Are Your Retention Knobs Too Tight?

To All:

Here are some excerpts from a MMSOnline article:

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The Knob Problem

The retention knob is an unmistakably critical component of the machining process. However, the tightening of the knob itself can lead to the toolholder not seating securely in the machine. You may be losing tool life to knob tightness without even knowing it.

The study found that across various makes and sizes of tapered toolholders, overtightening the retention knob by even a mild degree was enough to produce a bulge in the narrow end of the holder.

In fact, Mr. Stoneback says that in some cases just tightening the knob, not overtightening, was enough. The company has measured the effect in cases where just 10 to 15 foot-pounds of torque was applied. As a result, the toolholder loses the shape that matches the cone of the spindle. This means the toolholder doesn?t fit the spindle precisely, leaving it free to move like a clapper in a bell.

Potential Impact

What this might mean for the stability at the tool tip and the life of the cutting tool are not hard to imagine. Carbide cutting edges are brittle when experiencing impacts other than those in the cutting direction. Where play exists between the toolholder and spindle taper, the resulting hammering of the tool is likely to speed the cutting edge toward failure. ===========================================================

Reply to
BottleBob
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Does Mr Stonebreaker sell retention knobs? Tell him that the studs also wear out from extended use, probably much sooner than anything else. lol! Michael

Reply to
michael

Michael:

You looked, eh? Yeah, he makes retention knobs. Ones with treads on the end and the back relieved, with the following claim:

"...this alternative knob design deforms the holder less because the threads take hold deeper into the taper, where the surrounding thickness is greater."

Too bad retention knob design couldn't have been standardized so they wouldn't have to be removable for different machines to use the same toolholder. I never liked the Haas long retention knobs, OR not being able to insert the tools in the carousel by hand. The long knobs don't let the spindle keys enter the flange holes before drawbar activation. Bad design IMO, since if you put them in slightly misaligned when the drawbar activates the keys can sometimes catch the edge of the tool flange keyway with a KAASNAAP!!!. I always turn the spindle by hand so the key was facing forward for easy visual alignment. But not everyone does it that way.

Reply to
BottleBob

hmm, my new haas VM-2 has short retention studs. But what a sweet machine! and yes, the drawbar grabs the heck out of the studs. I'm doing an all nighter on a mold to deliver in SC at noon Friday. Piece of cake.

Michael

Reply to
michael

Michael:

Well it's good you got a Haas with short retention knobs. It's a sign they are listening to customer complaints.

Reply to
BottleBob

My YCI Supermax Rebel 1 uses Hass long style knobs. On a toolchange my keys enter the slots before the drawbar pulls up tight. Must just be a Haas thing.

Thank You, Randy

Remove 333 from email address to reply.

Reply to
Randy

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I bought a pullstud socket from

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awhile back. We torque them to 35 ft/lbs. Haven't had any problems to speak of. Anytime the holder is removed from a machine to change the cutting tool, we double check the torque to make sure it's still tight.

Reply to
Joe788

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Joe:

We took a short piece of angle iron, milled a slot in one leg the width of the retention knob flats, screwed it to the edge of the bench next to the collet tightening fixture and just hand tightened the knob by grabbing the toolholder an giving it a quick jerk. To untighten, just give it another quick jerk.

Reply to
BottleBob

I actually studied this as retarded as that might sound. The place I was at got a new haas and already had 2 older haas's, and the owner said buy the best toolholders for graphite you can find. So I bought these badass shunk hydraulic holders from Heaven itself. So I was trying to prove that we couldn't share the new toolholders and expect them to repeat to .0001. Nobody would believe me. So I high spot blue'd em and stuck the new ones in the old spindles and damn if it didnt grap on two tiny rings prolly less than .100 thick. But when I stuck the old stuff in the new spindle I checked the tightness of the knob at the end and it was freakishly tight. I asked how tight are these "as Hard as I could get them with my 14" crescent wrench". WHOLLY shit I laughed...Your belmouthing the ends you dumbass? So to prove it I blue'd it up and stuck it in the spindle...and guess what, the DAMN spindle ends an inch from the end. There's no chance in hell of a bellmouthed holder being effected or effecting anything, it's miles away from the contact area in the spindle.

