As a experienced oil field machinist used to doing deep bore work If your looking for a good finish use a 55 degree D insert and back bore that same cut from inside to the face Chips will stay behind tool No chip rub or damage and it will be way better
I find it interesting that the original comment did not discredit, nor refute Titan. Came in, gave reasonable advice and said where it came from and you all decided to immediately attack them.
@@a-iz4pg Thank you for your comment! I'm with you 100%! I'm so sick of experienced machinists acting like they know everything. I dont need experienced machinists offering machining advice based on their years/decades of experience. I come to TOCNC to watch their videos and hopefully learn some new machining techniques. I dont come to TOCNC to learn new machining techniques from people who aren't part of Titans of CNC. These people who spam the comment section with different tips and tricks that they've learned over decades of trial and error are so obnoxious. I'm glad you spoke up and let all of them know that WE DONT CARE ABOUT HOW THEY MACHINE PARTS!! We dont want any of the knowledge these people have gained from decades of on the job experience. We only want TOCNC knowledge bc nobody on this planet knows better than TOCNC. So please stop giving us different ways to tackle a machining problem! 🙄🙄🙄🤦♂ And fyi...if it went over your head...This is a condescending sarcastic comment. Just bc youre not intelligent enough to realize that its always worth listening to an experienced machinist who's offering his knowledge.....please just stfu because I (as well as most others her) appreciate when others offer different techniques.
Call me old school but I was taught that the cut should be bigger than your radius, this stops the vibration. Would you believe it the smaller insert worked better but I bet if the larger rad insert was given a bigger cut it would also work fine
@@travisjarrett2355unfortunately not everyone can afford solid carbide shank tooling. How much was that boring bar? Easily several hundred am I correct?
@@travisjarrett2355 I'm by no means an expert machinist, but i have had to use some clapped out gear before and i experimented with lead tape from a golf shop before, and bitumen car body dampening foil.... it's actually quite amazing what a bit of dampening can do. Hell... not recommended, especially on a cnc, but just pinching the bar with fingers is an enormous difference
An old colleague who freaked about vibrations on the late, solved about all of them with rubber and sand. He had a whole box full of rubber parts of all kind, seals, inner tires, O-rings,.... He fixed them over or inside the part to be machined, added sometimes some more, until he eliminated the vibrations. He had also a set of selfmade cutting tools that he turned hollow at the end and filled with sand or oil and sand.
Good video Travis! I haven't ran a CNC lathe for many, many years. But this video walks you through what can take months and maybe years of learning how to apply the right holder, the right insert, the right feed, the right spindle speed to achieve the correct surface finish in about 15 minutes. It is a must watch for all newbies. Learn something new and save the time and the headache of learning the hard way.
The new generation of machinists are really lucky to have so much knowledge available. It was like pulling teeth to get old machinists to show you tricks back in the day.
With a steel bar anything over a 4 to 1 ratio will chatter as a general rule. I’ve gone up to 12 to 1 with a solid carbide bar or even higher with a Sandvik Devibrator boring bar. Great video. Thanks for all your hard work and expertise!
Shhhhh! I have a feeling they're keeping silent about those tools (pun intended) since they work so much better than even carbide. Certainly in another category entirely when it come to price as well though. :/
@@bosanaz2010 I have seen oil dampened 'silent' tools as small as 10mm shank diameter, but not sure if anyone makes any smaller than that. For anything smaller than that, I would probably use a solid carbide bar from Circle Tools or Micro 100.
I learned this the hard way. Was getting a lot of chatter in my parts, so I switched the feed to .005 ipr and .035 D.O.C. For a .0086 radius carbide cutter. Immediately I got a 23.56 RA. On the hard parts, I use ceramic inserts with a .016 radius. .005 D.O.C and .005 ipr. Got a 15.8 R.A.
That's almost the entire tool. Would reduce chatter for sure but on something that small I'd be afraid so much engagement would just shatter it off. (Wait you mean lathe tool, nevermind. I thought you meant like an endmill)
Thank you guys for this video. Seeing this testing/process using fixed and changing variables to teach us how to solve a problem was super helpful. PLEASE do more videos like this!
Okuma variable spindle (M694/M695) works awesome for getting rid of chatter. I still do everything I can with tooling/ programming but I haven’t had to duct tape a strap clamp to a boring bar since I started using variable spindle 😂.
Something to also take into consideration with insert geometry and chatter, a rule of thumb, you must go as deep as the radius of your insert in order to reduce chatter, 👍
Thank you for this test! Such good information! When you are in deep in a job and run into these issues, it's one of those things you wish yourself you slowed down and took the time to run a test like this. It takes a huge amount of resources to run test like this. Much appreciated Travis! Great job!
I remember we had boring bars that were dampened and also some that was a split combo dampened and heavy metal. But else, every lathe was equipped with Sandvik Capto holders and dampened boring bars. It's another world in comparison to the old shop I was at
Machining in all my years for the best Ra in boring finishes was to use a burnishing tool. You can get a 2Ra once burnished just leave the bore .0005 to .001 undersize. then burnish it.
Disappointing video....This is just product placement, and even then there's no mention of dampened bars or other methods of chatter reduction. Sure, there was mention of changing speeds and feeds, but if you're trying to make machining accessible to everyone, why not talk a little more in detail about which direction to go? I guarantee you with the correct speeds and feeds that steel bar would've worked just fine for a 32 finish. Bar diameter, chip buildup, coolant, Y-axis, chuck jaws....All really quick and easy topics to touch on that can also affect chatter.
I disagree. He said at the very start it is a diverse and complex topic and even with three different boring bars and three different tip radii, not to mention speed, rigidity, material type, it stretched into a 15 minute video. As for the product placement, if you wish to avoid that you better move to another planet. Experience and insight are king, but remember, this is not aimed at the experienced machinists. To someone on a learning journey this is invaluable.
