Tormach 770: Steel Feeds & Speeds Test! WW142

[@pyroconner1]

Loving the higher production quality on this video! This also happened to be the exact type of video i was looking for!

[@mariusb6035]

Another tip to avoid chatter is to set your WOC and DOC so that as many teeth as possible of the cutter are engaged in the workpiece, if you facemill a 0.5" wide workpiece with a 3" diameter facemill each tooth will hit the workpiece and go from zero to 100% cutting force. However if say 4 teeth are engaged at once then one will "leave" the workpiece => cutting force drops to 75% and the next one engages, going back to 100% cutting force, thats a much smoother transition, additionally you get very strong chip thinning with small WOC (worst case rubbing) so similar to lathe tooling you shoulnd't step below a certain minimum of WOC or alternatively increase your IPT to compensate. There are some great mini videos from sandvik on this, definitely worth to check those out.

[@daniels1905]

Great video John. Thanks for posting. Did you notice that the .375 depth of cut pass that chattered was around half the material removal rate as the .1875 DOC pass with a larger width of cut? If you pull out your handy feeds and speeds calculator, (G-Wizard, FSwizard etc...) plug in the parameters, it would tell you that the cut that worked great has around 2X the deflection of the one that chattered. How can that be...? The reason is that all the feed and speed calculators (that I've used) do not calculate the cutting force directly, instead they start by calculating the power required from the MRR and machinability data of the workpiece material. Then from power and rpm calculate torque, from torque and diameter calculate cutting force. This results in an average force number, which is fine for cuts where one or more flutes is always engaged. When taking a small WOC only 1 flute is engaged at a time and the power based force calculation becomes less like reality.

[@bcbloc02]

I think I would push the WOC more. I usually like to start at 1/3D for WOC and 2/3D for LOC with .002IPT. I really liked the close up footage of the cutting action.

[@danmenes3143]

The video contains an error at about 7:21. I know this is an older video, but I found it helpful while researching feeds and speeds for my first cuts in steel (on a 770 Series 3). For your last cut, you say you have 0.002 feed per tooth, 4583 RPM spindle, and 25.7 IPM feed. These numbers are not mutually consistent. If the 0.002 IPT is correct, then your feed was 36.7 IPM. If the 25.7 IPM feed was correct, then your chip load was only 0.0014

[@vilts]

I see you've added some lighting equipment to your videos. Very nice indeed, big jump in quality and clarity. Thanks for all the cool content!

[@TAWPTool]

I'm glad that I have been a Patreon supporter of yours. I downloaded the Excel spreadsheet and I find it very useful! I also have GWizard, but this spreadsheet is nice and fast. Thanks John!

[@sparty837]

It would be nice to see a video comparing the 440, 770 and 1100 on speeds and feeds if you get a chance or are looking for video ideas.

[@TAWPTool]

How timely! I've had my 770 for a week. Thanks for providing this very useful info for this newbie. Keep it up!

[@TAWPTool]

I also headed over to Patreon and downloaded the Excel file. Thank you John!

[@mortcs]

Just got my 770 a couple weeks ago, broke a bunch of bits in the first 2 days.

[@traviswiebe3711]

I'm not sure what Lakeshore recommends, but if you're running below the high-performance endmills recommended speeds and feeds you may get better life out of the general purpose endmill. Our supplier stresses that the high-performance endmills we use need to be run within recommended specs to gain maximum life, too slow can be just as hard on a tool as too fast. Not to mention if you're running them slow you might as well save the money and use the cheaper endmill that you can run at recommended specs. I would also say you shouldn't use recommended speeds and feeds from the general purpose tool as "low end parameters" for the high-performance tool, there is likely more at play than just the tool geometry.

[@thegreatga]

Would have been interesting if you tried it in the haas. Curious to see if the same result in chatter. Thanks for the excellent video, looking forward to the open house!

