Grinding HSS Tools

[jocat54]

I don't really have a question, so this may not be the right place to post this. Please move if needed.
I have been using carbide inserts to learn on (a complete newbie) and haven't been very happy with them, as far as finish goes. I tried my hand at grinding some HSS today and man what a difference--my finishes are much nicer and my threading is much smoother.

I have only ground two tools so far but I think this will be what I use most of the time now. Hopefully my grinding will get better with more practice.

 

[Tom Griffin]

Carbide is actually a very poor choice for light duty machines such as small lathes and bench mills. Their lack of rigidity makes it very difficult to get a good surface finish with carbide, carbide is very expensive compared to high speed and it is less forgiving and chips or breaks much easier than high speed. High speed can be ground over an over to exactly the shape needed and as you have already found out, it generally creates a much better finish than carbide.

There is an excellent guide to grinding high speed tools in the download section that you might like to check out.

How to Grind Lathe Tools

Tom

 

[hq308]

I did the same thing when I bought my (first) lathe about 18 months ago. I bought one of those cheap carbide tool sets with the replaceable inserts and a couple of HSS blanks. I started off using the carbide tools and all I managed to do was chip the inserts so I decided I would use the HSS tools until I got some experience so I didn't damage any more of the carbides. To my suprise the HSS was so much better to work with. The carbides are still in the drawer and will probably stay there, I like using HSS to much.

 

[GK1918]

I see that you have a 45 South Bend, I also have one and It positively does not like it. I think all will
aggree these tools are reserved for new high teck machines. I think you have to be a lot aggressive
with them in which the SB is not. stay with HSS sam

 

[Ozwelder]

Hi,
HSS tooling for me.
I am an Industry trade teacher and golly is it difficult to break the mindset that you should have Carbide inserts as they are "better" than carbide inserts.

It is a very much horses for courses type of thing.

Rigidity of your lathe and tool post is certainly a consideration but there are others.

Being hobbyists not a lot of us have have the budget to buy lots of carbide tooling.The shape and application of carbide inserts dictates the shape and configuration of the tooling holder.
This usually means a dedicated carbide shape and tool for each process.

A piece of square HSS can be ground to many profile sand generally requires fewer tool holders than the carbide.
HSS can achieve some really nice work and not break the bank.When i first got my 12 x 36 lathe I fell into the trap believing the hype.
I purchased a brand name insert and holder against the advice of the man selling it to me- you need HSS.

Four years later I grind my own tip tools and HSS drill bits freehand too - no bloody drill doctors either.

I still have the original carbide insert -with 2 edges buggered -they do not like hit and miss cuts. I have a right hand tool,left hand tool hardly ever used , and a couple of parting off tool and holders
Hope this helps
Ozwelder

 

[SE18]

I'd like to piggyback with a newbee question added to this question if that's OK?

Can I use HSS to turn mild steel bars?

I don't have HSS, I only currently have the carbide tip HF set with the red shanks

Since there's no name on the tool I don't even know what tool does what job as they all look pretty similar to me

 

[SE18]

thanks

 

[Tom Griffin]

I'd like to piggyback with a newbee question added to this question if that's OK?

Can I use HSS to turn mild steel bars?

I don't have HSS, I only currently have the carbide tip HF set with the red shanks

Since there's no name on the tool I don't even know what tool does what job as they all look pretty similar to me

You can use carbon steel if you like. The entire industrial revolution was tooled by plain old carbon steel tooling well into the 1920's. High speed steel was introduced shortly after and tungsten carbide wasn't adopted until just before WWII. Just keep an eye on the cutting speeds. High speed steel can't tolerate as much heat as carbide so watch the color of the chips. If they start turning straw colored then back off on the speed or the feed rate.

Tom

 

[fluxcored]

Quick observation.

I mostly use HSS for the little bit of fiddling that I do but got really frustrated last year when turning down an old cast iron dumbbell.

My HSS tool needed to be sharpened often and the going was very very slow.

Switched over to a carbide tool I had and it turned the dumbbell down quite quickly.

 

[Tony Wells]

Each has its place. How about this: How many of you use carbide drills? Not many, I'd guess. That leaves the various grades of HSS for most all of your drilling. Somehow, it cuts most everything except concrete, right? Why then, is there doubt about cutting steel with HSS? Unless it is hardened, you can cut it just fine with HSS. If it is hardened beyond a certain point, you can't drill it with HSS either. THEN it's time to consider other means. Now, that being said, it should be accepted that a properly selected machine and carbide tooling will run much, much faster than any HSS on the same job. That's really most of the deal between the two. Small, light machines can't meet the requirements that carbide tooling demands to outperform HSS. That's why most people with smaller machines and ample time use HSS instead of carbide. It's easy on the machines, easy to get a good finish, and since most people aren't making hundreds of parts, rapid tool change without resetting the machine is not a concern. Plus it's much, much more economical for those in this for fun, rather than pushing all the limits trying to turn a buck.