# Problem parting aluminum with a mill



## TXShelbyman (Jun 3, 2017)

I used my Rong Fu 45 clone to part off a piece of 1/4" aluminum angle and had issues with my end mill collecting aluminum. It is a cheap 3/16 4 flute HF end mill. It looked like the aluminum was sticking to the end mill and building up. It would eventually quit milling. I would take it out and use my machinist scale to pop the aluminum out and the end mill would cut again. It worked great facing the edge, but not parting off a section. I was running the mill @ 1180 rpm and hand feeding. Am I doing something wrong? Thanks!


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## 4GSR (Jun 3, 2017)

Change to a two flute end mill.  Four flute end mills are not made for milling aluminum.  Use a cutting fluid, too.  That should help keep the aluminum from building up on the flutes of an end mill.


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## kd4gij (Jun 3, 2017)

WD40 will be your friend for this


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## Tony Wells (Jun 4, 2017)

Lube and speed things up. That's a little slow for a 3/16" end mill. But the main thing to prevent or lessen chip welding is lube. If you have to do it dry, keep a constant air jet in the cut to keep it clear of chips. That will help a great deal.


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## celtic1522 (Jun 4, 2017)

CRC 556 or WD 40 is good, anything with Teflon in it works well. Cutter must be sharp and keep feeding the cutter into the material. Too much speed is as bad as too little I find, both cause addhesion to the cutter.


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## T Bredehoft (Jun 4, 2017)

I've found that rubbing alcohol works well. Little if any adhesion and zero residue. But only on aluminum.


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## TXShelbyman (Jun 4, 2017)

Thanks! I will try some lube and see what happens.


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## Wreck™Wreck (Jun 5, 2017)

4gsr said:


> Change to a two flute end mill.  Four flute end mills are not made for milling aluminum.  Use a cutting fluid, too.  That should help keep the aluminum from building up on the flutes of an end mill.


A 4 flute endmill will work fine in aluminum it is merely slower, the number of flutes is unrelated to the built up edge problem, only coolant or cutting fluid will solve that, coatings, climb milling and speed will also help. I suspect that the OP may be working with 6063 alloy readily available in hardware stores, this material will glue itself to anything without coolant, very difficult to machine.


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## TXShelbyman (Jun 5, 2017)

You suspect right Wreck. It was angle purchased at the local hardware store. My little mill tops out at 1970 rpm and that would be  giving her all she's got. I will go up from 1180 and add some cutting fluid. Thanks again!


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## tweinke (Jun 5, 2017)

Same experience here with hardware store aluminum. Seems to be a toss up too, some cuts nice some terrible. WD40 works about as well as anything but speeds and feeds appear to be a narrow window between works and don't.


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## BROCKWOOD (Jun 5, 2017)

I bought some aluminum rounds off eBay & haven't worked with aluminum yet.  Most excellent suggestions that I'm sure to be trying myself in the near future!


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## Rockytime (Jun 7, 2017)

I use auto trans fluid for cutting everything including aluminum. That includes milling, turning, drilling, parting, tapping and threading. It's cheap and it works really well.


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## sabb0 (Jun 8, 2017)

Ive always had success using kero or watered down metho on aluminium.

Sent from my SM-G920I using Tapatalk


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## Ebel440 (Jun 8, 2017)

6063  is always gummy. It's an alloy made for forming and as a result is soft. The end mill most likely has begun welding to the aluminum and will never really come off completely. The aluminum will keep sticking.  You could use it to cut some steel which will help clean it off. Best to use a new sharp end mill if you are going to continue cutting the 6063.


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## Wreck™Wreck (Jun 8, 2017)

TXShelbyman said:


> You suspect right Wreck. It was angle purchased at the local hardware store. My little mill tops out at 1970 rpm and that would be  giving her all she's got. I will go up from 1180 and add some cutting fluid. Thanks again!


Try not to buy aluminum stock that does not have the mill info printed on it as you will have no idea what alloy or condition it is in, often the material that is available in hardware stores for homeowner use is unmarked and is often 6063. One thing that I have noticed in 30+ years in the machining business is that 6063 structural shapes have sharp corners, commercially available shapes almost always have generous radii at the corners but not *always*.

One of last weeks jobs, drilling the OD of an aluminum disk cut from plate, the mill info is clearly visible, manufacturer, alloy, temper, thickness and heat# in red.


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## TXShelbyman (Jun 10, 2017)

Wreck™Wreck said:


> One of last weeks jobs, drilling the OD of an aluminum disk cut from plate, the mill info is clearly visible, manufacturer, alloy, temper, thickness and heat# in red.



Geezzzz!  That is quite a slab of aluminum!


