Machining 4140 with LakeShore Carbide & Tormach PCNC - Part 2

[@Squat5000]

I dont believe it. I cant believe that finish! I honestly did not see any difference between the conservative cuts and the super hog. Awesome. Absolutely amazing. I am with you on the recipes. I am no cutting expert, and that is where I get hung up. I simply never feel like I hit the right recipe, even with gwizard and patience. Great work, and thanks again for these recipes. Next type of failure to try... a high DOC with high MRR. That may lock it up. Basically, this feels like something for a hogging operation. Last note, 7:45-7:55, don't sell yourself short. You just showed you are a real EFFICIENT machinist, but the rest of your videos show the practical sides of you being a machinist. Real machinist... Real you are. Tormach would not sponsor you if you were not pretty good.

[@Squat5000]

NYC CNC The main thought behind that is that it increases load and really tests the rigidity of the cutter. A cool test, make a cut on BOTH sides of the stainless, then measure the width on top and bottom, measuring the tool flex. High DOC, basically making a platform to measure.

[@chrisrillahan640]

This was a great video. Thank you for posting it. I love your channel because it is a great way to learn some of these machining operations in an non-intimidating way. I've been using a milling machining for a short time at a local makerspace but it has been an intimidating process. The web is filled with a lot of good info but it is typically very technical. Plus when your working on a powerful machine, which isn't yours, it limits your ability to test things out. This video was great because it put thing in perspective and coupled what you see in the machine to the technical decisions that you made. Great work, keep it up.

[@daque1960]

Nice! You asked for some suggestions so here goes nothing. How about showing long depth of cut with small width of cut and fast feed rates like in high speed machining? Something like using an inch of the cutter with 15% step over and see how fast you can push the feed rate. Torque did not seem to be a problem unless I missed it so I'm for more 5,000 rpm cuts. Keep in mind it's not my machine and body parts that may be injured by such speeds. If your looking to push the cutter until it snaps add some inside corners. This next set could be as much fun as nascar with crashes and parts flying. Whatever you come up with I will watch! Good luck with the open house, I wish I could make it.

[@zilogfan]

most fun of any video you have done, and I think they are all great! Best part was the stepping up and the discovery. Do this again and start with a length of cut that will after increasing woc it will break the tool. A 3/8 dia tool will get you to your target sfpm with the 5000rpm limit. Really fun video!!!

[@MrKillavolt]

Man, I am not a machinist, I have a small mill and I am always careful about speeds and feeds. I enjoy your videos immensely.

[@BigMjolnir]

John, that's very interesting data. Knowing how hard you can push your machine and still get good results equates to faster production which means more dollars per day if you have the work available. If you are going to do more it would be interesting to see how the results differ if the cut is a slot rather than an edge. Chip clearance may be a limiting factor there. Coolant or air blast will probably need to be factored in too. The Tormach is impressive and Lake Shore Carbide is looking good too! -- Mike

[@pierresgarage2687]

Hi John, Now You're Talking.... The tools are more prone to heat or break if you get them too slow or don't feed fast enough. As for wear rate, 30 under rated baby cuts compared to 2-3 well planed cuts, 30 baby cuts are a tool killer... As you get comfortable with the machine you just push it, except, you plan a safe space in case of a crash, so make the tool break before the machine hits the workpiece. Great demo, with getting the most from a smaller CNC, Pierre

[@bertr5650]

Hi John nice vids. I like debunking things to see what actually happens in real life. Was there coolant flowing or just air? How hot did the head and motors feel? Looking at your numbers, do you now feel it may be quicker to take more material slower or less material faster - from a work, tool life etc perspective?

[@Hirudin]

Another great set of videos! Did you forget the still photography or did I just miss it? There really was a STARK difference between 6 and 11 (or, whatever two cuts you showed in your hand at the end). "What would [I] like to see?" Hmmm... I like your going up in end mill size idea. Perhaps check 5/16" and 3/8" speeds and feeds and find which size fits with Tormach's power band the best and then see what you can do to get the best MRR. Then that can be your go-to "recipe" (good word) for the times you need to get rid of a lot of stock. If you're sorta doing the "I'll break some bits for science" thing, maybe increase the stickout to purposely introduce some tool (and holder... and everything else) deflection. You know, see what would be some appropriate speeds and feeds for those times when you need to do a thick part. And speaking of which, it might be interesting to mic the remaining stock every time to see if the amount of deflection is measurable. To take it even further, you could compare your measurements to the estimates in G-Wizard. (I feel a little bad recommending things I'm too lazy to do myself. :p )

[@Hirudin]

NYC CNC What do you do if you need to make a deep and narrow cut?

[@RoboCNCnl]

Man thats awesome work buddy.... Hope to own a machine like that one day... Keep up the great work and information.. !

