Thought this deserved a free plug. Mari tool boring bars

As most of you are probably in my boat with this, we are plagued with tiny holes for the lathe, that must be bored, and are crazy deep for the size of tool. Ive tried many many bars, and have found that Iscar has a great boring bar, but are expensive. Kennametal, and some others really sucked, and are paper weights now. Carbide bars never lasted. BUTT, I purchased some Mari tool steel shank bars in 1/4, 5/16, and 3/8. We routinely have these out between 4 and 5 times diameter. 4 is really a sweet spot. Using a simple ccmt 21.51 Ingersoll insert. Running M2 and M4 material, .02 depth per side at .004 per rev with a .004 finish stock, BEAUTIFUL finish. Not a peep coming from the tool and the insert has great life. Im impressed.

This may be the norm for others, but this has been a thorn in my side for a long time. Now, if you will excuse me, Im off to Maritool to order some more.

My .02 cents,
Gary

Good to know about.

FWIW, I've got an old 1" steel shank Kennametal bar that takes TNMG inserts. It seems to be one of the sweet spot bars that will work well on extended reach. I've tried a Pafana bar, same configuration, but just doesn't work well at all at anything approaching more than a 2 to 3" overhang. It makes one stand back and head scratch and puzzle and still come up clueless as to what makes certain bars work well.

On another tool, I have a cheap set of Shars 3/4" shank boring bars to use in their cheap adjustable boring head in the mill. They are amazingly quiet cutting at 6:1 overhang, you'd never expect them to be that way.

Maybe some steel carries a curse that never goes away