I have to disagree with you. For one I wouldn’t even waste my time with a steel boring bar when I know from experience the best place to start is carbide. If you watch this vid you can quickly grasp what they were trying to communicate! In my experience you can beat chatter a few ways! One is slowing down the rpms, maybe you can shorten your bar, maybe you can push the part further in the chuck. Maybe using some cutting oil. Point being if you don’t want to put in all of that work to figure it out, this vid serves as a great starting point. That starting point is, radius matters, type of bar construction material matters, the more rigid the better, Best wishes.
CNC lathe guy here. I use a method “tuning the boring bar” by adjusting the screws in the holder (front screws loose, back screws tight). I always use full slot holders so my set screws engage with the bar directly. I also usually try to run a finish pass of about .007”. My chatter problems have been heavily mitigated.
thats interesting, being a manual lathe monkey I always tighten the toolpost screws gutten tight to increase rigitity anywhere I can - that and slow the speed and sometimes rest a nylon mallet on the bar or the work xD..
I do both - cnc and manual lathe. One hard lesson I’ve had to learn is many of the tricks and ideas aren’t transferable. Things that always worked on my manual machines don’t work in the cnc machine and vice versa. I do a lot of aerospace bushings and it’s *always* deep bores in long thin parts. Chatter is a nightmare…. I still don’t know enough. And the good tools are eye wateringly expensive.
A part like the one you are showing. I would finish from back to front so chip is not bothering the tool. Would use a steeper side angle insert. Since the tool you are using could not finish from back to front.
Great video on chatter being a lathe machinist first chatter was my mortal enemy, and like you said. There is infinite variables in what causes chatter! And would take so much more time to cover it all, when in doubt, keep it short and stout!
I work at a pump repair shop and I have to make stainless pump sleeves from time to time. We don't have a wide array of tooling nor easy access to exotic cutters. The best way I have found to reduce chatter is the good old threading bar.
"We don't have a wide array of tooling nor easy access to exotic cutters..." sounds like much of my working life making the best of whatever a manager or director had been assured (by a salesman) was perfect for our work...
The whole video is to make all the people here in comments look stupid. Would’ve been a descent comparison if all the parameters were the same like how you said the “feed rate will be locked in place” and then changed it. After the first piece you changed the macro, went from 750 sfm and cut it in half to 375 sfm, then stepped down the depth of cut from .030 to .020, then changed the feed from .004 to .0024 and all descending in that same order from a steel bar with a large radius to carbide with the smallest radius. A real test by a real machinist with real world costs who wants to help a novice get better at his craft and not try to push product would be to leave everything EXACTLY the same and run with it with a vibration meter on the base, that’ll actually show you something. Bet me that I can’t do better than your best ra with a steel bar and the middle insert on the same machine if ra is what your going for and you’ll loose and you know it, that’s sad and no way to pass along any kind of knowledge to “ease the pain….” of chatter. I wanted to see the test to compare the differences but there was no comparison. Instead heard a slow way of saying if you turn everything way down and have a sharper bit with a stiffer bar things will improve, could do that with one bar and insert and changed parameters like you did to reduce chatter for improved ra. ***Dont be mislead, watch some other videos, don’t buy expensive tooling you don’t need in place of knowledge or knowledge that’s shadowed for their gain***
Nothing worse than when a machinist spends a lot of time on getting rid of chatter 😜 2 out 9 good parts isn't ideal either. Some days be like that though. 😄
Been a machinist for nearly 15 years would have started the same place you said you would with the carbide bar with the .4mm tip but watched the full video great video nice to actually see the differences side by side
@@intheheatoflisbon5311 I've had great results with this technique. Unfortunately, a lot of older Mori Seiki lathes would not allow any manual spindle speed changes once running the program (maybe a parameter setting?), which was crippling to getting good results. I figure it's only a matter of time before some machine control manufacturer designs it into their system to have a sensor detect chatter and automatically vary spindle speed randomly to eliminate chatter. Cheap and easy if it's built in, and would work wonders for threading too.
@@Dyna78 I prefer doosans to moris for that reason been using ez guide recently but still prefer the "old school" g76 for threading stuck in my ways you could go long hand and fire in some speed changes although it would be a long programme
I’d have been interested to see how an increase in DOC would have helped the .031R. I do Swiss machining and programming and use positive profile inserts and have to adjust the radius dependent on DOC to get past that nose radius since that profile will establish a V that stabilizes the cut. With a .030DOC the insert was pushing away. Based on the lead angle that appears to be present in this video on those bars, similarly to our setup, the .008R self-stabilized.
my shop won't buy anything smaller than 1/32" R inserts. my supervisor doesn't want to be bothered with improvements to the shop or ordering stuff so even what we do carry runs out a lot and we still get told to get parts done somehow. which is why i'm leaving manufacturing and going into IT. hopefully i can make enough money to put a CNC in my garage and start a little shop doing custom gun stuff and R&D for my own pet projects.
I believe depth of cut matters on a finish pass depending on tool nose radius. That's why a .008 tool nose radius will have lass chatter than a .031 on a .03 depth of cut. Give it a .06 depth of cut and the .031 tool wont chatter as much.
Great knowledge sharing! Love it. I had to beat my head against the wall for years to learn how to combat it. One thing that helps the most is rubber bands and or sound deadening mat like dynamat.
@@albertaoridge Both. It absorbs vibrations and helps eliminate resonance. Chatter isn't just vibration while cutting. It is actually caused but a resonance frequency in the material and tool. That is why common strategies are to change tool length (unsupported from the holder) or to fluctuate rpms in the spindle. There is actually a tool you can get that will test for the frequencies that cause resonance. Then you can find the optimal speed and feed for the tool based on that data. Happy chip making friend. 😊
A guy I work with told me they would fill thin wall tubes with coolant and put a bung on both ends for chatter free OD turning. I'm definitely keeping that one in mind.
