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Your Old Dog
02-07-2008, 06:55 PM
I was trying for a nice slick cut through about 1" x 3/4 aluminum 6061 billet ! This happend twice, both at about the same point in time. I theroize that as I got nearly all the way through, enough heat built up that it allowed the aluminum to expand and capture the blade. The torque built up in the spinning geared head just kept spinning as the blade fractured and piled up like a proverbial train wreck.

http://bbs.homeshopmachinist.net/http://inlinethumb58.webshots.com/4729/2396787700102651310S600x600Q85.jpg (http://good-times.webshots.com/photo/2396787700102651310LvxCcB)

Mcgyver
02-07-2008, 07:05 PM
ooooo thats a good one! i can see whats wrong, you were going too fast and at too high a feed. what were the speeds & feeds again :D

agrip
02-07-2008, 07:16 PM
Saw slitting aluminum requires attention to chip formation.

A spreading chip with limited coolant will drag the sides, becoming even hotter and make a dandy snowball gall. That makes a really good grip for the following snowball gall. etc etc >> scratch one sawblade.

You can convince youself with trying a lathe P/O blade that forces the ship to spread.

Hence, the concave top P/O blades work really well, with a minimum of oil.

Hth ag

jimsehr
02-07-2008, 07:23 PM
Were you cutting into a hole in block? If so I think the block pinched the blade.
jims

boslab
02-07-2008, 07:25 PM
tallow on the blade/ hollow ground HSS is what i have on an eisel ali saw, sure you didnt get some sidethrust there?
regards
mark

Evan
02-07-2008, 07:26 PM
Use Wd-40, kerosene or even plain old oil, any type and that won't happen no matter how fast you cut. Now, for a really nasty metal to cut try lead. It will grab that blade in an eyeblink no matter what lube you use.

[edit]

What's most likely happening is that it is getting hot enough to locally anneal the metal which turns aluminum to glue, like lead.

Larry Jaquay
02-07-2008, 07:30 PM
Hello
Use Anti-Selze when cutting slots for lub.,also is good to put on threads of R-8 collets,not my idea,from PM,MI,PS (mag.) 20 to 30 years ago!!

Larry

Note: for deep slots just drill end hole (so it won't crack) then,bandsaw 2 & 1/2 x blade size , so you can saw one side of slot then the other,done it for years

Oldbrock
02-07-2008, 07:54 PM
Use A 9 aluminum (aluminium for the limeys, I'm one) this is the best cutting fluid for this material by far. Peter

Virgil Johnson
02-07-2008, 08:02 PM
>I was trying for a nice slick cut through about 1" x 3/4 aluminum 6061 billet !

Try regular bar stock next time. That billet stuff is pretty nasty to machine. :-)

Virgil Johnson
02-07-2008, 08:05 PM
I would say the set off the saw was off ever so slightly and this combined with a bit of runout in the arbor produced the result.

Your Old Dog
02-07-2008, 08:12 PM
As I recall I was cutting at 90 rpm with a 2.5" blade. I was using lots of WD-40 and feeding by hand in the Y direction. Think I'll order some thicker blades. These were some .032 eBay blades I believe. Anytime I'm likely to saw it's to be able to pinch another piece of roundstock with a bolt. This blade is too thin for that application anyway.

JCHannum
02-07-2008, 08:44 PM
There are slitting and slotting saws. If you slit with a slotting saw a jam can the result.

CCWKen
02-07-2008, 08:52 PM
I save that headache buy running my aluminum blocks through the table saw. :cool:

pntrbl
02-07-2008, 09:16 PM
Thanx for the pic YOD. I haven't wrecked that particular train yet so I'm paying close attention on this one.

SP

Rustybolt
02-07-2008, 09:34 PM
Little bites and moderate speeds and slow feed and like everyone has said, lots and lots of coolant. Flood coolant is best. Sharp, sharp cutters.

J Tiers
02-07-2008, 09:38 PM
S'posed to use a saw with side teeth for deeper slots.

Slotting saw has no "dish", so it's not good for much deeper than the teeth, if that deep.

Slitting saw is ground "hollow" with some "dish" so it can cut deeper.

