cgmaster
Cast Iron
- Joined
- Jun 9, 2008
- Location
- Ocean Springs, MS
I am looking for a recomandation for a thread mill. Right now I need to cut 1"8un internal threads 1.5" deep however I have another job that I do fairly often that is 1" -8un internal thread 2" deep.
I have been using Xact Form thread mills TMH0075-88-21 with kc20c grade inserts but it seems like I am constantly chasing tolerances having to adjust tool comp every few holes and having problems with inserts holding up. I have not had much luck with Tech support either. I have just been given info already in the catalog.
For example the job I am on now I am cutting AR500 plate 1.25" thick. I am only getting about 10 holes per insert. I am running 1700 RPM = 330sfm and 2.5 ipm = .0014" per tooth. I have gone down to 1.7 ipm = .001" per tooth. Speeds I have tried have been from 1018 (200sfm)- 2200 (431 sfm). My stepover is .0153" and 3 passes.
In standard 4140 holes 1.75" deep I am getting about 20 holes per insert. I finally settled on 1440 rpm/ 282sfm and feed in at 3ipm and increase to 8ipm after a full revolution.
The inserts don't always chip at the front sometimes they chip at the back like it is rubbing.
To throw another curve someone put an insert in backwards yesterday morning somehow it held up and cut 15 holes in the AR500 before I caught it. ???
I have also had 2 of the screws for these holders break while they were in the hole destroying the thread mills.
I have been using Xact Form thread mills TMH0075-88-21 with kc20c grade inserts but it seems like I am constantly chasing tolerances having to adjust tool comp every few holes and having problems with inserts holding up. I have not had much luck with Tech support either. I have just been given info already in the catalog.
For example the job I am on now I am cutting AR500 plate 1.25" thick. I am only getting about 10 holes per insert. I am running 1700 RPM = 330sfm and 2.5 ipm = .0014" per tooth. I have gone down to 1.7 ipm = .001" per tooth. Speeds I have tried have been from 1018 (200sfm)- 2200 (431 sfm). My stepover is .0153" and 3 passes.
In standard 4140 holes 1.75" deep I am getting about 20 holes per insert. I finally settled on 1440 rpm/ 282sfm and feed in at 3ipm and increase to 8ipm after a full revolution.
The inserts don't always chip at the front sometimes they chip at the back like it is rubbing.
To throw another curve someone put an insert in backwards yesterday morning somehow it held up and cut 15 holes in the AR500 before I caught it. ???
I have also had 2 of the screws for these holders break while they were in the hole destroying the thread mills.