So many ways. Even the high pressure coolant before you start your cut can contribute..one of my favorite remedies is a piece of weather stripping on the inside neck of the bar. It is durable, doesnt get in the way, and absorbs a good amount of the chatter.. rubber bands work good too.
Just a couple of weeks ago, I had a small job where I had to do very similar parts as you used in your video. It was so frustrating since we didn't have the right (or best) tools for the job, and ordering new ones wasn't an option. The only thing that worked for me was reducing the speed by half and almost tripling the feed rate. Damn, that was scary at first since my spindle chuck could only grab about ⅙ of the part's length. Even though the whole job was really frustrating, never ever had I learned so much about inside turning and the capability of my tools and machines.
Yeah not sure the point of this resonated with me either. He dropped the second last one on federate after saying In the beginning that we wouldn’t. Feel like could have played with the cutting parameters on the steel boring bar to make that cut better to be honest
Plus a huge overhang of both the tool and the tool holder. On conventional lathes, the cutter is attached rigidly, practically does not hang in the air, and even a steel cutter works great there
Plus a huge overhang of both the tool and the tool holder. On conventional lathes, the cutter is attached rigidly, practically does not hang in the air, and even a steel cutter works great there
I have had some chatter on some parts that didn't require a fine finish. It was those time I wish I could replicate those patterns the chatter kicked out.. looked awesome
I notice you aren't using clamshell sleeves. We've found switching to those has provided a stiffer tooling setup and we were able to prove that via tap testing the tool to show the stability curves. Does Kennametal not offer bars and sleeves like this?
We've used them before and you are right, they are definitely helpful. We did not want to introduce too many variables for one video though. Thanks for mentioning those.
I'm gonna make a guess though. So far chatter _sounds_ like metal on metal creating an audible frequency. This could be the tool repeatedly binding and releasing. I would start by changing the surface contact size, less grip, so more layers that are thinner being removed. Lubricant? Change that somehow? Tool speed, slow the spin down. I got one other guess, resonance. Change the rotational speed or change the mass of the piece? That'll change the harmonics. Outside of those laymans-understanding of lathes, that's all I got.
Ah, so you can change the bit that holds the bit. Different material will change the harmonics of the completed tool, putting the chatter outside of the audible and (hopefully) visual spectrum.
And of course that's the fascinating part, isn't it? _It never stops chattering, ever_ The tool is always vibrating, both visually and audibly when the chattering is bad. That surface finish Ra thing is the maximum permissible amplitude for chatter, peak to trough. Low chatter gives you a low Ra. High chatter gives you a high Ra. Being audible is a happy accident, bad chatter is loud. So you adjust the speed, depth and material of the tool to get the charter below 32 Ra. Very cool. ☕🧐👍🇬🇧
"To all the keyboard warriors out there criticizing those who share their hands-on experience: You need to understand that machining in the real world isn't black and white. Like the video mentioned, there are *MANY* variables when it comes to chatter. It takes time and experience to even recognize what a good cut sounds like, let alone how to achieve it. Sometimes, having different approaches can be exactly what helps you get out of a jam. There's theory, and then there's practice-some of us live in a place called 'reality.'"
For a steel holder, the overhang is used up to 3D. For carbide up to 6D. For larger borings used is anti-vibration bar. And of course the depth for the finish pass 0.7mm (0.03inch depth of cut) is very large.
Hello , great video, many experince years in just 15 minutes, I recomend also oil thru this case is also a good test because holee is to long. Excellent.
what i can give u as advice as 15 years of cnc machining, is ur workholding and your fixture from tools has to be perfect strong and valid. the second thing is what i can give u advice is take the shortest tools u have. my third tip is for inside tools is. if u use a boaring bar to turn a hole be sure dat shaft is atleast 2/3 of the diameter of the hole. if u hole is 21mm ur boaring bar should be atleast 14mm, whith this setting u can turn with boaring bar atleast 3 times the diameter of it so if it is 14 mm u can turn atleast 42mm setting the boaring bar 45 mm out (safety space 3 mm) with this u have the space for the chips to get out and have maximal rigidity. my third tip would be take the smallest radius of each tool u can. my third tip would be reduce the RPM of the spindle
Well done video. I have found that I just bite the bullet and almost always purchase the carbide bars. I have also found that the .008 NR inserts are great but you better have the grade and chip breaker selection right or your always turning inserts. Great job Trevor. Udaman!!!!
Hey guy I got a question. I’m running a lathe and mill right now at the same time . I had the saw cutting a big piece of 14 inch stainless and I programmed a machine for another machinist . The run time on the lathe is 45 minutes . On the mill is 2 hours and the saw like 40 minutes I sat down and put my feet up on the table and watched this video and my boss came out and said “MUST BE NICE, I wish i can be tweeting and pushing buttons all day” Should I retaliate and pop his tires? Or watch another video?
we always use big radius for roughing plastic parts on a lathe and the littel one for the rest. the rest is always 0.1mm and in duroplast you get an really nice surface all the time.
Very intresting clip, I would try v shape inserts with grounded leading edge, maybe additiinal mass on OD and last if nothig help vibration dumping boring bar
Honest question. What is the calculation you guys use to figure out what feed rate you need for the specific tool nose radius to get a desired finish? I have one, and i built the calculator into google sheets and I'm coming up with a 1 radius (.0156) requires .00328 max for a 32 finish. Thanks for any response
I'd love to see this repeated using the carbide bar and the 2 smallest nose radii, but with different DOC, feeds, and speeds to get the highest MRR without chatter. Allow the surface finish to be a little rougher (50? 75?) but go after a high, chatter-free MRR.
I had some trouble with a 5/8 boring bar going 4in deep. Decreased depth of cut and put lathe to max. 2200rpm and .005 stock for finish pass at .003ipr. .0156 nose radius.