A regular saw for cutting deep slots looks like a thin alternate tooth side cutting milling cutter. If anything binds on it, the side teeth just cut it.

That said, slitting saws are cheaper, so I tend not to use the "real" saws unless I have to..... I don't have the ability to grind them (yet).

Your Old Dog
02-07-2008, 10:25 PM
I save that headache buy running my aluminum blocks through the table saw. :cool:

That's what I ended up doing anyway as the cut was wider and allowed more room for compression.

I did not know there were slitting and slotting saws. Guess I'll have to get into the catalogs look them over. Thanks for the heads up.

I bought a small 6" table saw just to convert to aluminum use. Might be a good time to look for a blade for it also.

darryl
02-07-2008, 11:26 PM
Yeah, I bought a slitting saw blade for real cheap, about 4 or 5 bucks as I recall- fairly large diameter one at that, about 7 inch- the store called it a skil saw blade though. :) I do as much cutting and milling on the table saw as I can, even before I use the bandsaw. The bandsaw is great for squaring up the cuts made by the table saw. Then the part might go to the mill for further machining.

I use the circular saw blades often because they are thin and don't have to remove as much material, and they're cheap so I don't have any excuse to be using a dull blade. I use a blade stabilizer with them to increase the rigidity- I think that should be considered a requirement. The cut is nicer, and the blade is selected mostly on the basis of the largest number of teeth I can readily find.

oldtiffie
02-07-2008, 11:53 PM
Check/read this extract from a book and my stub arbor - both posted previously.

Both work very well.

http://i200.photobucket.com/albums/aa294/oldtiffie/Slit_saw1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Stub_arbor2.jpg

I should have had a coarser blade - less teeth - as it will reduce clogging and assist with clearing of swarf etc.

As said by others - the thicker the saw the better - mostly!!

Use normal "wax-stick" type aluminium lubricant - or kerosene (paraffin in the USA?) or WD40 etc.

agrip
02-08-2008, 01:18 AM
Er Ah Er - - -
I don't know how to say this gently. I apologise.
This has been said many times before, this forum and several others. ONE more time.
If you had mentioned WD 40 in the first post, it would have been more gentle.

WD40 is a flush REPEAT a FLUSH. A coolant of sorts.
It has NO "long chain" molecules by definition.
It evaporates in 40 days.
(IIRC, Water Displacer lasting 40 days, is how it got its catchy name.)
Sure, it smells good and is easy to clean up, and comes in a nice looking can, with really cool name.
BUT it is NOT intended to be a load bearing lubricant.
It is also NOT a good penetrating oil.
And umpteen thousand people prove it every day, we should ask the marketing genius who dreamed up the name to solve the problems in the white house.

For doing slots you are best advised to use a cutting oil.
A real lubricant for working in close proximity to freshly cut metal surfaces with high contact pressures.

Get the pipe threading lube at eht gib xob erots.
You can make a nicer looking stuff by diluting ATF with kero or if you just gotta, gotta use it, dilute ATF with WD 40, but

Don't use, DO NOT use, STOP using WD40 as a cutting oil.
It's not. Never was, ask the producer.

I'm off my box now.

Ag

darryl
02-08-2008, 01:55 AM
From what I read, WD got it's name because of the number of tries it took to get the formulation right. On the 40'th try, they figured it was right, so that's why they called it WD 40.

I just figure the reason it works as a cutting lube is because of the fish oil. Fish seem to figure it's pretty slick :) Maybe the WD folks kept cutting it and cutting it, until it didn't smell fishy- at that point it was a go. Maybe.

lwbates
02-08-2008, 01:58 AM
Jimsehr is right, slit first, drill the hole second. By doing it in the reverse order your asking for it to bite the blade, due to built up internal stress.
lwbates

Evan
02-08-2008, 03:28 AM
Don't use, DO NOT use, STOP using WD40 as a cutting oil.
It's not. Never was, ask the producer.
You obviously don't have much experience machining aluminum. About the only lubricoolant that works better on aluminum than WD-40 is 96% ethyl alcohol. Incidentally, WD-40 most certainly is a lubricant. It contains about 50% light mineral oil, 25% low volatility paraffinic long chain hydrocarbons and 25% stoddard solvent.


