milling hardened steel

[REK Knives]

I work on a lot of hardened blades and was wondering if anyone can recommend some carbide end mills? jimping, nail nicks, fullers, thumb holes/slots, etc.

I know I should run at max rpm of my machine (3k rpm) which is slow compared to what I should be at apparently (20k rpm), and with an air blast only (no lube) but what can you do haha.

 

[danbot]

Look into http://gorillamill.com/

They run at slower speeds and higher feeds than most others. They are real tough cutters! Go to "Materials" on the homepage and drop down to Hardened Material (55Rc & up, dry cut).

 

[olymon]

They use Z carb in our shop to cut hardened materials and they can hog some material.

 

[kuraki]

How rigid is your mill and your setup? I would avoid anything with sharp corners. They're the first thing to fail. Doing some nail nicks at relatively low removal rate isn't a big deal but for anything that will be taking a full diameter cut I would tend to use .015 or .030 radius corners.

More than likely, in a Bridgeport or anything less, you're going to fracture tooling before wearing it out, so I wouldn't swing for the fences in price.

 

[butcher_block]

running carbide in anything smaller then a bridgeport and i feel there will be problems. i use 3/16 carbide ball endmills to plunge a pivot hole in a folder blank now and then but even that feels liek pushing things (they are just chasing a pre drilled hole ). im lucky my bridgeport find shoudl be called the knife maker special cause it has a top speed of abotu 5400rpm and has a table of just 32 inch that al adds up to a great knife maker package

 

[danbot]

Here is an example of the feeds and speeds for the Gorillamill cutters. It's really quite counter-intuitive, but they really do work well!
This is for a 3/16" endmill...

 

[REK Knives]

How rigid is your mill and your setup? I would avoid anything with sharp corners. They're the first thing to fail. Doing some nail nicks at relatively low removal rate isn't a big deal but for anything that will be taking a full diameter cut I would tend to use .015 or .030 radius corners.

More than likely, in a Bridgeport or anything less, you're going to fracture tooling before wearing it out, so I wouldn't swing for the fences in price.

So you think the corner end mill could be used to make shallow cuts? Guess I can just try and find out... worse case it chips off and I have to send it off for sharpening.

Here is an example of the feeds and speeds for the Gorillamill cutters. It's really quite counter-intuitive, but they really do work well!
This is for a 3/16" endmill...

That is outstanding! Unfortunately, while their site is easy to use and they have a lot of great stuff you HAVE to order from them through a distributor and I don't have time to track down a good distributor to use (MSC doesn't seem to have their stuff listed even though they are listed). What a pain that you can't order direct ugh. I'll probably just stick to OSG

 

[danbot]

So you think the corner end mill could be used to make shallow cuts? Guess I can just try and find out... worse case it chips off and I have to send it off for sharpening.



That is outstanding! Unfortunately, while their site is easy to use and they have a lot of great stuff you HAVE to order from them through a distributor and I don't have time to track down a good distributor to use (MSC doesn't seem to have their stuff listed even though they are listed). What a pain that you can't order direct ugh. I'll probably just stick to OSG

Okay, that is a bummer. Mitsubishi has a line of hardmilling cutters called "impact miracle". Maybe they would be easier to source? They run a lot faster, but are also tough as hell!

 

[Nathan the Machinist]

I've done some hard milling with the hard mills at Lakeshore carbide with good results. Peal milling, high feed with shallow engagement. You can fill up a small trash can with chips from one cutter.

 

[REK Knives]

I've done some hard milling with the hard mills at Lakeshore carbide with good results. Peal milling, high feed with shallow engagement. You can fill up a small trash can with chips from one cutter.

By peel milling you mean basically full depth cuts and 'pecking' at the side, basically having high radial force but shallow cuts on each peck?

 

[Salem Straub]

I'll second Lakeshore Carbide as a source for reasonably priced carbide endmills... that's where I shop since Nathan recommended them years ago.