Good video sir. First, I would chose a carbide b/b as big as you can, Stick out as short as you can and indicate the b/b. Second, use .008 Radius. This will do it.
This insert definitely has a place. If your bar length was shorter for example and you were taking heavier cuts the .031 insert could be the ideal choice.
I need to see the readings on chatter-free surfaces at the chuck, because feed rate and cutter radius leave specific roughness on their own. Then maybe subtract those to isolate the chatter-induced component. Also compare with theoretical chatter-free roughness... And that is how you get from one sheet to the full binder in the beginning of the video
Other common fixes that don't involve switching bars or inserts (if that isn't an option for you, and/or if your shop refuses to buy higher end equipment) Slowing the RPM, run out as little bar length as you can get away with, use as large a diameter bar as will safely fit in the bore you're cutting, raise your feed rate slightly, if you're in an open lathe wrap your part in rubber hose or some other vibration tape ing material and secure it tightly, slap some heavy magnets on the tail end of your bar, use s steady rest. If you're a new machinist hope that helps, if none of the above apply ask the more experienced guys at your shop, each one will give you a different solution, all of them will claim theirs is the only correct one, try them all until one works.
Im more impressed with seeing a mitutoyo surface roughness gage where the batteries actually work. It seems like every one I've ever used needed the power chord plugged in to work.
it happens to me on a full bar, sometimes only at a certain distance from the jaw, then I change the revolutions and the speed of the knife movement or go shallower
Anytime you have chatter issues especially with large contact area radius form tools run your tool upside down although it would require you to get use the other hand tool to remain on the near side of the bore. Note- Many European manual lathes double rpm if you run them backwards it is to accommodate returning a threading tool to the start position without disengaging the lead screw it's just how they thread also why they don't have a thread chaser dial I found that I actually prefer this method of threading it gives you more control one less lever at the end of a thread to worry about also same from the beginning of the thread you don't have to look for the thread chaser and worry about missing the drop. The reason why inverting you cutting tool works to stop chatter it changes how the cutting forces build up within the carriage causing it to bounce off the bed-ways harmonically to lifting and carrying the entire weight of the cariage
I usually start backing off SFM and turning up feedrate, but with some parts, it's difficult to manage, sometimes a HSS tool helps, because they are sharper. there is a company making HSS indexable inserts, they are awesome for long turning work.
To reduce chatter, you can wrap the part with wet rags or if you are making a sleeve, fill the inside of the sleeve with wet rags. ///Changing feed and speed is the easiest way to deal with chatter.
As a experienced oil field machinist used to doing deep bore work
If your looking for a good finish use a 55 degree D insert and back bore that same cut from inside to the face
Chips will stay behind tool
No chip rub or damage and it will be way better
Sorry, but is your name Titan of CNC? Didn't think so.
I find it interesting that the original comment did not discredit, nor refute Titan. Came in, gave reasonable advice and said where it came from and you all decided to immediately attack them.
@@christopherjones7191 Shut your trap, Globalist.
Things that weren't addressed were taper in that long of a cut and going up in bar size in addition to the aforementioned insert geometry.
@@a-iz4pg Thank you for your comment! I'm with you 100%! I'm so sick of experienced machinists acting like they know everything. I dont need experienced machinists offering machining advice based on their years/decades of experience. I come to TOCNC to watch their videos and hopefully learn some new machining techniques. I dont come to TOCNC to learn new machining techniques from people who aren't part of Titans of CNC. These people who spam the comment section with different tips and tricks that they've learned over decades of trial and error are so obnoxious.
I'm glad you spoke up and let all of them know that WE DONT CARE ABOUT HOW THEY MACHINE PARTS!!
We dont want any of the knowledge these people have gained from decades of on the job experience. We only want TOCNC knowledge bc nobody on this planet knows better than TOCNC.
So please stop giving us different ways to tackle a machining problem!
🙄🙄🙄🤦♂
And fyi...if it went over your head...This is a condescending sarcastic comment. Just bc youre not intelligent enough to realize that its always worth listening to an experienced machinist who's offering his knowledge.....please just stfu because I (as well as most others her) appreciate when others offer different techniques.
Chatter, one of the most common nuisances in the machine shop. Great video, Travis!
Why can't they wait for the tea breaks!
Call me old school but I was taught that the cut should be bigger than your radius, this stops the vibration. Would you believe it the smaller insert worked better but I bet if the larger rad insert was given a bigger cut it would also work fine
Spot on :)
What that mean by cut,
Is it Depth of cut ?
The comparison between the carbide shank and a dampened shank would be very cool.
Might be a future video my friend. Thanks for the suggestion!
@@travisjarrett2355unfortunately not everyone can afford solid carbide shank tooling. How much was that boring bar? Easily several hundred am I correct?
@@justin_704 If you're not a hobbyist and have a business you need it you buy it, simple as that.
@@travisjarrett2355 I'm by no means an expert machinist, but i have had to use some clapped out gear before and i experimented with lead tape from a golf shop before, and bitumen car body dampening foil.... it's actually quite amazing what a bit of dampening can do.
Hell... not recommended, especially on a cnc, but just pinching the bar with fingers is an enormous difference
@@travisjarrett2355 u aint helping yourself using a 80 degres insert, go for 35 or 55 so you minimize the contact between the insert and the bar
An old colleague who freaked about vibrations on the late, solved about all of them with rubber and sand. He had a whole box full of rubber parts of all kind, seals, inner tires, O-rings,.... He fixed them over or inside the part to be machined, added sometimes some more, until he eliminated the vibrations. He had also a set of selfmade cutting tools that he turned hollow at the end and filled with sand or oil and sand.