[@brucec954]

Great video John and glad you're using a 770 as that's what I have. I have done a fair amount of 1018 steel and have found a couple of things;- Don't use over 3/8" dia cutters so you can keep the rpm's up as the 770's torque at low rpms can be an issue. Compared to the 1100, take advantage of the higher rpm range and faster ipm capability.- Maybe it's just my machine but if I try heavy cuts the EM/TTS can start to pull out with the power draw bar. If I tighten by hand its fine but that defeats the purpose of the PDB. I went through the Tormach white paper on this and tried a new collet and using bluing without much help. Have you had this issue?? Overall I love my Tormach and can't wait to see some more feeds and speeds (its cheaper to learn from someone else's mishaps!)

[@lineage13]

I started milling in low RPM with my drill press & cnc router. I noticed when I mill in lower SFM more heat is dumped into the carbide cutter. I still mill with low RPMs on my drill press for aluminum. But I think higher SFM for steel works best.. my tool life is really good & the end mill is cool to the touch after an operation. I run my ALTIN coated 0.25" carbide cutters at 1296 SFM or 19,800 rpm. HSM adviser recommends 15,432 rpm but I find 19k rpm runs a bit smoother. Im only going 120 inches per minute vs what HSM adviser recommends at 177 inches per minute tho..

[@travezripley2776]

Awesome, thank you for this great explanation. Also I double thank you as a Patreon... So much help!

[@Nir.Arieli]

so much fun to watch your stuff keep uploading :)

[@larryblount3358]

John, What would you choose today the 770 or 1100 if it was your first machine? I am torn between the 1100 for larger parts versus the 770 for higher rpm. I am going to love your speeds and feeds widget from Patreon!

[@qwertyg33ks]

New camera or something? Nice to see some chip slow mo action!

[@celexalexandersson]

Variable flute is like some tires have variable patterns. It makes the car goes more quiet. With standard pattern on the tires, you hear the sound from the tires and it makes more sound in the car. With variable patterns on the tires doesnt have the same dopplersound effect as other standard/older tires.

[@occamssawzall3486]

Ulf Alexandersson Variable helix eliminates chatter by increasing stability in the cut and reducing harmonics in the tool. The noise reduction is just a byproduct of reduced resonance frequencys in the tool and material.

[@celexalexandersson]

Just what I tried to say with my limited English ;)

[@AmishSolanki]

solid slowmo footage

[@billmoran3812]

John, I am struggling to understand why there is such a large difference in spindle and feed speeds between manual milling and CNC. Is it the use of smaller tools in the CNC machines? The greater cooling available?

[@andrewbishop7066]

Excellent as always any chance of a metric version off your spread sheet for us stuck in the metric zone Keep up the good work Andrew England

[@andrewbishop7066]

thank you very much for that good of you to take the time Thanks andrew

[@dkohler54]

Chips should be straw colored for HSS tooling and blue/purple for carbide if your looking to get the most from your tooling. Also check your chip thining effect when taking light cuts rubbing will cause chatter especially at long DOCs.

[@occamssawzall3486]

dkohler54 You want straw no matter what. Blue chips means you've dumped all the heat you can into the chip and still have more to dissipate. That heat will go into the tool and the part. You want to get an 80/10/10 heat dissipation. 80% into the chip. 10% into the part. 10% into the tool. If you're generating so much heat that the maximum amount the chip can hold is 60%. You're doubling the amount of heat going into the part and tool. You'll end up work hardening in no time.

[@dkohler54]

Straw is ideal for stainless as it tends to work harden easily but for your carbon steels blue is ideal for coated carbides as stated in just about every piece of literature wrote in the past 20yrs. Chips can still absorb more heat shown by colors blue

[@177racing]

thanks for the upload. #noteSquad. btw.. starret factory tour.. legendary!

[@TheSamcorrigan]

Do you have a metric versions of the speeds and feeds sheet?

[@makun16]

How ironic, I am looking at buying that mill! Great to see it in action before committing to a purchase first. Would a 6 inch vise fit that table? I'd like to run 2 vises for first and second ops in the same program. When you were cutting, was the mill in high or low pulley setting?

[@ashjo17]

Hello, where can I find this excel sheet please?

