08-24-2017, 11:32 PM
(08-24-2017, 10:21 PM)f350ca Wrote: ..................On a lighter note, the shank on that threading tool is about 1 inch deep, my largest holder is about 3/4 so I was going to mill the shank down. A file said it was hard but how hard can it be. A 1 1/4 indexible end mill made sparks at 600 rpm. Plan B, make a bigger holder.
We know that Armstrong-style tool holders were forged and my - obviously incorrect - former opinion was that except for surface scale, forgings were not that hard. I just dragged a file across several 3/4 Armstrong holders and it skidded off like they were made of HSS.
Can't think of a need for the holders to be that hard, maybe just a little bit for wear resistance ? Perhaps to increase the yield strength ? It's a mystery
Regarding machine tool admiration (worship ?) I was visiting a friend two days ago, a retired millwright who now operates a very successful one-man shop to support some specialized local industries. He has a Japanese-made gearhead lathe, around 18 inches, can't recall the manufacturer. He made a 1,000 mile round trip to obtain it and has special feelings for this particular machine.
He made the comment that even after ten years, when visitors come into his shop, he watches to see their reaction when they see the lathe. Maybe from an observer's perspective, it doesn't look like much but Stuart sure loves it !