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Liger Zero
05-19-2009, 07:19 PM
Ok the print shop I work at I do quite a few fixtures, tools and odds and ends out of aluminum. Mostly 6061 and "wait, what... there are different KINDS of aluminum?!" mystery-metal.

Now that I've proved that I can make the Bridgeport go, Boss wants to know what sort of endmills we should be ordering. I showed him a catalog and we're both kind of bewildered. He had been grabbing 2 and 4 flute mills from Fastenal as they get battered.

Now I know just enough to get me in trouble, being a home-shopper and all... My machine of choice is the lathe not the mill so I could use a few pointers. Normally I get my endmills from Little Machine Shop for home use.

What sort of endmills should we be using given the information I specifed above?

kmccubbin
05-19-2009, 08:03 PM
Well, I'm no expert, but I recently tried some 3 flute endmills and I like them. Seems to be the best of both worlds. It might save you from telling him you need an assortment of 2 flute AND an assortment of 4 flute.

Kerry

dockrat
05-19-2009, 08:07 PM
this is my favorite source for endmills for cutting AL:

http://cgi.ebay.ca/1-2-3FL-USA-Harmonicut-AL-carbide-end-mil-Zir-14739_W0QQitemZ390051428788QQihZ026QQcategoryZ2526 0QQcmdZViewItemQQ_trksidZp1713.m153.l1262

Bruce Griffing
05-19-2009, 08:15 PM
A good source of end mills is Lake Shore

http://www.lakeshorecarbide.com/

I know carbide is expensive, but it is lower cost in the long run. Also, if you have been buying from fastenal, it won't seem so bad.

Note that it is best to buy specific mills for the material you use. Call the Lake Shore and ask for advise.

sansbury
05-19-2009, 08:44 PM
What sort of endmills should we be using given the information I specifed above?

To paraphrase Freud, sometimes an endmill is just an endmill. A lot of guys like a 3-flute for aluminum, some prefer carbide to cobalt to HSS, and some will swear by variable-helix $40 specials over $4 Chinese ones, but for run-of-the-mill MRO jobs on a manual machine, it's probably not a subject worth losing more than a few minutes of sleep over.

Mcgyver
05-19-2009, 10:28 PM
i think any endmill will do, but the guys that cut AL all day long use higher helix angle end mills specifically for AL

http://www.productionmachining.com/uploadedimages/Publications/PM/New_Product_Announcements/0109_Primary-Cutter_Supermill.jpg

MTNGUN
05-19-2009, 11:54 PM
Generic roughing mills from Enco or whoever.

moldmonkey
05-20-2009, 12:02 AM
For work I do one-off & short run (there can be quite a bit of work in each piece) in Acetal, 6061, some steel. This is my WORKHORSE (http://www.mcmaster.com/param/asp/PSearch2.asp?reqTyp=parametric&act=psearch&FAM=endmills&FT_158=105860&FT_2402=105867&FT_239=177211&FT_2433=106617&FT_1624=88682&FT_2488=107362&session=endmills;158=105860;2402=105867;239=177211 ;2433=106617;1624=88682;2488=107362&sesnextrep=383362669940953&ScreenWidth=1280&McMMainWidth=873) Pretty plain jane but is high helix for aluminum. They will last forever. These are Atrax brand.

Save the "fancy" tooling for production work where the extra cost will be offset by the increased productivity.

Liger Zero
05-20-2009, 02:05 PM
Ok thanks for the advice when I go back tomorrow I'll show him these suggestions.

I want to have at least five endmills on hand, of different sizes. Lathe tooling I gladly supply because I managed to score a huge pile of brazed carbide and HSS blanks from a shop that closed down just recently along with a Really Cool Boring Bar that uses inserts and some other stuff... all for the low low price of "meh, take it saves me from having to identify and price it." :D

Sure wish I had grabbed endmills too, now. :)

Scishopguy
05-20-2009, 02:42 PM
If you do a lot of Aluminum work treat yourself to some high helix end mills, such as the Weldon Ski cut (the Enco are almost as good too). They are two flute but cut with little or no chatter and clear the chip out better than standard helix do. They are good for plastics and other softer materials too. For hogging steel you want a couple of sizes of the roughing mills, sometimes referred to as "corncob roughers." Otherwise, you will need an assortment of sizes of two and four flute standard end mills to handle odd jobs. If you are careful and have a means to resharpen them a set of end mills will last a lifetime. I have some that I have had and used for years, with only a periodic sharpening of the ends. I had a sharpening fixture for the surface grinder that did a neat job on them and got pretty good at keeping them sharp (if I don't say so myself!).

Liger Zero
05-20-2009, 02:48 PM
I have a fellow who has offered to resharpen the ones we have for a case of beer... I dunno you can see where they collided with the vice and other signs of painful abuse.

That's why I want to start over with a set of new endmills. Even if I leave here for whatever reason (not planning to) I want them to have the "right tools" on hand rather than stumbling along like they have been.