[@jsseehorn]

I'm not sure where you are getting your cut HP info but part of the reason you didn't notice any stress on the spindle is that most of those formulas can't take in to account the lubricity of coatings. If you are getting the cut area hot enough to activate the tialn coating that is giving you a slicker tool than what the calculation is really thinking so it doesn't take as much to turn it as it would an uncoated end mill. Hope that made sense. Thanks for the videos!

[@jsseehorn]

Yeah modern coatings properly used can accomplish amazing things. That is part of why coolant with tialn isn't a good idea most of the time though it doesn't really get slippery until 600+ degrees.

[@atomkinder67]

Jeremy Seehorn AlTiN oxidizes at roughly 1400°F, so yeah, it needs to get hot!

[@AmateurRedneckWorkshop]

Great video. The Tormach is certainly a great machine. Thanks for sharing.

[@honel440]

Something you may want to talk about (if you continue pushing the machine) is holding down the workpiece. As you push things (in my experience width of cut has more effect on this than other things) you impart much more force to the work piece laterally. Typically if you're in a good set of soft jaws or a fixture it's not a problem, but if you're running a vacuum table you should be cautious. I've seen a piece thrown off of a vacuum table before and it's just plain scary. There are enough things to worry about when you're milling- no need to be worried about your part taking leave of the table!

[@RallyRat]

Great video! It looks like the helix angle is such that one flute leaves the cut just as another enters. It's always good if you can match DOC with the cutter in this way, as vibration is minimized because the loads on the spindle won't fluctuate as the tool rotates. In other words, the DOC should be close to a whole number multiple of the end mill's lead divided by number of flutes. It would be interesting to compare the same feed and WOC with only .125 DOC; I bet there would be a lot more noise and vibration, even though power and average cutting forces will be halved.

[@davidriley7659]

I'm looking forward to seeing the photo of the work piece :D If it's not obvious can you please draw an arrow or something so we know which was the first cut and which was last?

[@goptools]

Hi John, Very interesting video and results! To increase the load even more, you could try full WOC and increase the DOC too. The Tormach didn't seem to be straining at all. I would think the tool would break before the machine would complain. I don't know how far you want to push it, though. In any event, it seems like you are pretty safe pushing it a bit harder than you have been for your daily work. Thanks, -mike

[@rchopp]

Very interesting, I would like to see results from different materials. I'm just wondering maybe it was just a reflection but at the end of every cut say about .250 from end it looked as though there was a step or some type of offset did you notice it, or are my eyes playing tricks on me.. good video John, thanks.

[@fiveaxis3482]

NYC CNC The area in question stays constant with left to right motion and anyone with a basic collage physics understanding knows that is a feature in the work peace not just a reflection. This was caused as the load on the tool abated at the end of cut and the deflection of the machine subsided.

[@vdub5818]

PLEASE run the 5 flutes! I have a few lying around for an upcoming massive cleaver project in CPM 3V. Love the vids sir

[@TheJR914]

Sweet! Keep it up. How is Grand Pa recovery? Fine I hope.

[@rowlandcrew]

My vote for next tests would to compare finishes between a ball mill and an end mill with a corner radius. The point is what quality finish can I get with a single expensive cutter. The test could be made more realistic for the budget machinist by using cheap scrap steel

[@jeffkeen6943]

John, Thanks for the great video and a look at your recipes. It would be very informative if you could source a good infrared thermometer and compare the temp of the part, the temp of the tool and the subsequent temp of the chips [could be hard as they are so small]. I would be interested to know if run 6 left more heat in the tool [as it was not evident in the chip colour] and/or part. And conversely the difference in say run 11 where the chips were obviously taking heat from the cut. And lastly if you want to be very thorough [and get to destroy a tool as you wanted... ;-) ] you could show how a carbide tool reacts to taking a very shallow cut and effectively 'polishing' as you described. And lastly [again] you could compare two identical tools. One new and sharp, and another old and worn. The temp variations between the two would be facinating... Keep up the great work, Cheers from DownUnder, Jeff

[@BrianFyhnPetersen]

Please also make some HSM videos where you take shallow cuts and go with a significantly higher feedrate, not being too concerned about the surface finish (finishing cut made at last). You should be able to remove much more material. Great video.

[@atomkinder67]

FYI HSMAdvisor gives a recommended 5120 RPM @ 37.78 IPM for your .25/.1" cuts for 408 SFM @ .00184 chipload. That's a .7 HP cut with an MRR of .94 cubic inches per minute. Let's see it, I bet you'll be surprised ;-) Also sad to hear you have no spindle load meter! Also, every number of yours that I put in gives me lower HP. Don't know how GWizard calculates these but I didn't see a coating section. Probably why at that "1.48" HP cut your machine didn't sound close to its limit. At least I didn't get that from the video. It's your machine though, how close do you think it really was to its mechanical limits?

