How fast (SFM) can you run HSS in 6061?

[Finegrain]

I'm running a Whitney 5/32" bullnose cutter in 6061 to put a bullnose all the way around a ~5" x 20" part. I actually don't know what the practical limits are for HSS cutting 6061. I'm running 1,300 SFM right now, and all seems well. I'd like to go faster, of course, but I don't want to prematurely dull this expensive cutter. I have several hundred parts to make.

Anybody running HSS in 6061 at "very high" SFM's?

Thanks, and regards.

Mike

 

[Philabuster]

Any reason not to run a carbide tool?

 

[Conrad Hoffman]

I dunno, 1300 SFM seems way high to me. Usually you lose the corners and edges on HSS quite quickly if you go too fast. OTOH, it probably depends on the specific tool quality, coolant and how much crap is in the 6061. As we all well know, not all aluminum is created equal, regardless of what they claim.

 

[Philabuster]

Would this Harvey tool work for you or do you need to ask them to modify the dimensions? My opinion, carbide tools are cheap compared to wasting time with HSS.

Harvey

www.harveytool.com

 

[Finegrain]

Any reason not to run a carbide tool?

The only carbide equivalent I know of is Harvey 32810, but it is only 3/4" diameter and 4 flutes, while the Whitney tool is 1-5/16" diameter and 8 flutes. With scallop height considerations, I probably would have to run the Harvey tool faster than my 16k RPM max to get the same finish as I'm getting with the Whitney tool.

If there was a larger diameter high-flute carbide or carbide-tipped cutter out there, I'd be interested.

Regards.

 

[jaguar36]

I've always tried to run HSS at around 600 SFM. My understanding was that gave the best compromise of cutting speed and tool life. I imagine that it does vary based on what flavor of HSS you're using though.

I don't see an HSS cutter making it through all those parts regardless though, so I'd grab a carbide one and let er rip. Can always get a custom one made if needed, they aren't really that expensive.

 

[Philabuster]

The only carbide equivalent I know of is Harvey 32810, but it is only 3/4" diameter and 4 flutes, while the Whitney tool is 1-5/16" diameter and 8 flutes. With scallop height considerations, I probably would have to run the Harvey tool faster than my 16k RPM max to get the same finish as I'm getting with the Whitney tool.

If there was a larger diameter high-flute carbide or carbide-tipped cutter out there, I'd be interested.

Regards.

Got it.

Looks like Whitney makes a carbide tipped version with 6 flutes but currently backordered on MSC.

https://www.mscdirect.com/product/details/01232859

McMaster has a 6 flute 1" HSS cutter on the shelf for $145 if you do end up dulling out your current cutter before you finish your parts.

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[Finegrain]

Thanks guys! Since I already have the Whitney HSS tool from making the prototypes, I will let it fly and see how long it lasts.

Regards.

Mike

 

[MaxPrairie]

I always just have my endmill guys pop a radius on something off the shelf if I need an odd one.

 

[jim rozen]

"I've always tried to run HSS at around 600 SFM."

In what material?

 

[eKretz]

I'd like to hear an update about this when you're done to see how long it makes it. It sounds like you are only nipping the corners? Is that a convex corner rounding cutter then? That should allow you to push the speed up pretty good, but I wouldn't have expected 1,300+ SFM.

 

[Mtndew]

I will let it fly and see how long it lasts.

What is your feed per tooth?

 

[Finegrain]

I'd like to hear an update about this when you're done to see how long it makes it. It sounds like you are only nipping the corners? Is that a convex corner rounding cutter then? That should allow you to push the speed up pretty good, but I wouldn't have expected 1,300+ SFM.

The previous operations leave a 6mm thick square edge with .01" extra, so yes, the bullnose isn't removing a lot of metal.

Regards.

Mike

 

[Finegrain]

What is your feed per tooth?

.0025". More than that and the scallops get a bit more visible than I'd like.

Regards.

Mike

 

[Finegrain]

I'd like to hear an update about this when you're done to see how long it makes it.

65 parts in and so far the surface looks fine. Overall cycle time for the part is 9 minutes so it might be a few days before I know how far it got.

Regards.

Mike

 

[rogertoolmaker]

I dunno, 1300 SFM seems way high to me. Usually you lose the corners and edges on HSS quite quickly if you go too fast. OTOH, it probably depends on the specific tool quality, coolant and how much crap is in the 6061. As we all well know, not all aluminum is created equal, regardless of what they claim.

 

[Garwood]

I've run large (.75R) HSS corner rounds and 3" HSS slitting saws at obscene SFM and they seem to hold up great with lots of coolant in 6061.

 

[rogertoolmaker]

I agree the 1300SFM is way high. Shops seems to have a love for 6061T6 which is not the best aluminum for machining. It is used for extruded parts and as such is mealy and has a tendency to stick to cutting edges.

 

[jaguar36]

"I've always tried to run HSS at around 600 SFM."

In what material?

In Aluminum, mostly 6061 although I've done it in 7050 too although I can't say I gave changing it for that any thought.

 

[metalmagpie]

It's good to see you back in the swing of things, Mike.