End mill usage

[Grinderman]

Hello,
I picked up a whole box of end mills at an estate sale today cheap. Among then were a half dozen of these carbide 3/8 end mills still covered in wax. They were obviously resharpened but with a lot of relief behind the cutting edge. For what purpose would you need that much relief? Thanks for any input

 

[talvare]

I'm certainly no expert on tool grinding, but I'm wondering if the extra relief would provide better plunge cutting performance.
Just a guess.
Ted

 

[projectnut]

Those end mills wouldn’t be used for plunge milling they aren’t center cutting. Most likely the relief angle would make chip evacuation easier at higher feed rates

 

[talvare]

Those end mills wouldn’t be used for plunge milling they aren’t center cutting. Most likely the relief angle would make chip evacuation easier at higher feed rates

Yup, you're correct. I wasn't paying attention to them not being center cutting, I was just thinking about the chip evacuation while plunging.
Thanks for straightening me out.

Ted

 

[Grinderman]

Actually a couple of them are center cutting with that same geometry. They seem to cut well on 6061, I’ve just never seen an end mill with that much relief. Just wondering if they were ground for some kind of special material.

 

[Grinderman]

This was my end mill haul today for $20. All the ones in the tubes are new, some 4 flute, some 2, some ball end, mostly Weldon brand. All the ones on the right are carbide. It was a good day!

 

[markba633csi]

You did very well, that's even better than the collection I got for 30$
Estate sales can really be good bargains

 

[m1kemex]

Estate sales can really be good bargains

You're literally celebrating people dying...

 

[Grinderman]

Some day someone will get a good deal on my stuff

 

[m1kemex]

Some day someone will get a good deal on my stuff

Us both!