I recently purchased (received 11 Dec 06) a R8 boring bar and head set (model 800-5945) from H&H Industrial Products: .
The head works quite well. However, the boring bars are no so fortunate. The brazing of carbide inserts to bar is quite sloppy, with little bits of braze metal in the wrong places, such as on the face and edges of the carbide insert, and the nearby surfaces of the steel bar, and the braze-metal surfaces looking pebbled or bubbled, as if overheated during brazing.
But the brazes do look strong enough, so perhaps this is cosmetic only, and I attempted to bore a ~1.00" diameter hole in a piece of 0.250" thick 5025 aluminum plate, starting with a 7/8" rough hole, taking ~0.020" diameter passes, using the smallest boring bar provided, 3/8" shank by 2.25" overall length.
Total failure. The tip of the boring bar is not correctly shaped, allowing the heel of the carbide insert to drag on the walls of the hole, preventing the cutting edge from touching the wall, so the bar was totally unable to cut, and was instead trying to force its way through the metal. Much drama, but fortunately I was able to stop it in time, and nothing was damaged. The advantages of a manual machine.
I substituted a used Criterion boring bar (SBT-375A) of similar size (OAL is ~3.20", tip is slightly smaller), and everything went well, so the head is not the issue. In fact, the head appears to work perfectly.
Now, in the catalog description of 800-5945, it claims a minimum boring diameter of 0.197", which is one fifth of the 1.00" that didn't work, so the smallest boring bar should have worked, but cannot. Actually, the tip of the boring bar is about 0.36" in diameter, and so 0.197" would be impossible even if the heel didn't drag.
So, there are two problems. The product is not quite as described, and the provided boring bars are not suited for their intended function.
My guess is that the final grind-to-shape step was omitted during manufacture of the boring bars.
H&H Customer Service replied on Monday 18 Dec 06 to my query of the prior evening with an email saying that their guy that knows about this product will investigate. Stay tuned.