The fellow who I've been working with is Not A Machinist but he's puzzled out quite a bit on his own, and I'm passing along what I know about "the right way" in exchange for information on pad and screen-printing. :)

I gather by the oblique comments some of the "damage" may have occurred while he was learning. That's NEVER happened to me, I've never crashed an endmill into the vice or poked a hole in the table AT ALL EVER. *nose grows 72 inches, pants burst into flames*

Evan
05-20-2009, 03:13 PM
I use Garr carbide for most things. They are razor sharp and stay that way. The Al doesn't stick to them the same and expecially in the smaller sizes the stiffness is much better. 2 flute for most cutting but 4 flute for slots and fine finish.

The main thing is do not use your aluminum cutters on ferrous metals. It takes the super sharp edge off in a few moments. If you need to then paint the flutes so you can tell which is for what. Aluminum does cause wear on HSS because most alloys contain some silicon. Casting alloys contain a lot of silicon and carbide is a must.



That's NEVER happened to me, I've never crashed an endmill into the vice or poked a hole in the table AT ALL EVER. *nose grows 72 inches, pants burst into flames*


Someday I should take a picture of the vise on the really large mill/drill at the job shop in town. It looks like it just barely survived reentry from high Earth orbit. Still works though.

Liger Zero
05-20-2009, 03:29 PM
From what I gather they power-fed the endmill into the corner of the vice four or five times before they realize the speed control exists for a reason. Hey, it happens. Been there done that had to ask for another endmill, got screamed at by the penny-pinching accountant. :D

That said, adjusting and repairing said power-feed is my next topic.

Tomorrow. :D I have a Day Off today and I can't read the nameplate from here. :p

macona
05-21-2009, 08:52 PM
I use Garr carbide for most things. They are razor sharp and stay that way. The Al doesn't stick to them the same and expecially in the smaller sizes the stiffness is much better. 2 flute for most cutting but 4 flute for slots and fine finish.



4 flutes will cut oversize on a slotting operation. Use two or 3 flute then. But thats about the only time I intentionally use 2 flute mills. Usually 3 or 4.

Some of the new coatings are really nice. They allow you to cut aluminum dry without any coolant to keep it from piling up on the cutter.

Evan
05-21-2009, 09:23 PM
4 flutes will cut oversize on a slotting operation

I don't have a problem with that but that might be because I run .250" end mills at 5000 rpm. You do have to watch the lubrication though as there isn't a lot of clearance for chips with a 4 flute. When I used to use my lathe for milling then 2 flute was the best for slotting.

Circlip
05-22-2009, 05:38 AM
Since you're using a manual Bridgy LZ you need to determine the jobs you're machining to decide which TYPE of cutter to use. I mention "Manual" cos the sh4t or bust speeds and feeds multi toothed cutters used on CNC don't do EVERY job on mere handraulic machines.

Two flute cutters were/are and forever will be SLOT drills and are for milling -------SLOTS. Cos they are an over centre cutter, you can plunge vertically into material to get a start to mill a slot. Slots require that the chips are cleared quickly thus two flutes, BUT,If yer start to cleave down the end/side of a lump of job,the CORE strength of the cutter is compromised and the get out is to use a multi flute cos even if the chips don't fall away, there's no fear of Jamming. Before the screamers start whinging that two flutes ARE Ok for END milling, bits of HSS or carbide "travelling faster than a speeding bullet, Is it a car, Is it a plane???" NO, It's bl**dy sharp and could cause a vexing cut.

One point about getting the "Old" cutters resharpened is, if "Old School" at least the pedigree of the material is known.

Regards Ian.

Liger Zero
05-22-2009, 07:19 AM
4 flutes will cut oversize on a slotting operation. Use two or 3 flute then. But thats about the only time I intentionally use 2 flute mills. Usually 3 or 4.

Some of the new coatings are really nice. They allow you to cut aluminum dry without any coolant to keep it from piling up on the cutter.


Coatings... Would these coatings prevent over-aggressive ham-handed haxxzors from welding aluminum to the bit? Going through the assortment on hand I see several in this condition.

Which leads to the question... is is possible to unweld the crap on these bits and attempt to salvage them?

By the way did I mention I'm having fun here? I learned two different methods for hand-making industrial brushes this week in addition to printing an iso****ton of printable things. :) Depending on the Holiday Schedule I may attempt to make a brush at home using what I learned. Stay tuned and keep checking the police reports. :D

Evan
05-22-2009, 09:10 AM
I have never had a case of aluminum "welded" to a cutter. This may be because I routinely use cutting lube such as ethanol or "WD-40 like" fluid. Or, it may be because I rarely cut the low strength non-heat treatable alloys. I don't generally use coated cutters either in HSS or carbide. I have no reason to spend the extra money.

Duffy
05-22-2009, 01:12 PM
Since the term is "salvage" the cutters, toss them in a glass dish, (gently,) that contains a solution of lye. Drano will probably work. The important point is that the alkaline solution will not corrode the steel bits. Rinse them quick though! And before the self-styled OSHA police start to scream, dont drink it, dont put it in your eyes, and generally BE CAREFUL, and wear gloves; lye CAN cause nasty burns. Duffy