So the whole thing is nothing more than an urban legend.

too funny. What will effect it if we are talking cat 40 is spindle rpm. At somewhere around 11 grand the spindle itself belmouths, and that causes a little runout, a tenth or two, and the holder goes up into the spindle a few tenths or more. The when it's time to release it...KABANGGGG!!! Those mills with a top rpm at 12 grand and cat 40 is a joke. If you go over

11 at all your losing your depth and screwing up your spindle and holders by overclamping.
Reply to
vinny

Vinny:

Urban legend? Perhaps, perhaps not. How many different brands of toolholders did you check, in how many different machines? And how accurate is bluing up the taper in telling exactly how "bellmouthed" a toolholder might be? One test result is not statistically significant. Did you see the test fixture they used in the article? Pretty nifty. *BUT*, if they weren't checking the toolholder expansion "at the upper spindle contact line", but at the very tip, then their data is meaningless. AND they DO have a vested interest in this, since they manufacture the relieved retention knobs.

So it's my opinion that an independent laboratory should check this out.

Reply to
BottleBob

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=A0Pretty nifty.

check this out.

I've heard of , but never seen, places that will come out & grind or refinsih the inner spindle taper right on the machine. Then its new! You poley should get that done ever few years on the *accurite* machines, like Roders ect. 40k spindles as such, oh never mind thats HSK, or ones that are holding millionths! Ya right. Hey how many machines anyone seen with a 45 taper? Me 1 Cincinnati Milacron. circa 1978 10v2000- round ways- 80X24X26 travel. Tooling for that bitch was always double, because no body used that taper& the quantities weren't there like 40 &50's. Those new straight shank hydraulic lock collets are the ticket for us lowely under 11k people. Very little effert to tighten & loosen. Never had one move yet, plunging or ramping. Plus the are set up for thru spindle coolent. Broke a few 5/16-1/2"ers but never scewed up the collet yet unlike the old TG collets. Soon as you'd snap an EM off, the end of the collet is burred up & has to be cleaned out by stoning ect. The cutest are the 30 taper machines. I could put the tool holders in my back pocket! I need a machine like that! ie: Bridgeport DX32 Discovery 308 with a Troyke NC programmable rotery 4"C"axis - vert/ hoz, for my garage, just too show the grand kids someday what a CNC machine is or maybe cut some figurines & sell'm on the beach:-)

\|||/ (o o) ______.oOO-(_)-OOo.____________________ ~ Gil ~ the HOLDZEM=A9=AE king

Reply to
milgil

I've heard of , but never seen, places that will come out & grind or refinsih the inner spindle taper right on the machine. Then its new! You poley should get that done ever few years on the *accurite* machines, like Roders ect. 40k spindles as such, oh never mind thats HSK, or ones that are holding millionths! Ya right. Hey how many machines anyone seen with a 45 taper? Me 1 Cincinnati Milacron. circa 1978 10v2000- round ways- 80X24X26 travel. Tooling for that bitch was always double, because no body used that taper& the quantities weren't there like 40 &50's. Those new straight shank hydraulic lock collets are the ticket for us lowely under 11k people. Very little effert to tighten & loosen. Never had one move yet, plunging or ramping. Plus the are set up for thru spindle coolent. Broke a few 5/16-1/2"ers but never scewed up the collet yet unlike the old TG collets. Soon as you'd snap an EM off, the end of the collet is burred up & has to be cleaned out by stoning ect. The cutest are the 30 taper machines. I could put the tool holders in my back pocket! I need a machine like that! ie: Bridgeport DX32 Discovery 308 with a Troyke NC programmable rotery 4"C"axis - vert/ hoz, for my garage, just too show the grand kids someday what a CNC machine is or maybe cut some figurines & sell'm on the beach:-)

