my first part & insert-boring-tool question

[jwmelvin]

I’ve been a hobby machinist for about 30 years and always used HSS tools. However, I recently bought some tooling that looks very similar to what you purchased. They actually work pretty darn well. My advise is to just try them out and see how they work. And, the angle of the boring bar looks right. You need it for clearance.

Thanks Tony, I hear you. I made the second of these parts tonight and the tapered boring was super smooth. I like it.

I also took some heavier cuts when roughing the body diameter with the triangle-insert tools, 0.050”, with mixed results. The roughing was fine and went quickly. But the surface finish never really cleaned up with the finishing cuts. It made me wish I had some sharp HSS tools to take a skim cut with. Mounting my grinder is on the short list.

 

[G MORSCH]

I have a question for you though if its ok with @@jwmelvin i got the 3/8 set of accusize inserts with tcmt21.51 inserts.im looking to make my own boring bar or two using this style insert and i was wondering if you could point me in the right direction for decently priced inserts that are all purpose but as you said above are sharp so that i can creep up on a number and take off a thou if needed to?

Brento & All:
Stick with a major manufacturer such as Kennametal, Sandvik, Sumitomo, Iscar, Kyocera, Tungaloy, etc. Almost every month, MSC will have sales on someone's inserts. Since powder metal cannot be molded to a dead sharp edge, it is necessary to grind the insert to achieve a sharp cutting edge. In your quest, you mention TCMT2151 inserts. Look for TCGT2151 inserts, preferably with a PVD, TiAlN or AlTiN coating. Both coatings are excellent and improve wear resistance significantly. If you see a really good deal on uncoated "G" tolerance inserts, they will also deliver good service as well. Stay away from flat top inserts unless all you do is cast iron. Look at and evaluate the top topography of the insert. The top topography is often described by a couple of wild card numbers or letters trailing the ANSI/ISO numbers. For example Kennametal TCGT2151HP indicates a High Positive, sharp cutting edge of 15 deg. I often cut heat treated 4140 and HSS with the HP topography. All the manufacturers above make excellent quality tooling. Pick one that will give you the price you can live with. Check Ebay and Amazon as well. If I can buy 10 good quality inserts cheap, I simply make a holder for the insert.

Good luck!
Gary