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