Hard Turning Between Centers

MrWhoopee

MrWhoopee

H-M Supporter - Gold Member
H-M Supporter Gold Member
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Jan 20, 2018
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A few months ago a friend gave me some taper shank endmills. At first I thought they were MT2, but closer examination revealed that they were B&S 7 taper. After checking eBay to be sure I wouldn't be able to retire comfortably if I sold them, I decided to turn the shanks straight so I could hold them in a collet.
The first one went well. It was hard, but only somewhere about Rc 45. No problem.

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The rest were another matter, a file wouldn't even make a mark. I had been using a Chinese CCMT insert. It cut, but chipped on the first pass. I switched to a different tool, which was loaded with an insert from a pack I had inherited.

WP_20200130_12_40_32_Pro.jpg

I was able to turn the remaining 3 endmills with one corner, though it showed some wear after the first pass.

After finishing the turning, I decided to try to part the shanks to length. Not having a carbide parting tool, I tried HSS. roflmao2.gif
It wouldn't even make a scratch. I ended up plunging the turning tool to make a groove and will cut them off when I get a cut-off wheel for my angle grinder.

WP_20200130_12_43_40_Pro.jpg

It was fun.
 
On the B&S shank end mills that I have seen, the shanks have been relatively soft, they are usually butt welded non HSS material on the shanks.
 
benmychree said:
On the B&S shank end mills that I have seen, the shanks have been relatively soft, they are usually butt welded non HSS material on the shanks.
Click to expand...

That was what I expected, like drills. Then I thought maybe the shanks were case hardened and ground. Not that either. I can't imagine what it costs to make them from solid HSS. I'll be saving the cut-offs.
 
I picked up some cut-off wheels yesterday and zipped off the shanks. It took about 2 minutes per, and they were hard to the core. Successfully faced and chamfered with the same insert corner that I turned with. I'll be saving the rest of those inserts for the tough jobs, I'm sure I can't afford to buy more.
 
I decided to try one of these endmills today on some aluminum. To my surprise, they are left-hand cut with left-hand helix. Left a nice finish though.
 
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