Tool Carbide or HS Tooling?

[Former Member]

I had a conversation with a tooling supplier that has been in the business for years regarding this debate.

To be fair for a few very speciality tools for the Lathe I use HS tools for ease of getting a blank and shaping it to my requirements.

For all else, Carbide.

Now for the real reason, Carbide is becoming the goto in industry, as a result HS tooling manufacturing is disappearing or has become a specialty item.

Cuts better, last longer, strong, stiffer etc. It does require a bit of care to avoid impacts but beyond that way more versatile. The other reason is ROI, even for hobby applications, longer life means lower long term cost.

Now if you can get HS tooling cheap enough it becomes a disposable, go for it. If its slightly less, go with carbide.

Again HS has become a very specific application tooling, Carbide has become the norm for everything else.

If you're reluctant try a cutter here or there, once you figure out the differences and experience the benefits you find you HS tooling sitting in storage.

 

[trevj]

My observations, spending around 30 years as a hobby machinist, and 8 teaching Trade Apprentices the basics of keeping all their fingers, in a manual machine shop.

Both have their place. Carbide is costly and frustrating to use, until you have the confidence to move the machine the correct direction, at the correct time. On a lathe in particular, the leading cause of failed inserts, was touching the tip against the work, or any other part of the lathe (,cough> chuck jaws!), when it was not moving. Following close after that, was a panic stop while the tool is still in contact with the work! It takes remarkably little force to scab off the cutting edge, and unless you are one of those rare souls with a slow speed grinder to lap a facsimile of the original edge back on the insert, that cutting edge is now scrapped. That was always the first thing to look at with the apprentice, if they complained that the surface finish was not coming up. We had the benefit of being able to use the comparator that was built on to the tool and Cutter Grinder, so we could see the damage in profile, at 50 to 100x scale, at which point it was REALLY obvious. but once you became familiar with the cause/effect cycle, simply running a fingernail over the edge usually told you what you needed to know.

We often had threads to cut in our shop, that were not readily available as Inserts, (UNJ spec threads in various sizes, in particular) so we started everyone off getting familiar enough with grinding a HSS blank in to a working tool, so that when they had to make a custom, they were not ready to crap their drawers in fear of the stuff. Same with grinding a radius form tool, custom angles (we made thousands of filler rings to fill in the countersink holes on aircraft skins, when there was going to be a scabbed on piece of sheet stock put over the surface), trepanning tools, and so on.

HSS lathe blanks are cheap as chips, and everyone should have some around, and become passingly familiar with setting up a grinder rest so as to minimize the drama of grinding a clean, straight line. I don't buy the garbage from some of the 'old guys' about being required to NOT use a rest!

Definitely a place for carbide in a home shop, though I think of it as a solution to specific problems, rather than a go-to for all purposes. My observation has been that the prices on smaller carbide milling cutters, say, 3/8"/10mm and below, are pretty affordable, the volume of carbide rod used to grind the larger ones, drives even the price of the REALLY cheap import ones up really rapidly. Again, my observations have been, new users are REALLY tough on them!

Carbide has become the Norm in Industry, because it makes them money. The price of the tooling and inserts to hold it, gets picked up by the customer, in the end of the day. And, paying a couple hundred bucks a box for inserts, is well worth it, if it increases the profit at the end of the day. Or year.