For doing slots you are best advised to use a cutting oil.
You really don't want to do that on aluminum. Really. You won't like what happens.

oldtiffie
02-08-2008, 04:38 AM
Thanks Evan.

Much.

John Stevenson
02-08-2008, 07:47 AM
clumsy bastard.............



.

DICKEYBIRD
02-08-2008, 08:10 AM
Go down to Home Cheepo, get yourself a blade like this and make an arbor for it. Make a shallow (.060" or so) cut first; crank it in full depth and listen to the blade to judge the feed. I cut numerous chunks just like yours, into a hole and never heard a whimper. I tried several speeds, 100 to 350 rpm and couldn't tell much difference....other than getting through faster.:) My HSS steel slitters are all gathering dust now.

After having so much success slitting with an intended-for-wood blade, I started using an 80 tooth, 10" blade in my intended-for-wood miter/chop saw to cut 2x4 chunks of 6061 down to size and was amazed at the speed & smoothness of the cut.

http://i57.photobucket.com/albums/g227/DBAviation/SawArbor3sm-2-1.jpg

http://i57.photobucket.com/albums/g227/DBAviation/SawArbor3sm.jpg

Bill Pace
02-08-2008, 08:56 AM
Good thread.....

Poor WD, gets beat up on all over the place ----- EXCEPT!....as a lube for cutting aluminum!

Seem odd to see such a strong put-down as Ags on it in that respect. I suspect he in in quite a minority with that opinion.

I had found this ability of the stuff by hit & miss, just trying out different things around the shop, with a noticable difference using WD when cutting Al ...hacksaw, bandsaw, mill, lathe, WD just eases the cutting of AL as well, or better'n anything (that I've tried!) I find Kerosene does a pretty decent job with Al also.

Your Old Dog
02-08-2008, 09:35 AM
clumsy bastard.............

ROFLAMO :D Thanks for the moral support big John. I know'd I could count on you!




I find Kerosene does a pretty decent job with Al also.

Actually, I think Kerosene is what caused the paint on my SB9 to get messed up. I don't think WD-40 is nearly as harmful on paint. I say this because I used Kerosene all the time and only recently learned about the benefits of WD-40 where alyouminiumumommm (as the Canucks call it) is concerned !

Thanks for taking the time to get the pics Dickeybird. I'll have to try that as it hurts my feelings when the mill crashes. You get the big dogs running in here and trying to nip on your ass when you down and feeling helpless if you know what I mean :D

A.K. Boomer
02-08-2008, 09:53 AM
Don't feel bad YOD, Iv blown up two hollow ground carbides at something like 65 bucks a pop, I hate it when it happens and it even makes me a little shaky afterwards, Like everyone said dont skimp on the coolant esp. with aluminum and nurse it through steady --- the one thing I have to add is listen very carefully to the cutter, its no guarantee but sometimes you have time to hear the chip stick and build ---- as soon as theres a deviation shut er down and find the tooth with the material on it and remove.

Orrin
02-08-2008, 11:09 AM
Dickeybird beat me to it. The first time I had to cut a chunk off a piece of 3.5" thick alumuminum plate I made an arbor and mounted a carbide-tipped wood saw blade on it. I've never had a bit of a problem with that setup.

On the other hand, whenever I've tried to use a slitting saw to cut aluminm, no joy! Even when using a lubricant, I've had trouble with aluminum gumming up the saw. It only takes a wee little chip of aluminum to bind in the cut and something's gotta give.

The only way I know of avoiding disaster with a slitting saw is by doing Rustybolt already said:

Little bites and moderate speeds and slow feed and like everyone has said, lots and lots of coolant. Flood coolant is best. Sharp, sharp cutters.

Orrin

A.K. Boomer
02-08-2008, 11:17 AM
It really is a bad train wreck --- its like the lead engine - all the mid cars - Plus the caboose to boot, One would almost think that YOD was in a different room when the fumets hit the windmill:p

J Tiers
02-08-2008, 08:23 PM
Yow...... fewmets....... another Olde English scholar. :D

jimsehr
02-08-2008, 11:06 PM
I still wonder if you were slitting into a bore or hole.
jimsehr

John Stevenson
02-09-2008, 04:51 AM
I have skimmed thru this post so I'm not sure if it's been mentioned but if so my apologies to ???