\|||/ (o o) ______.oOO-(_)-OOo.____________________ ~ Gil ~ the HOLDZEM©® king

I ran a bostomatic once with a 30 taper. I loved em, they were light as a feather. The best part was the machine was like 1000 years old and it came with all the tooling, i bet there were 200+ holders, all solid, and with stands to stack em up. We would load a tool in, and engrave what size it cut cause they permanent. lol We used it for graphite, had a high speed option in the controller if you stripped the code bare, and for its day a whopping 100IPM rapid. It was better than anything Iv'e ran since and here's why...it had 2 spindles mounted right next to each other connected with a belt. Once you got your 2 fixtures finally set the somebitch would machine 2 damn parts at a time! The cutters were a little tricky to get to cut the same due to runout, youd have to rotate em around till you got within a tenth of the other, but since there was no tang you just marked the front, but we had so many holders once it was tweaked, it was set for life. And that was back before the days of poco3 and all this crazy nasty graphite they got now. Back then the cutters literally never wore out in graphite. Now...shit a diamond coated one needs replaced once or twice a week.

I swear we've taken 3 steps forward and 2 steps back.

Reply to
vinny

plastigage

Reply to
Brother Lightfoot

This is the cool thing bout Big-Plus spindles. I can run our Matsuuras at 20K rpm for long runs and see very little to no change. No KABANGGGG when you change tools either. I just wish the big plus holders were more in line with "conventional" type holders in terms of price.

Reply to
Zymrgy

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Poco3 - what a $luxury$ Shop owners/bean counters would never go for true "Poco" unless it was extremely fine detail/deep thin ribs ect. I cut some .005" thick ribs - milled in Poco3 copper impregnated- good shit man. No chipping when milling climb or conventional. Tough on cutters but all pays off in the ol sinker - nice finish- no DC arc's. Heck I just read a trade publication article in EDM Today. Its still the same as 20 years ago. The name of the game is Flush, Flush & then Flush. No shit sherlock.

Back in the day we used this shit graphite called KK-12 (kost kutter-12) It would peal off in flakes. Man we were bamboozed get'n in this trade Well kid here's a HRP64 Elox tube type 30amp EDM die sinker, lets see what you can do.

1st clean out sludge in bottom tank- (after 10years of use). MFer was over the top of the clean out door! I ruined my good Disco shirt that day EDM sludge is raunchy & stains everything it comes in contact with.

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D ______ /_____/\ Best Regards, /____ \\ \ Gil Pawl /_____\ \\ / HOLDZEM=A9=AE /_____/ \/ / / /_____/ / \//\ West Chicago, IL \_____\//\ / / USA \_____/ / /\ / \_____/ \\ \ \_____\ \\ \_____\/

Reply to
cncmillgil

Poco3 - what a $luxury$ Shop owners/bean counters would never go for true "Poco" unless it was extremely fine detail/deep thin ribs ect. I cut some .005" thick ribs - milled in Poco3 copper impregnated- good shit man. No chipping when milling climb or conventional. Tough on cutters but all pays off in the ol sinker - nice finish- no DC arc's. Heck I just read a trade publication article in EDM Today. Its still the same as 20 years ago. The name of the game is Flush, Flush & then Flush. No shit sherlock.

******** it seems obvious to you, and me too. But all I can say is everywhere around here...is flushless. NOBODY flushes anymore. I blame it on the fact that people have too many edm's for their own good. If they just had one or two like decades ago, they would better manage the speed of the burn. Now, there's such a surplus in every shop people just load em up, no flush, out of the box settings running poco 3. **********

Back in the day we used this shit graphite called KK-12 (kost kutter-12) It would peal off in flakes. Man we were bamboozed get'n in this trade Well kid here's a HRP64 Elox tube type 30amp EDM die sinker, lets see what you can do.

