This is my first post here so I should point out that I am in the UK and that I am a design engineer (production automation machines) who got fed up being let down by local subcontract shops and have bought a new mill and lathe (Hurco VM20i and TM10). I have spent several years making prototype parts on my manual machines using HSS tools and had hoped that the transition would be a little easier than it has been - imagine that!
I have some flame cut profiles that are 2" thick and 10x34" square. They are in a grade S275JR structural steel from a reputable supplier (I can have material certs if I pay a little extra) which has a minimum yield of 275n/mm but could possibly have a UTS of 560n/mm which I think may be a little tougher than A36 in the USA.
I had a real problem getting YG1 V7 solid carbide cutters to work on this stuff using the suggested settings for a low carbon steel and we (myself and the tool sales guy) have settled on treating it as a high strength structural steel (250-650Hb instead of 100-320Hb). This seems to work for milling (faceing and shoulder) but I keep breaking taps!
I have 33 M6 holes and 12 M10 holes. The M6 tap broke on the 15th hole and the M10 on the 10th hole. The M6 tap went on the way in and the M10 on the way out just as it started to reverse. The M6 was tapping 15mm deep and I reduced that to 6mm with a view to hand finishing to depth (not really why I bought the mill but anyway...). The M10 were reduced to 15mm deep in view of the M^ breaking and I was shocked that it broke an M10 tap on the way out.
The taps are both HSSe YG taps - both brand new spiral flute machine taps and the drill was 5mm/M6 and 10.5/M10. It is very frustrating as I thought I hade everything correct but I clearly have something badly wrong. I hope that someone might have experience with structural steel and also be prepared to share any advice they have.
Living in hope,
Mark
I have some flame cut profiles that are 2" thick and 10x34" square. They are in a grade S275JR structural steel from a reputable supplier (I can have material certs if I pay a little extra) which has a minimum yield of 275n/mm but could possibly have a UTS of 560n/mm which I think may be a little tougher than A36 in the USA.
I had a real problem getting YG1 V7 solid carbide cutters to work on this stuff using the suggested settings for a low carbon steel and we (myself and the tool sales guy) have settled on treating it as a high strength structural steel (250-650Hb instead of 100-320Hb). This seems to work for milling (faceing and shoulder) but I keep breaking taps!
I have 33 M6 holes and 12 M10 holes. The M6 tap broke on the 15th hole and the M10 on the 10th hole. The M6 tap went on the way in and the M10 on the way out just as it started to reverse. The M6 was tapping 15mm deep and I reduced that to 6mm with a view to hand finishing to depth (not really why I bought the mill but anyway...). The M10 were reduced to 15mm deep in view of the M^ breaking and I was shocked that it broke an M10 tap on the way out.
The taps are both HSSe YG taps - both brand new spiral flute machine taps and the drill was 5mm/M6 and 10.5/M10. It is very frustrating as I thought I hade everything correct but I clearly have something badly wrong. I hope that someone might have experience with structural steel and also be prepared to share any advice they have.
Living in hope,
Mark