5. When is Chatter OK?

[@MagnetOnlyMotors]

5:21 I was sawing a 6” dia chunk of round cheap grade cast iron and part way through was an old unmelted bolt inside….. just like one time my Dad was chain sawing an old tree and buried deep in a branch crotch was a red house brick. Surprisabus surprisabus !

[@886014]

John I think this would be a good candidate for "a picture is worth a thousand words" and running cutters through some material to get chatter, then changing each of the parameters to eliminate the chatter. Video the results. I love ER collets. A tip to reduce runout to pretty much zero is to insert the tool and tighten normally. Before running it indicate the shank of the tool with a sensitive DTI and tap the high spot of the NUT with a copper hammer (or similar). It will shift the whole collet over just enough to take the runout out. Obviously you can get as fussy as you like with this until the runout is immeasurable, but personally I find one or two taps is all it needs. Note tap the NUT and not the tool, it sounds counter-intuitive but try it and I think you'll be surprised. Don't go crazy with the tapping, it's a tap not a whack. Don't hit the tool, it doesn't do anything, except break it if you're having a bad day. The tool won't shift away from this new position in use. The Swiss are clever people.

[@NendoCrescendo]

I had a 1/2” 2 flute and my setup was pretty ridged. Forgot to set my tool radius for G41 and plowed through full radial and axial cut. Even though it was aluminum I was still surprised to see it power through it. It did have chatter and I probably needed to push it harder than the .002 per tooth I had it at. I’m newish to this world.

[@BigMjolnir]

John, good info for sure. Some of it even applies to manual work. For example, when parting off on a lathe if I get chatter, I increase the feed pressure until it stops (assuming that I've already verified that the tool height is correct, the tool is sharp, un-damaged, etc.). Thanks! -- Mike

[@BLACKNBLEW1]

You've managed to compile atleast ten years of machining experience into 5.5 minutes! Congradulations and well done. Been a machinist about 15yrs now and what you shared here is 50% the battle. Eveything must work together for optimal performance. I always like your vids! You inspired me to get an arduino and im working on a mini cnc!

[@b3nsb3nz]

Do you buy endmills with flats or grind them in when using your set screw holders?

[@zagmongor]

Hey John, new to cnc machining here. Have you done a zig zag method with aluminum? How can we analyze aluminum chips since they won't have the telltale color change like steel.

[@zagmongor]

Or any other material really, brass, copper, plastics etc.

[@skmetal7]

What's a good method for keeping long endmills from chattering? Like pocketing out an AR-15 lower receiver, you need a long cut endmill. Is there any way to be chatter free (I used a 1/2" carbide endmill with lots of chatter on mine)?

[@harrelsontrumpets]

If you're in aluminum, there's often a sweet spot at much higher rpm using long endmills. The answer always depends on the rigidity of your workholding, toolholding, mass distribution, as well as the feeds and speeds. One way to prevent chatter is to transfer the force into the machine by using flat cutting drills to remove the majority of the material before a finishing pass. Flat cutting drills can overlap holes allowing you to remove material with a vertical plunge that alleviates most of the chatter problem.

[@TheMetalButcher]

How would you recommend reducing chatter side milling a 1" by say 3" block of steel?

[@kchigley5309]

"Don't just assume that your setup is perfectly rigid." All day this. I watched a product demo video from DMG Mori Seiki where the part moved in the vice during the cut. One would assume with a company that prolific in the industry that their setups would be perfect for official demo videos. Never assume perfection. This goes along with one of my mottos: Trust, but verify.

[@sleddarcheddar]

I absolutely love my Rohm hydraulic tool holders. Problem is they are expensive as hell. Literally switching from an er32 holder to my rohm in steel you can hear the difference with no other change. And tool life improved dramatically. I'm enjoying your take on tool life and all of this as it matches much of my own opinion. My boss is always saying to go easy on shit and I am the one that has to prove to him that it isn't true, and to take that cut. But he's also the one that has destroyed inserts on our 3" face mill with steel specific inserts cutting at .002 ipt when it really wants at least .008. I haven't finished your series yet, so correct me if I'm out of line, but one thing to check when doing IPT is actually measuring the chip and adjusting. A lot of calculations will get you into the region you need to be but you almost always need to measure the chip after a test cut and then adjust accordingly to account for chip thinning or the WOC you're attempting. Onto lathe stuff, the DOC is ABSOLUTELY important on the recommended settings. I have a large radius roughing cutter that will work with a shallow DOC but it really really needs that cut. It all comes down to tool pressure in the lathe. My tool 2 on both the lathes I run is a small radius finishing cutter at a -14 degree rake. If I have tiny amounts to take off that's my go to girl. Wow...I just wrote a novel, apologies.

[@ScottMoyse]

+akromix great points, and I love it when I meet people who appreciate a good holder!... just a note to consider, if you love your Hydro chuck, then check out the Albrecht Uberchucks... amazing. They blow hydro's out of the water when it comes to holding power and vibration damping. Run out is a bit better, but not enough to be significant. It's the first two points that set them apart.

[@RzAn8]

+akromix What I often had to do on my cnc lathe ( at work), primarily with boring bars and inside threading is loosening a screw or very light pressure on the tool holder or at the turret to get rid of chatter Mostly one of the first on the upside and/or downside DOC or changing speeds couldn't fix it and with the screw adjusted DOC didn't really matter I could go with light or heavy cuts grtz

[@sleddarcheddar]

+NYC CNC no they're not but we also don't have the need for shrink holders. We may get there some day but right now it's a negative

[@ScottMoyse]

NYC CNC That elf/santa video is hilarious. But take a look at the videos on www.albrecht-germany.com/ also I have a short comparison video on ChipX.co.nz

[@ScottMoyse]

akromix NYC CNC Yes, Hydro chucks absolutely are better than shrink ons! Shrink On chucks have been superseded in quality with advancements in hydro chuck design and the insane clamping force & damping quality of the Albrecht mechanical clamping system. Shrink ons still have a valid use case when you need clearance around the tool and holder, you can't beat them then. The other issue with Shrink ons, is that after a 100 or so heating cycles, their clamping force drops off... Shrink ons are still riding on the reputation they rightfully gained in the late 90's/early 2000's.

[@jacksonlefteye]

good video...also Lakeshore is badass

[@SKEL45]

set screw holders? doesn't that make the tool go off center still thumbs up XD

[@Szpulenso]

What is he saying? Thau per tooth? I cannot understand this pronunciation

[@johnhardwicke2980]

He means thousandth of an inch (.001").

[@camilewis87]

i gotta show this video to the guy im training. you would think a lot of those things you said at the end of the video are common sense but I cant tell you how many times Im like, why do you have that tool sticking out so far? Why arnt you holding that part further down in the vise? why why why?!!?! lol