Great video, it’s so useful to see the actual results of doing things different ways rather than just being given a rule of thumb
There is only one way,...the right way
Good video Travis! I haven't ran a CNC lathe for many, many years. But this video walks you through what can take months and maybe years of learning how to apply the right holder, the right insert, the right feed, the right spindle speed to achieve the correct surface finish in about 15 minutes. It is a must watch for all newbies. Learn something new and save the time and the headache of learning the hard way.
Why do I feel like this video was intended to be an internal training video for Barry and some how got leaked on UA-cam 😂
Whatever Trevor!
@@barrysetzer 😂 there definitely wasn’t any chatter on that grill though 💪🏼
haha
So if it wasn't for Bary we would not have seen this great video 😅 Big thanks to Bary jaja.
Why dont you guys hire a lathe operator who knows what hes doing instead of making some trial and error video?
The new generation of machinists are really lucky to have so much knowledge available. It was like pulling teeth to get old machinists to show you tricks back in the day.
Solid advice Travis. You can tell a lot of time was involved making this super informative. Great work editors!👏
With a steel bar anything over a 4 to 1 ratio will chatter as a general rule.
I’ve gone up to 12 to 1 with a solid carbide bar or even higher with a Sandvik Devibrator boring bar. Great video. Thanks for all your hard work and expertise!
11 to 1 i was running personally, VBMT cermet insert, 0.1mm above center line, steel bar.
Shhhhh! I have a feeling they're keeping silent about those tools (pun intended) since they work so much better than even carbide. Certainly in another category entirely when it come to price as well though. :/
@@Dyna78 are there even oil filled bars in like 6mm or 10? or closer? Same for the spring ones
@@bosanaz2010 I have seen oil dampened 'silent' tools as small as 10mm shank diameter, but not sure if anyone makes any smaller than that. For anything smaller than that, I would probably use a solid carbide bar from Circle Tools or Micro 100.
I learned this the hard way. Was getting a lot of chatter in my parts, so I switched the feed to .005 ipr and .035 D.O.C. For a .0086 radius carbide cutter. Immediately I got a 23.56 RA. On the hard parts, I use ceramic inserts with a .016 radius. .005 D.O.C and .005 ipr. Got a 15.8 R.A.
That's almost the entire tool. Would reduce chatter for sure but on something that small I'd be afraid so much engagement would just shatter it off. (Wait you mean lathe tool, nevermind. I thought you meant like an endmill)
Perhaps one of the most useful videos of the last year and a half!👍
Thank you! Appreciate that!
Thank you guys for this video. Seeing this testing/process using fixed and changing variables to teach us how to solve a problem was super helpful. PLEASE do more videos like this!
It would also help to turn the OD after finishing the bore so the material is more rigid
Okuma variable spindle (M694/M695) works awesome for getting rid of chatter. I still do everything I can with tooling/ programming but I haven’t had to duct tape a strap clamp to a boring bar since I started using variable spindle 😂.
Incredible attention to detail in this video. Awesome video Travis and great job Tyler!
This is an excellent video! Going to use it for training. Thank you Titans of CNC Machining!!!
Something to also take into consideration with insert geometry and chatter, a rule of thumb, you must go as deep as the radius of your insert in order to reduce chatter, 👍
Excellent lesson! Boring bar chatter has always been a nightmare for everybody.
Thank you for this test! Such good information! When you are in deep in a job and run into these issues, it's one of those things you wish yourself you slowed down and took the time to run a test like this. It takes a huge amount of resources to run test like this. Much appreciated Travis! Great job!
The shop cop is teaching us to make great quality parts. Thank you sir.
I remember we had boring bars that were dampened and also some that was a split combo dampened and heavy metal. But else, every lathe was equipped with Sandvik Capto holders and dampened boring bars. It's another world in comparison to the old shop I was at
Machining in all my years for the best Ra in boring finishes was to use a burnishing tool. You can get a 2Ra once burnished just leave the bore .0005 to .001 undersize. then burnish it.
Disappointing video....This is just product placement, and even then there's no mention of dampened bars or other methods of chatter reduction. Sure, there was mention of changing speeds and feeds, but if you're trying to make machining accessible to everyone, why not talk a little more in detail about which direction to go? I guarantee you with the correct speeds and feeds that steel bar would've worked just fine for a 32 finish. Bar diameter, chip buildup, coolant, Y-axis, chuck jaws....All really quick and easy topics to touch on that can also affect chatter.
I disagree. He said at the very start it is a diverse and complex topic and even with three different boring bars and three different tip radii, not to mention speed, rigidity, material type, it stretched into a 15 minute video. As for the product placement, if you wish to avoid that you better move to another planet. Experience and insight are king, but remember, this is not aimed at the experienced machinists. To someone on a learning journey this is invaluable.
My dude this whole channel is product integration. Just let it be.
Haters gonna hate....
I have to disagree with you. For one I wouldn’t even waste my time with a steel boring bar when I know from experience the best place to start is carbide. If you watch this vid you can quickly grasp what they were trying to communicate! In my experience you can beat chatter a few ways! One is slowing down the rpms, maybe you can shorten your bar, maybe you can push the part further in the chuck. Maybe using some cutting oil. Point being if you don’t want to put in all of that work to figure it out, this vid serves as a great starting point. That starting point is, radius matters, type of bar construction material matters, the more rigid the better, Best wishes.
@@Soundslikeden Did you actually read my comment or no?
for best results i always go (if possible ) to VNMG inserts that 35 deg and .008 C/R works like a charm
CNC lathe guy here. I use a method “tuning the boring bar” by adjusting the screws in the holder (front screws loose, back screws tight). I always use full slot holders so my set screws engage with the bar directly. I also usually try to run a finish pass of about .007”. My chatter problems have been heavily mitigated.
thats interesting, being a manual lathe monkey I always tighten the toolpost screws gutten tight to increase rigitity anywhere I can - that and slow the speed and sometimes rest a nylon mallet on the bar or the work xD..