When using thin saws NEVER use the driving key in the arbor, just nip the saw up and if it does grab you at least have a chance of stopping the machine before it turns to shrapnel.

Using a key guarantees it will shatter the blade when it grabs.

.

Your Old Dog
02-09-2008, 07:28 AM
I still wonder if you were slitting into a bore or hole.
jimsehr

Sorry Jim, I was slitting into a hole but had not reached it. I was taking little passes in the Y direction. My next pass or two would have been through the hole.

John, this particular tool has a key but I wasn't using it BUT I likely over compensated with the wrench when I tightened it up. I didn't want it to spin....and......... as you can....plainly see, well, it didn't :D

No Boomer, I was sitting right there in front of it as the fit hit the shan. Fortunately, the project caught all the little pieces and nothing went flying around the shop. No fewmets on the wall to wipe off ! Someone here said everyday in the shop was a learning experience and I have to agree.

J Tiers
02-09-2008, 11:41 AM
For doing slots you are best advised to use a cutting oil.
A real lubricant for working in close proximity to freshly cut metal surfaces with high contact pressures.



You really don't want to do that on aluminum. Really. You won't like what happens.

That's funny............

Just did a run of aluminum spacers recently, with the releasing tapper, and used cutting oil for part-off, drilling, and tapping. Harvey's thread cutting oil, to be specific.

Worked very well, did nothing bad to the aluminum, I LIKED WHAT HAPPENED.

Good clean part-off, shiny surfaces, good clean drilling and tapping......

What problems are you referring to?

Evan
02-09-2008, 12:25 PM
Any cutting oil containing suphur, which most such oils for steel do, will cause a chemical reaction with the aluminum that turns it to a black glue and acts as a strong friction additive. This is most especially the case when tapping aluminum and is an excellent way to see how much it takes to break a tap. The best oils for aluminum if you are going to use oil are "natural" oils such as lard oil. Yes, you can still buy lard oil. Aluminum benefits most from very low viscosity cutting agents. Because of the much higher cutting speeds thick agents don't do a good job of lubricating the actual cut. That's what makes WD-40 effective. It's basically light oil thinned with solvent. I can't stand the smell though so I use a similar product sold here by Canadian Tires stores. It's almost odorless.

Pete H
02-09-2008, 01:08 PM
There's also an "aluminum" version of TapMatic that works pretty well when milling aluminum. Smells nasty to me, but then I like WD40's smell.

Pete in NJ

HTRN
02-09-2008, 02:03 PM
You obviously don't have much experience machining aluminum. About the only lubricoolant that works better on aluminum than WD-40 is 96% ethyl alcohol.
Baloney. The best thing I've found for Machining Aluminum is Blaser Swisslube(water soluble) from a high pressure nozzle. And I used to fill four 55 gallon drums a day with 6061 chips. Alcohol doesn't even come close.


HTRN

Peter Neill
02-09-2008, 02:27 PM
I won't claim to be an expert here, but I use Isopropyl Alcohol when I'm milling or turning aluminium, and it does give a superb finish, far better than WD40 in my opinion, and leaves no residue.

However, I don't cut anywhere near as much aluminium as others that have posted here, and I'm sure that flood coolants like HTRN mentioned are quite possibly far better than intermittent squirts from my squeezy bottle.

Peter

A.K. Boomer
02-09-2008, 02:28 PM
HT, thats what my friend uses allot of and its what i have in my mister, good all around coolant and not too bad on the lungs when misting.

darryl
02-09-2008, 04:19 PM
I'm going to have to try some of these other fluids mentioned. As far as table sawing, I use one lube exclusively- an oxygen nitrogen compound with dihydrogen oxide present in varying degrees. There's probably also a bit of methane mixed in with that. It seems to cut just a bit better shortly after lunch or dinner. :)

A cut like YOD was doing would have been an automatic for me on the table saw. Done in about 15 seconds probably. I likely would have used some wood to prop up the part so it didn't move around during the cut- that reminds me, I've wanted for some time now to make a saw table vise to hold smaller parts for cutting. That's going on my project list now.