1st clean out sludge in bottom tank- (after 10years of use). MFer was over the top of the clean out door! I ruined my good Disco shirt that day EDM sludge is raunchy & stains everything it comes in contact with. *******

amen.

****

====================================================== ______ /_____/\ Best Regards, /____ \\ \ Gil Pawl /_____\ \\ / HOLDZEM©® /_____/ \/ / / /_____/ / \//\ West Chicago, IL \_____\//\ / / USA \_____/ / /\ / \_____/ \\ \ \_____\ \\ \_____\/

Reply to
vinny

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I saw this a few years back at the MMS high speed (performance) machining seminar(basicaly a sales bus trip to all machine sellers in the area) & just came back to me whilst on me tractor cutting the grass last night:

WTF? How many people use Tricordial milling? What the hell? Full depth of cut, Making F'n spark chips? at a gazillion F'n RPM. & rapid travel feed! Thats what machining has come too? Thats sure not moldmaking. Oh man gemme a freekin break. I don't get it. So here's the question: What machine, in a basic machine shop, removes materiel the quickest?

So ya got that one.

Now, what milling technique removes material the quickest?

pretty basic stuff right? To the best of my knowledge these still hold true till this day.

This outa be interesting now? Its Vinny's fault After reading his stuff I get...............well ..................... inspired?

just in case you did not see the other post:

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\|||/ (o o) ______.oOO-(_)-OOo.____________________ ~ Gil ~ the HOLDZEM=A9=AE king

Reply to
cncmillgil

"cncmillgil" wrote in message news: snipped-for-privacy@r33g2000yqn.googlegroups.com... On Jun 11, 6:22 am, "vinny" wrote:

I saw this a few years back at the MMS high speed (performance) machining seminar(basicaly a sales bus trip to all machine sellers in the area) & just came back to me whilst on me tractor cutting the grass last night:

WTF? How many people use Tricordial milling? What the hell? Full depth of cut, Making F'n spark chips? at a gazillion F'n RPM. & rapid travel feed! Thats what machining has come too? Thats sure not moldmaking. Oh man gemme a freekin break. I don't get it. So here's the question: What machine, in a basic machine shop, removes materiel the quickest?

********* Still the saw. If you add in unattended time, I'd have to say the wire edm, which is basically an electric saw. *********

So ya got that one.

Now, what milling technique removes material the quickest?

********** Still drilling. **********

pretty basic stuff right? To the best of my knowledge these still hold true till this day.

This outa be interesting now? Its Vinny's fault After reading his stuff I get...............well ..................... inspired?

just in case you did not see the other post:

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\|||/ (o o) ______.oOO-(_)-OOo.____________________ ~ Gil ~ the HOLDZEM©® king

**** Milling speeds have increased by insane amounts recently. The past decade the difference is shocking. But damn...edm speeds have totally dropped off. Nobody burns fast anymore, seems it's all about unattended operation. Most shops have gone away from circle and square orbital electrodes in favor of spherical orbited electrodes. The reason is it's easier to make the electrodes...I really can't figure out any other reason? It's literally half the speed of the 2D orbits? NOBODY is using flush anymore either? I'm seeing shops make all their electrodes at one orbit amount, and usually a small amount like .005 max. People used to make roughers, or even super roughers to speed up the process. I really don't get it? If mills have sped up so much, and programming software has gotten faster, why has one of the end products of those processes suffered? And this whole poco3 nonsence? Forget about brand names, that's not my point. My point is everyone feels poco3 is "premium graphite compared to edm200, or edm100. But that's not true, they are different grades, but not "quality" grades, they are density grades. If I was going to burn a cavity that made the tip of a needle probe, ok, id use poco3. The stuff is strong, and can hold a tiny little point. But If I'm going to burn a coffee pot mold, damn I'm using edm 200, or even poco100. The reason is the less dense stuff burns better. (providing you use flush). The pourous chuncks wear away making for a real clean burn, there's no buildup on the trode or any arcing because the material is literally disapearing at high rates. All graphite is not the same, so I'm only using poco as an example because it's the standard. But poco3 is so dence it creates all kinds of problems, and I know new machines have the abilities to adapt and deal with those problems, but damn, why not throw a piece of graphite in there thats half the price and cuts twice as fast with almost no tool wear, and then burns twice as fast with less chance of arcing and pitting. Damn, we have all these gains in milling, and backslide off the deepend on edm? Maybe that's why everyone is so sold on hardcutting.?
Reply to
vinny

.

