Harbor Freight 1/4" indexable carbide insert lathe tool set

[ddmckee54]

If anybody else has purchased a set of these and been less than impressed with them, I got a couple of tips that might change that.

First, check the relief angles on the tool holder. Three of the 5 tool holders in my set were contacting the part before the cutting edge was. A few seconds at the belt grinder fixed that. Then a couple of swipes with the cold blue and they're better than factory.

Second, and most importantly, change the crappy inserts that they come with. Mine came with absolutely no information regarding what insert could be used for replacements, apparently you are supposed buy a new set when you run out of cutting edges? It took me a while but I finally determined that they came with a TCMT09 molded insert. Molded carbide inserts do not have a sharp cutting edge, itty-bitty lathes like my Unimat and Sherline need SHARP cutting edges. I changed the inserts to TCGT09 inserts, they are designed for cutting aluminum and have ground cutting edges. I had heard from others that they were using ground "aluminum" inserts on steel with good results.

So, I ordered some on Ebay. Since they were only about a buck an insert it wouldn't hurt the piggy-bank too much if things didn't work out. I'm very happy with the results. I may have to go back to HF and get a second set so I can have one set for each lathe.

Don

 

[55fairlane]

Carbide likes negative rakes and dull edges to work to its potential, but small hobby lathes do not have rigidity nor the HP to effectively use Carbide, so why use it?

High positive rake tools help, but once again why?

Why not either grind HSS or buy HSS inserts ( Arthor Brown I think)

 

[Jasonb]

Why, well the small hobby lathes with their electronic variable speed become a bit gutless as you reduce the revs as work gets larger. By using carbide you can run approx 3 times faster spindle speeds which would not suit HSS and that puts the motor into it's sweet spot.

The HSS inserts are also a lot more expensive that carbide and will not cope with hard spots or chill in an iron casting which will take the edge straight off them.

Same when milling use solid carbide and carbide inserts (non ferrious type) on the hobby machines then the spindle speed can be kept high and as that means you can feed faster you get the job done quicker.

So why not give them a go.

PS Made by Arthur Warner

 

[55fairlane]

I will take my 39 years of bring a tool maker and shut up. I stand corrected, in the aspect I know nothing

 

[ChazzC]

Why not either grind HSS or buy HSS inserts ( Arthor Brown I think)

PS Made by Arthur Warner

https://www.arwarnerco.com/category-s/149.htm

 

[ddmckee54]

Um...yeah - HSS vs. Carbide. I'm going to listen to my piggy-bank on his one. Little Machine Shop offers a 5 piece set of 1/4" turning tools with indexable HSS inserts made by Warner. A single TPMW1.81.51 HSS { or TPMW0902 (ISO)} replacement insert from LMS goes for $11.95, which is fair because that's what Warner charges also. My Ebay TCGT0902 inserts cost me a grand total of $11.81, for 10 inserts including shipping.

All I saying is that these TCGT09's work for me - YMMV.

Don

 

[GreenTwin]

I tried HSS first (when I first started to learn machining in 2009).
Then I tried carbide inserts.
I find carbide inserts stay sharp for a very long time, will make some deep cuts without chatter, and often have three cutting edges, so you can rotate the bit as it gets dull.

I use carbide for everything now, and would never consider using anything else.
To each their own, but I love carbide bits for hobby work.
I always get consistent results with carbide.

I consider myself old-school, but I make exceptions when there is much to gain, such as using carbide bits.
I don't use VFD's.
One has to draw the line somewhere.
.
Edit:
Another benefit of replaceable carbide inserts is that you can hot-swap them; ie: if you are in the process of making a cut, and the bit is getting too dull, you can turn off the machine, retract the cutter a bit, change the insert, and then advance the cutter back in place again.
I suppose the same can be done with HSS, so perhaps this is a non-issue.
Carbide makes it so simple to keep a sharp bit at all times.

.