I do both - cnc and manual lathe. One hard lesson I’ve had to learn is many of the tricks and ideas aren’t transferable. Things that always worked on my manual machines don’t work in the cnc machine and vice versa. I do a lot of aerospace bushings and it’s *always* deep bores in long thin parts. Chatter is a nightmare…. I still don’t know enough. And the good tools are eye wateringly expensive.
It’s also a resonance issue - you’re basically de-tuning a tuning fork so it sounds ‘dead’.
A part like the one you are showing. I would finish from back to front so chip is not bothering the tool. Would use a steeper side angle insert. Since the tool you are using could not finish from back to front.
Great video on chatter being a lathe machinist first chatter was my mortal enemy, and like you said. There is infinite variables in what causes chatter! And would take so much more time to cover it all, when in doubt, keep it short and stout!
I work at a pump repair shop and I have to make stainless pump sleeves from time to time. We don't have a wide array of tooling nor easy access to exotic cutters. The best way I have found to reduce chatter is the good old threading bar.
"We don't have a wide array of tooling nor easy access to exotic cutters..." sounds like much of my working life making the best of whatever a manager or director had been assured (by a salesman) was perfect for our work...
Awesome video! Can't express how valuable this test was to a home machinist. Thank you Titans!
The whole video is to make all the people here in comments look stupid. Would’ve been a descent comparison if all the parameters were the same like how you said the “feed rate will be locked in place” and then changed it. After the first piece you changed the macro, went from 750 sfm and cut it in half to 375 sfm, then stepped down the depth of cut from .030 to .020, then changed the feed from .004 to .0024 and all descending in that same order from a steel bar with a large radius to carbide with the smallest radius.
A real test by a real machinist with real world costs who wants to help a novice get better at his craft and not try to push product would be to leave everything EXACTLY the same and run with it with a vibration meter on the base, that’ll actually show you something.
Bet me that I can’t do better than your best ra with a steel bar and the middle insert on the same machine if ra is what your going for and you’ll loose and you know it, that’s sad and no way to pass along any kind of knowledge to “ease the pain….” of chatter. I wanted to see the test to compare the differences but there was no comparison. Instead heard a slow way of saying if you turn everything way down and have a sharper bit with a stiffer bar things will improve, could do that with one bar and insert and changed parameters like you did to reduce chatter for improved ra.
***Dont be mislead, watch some other videos, don’t buy expensive tooling you don’t need in place of knowledge or knowledge that’s shadowed for their gain***
Great information! Excellent video as always, Travis!
This video came out amazing! Good work Travis and the editing team! You can tell a lot of time went into this
It was definitely a full house effort.
Nothing worse than when a machinist spends a lot of time on getting rid of chatter 😜 2 out 9 good parts isn't ideal either. Some days be like that though. 😄
That was very useful. Thank you. Nice and compact explanation in one source
Great experiment and explanation! I would like to see the milling version of this experiment please
Been a machinist for nearly 15 years would have started the same place you said you would with the carbide bar with the .4mm tip but watched the full video great video nice to actually see the differences side by side
And if in doubt rapidly changing the spindle speed up and down can help to reduce chatter with roughing lol
@@intheheatoflisbon5311 I've had great results with this technique. Unfortunately, a lot of older Mori Seiki lathes would not allow any manual spindle speed changes once running the program (maybe a parameter setting?), which was crippling to getting good results. I figure it's only a matter of time before some machine control manufacturer designs it into their system to have a sensor detect chatter and automatically vary spindle speed randomly to eliminate chatter. Cheap and easy if it's built in, and would work wonders for threading too.
@@Dyna78 I prefer doosans to moris for that reason been using ez guide recently but still prefer the "old school" g76 for threading stuck in my ways you could go long hand and fire in some speed changes although it would be a long programme
Great video. I would have liked to see you adjust the parameters to try and maximize the surface finish on the steel and heavy metal
I’d have been interested to see how an increase in DOC would have helped the .031R. I do Swiss machining and programming and use positive profile inserts and have to adjust the radius dependent on DOC to get past that nose radius since that profile will establish a V that stabilizes the cut. With a .030DOC the insert was pushing away. Based on the lead angle that appears to be present in this video on those bars, similarly to our setup, the .008R self-stabilized.
What are possible profile inserts? Did you mean positive..?
@@brandontscheschlogyeah autocorrect got me on that one. Oops!
my shop won't buy anything smaller than 1/32" R inserts. my supervisor doesn't want to be bothered with improvements to the shop or ordering stuff so even what we do carry runs out a lot and we still get told to get parts done somehow.
which is why i'm leaving manufacturing and going into IT. hopefully i can make enough money to put a CNC in my garage and start a little shop doing custom gun stuff and R&D for my own pet projects.
I believe depth of cut matters on a finish pass depending on tool nose radius. That's why a .008 tool nose radius will have lass chatter than a .031 on a .03 depth of cut. Give it a .06 depth of cut and the .031 tool wont chatter as much.
Great knowledge sharing! Love it. I had to beat my head against the wall for years to learn how to combat it. One thing that helps the most is rubber bands and or sound deadening mat like dynamat.
Just for the noise sound? Or for a better finish?
@@albertaoridge Both. It absorbs vibrations and helps eliminate resonance. Chatter isn't just vibration while cutting. It is actually caused but a resonance frequency in the material and tool. That is why common strategies are to change tool length (unsupported from the holder) or to fluctuate rpms in the spindle. There is actually a tool you can get that will test for the frequencies that cause resonance. Then you can find the optimal speed and feed for the tool based on that data. Happy chip making friend. 😊
A guy I work with told me they would fill thin wall tubes with coolant and put a bung on both ends for chatter free OD turning. I'm definitely keeping that one in mind.
