Yes, Rob, that is the most likely scenario.... the tool bit is touching below the cutting edge, where it should be ground for clearance....Bob
is the cutter fully relieved on the sides and front ?? the bottom of the 60 degree tool could e rubbing the wall of the tube and thats even more prevelent on smaller i.d tubes.threading internal i usually relieve the cutter a bit more than 60 degrees on the Z - side( chuck side ) .. So yes i end up with a 58 degree tool , but it always makes a perfect 60 degree thread ( or close enough
Here is the run down... Valve half to have 3/4" x 16 internal thread. Compound set at 29.5 (yes, compound facing correctly), feeding inward to thread, cross slide zeroed and backed away on each exit/backing out pass, thread dial (1-8, set at 1) . Half nut never disengaged as to maintain position.Bored the hole to the necessary diameter. As I thread, the threads cut, but the bore grows and grows while the thread depth seems to fall short of ever reaching depth. The hole just grows with seemingly shallow threads. I check and check with a thread gauge and the threads never reach depth.Any advice?
Quote from: Rob M on February 18, 2021, 04:30:53 PMis the cutter fully relieved on the sides and front ?? the bottom of the 60 degree tool could e rubbing the wall of the tube and thats even more prevelent on smaller i.d tubes.threading internal i usually relieve the cutter a bit more than 60 degrees on the Z - side( chuck side ) .. So yes i end up with a 58 degree tool , but it always makes a perfect 60 degree thread ( or close enough You know, could be. This is an indexable insert. Suspect the sides are not relieved more.
.995-.875 thread root =.060 wall in 7075, youd be fiine .thats assuming the threaded section is seeing pressure , if the oring is inboard before the threads, the 1502lbs could be greatly reduced.
Phil, what machines do you have......or have access to?
Hi Phil, If the tool isn't cutting to depth it sounds like the radius on the front of the tool is to big, or the angle is somehow greater than 60 degrees. hth.