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Yup yer right on. Their thinking is any time you can eliminate a machine setup& process yer ahead of the game. Which is correct most of the time. So it takes a 1-1/2- 2 times longer in 1 machine opp instead of 2 quick setups & cheap machines requiring skilled labor to run... like drill .010" flush lines connected into a internal "manifold" inside the blank. Things like how ya gonna make the trode & drill flush lines were taken in to thought before blanks were even made / maybe requiring a larger blank base or pre drilling flush before finish detailing/rad. tips. Charmelles had 2d orbiting down to a science with their charts for overburn, so did Elox but not orbiting, besides the rotating spindle that would use an electrode like a single lip cutter. How bout manual thread EDMing? The attachment clamps on the ram(locked) & the threaded graphite is feed by hand- guided by nylon insulated bushings for different thread pitchs. The last years I was in mold shops, the most efficient were in the 2 electrode mode. 1 rougher@.025/S- 1 finisher@.01/S unless thin ribs were involved. I do like the CNC sinkers that can burn helix's or threads in on coumpond angles- way cool. The "magic"tooling ball will get you anywhere in the universe on any angles as long as you can keep the "right hand rule" straight. No not the Hawaiian peace sign

Oh yes the mighty band saw is still king, drilling is proly right for

2nd choice metal removal. But....... plunge milling using a slight back-away technique- to keep sidewall squeal down - still kicks ass. Another lost "Art"

I got it. In about 10years we can open our own "Museum of American Machining" kinda like the Henry Ford museum/Greenfield village, charge a freekin huge amount for admission, like Dollywood or Great America, give demo's & BS all day long - Set up as a non-profit corp.(pay no taxes) - charge x-tra to push the cycle start button & Use AutoCad. or run a real CNC that makes an ash tray engraved with "your name here" =3D make $huge$ amounts like rock stars? Hey its not that far off. We anit making shit in this country any longer & soon wont be able to make anything in mass productions. Just talked to a buddy of mine, best 3D Injection mold designer I've been associated with in the Chi-town area, he got layed off a month ago. He's excellent in Pro/E, UG & Solidworks - an old CV guy. Places that are left are looking for college degree d "kids" $cheap$ of course. Oh I gave him his Cimatron training :-) \|||/ (o o) ______.oOO-(_)-OOo.____________________ ~ Gil ~ the HOLDZEM=A9=AE king

Reply to
cncmillgil

What you're talking about is a specialty of poor quality machines.

I've got a job that's been running 11 hours a day for the last two weeks. There's a finish dimension on the part that is .493+/-.0005. This part is sitting right at the center of rotation on a CAT40 horizontal. The finish pass is with a .500, 3 flute carbide endmill in a shrink fit holder, hanging out of the holder by 1.75, running

16,000rpm and 220ipm. It makes a pass at Z .2465, retracts, rotates the B axis 180 degrees, and finishes the other side at Z.2465. We hold +/-.0002 on the overall thickness, which is a maximum of .0001 error on the Z depth of the machine.

This is one of those times that it really comes in handy to have a newer machine with 5 decimal places in the offset register. This part has a 1 hour cycle time, so the shop can change temp a bit between that particular feature on two consecutive parts. If a part comes off at .4931, the tool length gets adjusted .00005, and the next part will be .4930. The hours between 7am and 11am are the trickiest, because the shop goes from about 70 degrees to 85 in that time. By noon, we are done making offsets.

Reply to
Joe788

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