Your Old Dog
02-09-2008, 04:19 PM
Any cutting oil containing suphur, which most such oils for steel do, will cause a chemical reaction with the aluminum that turns it to a black glue and acts as a strong friction additive. This is most especially the case when tapping aluminum and is an excellent way to see how much it takes to break a tap.

Well I can certainly backup the black glue claim. I was knurling some aluminum using 3-1 oil (it was convienant at the time). What I got was a black gooey mess and a crappy knurling job from brand new dies

Evan
02-09-2008, 04:26 PM
Baloney. The best thing I've found for Machining Aluminum is Blaser Swisslube(water soluble) from a high pressure nozzle. And I used to fill four 55 gallon drums a day with 6061 chips. Alcohol doesn't even come close.
I said ethyl alcohol. Not isopropyl and especially not methyl, but ethanol. Alcohols are not all the same and don't have the same properties. Most people haven't tried ethanol since you can't just walk in a store and buy 96% ethyl, not even a liquor store. Ethyl is the lubricoolant of choice for very high speed machining of aluminum.


Datron Dynamics, Inc. is the North American distributor for Datron Electronic, a German technology firm established in 1969....

We are differentiated in the marketplace by a focus on efficiency with small tools. Datron machines feature 60,000 RPM spindles that produce low force, feed rates of up to 1000"/minute and superior quality when tooling 0.250” and under. An integrated spray-mist ethanol alcohol coolant system provides for superb surface finishes, eliminates secondary processes like de-burring or de-greasing, saves production time, and helps to protect the environment.

http://www.datrondynamics.com/

Low-Viscosity Coolant. While high-speed machining inherently reduces heat, the task of cooling a rapidly moving micro tool often requires coolant. Those dedicated solely to high-speed machining with small tools understand that coolant used with conventional CNC equipment is not optimal — and this is a perfect example of where thinking “out-of-the-box” is necessary when undertaking applications that require high-speed machining . A small tool with intricate geometry turning at an extremely high RPM calls for a cooling and lubricating agent with a lower viscosity than water. Lower viscosity is needed because the coolant needs to make it to the cutting edge of the tool despite the high spindle speeds involved. Emulsion-based coolants have a higher viscosity than water, and thus are ineffective as a lubricant for high-speed machining with micro tooling.
But some micro-volume coolant spray systems can use ethanol, a form of alcohol which occurs naturally in the sugar fermentation process and exhibits a lower-than-water viscosity. The low evaporation point of ethanol makes it an extremely efficient cooling and lubricating agent for high-speed machining operations. Plus, while conventional flood coolant is petroleum based and needs to be properly disposed of, ethanol simply evaporates. This eliminates the costs associated with disposal. In addition, ethanol as a coolant does not leave any residue on the machined parts, thus eliminating the costly secondary operation of de-greasing parts.
Note: Ethanol coolant should only be used for machining of non-ferrous materials and not for machining steel-based materials.
http://www.microtooling.com/Why_HSM.html

HTRN
02-09-2008, 04:41 PM
HT, thats what my friend uses allot of and its what i have in my mister, good all around coolant and not too bad on the lungs when misting.

I LOVE Blaser Swiss(Specifically their "Blasocut" stuff) as alot of the really good cutting fluids will give you "machinist disease"(Dermatitis) which I'm incredibly prone to, especially the low concentration synthetics. It does a great job, and doesn't make me look like I have the plague. One former employer switched to it after seeing me turn into a leper shortly after starting there - they were worried about medical claims. So they switched over. It was more expensive than what they were using, but it got better finishs, and I stopped scratching;)

My biggest complaint about them is the way they sell the damn stuff - only through "authorized dealers". I just wish they'd wise up and start carrying it through retailers like MSC and J&L. Otherwise it's gonna have to be Rustlick(which is pretty good stuff too, just not in Blaser's league), as I can simply order a 5 gallon pail and not have to deal with a salesman.