@@JMill0420🤯
Spindle speed variation helps me a lot on some jobs. It is impressive how just a little of variation can completely remove chatter
The most valuable video I've ever seen in Ytube! Thumbs up!
So many ways. Even the high pressure coolant before you start your cut can contribute..one of my favorite remedies is a piece of weather stripping on the inside neck of the bar. It is durable, doesnt get in the way, and absorbs a good amount of the chatter.. rubber bands work good too.
This was a lot of work on your part. Thank you for making the effort as the various approaches and the results are very informative.
Just a couple of weeks ago, I had a small job where I had to do very similar parts as you used in your video. It was so frustrating since we didn't have the right (or best) tools for the job, and ordering new ones wasn't an option. The only thing that worked for me was reducing the speed by half and almost tripling the feed rate. Damn, that was scary at first since my spindle chuck could only grab about ⅙ of the part's length. Even though the whole job was really frustrating, never ever had I learned so much about inside turning and the capability of my tools and machines.
Scary to step out of the comfort zone huh?
@@drafty0183 seeing boring bars bend when entering the material sure is out of my confort zone 🤣
Wow! Thank you Travis! This video was great and will help me on me on my machinist journey! You're the best!
Watching this video, while machining... knowing you needed the carbide bar and smaller tool nose radius 😂 still watched the whole thing.
So, the moral of the story - start with the most expensive tool imaginable - a solid carbide boring bar.
What ismore expensive? A job that you lost because of vibration, or another grinding process, or a more expensive tool?
Yeah not sure the point of this resonated with me either. He dropped the second last one on federate after saying In the beginning that we wouldn’t. Feel like could have played with the cutting parameters on the steel boring bar to make that cut better to be honest
He did not use the most expensive tool out there. He didn't go and get the carbide reinforced Vibe damped bar.
That carbide bar looks more like fun, not boring :D
buy once cry on... ce you drop it and need a new one. lom
Excellent video. Thank you for posting this. Very informative. Feels like a 'project farm' video for machinists.
That learning is so awesome!! Thank You Titans of CNC.I would like to learn more from you,guys!😊
I did.. was simply trying to sum up and say they gave a good STARTING point which is beneficial to making matching accessible to everyone.
What helps for me as well when you do a finish pas, to increase the depth of cut
You are exactly right. Especially with a long hang out of boring bar.
Vibrations can stop if more metal is removed; the cutter simply bends to a certain distance in which its rigidity increases
Plus a huge overhang of both the tool and the tool holder. On conventional lathes, the cutter is attached rigidly, practically does not hang in the air, and even a steel cutter works great there
Plus a huge overhang of both the tool and the tool holder. On conventional lathes, the cutter is attached rigidly, practically does not hang in the air, and even a steel cutter works great there
I have had some chatter on some parts that didn't require a fine finish. It was those time I wish I could replicate those patterns the chatter kicked out.. looked awesome
My go do is always lower speed, then higher feed.
And or a sharper tool
I think i should add thats on a manual lathe
I notice you aren't using clamshell sleeves. We've found switching to those has provided a stiffer tooling setup and we were able to prove that via tap testing the tool to show the stability curves. Does Kennametal not offer bars and sleeves like this?
We've used them before and you are right, they are definitely helpful. We did not want to introduce too many variables for one video though. Thanks for mentioning those.
_sits watching a CNC guide as a software engineer_
I do not need to know this.
_continues watching_
I'm gonna make a guess though.
So far chatter _sounds_ like metal on metal creating an audible frequency.
This could be the tool repeatedly binding and releasing.
I would start by changing the surface contact size, less grip, so more layers that are thinner being removed.
Lubricant? Change that somehow?
Tool speed, slow the spin down.
I got one other guess, resonance.
Change the rotational speed or change the mass of the piece? That'll change the harmonics.
Outside of those laymans-understanding of lathes, that's all I got.
Ah, so you can change the bit that holds the bit.
Different material will change the harmonics of the completed tool, putting the chatter outside of the audible and (hopefully) visual spectrum.
And of course that's the fascinating part, isn't it?
_It never stops chattering, ever_
The tool is always vibrating, both visually and audibly when the chattering is bad.
That surface finish Ra thing is the maximum permissible amplitude for chatter, peak to trough.
Low chatter gives you a low Ra.
High chatter gives you a high Ra.
Being audible is a happy accident, bad chatter is loud.
So you adjust the speed, depth and material of the tool to get the charter below 32 Ra.
Very cool.
☕🧐👍🇬🇧
And CNC was invented by an American too, John T. Parsons. 👍
Thanks for this video. I've been battling with some 304 stainless lately.
Awesome video guys!! 👍 now let’s see one about the do’s and don’t on milling chatter
We actually did one and it’s on our channel
Thank you for the good video. Thanks to you, I got a lot of help 😍
"Thanks Donny". You guys cracked me up there.
"To all the keyboard warriors out there criticizing those who share their hands-on experience: You need to understand that machining in the real world isn't black and white. Like the video mentioned, there are *MANY* variables when it comes to chatter. It takes time and experience to even recognize what a good cut sounds like, let alone how to achieve it. Sometimes, having different approaches can be exactly what helps you get out of a jam. There's theory, and then there's practice-some of us live in a place called 'reality.'"
For a steel holder, the overhang is used up to 3D. For carbide up to 6D. For larger borings used is anti-vibration bar. And of course the depth for the finish pass 0.7mm (0.03inch depth of cut) is very large.
Awesome Video! Thank you.
Классное видео, рад что вы продолжаете просто объяснять сложные вещи.
Hello , great video, many experince years in just 15 minutes, I recomend also oil thru this case is also a good test because holee is to long. Excellent.
