great info guys! Thanks for contributing. I think having the option of the carbide in the shop, and seeing what it can do, I can compare my results better. The offsets that the new holders offer will be nice. I think the next step would be to improve my grinding station. It is just a green wheel for the carbides, and that has a table that I made a long time ago but needs to be tweaked, ie, when sliding the bit across the wheel, hard to hold it perfectly still so it tends to wander back, resulting in a not perfect front edge. I will get a photo later. For HSS, I rely too much on free hand and eyeballing. I added a few more tool holders with that bit order too so will be swapping between HSS and the insert tooling more readily. Good to know about finishing a cut with HSS. After posting this, I did more searching and found a good thread on Home Shop Machinist too in which the poster had pretty much the exact issues I have been having. The answers are similar to what you all have indicated too so it sounds like my issue is with sharpening. (But still glad I now have the carbide options )

How do I fet a better finish on lathe turned mild steel??? - The Home Shop Machinist & Machinist's Workshop Magazine's BBS

 

[Proxule]

I use a tool called a vertical shear tool for very fine cuts for finishing, On all materials.

Vertical Shear Bit

A simple to grind lathe finishing tool that works exceptionally well

www.gadgetbuilder.com

As for inserts,
CCGT or DCGT for steel or aluminum will yield a shiny crisp finish, buts its designed for aluminum.
Otherwise the common DCMT TCMT CCMT inserts are awesome for what you pay.

gluck

 

[ShawnR]

Continuing my research, I found this thread using a belt sander. With the 2x72 I made, it looks like I have all the tools in my shop already. I just gotta get my act together.

Modifying a Craftsman 2 X 42-inch Belt Sander For Tool Grinding – MachinistBlog.com

It will not take much to modify my platen or add the table from my grinder station.

 

[ShawnR]

I use a tool called a vertical shear tool for very fine cuts for finishing, On all materials.

Vertical Shear Bit

A simple to grind lathe finishing tool that works exceptionally well

www.gadgetbuilder.com

As for inserts,
CCGT or DCGT for steel or aluminum will yield a shiny crisp finish, buts its designed for aluminum.
Otherwise the common DCMT TCMT CCMT inserts are awesome for what you pay.

gluck

I have not seen that shape before. Another good to know. Thanks @Proxule

 

[6.5 Fan]

I use insert tooling very sparingly, prefer to grind my HSS as this is what i was taught back in the dark ages. Just a preference i guess and i don't usually have a need for high rpm's and deep cuts.

 

[Susquatch]

I have not seen that shape before. Another good to know. Thanks @Proxule

I didn't mention a shear tool because it wasn't what I thought you wanted.

But I TOTALLY agree with @Proxule . I prolly have a dozen different variations of hss shear tools that I have ground for different purposes. When nothing else works, a shear tool will make a beautiful finish on the worst materials you can imagine.

I don't generally use them for a final cut where the dimension is critical though. Perhaps I should......