Most people haven't tried ethanol since you can't just walk in a store and buy 96% ethyl, not even a liquor store. Ethyl is the lubricoolant of choice for very high speed machining of aluminum.

Evan, you can quote all you want, it isn't going to make it true. Most of my experience in machine shops is with "High speed machining of aluminum"(Does 7000RPM with a 1/2 coated Carbide endmill moving at 60IPM qualify?;) ) and been in dozens of shops that do it. NONE OF THEM USE ALCOHOL. Most use a water soluble mineral oil base, some use low concentration synthetics. The hot setup is Through the spindle coolant with a high pressure(anywhere from 300 to 1000 PSI) pump.

The typical high pressure coolant system is not meant as "coolant" per se, it's main job is to keep the chips off of the cutter, with additives to "lubricate" the cutter to preserve the cutting edge. Most of the heat goes away with the chip. In fact, that caused problems at one shop with a VMC without a chip conveyor - we cut so much aluminum in a day, that with the coolant draining through the chip bed(at one point it was 2 feet deep in the machine) that the temperature of the coolant climbed over 60F in the 80 gallon tank over the course of a shift.

And oh, you can buy 95% Ethyl Alcohol here in the US. in a huge variety of locations. It's called Everclear.;)


HTRN

jkilroy
02-09-2008, 06:46 PM
I have a setup just like Dickeybirds, same blade in fact. Those nice little carbide teeth give some relief on the blade so it doesn't run in the cut, works great. With a setup like that, trying to make the cut your were making, just do like he said, take a shallow initial pass, like .125, then set the blade over full depth and LET ER RIP! Forget that 90 rpm crap, try 350 to start and don't be afraid to go up. I have cut aluminum blocks with mine at 1000 rpm with no problems. The blade form really helps remove the chips. No need to go overboard on the coolant, a shot of the afore mentioned WD-40 every now and then works great.

Evan is quite right on dark sulfur based oils on aluminum, they will stain the metal readily, not good. He is also right about Ethanol on as a coolant.
High speed machining in aluminum starts at 3,000 sfm, you would need to turn a 1/2 mill 22K. At the ragged edge, with diamond tooling, there are aerospace folks hitting, get ready for this, 30,000+ sfm. For feeds, a real high speed application will start at 300 ipm and go well beyond 1,000 ipm.

Lots of these folks are using high purity ethanol like Evan said, but many are doing away with coolant all together and using high pressure compressed air only.

HTRN
02-09-2008, 07:39 PM
JKilroy, those are considered "exotic process" machines, about the highest speed you'll see in a conventional machining center is 30K, and even that it's fairly uncommon. A general rule of thumb has been RPM's over 10K as a definition of "High speed machining". A better one is the balance requirement - when you have to balance toolholders to G2.5 or better, you're doing high speed machining.


HTRN

Rustybolt
02-09-2008, 10:24 PM
WD 40 leaves sticky residue. I don't like to use it. kero with a little mineral oil works well. Grease is good for hand tapping, but if you're machining hundreds or thousands of parts flood coolant is best . I've tapped thousands of holes in alum using water soluble coolant with the same tap.

Evan
02-09-2008, 11:24 PM
JKilroy, those are considered "exotic process" machines,

Not any more. That's why I built a spindle that does 27k. It can't be all that exotic if I am approaching those speeds in my basement. I would go faster but then I would have to figure out some better bearings, maybe magnetic suspension with squeeze film damping.

Regardless, ethanol leaves the best finish and works the best overall even at 1937 South Bend speeds. I have been working aluminum for 35 years, some of that time as my job. It's no small advantage that it is a disappearing lube too. High speed is the norm in many shops. Time is money. You may chose not to believe those quotes but the manufacturers of those high speed machines are making money. It isn't just a very few that are using ethanol, it is commonly used on the large gantry routers too and has been used in aerospace work since I was working in it in the 70s. It isn't new.

HTRN
02-10-2008, 11:48 AM
Yes, THEY ARE. They're incredibly expensive. The only time I've ever seen a machine ABOVE 30K rpm in the last ten years of Industrial auctions, was at a defense plant, that you had to undergo a background check before they let you in. It was used to mill bulkheads on mil. aircraft. The 30K machines are mostly EDM mills where high feeds and speeds are really required becuase of stepover requirements.