LOL I see Beau Nogo made an appearance! It's about time!
what i can give u as advice as 15 years of cnc machining, is ur workholding and your fixture from tools has to be perfect strong and valid. the second thing is what i can give u advice is take the shortest tools u have. my third tip is for inside tools is. if u use a boaring bar to turn a hole be sure dat shaft is atleast 2/3 of the diameter of the hole. if u hole is 21mm ur boaring bar should be atleast 14mm, whith this setting u can turn with boaring bar atleast 3 times the diameter of it so if it is 14 mm u can turn atleast 42mm setting the boaring bar 45 mm out (safety space 3 mm) with this u have the space for the chips to get out and have maximal rigidity. my third tip would be take the smallest radius of each tool u can. my third tip would be reduce the RPM of the spindle
Excellent video. Well done and good samples. Thank you.
Well done video. I have found that I just bite the bullet and almost always purchase the carbide bars. I have also found that the .008 NR inserts are great but you better have the grade and chip breaker selection right or your always turning inserts. Great job Trevor. Udaman!!!!
Sounds like Jessie running a mill! Nice video Travis!!!
Hey guy I got a question.
I’m running a lathe and mill right now at the same time . I had the saw cutting a big piece of 14 inch stainless and I programmed a machine for another machinist . The run time on the lathe is 45 minutes . On the mill is 2 hours and the saw like 40 minutes I sat down and put my feet up on the table and watched this video and my boss came out and said “MUST BE NICE, I wish i can be tweeting and pushing buttons all day”
Should I retaliate and pop his tires? Or watch another video?
we always use big radius for roughing plastic parts on a lathe and the littel one for the rest. the rest is always 0.1mm and in duroplast you get an really nice surface all the time.
This video is gold. I saved it away thank you.
Very intresting clip, I would try v shape inserts with grounded leading edge, maybe additiinal mass on OD and last if nothig help vibration dumping boring bar
Really wish you guys could get Mike Rowe on the podcast, I think he'd be an AMAZING guest. Awesome video as a lathe guy, keep up the amazing work!
Now this is the kinda vid I sub'd for! 👍
Honest question. What is the calculation you guys use to figure out what feed rate you need for the specific tool nose radius to get a desired finish? I have one, and i built the calculator into google sheets and I'm coming up with a 1 radius (.0156) requires .00328 max for a 32 finish.
Thanks for any response
Great video Travis!
I'd love to see this repeated using the carbide bar and the 2 smallest nose radii, but with different DOC, feeds, and speeds to get the highest MRR without chatter. Allow the surface finish to be a little rougher (50? 75?) but go after a high, chatter-free MRR.
Can you share the boring bar setup length, feed rate, and spindle speed in attaining 32 Ra?
I have seen some people sticking a magnet on the boring bar to change the resonant frequency, does that actually work well in practice?
I had some trouble with a 5/8 boring bar going 4in deep. Decreased depth of cut and put lathe to max. 2200rpm and .005 stock for finish pass at .003ipr. .0156 nose radius.
More videos like this plz .. this one was great
Thanks for sharing this problems. How about shape of chip in this case?
Good video sir. First, I would chose a carbide b/b as big as you can, Stick out as short as you can and indicate the b/b. Second, use .008 Radius. This will do it.
Thank you Travis! Where would one use a .031 radius insert then?
This insert definitely has a place. If your bar length was shorter for example and you were taking heavier cuts the .031 insert could be the ideal choice.
Thank you for sharing this great experimentation.
I need to see the readings on chatter-free surfaces at the chuck, because feed rate and cutter radius leave specific roughness on their own. Then maybe subtract those to isolate the chatter-induced component. Also compare with theoretical chatter-free roughness...
And that is how you get from one sheet to the full binder in the beginning of the video
Other common fixes that don't involve switching bars or inserts (if that isn't an option for you, and/or if your shop refuses to buy higher end equipment)
Slowing the RPM, run out as little bar length as you can get away with, use as large a diameter bar as will safely fit in the bore you're cutting, raise your feed rate slightly, if you're in an open lathe wrap your part in rubber hose or some other vibration tape ing material and secure it tightly, slap some heavy magnets on the tail end of your bar, use s steady rest.
If you're a new machinist hope that helps, if none of the above apply ask the more experienced guys at your shop, each one will give you a different solution, all of them will claim theirs is the only correct one, try them all until one works.
Extremely valuable information, Thank you. I wonder what your feed rate was on that Final Cut and you did not say anything about RPM most of the time.
Great Video Team!
More please!
Just like this 👌
Im more impressed with seeing a mitutoyo surface roughness gage where the batteries actually work. It seems like every one I've ever used needed the power chord plugged in to work.
it happens to me on a full bar, sometimes only at a certain distance from the jaw, then I change the revolutions and the speed of the knife movement or go shallower
Anytime you have chatter issues especially with large contact area radius form tools run your tool upside down although it would require you to get use the other hand tool to remain on the near side of the bore.
Note- Many European manual lathes double rpm if you run them backwards it is to accommodate returning a threading tool to the start position without disengaging the lead screw it's just how they thread also why they don't have a thread chaser dial I found that I actually prefer this method of threading it gives you more control one less lever at the end of a thread to worry about also same from the beginning of the thread you don't have to look for the thread chaser and worry about missing the drop.
The reason why inverting you cutting tool works to stop chatter it changes how the cutting forces build up within the carriage causing it to bounce off the bed-ways harmonically to lifting and carrying the entire weight of the cariage
I usually start backing off SFM and turning up feedrate, but with some parts, it's difficult to manage, sometimes a HSS tool helps, because they are sharper. there is a company making HSS indexable inserts, they are awesome for long turning work.
To reduce chatter, you can wrap the part with wet rags or if you are making a sleeve, fill the inside of the sleeve with wet rags. ///Changing feed and speed is the easiest way to deal with chatter.
I would like to see you guys remake this, and the variable you change is your work holding to a 6 jaw chuck
How do you determine feed per surface finish?