[@born2ryde05]

John, when you tried to go to full depth of cut, you said you didn't know why you encountered chatter. Did you talk to Carl @ LSC to try to figure out why? I'd LOVE to know. The change you made to steer away from chatter seems to go against your preference of deeper DOC and narrower WOC to take advantage of the flute length on your end mill (assuming SFM and CPT are in range). Is there a better way to calculate the balance between DOC/WOC other than trial and error? Thanks for your help. I'm battling a very similar issue on my 770 cutting 4140 steel, so I was very excited for this video.

[@mfisch94]

I would use 10000RPM and 50IPM, if it chatters more feed, up to 200 IPM. If chatter goes not away, use a smaller WOC.

[@occamssawzall3486]

You'd have to drop your WOC so low you'd be rubbing rather than cutting. Also. Adjust your RPM first to eliminate chatter. Feed and woc second. Most chatter can be eliminated with an RPM adjustment.

[@zed65656]

Hey John, what do you think about the imperial vs metric system? Will the imperial units hang in there? Do they make "all" the new mill and lathe´s in imperial? I'm self a metric guy:) thanks for the upload!

[@jeremiahhale5001]

Nice camera work!

[@occamssawzall3486]

You could have gotten that full DOC to work. Tool and work holding were fine. Give you a hint... it's why SFM actually matters Self-excited vibration is another hint. Think. Tuning fork. All chatter is a variation in chip per tooth in a cut. Technically speaking all cuts chatter, the greater the CPT variation the more chatter you get. Get enough variation and that's when the bad noises start. DOC is just a factor of HP. That's it. The machine sounded fine and the motor wasn't struggling. So it can take that DOC no problem.

[@TeslaAtoms]

Explain please, i dont quite get it . Why is DOC just HP dependant? Less rigid machines will change your deflection, thus producing chatter, independently of HP. Then, reducing SFM reduced chatter. Ok, granted. But, what about turning fork?

[@occamssawzall3486]

TeslaAtoms A deeper depth of cut increases cut stability, not decreases. More tool is in contact with the part decreasing its ability to deflect. But, because it's increasing its material removal rate, it requires more Hp. And to reduce chatter you want to increase, not decrease your SFM. As for tuning fork. The endmills contact with the material can be converted into a frequency. Say you're at 10k rpm with a 4 flute cutter. Rpm/60 gives you Hertz 10k/60 is 166. For every rotation the endmill impacts the part by he number of cutting teeth. In this case 4. 166 * 4 give you a cutting frequency of 664 Hz. If the cutting frequency matches the harmonics of the material or the cutter, you get chatter. Just like a tuning fork.

[@mikem1286]

Great vid. Your videos are always informative. I've picked up several good tips.

[@LumaLabs]

Dumb question- why not plug everything into HSMAdvisor or GWizard?

[@colinworobetz6662]

Personally I find that HSMAdvisor and Gwizard are great places to start. But every machine's little quirks and individual cutting tool geometries vary. Doing testing like this is the best way to take that good head-start that Gwizard will give you and dial it in for your application.

[@themodernrenovator20]

can you make a review about ebay cnc because we can not afford tormach

[@bmonty65]

Any reason why you are not climb milling with this tool?

[@bmonty65]

Yes it is, my apologies i'm obviously intellectually challenged.

[@Sicktrickintuner]

I noticed that all tools seem to move clockwise around the parts, what happens if it goes against it the other way counterclockwise from looking down from the ceiling so to speak.

[@occamssawzall3486]

Sicktrickintuner You would be conventional milling. It's harder on the tool and requires more HP to make the cut. And you run the risk of recutting chips, which takes a heavy toll on the cutter. The trade off is that conventional milling is a far more stable cut and tool deflection is predictable.

[@Jr9303]

Can you provide chip thickness also/instead of chip per tooth in these videos?

[@sunppaa]

Chip thickness is more important than IPT. When using adaptive trochoidal milling, it is possible to use very high IPT while having thin chips, because the WOC is so small. Just like using a high feed face mill with low lead angle, high IPT but thin chip. I think the suggested chip loads in those charts are for traditional slot milling with 100% WOC, where the peak chip thickness = IPT. I run my carbide cutters on steel with 10-20% WOC, full DOC when needed and IPT of 3-6 thou depending on tool dia and WOC. However, no one ever provides chip thickness information, maybe because it's so difficult to calculate :-).