Remember, High RPM is not a goal, it's a means to an end. The real goal has always been high metal removal rates(I once heard it described as cubic dollars per minute). That means both high RPMs, an extremely rigid machine, and lots of Horsepower. Once you get beyond 10,000 RPM you're talking balancing every toolholder every time you insert a new tool(that runs into money, a tool balancer is $15K), you have to worry about cutter deflection, getting coolant at the cutter(Hence the use of high prssure TSC), and a whole host of other things. I can imagine what G1.0 tool holders cost.

Hell, DMG doesn't offer anything faster than 42K RPM, and that's in a $$$$ machine..

Let me put to you this way - Show me a 100,000 RPM machine that doesn't cost more than a million dollars. Yeah, machines that fast are out there, but so are F1 cars, and when was the last time you saw one at the drive through?

One more thing, I just checked my Command systems catalog(Command makes $$$$ toolholders - makes Parlec look cheap), and they list their "Mass Symetry" tool holders as good up to 20K rpm in most models. They also list "toolholders specially balanced up to 30K RPM as custom work(I believe it requires the G1 balance standard), and also that they'll make toolholders good beyond 30K RPM. That means that it's not common enough for them to be a regular production item.


HTRN

jkilroy
02-10-2008, 12:29 PM
Many of the machines doing real high speed work I spoke of don't use insane RPM to get the sfm up, they use large diameter cutters. With a 2" cutter you just need to crack past 5K to enter the 3000 sfm zone.

What you do need is HORSEPOWER. The general rule is 1hp per inch diameter per 1000 rpm just to spin the cutter, not do any work. So a 2" cutter spinning 6000 rpm needs 12hp just to get to speed. The machines are not super top secret stuff, you can call Mazak up and order a machine with a 100hp 25,000 rpm 50 taper spindle if you have the cheese. Honestly I'd be scared of a 50 taper tool spinning around at 25K! Imagine breaking a pull stud off in that!!

J Tiers
02-10-2008, 01:28 PM
Any cutting oil containing suphur, which most such oils for steel do, will cause a chemical reaction with the aluminum that turns it to a black glue and acts as a strong friction additive. This is most especially the case when tapping aluminum and is an excellent way to see how much it takes to break a tap. The best oils for aluminum if you are going to use oil are "natural" oils such as lard oil. Yes, you can still buy lard oil. Aluminum benefits most from very low viscosity cutting agents. Because of the much higher cutting speeds thick agents don't do a good job of lubricating the actual cut. That's what makes WD-40 effective. It's basically light oil thinned with solvent. I can't stand the smell though so I use a similar product sold here by Canadian Tires stores. It's almost odorless.

The Harvey's is sulphured, but not too dark. I have used Mitee (black oil) with no staining also.......

Apparently it does not always happen.

HTRN
02-10-2008, 09:08 PM
Honestly I'd be scared of a 50 taper tool spinning around at 25K! Imagine breaking a pull stud off in that!!

I've had small endmills self destruct and send chunks into the acrylic windows.. The idea of a toolholder flying free at high RPM makes me twitchy.. I wonder how expensive it would be to replace the acrylic windows with the stuff they use for bulletproof glass?

I don't think anybody uses 50 tapeer too far above 10K rpm. Haas's 30K option uses a BT30 spindle, and DMGs HSC machines use a HSK A63..


HTRN

jkilroy
02-11-2008, 10:36 AM
If you look at the Mazak site, the machines with the big RPM 50 taper spindles don't have any windows! I guess there are some video cameras in there! Probably a reason for that. You could replace a window with Lexan for probably no more than they would charge for a factory replacement part. .5" lexan will stop a .357 without much reason for concern.

Your Old Dog
02-11-2008, 11:03 AM
.5" lexan will stop a .357 without much reason for concern.

Maybe so but I'll find another place to stop and pick my teeth :D

darryl
02-11-2008, 04:07 PM
Hmm, all that power and rpms- I'd be happy just to be able to cut shapes in sheet material without a hassle. Metal removal rate to me means how fast can I strip the teeth off the jigsaw blade- :)