Machining 4140 with LakeShore Carbide & Tormach PCNC - Part 1

I was cutting a piece of 4140 last week and really loved the way it was cutting: it sounded great (very quiet!), it made a beautiful chip stream and left a superb finish. It got me thinking: let's test out various cut recipes to machine 4140 and dive into some of the speeds and feeds details for RPM, feedrate / IPM, chipload per tooth, SFM, etc!
I was using LakeShore Carbide endmills and mentioned this test project idea to Carl at Lakeshore; before I knew it, I had an email from LakeShore Carbide's shipping department - Carl (against my wishes!) supplied the end mills for this test. Please trust his generosity did not influence my review.
The proof is in the pudding, so you'll just have to watch to see how it all ended!
Excel worksheet download link at bit.ly/1MFaYAl
End mill used in testing: bit.ly/1EpE1WO
If you enjoy this NYC CNC video please hit the like button and share with a friend, it really goes a long way!
Recent Videos:
Turning & Threading on the Tormach CNC Lathe: • Turning, Facing & Thre...
DIY Arduino CNC machine with GRBL: • DIY Cheap Arduino CNC ...
Subscribe For More - kzbin.info_c...
Follow on Twitter - / nyccnc
Facebook - / nyccnc
Instagram / saundersmachineworks
Music copyrighted by John Saunders 5 Reasons to Use a Fixture Plate on Your CNC Machine: bit.ly/3sNA4uH

[@russtuff]

Fantastic. I enjoy doing test like this myself, and then I've been compiling them into a spreadsheet for quick reference.

[@Nordic_Goon]

4140 speeds and feeds work great on glock slides for RMR cuts.

[@AmateurRedneckWorkshop]

Great video. You certainly have a nice machine there. I cannot imagine a project that would be too tough for it. Thanks for the video.

[@ydna]

I notice a lot of people commenting about the climb vs conventional path. You may wish to reiterate in the future that you should ALWAYS climb mill when cutting steel (as long as the machine can do it). You can get away with either direction in softer metals, but steel produces too much heat on the cut's exit because the chip is huge and lacks support. It's so important that when facing a block you would want to make two passes instead of one, just to ensure the chips are thin at the cut's exit.

[@Liberty4Ever]

So much for the people who tell us that home shops and garage shops need flood coolant for surface finish, material removal rates, tool life, etc. I think it certainly has its place and is appropriate in larger machines, but at 3 HP and below spindles, the tooling available today seems to run very well as long as air is used to clear the chips and mildly cool the tool. A little drop of coolant in the air blast doesn't hurt, but it's impressive what can be achieved with clean dry air, without the cost and particularly the mess, smell and maintenance of using coolant.

[@MrBenski81]

Very impressive! Unfortunately I only have access to a manual mill. One day, maybe, I will get to use one of these! Subbed!

[@TurboBrooks]

Great video! I had a tormach for a while and sold it to open my business (which I promptly closed!!). I had similar problems to John, tool pull out was surprisingly easy. Now, I just got a converted MD001 with ATC and it uses TTS tooling, it easily surpassed my PCNC as far as cut capacity. I was considering making a similar video - this is some good info!!

[@TheWidgetWorks]

You do have a load meter it's right on the drive! open the panel and start the spindle you should see the the drive display the % torque that it is currently applying to the motor. I just cut a hole in my door over the drive and bolted a piece of plexiglass over it. Works awsome, I get a digital readout of the actual torque and if you overload the drive you get the warnings right on the drive display.

[@GregsGarage]

Interesting experiments.

[@glennedward2201]

Have had good luck with a number of end mills in 4140. Even variable 3 flute uncoated seem to plow through 4140 fine. Problem is finding small 5/64 and 1/16 end mills. Lakeshores site doesn’t clearly state length of cut, etc otherwise I’d buy from the site. If LOC didn’t matter I wouldn’t care. Oddly many companies make their flutes too short unless you’re cutting sheet metal they’re worthless on simple 3/8 plate and 1/4 doc with a shoulder your stuck in a job you can’t finish. One of my main goto brands is GARR. Local company sells them really cheap and they plow full depth of cut through most materials. I’ve ran their aluminum 3/8 at 90ipm, 12k spindle, and 1/2” doc. Lots of flood coolant of course. Wouldn’t normally take a cut that deep but it was a good indicator of its potential.

[@derekschommer1465]

in 4340 I was trying to use one of their 6 flute taking 1.3" depth of cut and .1" step over but I kept getting the end mill slowly pulling out of the hydraulic holder when it hit the corners it was so grabby. Had it at 400 SFM and .003" chipload(Yes I was trying to push the hell out of it lol.)

[@metaling1]

Beast end mill John! I can't tell what coating it has.. Colour looks TiAlN? 4140 sure is nice. I almost want to use it all the time. I was nervous first time I cut it, thinking it would be way more difficult... I'm learning that 'machinability ratings' for steels don't always translate as the % number would suggest.

[@zaz4667]

Where are all these high feed - speeds and feeds charts/information at? I would like to try some of this type of thing. The Machinerys handbook and the charts where I go to look are just conventional.

[@atomkinder67]

I've been running your parameters through HSMAdvisor v1.144 and I don't ever get to 1HP for 4140 (non-PH that is). That final cut is being measured as .5HP, although it is getting a little close to the torque limit of the tool (76%). On to the next video though!

[@Warmachinellc15]

Awesome! Pretty much all I cut is 4140HT and with Lakeshore Carbide tools so I'll probably learn something new. With coolant off I've got my chips coming off dark blue/purple. Most of that is with the fireplug. I've cut up around 65ipm with the fireplug too. Is that piece HT or annealed? It looks like a nice bar, is that the way it comes? If so from where? I've been shopping around for a different supplier lately.

[@JohnGrimsmo]

Awesome!!! When I enter those settings from the spreadsheet into Gwizard everything else matches except for your HP values, yours are reading 3x what mine are. For your most aggressive cut #11 I only see 0.52 hp. That being said I never really run more than 0.3 hp rating because I get toolholder pullout or other problems. Maybe one of my settings is off or something.

[@RyanWeishalla]

How much does it matter if you are climb milling like it looks you are and if you were conventional milling?

[@xavier8351]

What do you suggest for cutting speed and feed plus DOC and WOC for milling 4140 annealed flame cut using carbide inserts? The plate is Blanchard ground to 1/2".

[@boreychhitful]

can you add Excel worksheet download link again please

[@zaz4667]

All of these cuts from the same end mill? My various end mills I have tried start sparking at around 100 inches machined and then I have to change them at about 200 maybe 250 inches machined. I got to be doing something wrong when machining 4140!