[@auhopu]

Correct, chip thickness is more important than "chip load" and it's what you should be after, unless slotting (then they coincide). Another way to think of it is "chip load" is the capacity and "chip thickness" is the result. Or "chip load" is the pipe and "chip thickness" is the water. C=(T*D)/(2*SQRT(D*W-W^2)) where C=chip thickness T=chip load D=tool dia W=WoC The same formula is used both by Bob in GWizard to calculate the "adjusted chipload" and by Helical Solutions in HMAdvisor to calculate chip thickness. blog.cnccookbook.com/2017/03/14/cnc-chef-video-chip-thinning-clear-present-danger-ignored/ www.helicaltool.com/secure/Content/Documents/Tech_ChipThinning.pdf

[@repalmore]

This is where business decisions influence things like feeds and speeds. Even a part run of like a 100 part, getting a decent chip is good. If you have a parts run of 100,000 it's worth the extra time to get nearly the perfect chip and every ounce of un needed movement out of the G code. Even things like step over height can be looked at on a large run. Running one or two parts? I wouldn't worry to much about even getting a good chip and just focus on a good surface finish and not worry about the extra few seconds that it takes to make the part. Good business decisions affect every step of a business. Check out lean manufacturing. Cool concept.

[@chelseatown3151]

Great series, thanks so much!

[@HandsonCNC]

love those 960fps shots!

[@Anonymouspock]

I don't know what I'm doing, but it looks an awful lot like the spindle wasn't quite rigid in that last slow motion clip.

[@GeofDumas]

Copper - fun to machine, a chore to drill

[@occamssawzall3486]

Geof Dumas Nightmare to tap!

[@GeofDumas]

Form tap to save headaches! Makes a stronger thread, too

[@occamssawzall3486]

Geof Dumas Thru holes maybe. Blind holes I've never had good luck with a form tap over 4-40 in copper. Galls and seizes up even with liberal amounts of moly D and a 65% thread. I usually just thread mill it to save myself the headache of digging taps out. Even taking with 3 different tooling manufacturers they couldn't give a good answer. Basically they said thread mill is the best way.

[@GeofDumas]

Ah, right! I've never done blind tapping in copper. I've only had trouble with titanium

[@antshark]

Hi John. I use a brand called Helical Solutions. They offer variable flute endmills as well and are comparable to other high end endmill manufacturers. They have an app on their websites (www.helicaltool.com/cms/millingadvisor_367.aspx) that calculates and recommends all the speeds, feeds, rdoc, adoc....etc. You just type in the specific tool you're using, the material and the type of cutting strategy (high speed, light rough, finish etc) and it will recommend a really good formula. It's worked really good for me with adaptive clearing on sst and cold roll steel. Btw, I wouldn't recommend coolant when machining 1018 steel when cutting with these cutters/coatings. I've found that tool life is extended dramatically. The coolant causes thermal shock which causes the edge of the endmill to chip. Anyhow, give that app a try, I think you'll like it.

[@menow.]

I enjoy your vids. It's RPM, not RPMs.

[@axised001]

Watching steel getting cut against the direction of feed always hurts my heart...

[@nitwimp]

climb milling?

[@StickerMedia]

F20 and F21 have typos :)

[@StickerMedia]

That's a shame, you can correct it in your spreadsheet though ;) Keep the video's coming, I really enjoy your channel! As a mechanical engineer from the Netherlands I envy your job!

[@Eggsr2bcrushed]

fast af

[@jeffl1356]

Have you ever tried using cnccookbook? There is a speeds and feeds calculator that might help guide you to more successful aggressive cutting recipes.

[@kidzcannon]

I so want you to machine something out of gold. But gold just happens to be expensive... :/ But still!

[@zackpetrick483]

problem with video

[@Eggsr2bcrushed]

Zack Petrick fine for me, restart browser

[@zackpetrick483]

thanks