[@atomkinder67]

And a little more info: the reason you saw color change with an increase in stepover size was that now your flute is engaged in the material longer. It's not necessarily hotter at the cutting edge, it's just in the cut for a greater amount of time, letting the heat build up. This is where increasing feed and surface speed works to your advantage. Do some research on the chip thinning effect for a better explanation than I can give. www.zero-divide.net/?page=54&shell_id=151&article_id=4413

[@atomkinder67]

NYC CNC I don't think you need to consider yourself naïve or silly. I trust HSMAdvisor quite closely, as the developer is constantly working on it, active in the two forums that I frequent, and routinely returns numbers that always work for me. In addition to that, it has a machine profile for both the Tormach machines, including power and torque curves. I highly recommend it.

[@dennyskerb4992]

Hey John, awesome carbide cutters and very informative. Does Judd still have his treat email?

[@GAcaley321]

John, Awesome video great info. Could you do one in the same stlye for like 304 with lakeshores 5 flute mills and maybe a 6061 with Lakeshore's ZrN coating too. Great info as always -G

[@charles1379]

from the excel spread sheet it confirmed that you were climb cutting with a depth nearly the width of the cutter. I have always been told to do normal cuts for roughing and only climb cut for finishing. What in your setup allows you to do such great cuts?

[@atomkinder67]

The conventional roughing comes from manual machines without pre-tensioned ball screws, as they will jump if there is any play in the lead screw. On a CNC it is nearly always best to climb mill.

[@kchigley5309]

Put in the stubby, stay at .250 DoC and 3300 RPM, but make your WoC .180 push the feedrate to 26 IPM which is .002 IPT. That's at the upper power limit of the Tormach at 1.42HP and an MRR of 1.19. Also of note, if you were to do the same cut as above but at 5100 RPM, you reduce your chipload to .0013 IPT AND your torque needs by nearly half. HP and MRR would stay about the same. .001 IPT is a finishing pass for me. I rough at .003 and above. But then again, we're sponsored by Haas at The Geek Group and they've so graciously donated a VF-2 with a 30HP x 8100RPM spindle :P I've managed to stall that motor only once at .250 DoC, .050 WoC, .005 IPT, 400 RPM with a 2 inch face mill.....in a chunk of railroad track lol.

[@kkendall99]

Super cool!!

[@Skraap]

Just a quick FIY: You can get Pi in Excel with pi(), not that it really matters or anything :D

[@rlockwood2]

Increase DOC.. 4140 is butter, i'd usually take a 5/8" cutter at 11k, full DOC @ .060" WOC and basically as fast as I could feed (around 200ipm) Only problem was clogging the conveyor.

[@rlockwood2]

NYC CNC True :) I don't think you'd get away with the side-lock-holder/no-weldon-flat at my speeds/feeds either! Pretty good video, but it seems like your tests never really made it out of the comfortable zone. I expected a broken tool, stalled spindle.. something fun like that..

[@erichkopp5381]

I'd like to find out, at what point will you get TTS pullout from the R8?

[@erichkopp5381]

NYC CNC That's interesting. So what property does a 1/2" tool have that a 1/4" tool doesn't, that could cause pullout? Is it the length? If that is the case, then a stubby 1/2" tool should be less likely to pullout when pushing the machine close to the limits like in this test.

[@TheJeeperx]

NYC CNC To put it plainly, it is mechanical advantage. It's similar to if you can't get a bolt loose, you get a bigger ratchet. Only you're trying to turn the ratchet with the bolt in this case, but If you want to find the limits of your machine, diameter will show you pretty quickly.

[@CleanEdgeProductions]

There is a 3D printed adapter that will allow you to add macro capability to any lens. Do you have a cannon or nikon? I still owe you a free print remember ;)

[@CleanEdgeProductions]

Ok printing now! should have it to you by this Friday or Monday

[@CleanEdgeProductions]

Np! I just printed out one and it looks like you will get different macro shots based on the lense size. I have a 50mm 1.8 lens and a 11 to 17mm however it looks like the length of the tube effects the macro. What lenses are you currently using so I can print you out a couple or one for different size lenses

[@jaydee123ish]

Brand new?

[@redwingstash8641]

Keep the higher 5000 rpm as well as upping your feed per tooth it looks like you can go more aggressive

[@vdub5818]

Also, see if he will get some of those fireplugs for you. If not I would be more than willing to donate one for you to T&E

[@gbowne1]

John, Need any other recipies? I have a few I will share. I'd like to see some in 1045, 1018..

[@markrich3271]

Ramp the feeds n speeds break it or to that point.

[@gabejohnson6229]

try endmills by helical solutions

[@glennedward2201]

Even 5 years later helical can plow full doc through tool steel and chips fly everywhere. Flipped hot chips. Ran a 1/2” 6 flute through 8620 at 5/8doc before and that was down the centerline of the block ramping off the part.

[@jaydee123ish]

Ya u should get thats to lens of mine goes great with your Canon 70d

[@russtuff]

Let see it at 2X depth :)

[@mikekeystonefl]

Great video, but like you said you failed to show us the objective. Do not be afraid to push it. Thats the idea to see what the limit is. Go deeper or faster or whatever you can do to max out the machine. I think the machine will fail before the tool but who knows... Lets see