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## Wreck™Wreck (Jun 11, 2017)

35" OD X 1 1/2" thickness, 135 pounds or so, the tapped hole is for a lifting eye that will greatly ease the lathe operations to follow , fortunately for me I can only swing 34" so it is being farmed out to another shop with a HBM.


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## markba633csi (Jun 11, 2017)

ImPRESSive drill press you got there
Mark S.


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## Wreck™Wreck (Jun 11, 2017)

markba633csi said:


> ImPRESSive drill press you got there
> Mark S.


Thanks, unpleasant would be a better description however, it is frightening in many ways.

Not intimidated by old machines so I have that going for me, we have an old Morrison Keyseater that causes a feeling of dread every time I have to run a job with it.


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## markba633csi (Jun 11, 2017)

LOL that sounds like an interesting side-story... 
Mark S.


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## benmychree (Jun 11, 2017)

sabb0 said:


> Ive always had success using kero or watered down metho on aluminium.
> 
> Sent from my SM-G920I using Tapatalk


Kerosene is the old stand by for aluminum; use deodorized kero. to avoid the stink; likely cheaper than WD40 or other similar substances; Tapfree also works well.


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## Wreck™Wreck (Jun 12, 2017)

markba633csi said:


> LOL that sounds like an interesting side-story...
> Mark S.


A keyseater is just a shaper with a round vertical ram/arbor that holds the cutting tool for the keyseat, place the bored hole over the arbor and clamp in position. The arbor moves up and down and the table advances the work at a set feed rate until the desired depth is reached, it is difficult to measure the seat depth without removing the part from the machine because the arbor is in the way. They work a charm yet are set up intensive, it would take me nearly one hour to set up a 1/4" square keyway in a 1" bore and roughly 5 minutes to cut it.

They are however indispensable when the keyway is longer then a simple push broach can handle and way cheaper then pull broaches and their required equipment.

As seen here, this is some sloppy work as the part is not securely clamped it can be seen moving around.

The feed mechanism is also decidedly old school, ratchet and pawl on the handwheel, some may find this "charming" I merely find it annoying and unpredictable.


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## benmychree (Jun 12, 2017)

In my shop, I had a Mitts & Merrill keyseater, the next to the smallest model which can cut up to a 1-1/4" keyseat 12" through the bore; not a bit like the Morrison, a single tooth cutter is pulled through a slot in the post that the work is mounted on and there is a wedge behind the cutter that both relieves the cut on the up stroke and feeds the cutter out at each subsequent cut; one cranks the feed out until a small chip is removed at each side of the cutter, then a scale is set to zero with an indicating arrow, then a hard stop is set and the ratchet pick set at whatever feed is appropriate and start and run until finished depth is reached.  Nowadays, I have broaches for ordinary work and a 6" Pratt & Whitney vertical shaper (slotter) and a slotting attachment for my B&S mill AND, I can still go back to my old shop and use the Mitts & Merrill if need be.
Since the cutter rides in a slot in the post of the keyseater, there can be no deflection of the bar as with the Morrison and chatter is unknown and the part being keyseated is always centered on its bore and not by its OD.


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## Wreck™Wreck (Jun 12, 2017)

benmychree said:


> In my shop, I had a Mitts & Merrill keyseater, the next to the smallest model which can cut up to a 1-1/4" keyseat 12" through the bore; not a bit like the Morrison, a single tooth cutter is pulled through a slot in the post that the work is mounted on and there is a wedge behind the cutter that both relieves the cut on the up stroke and feeds the cutter out at each subsequent cut; one cranks the feed out until a small chip is removed at each side of the cutter, then a scale is set to zero with an indicating arrow, then a hard stop is set and the ratchet pick set at whatever feed is appropriate and start and run until finished depth is reached.  Nowadays, I have broaches for ordinary work and a 6" Pratt & Whitney vertical shaper (slotter) and a slotting attachment for my B&S mill AND, I can still go back to my old shop and use the Mitts & Merrill if need be.
> Since the cutter rides in a slot in the post of the keyseater, there can be no deflection of the bar as with the Morrison and chatter is unknown and the part being keyseated is always centered on its bore and not by its OD.


Sounds like a better way to me, I hate that Morrison a good deal.


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## benmychree (Jun 12, 2017)

I think the only good point of the Morrison is that it uses tool bits for cutters, much cheaper than the M&M, but I was able to find a lot of cutters cheaply at a used machine tool dealer that I knew well, and I had bought the machine from him, knowing that as tooling came along I'd be first in line for it.  Another thing I did not mention is that the way parts are located by their bores, the ends of the part do not have to be even faced off.  The biggest models that they made could cut, I think, 4" wide keyseats 4 ft. through.  The shop that I apprenticed had one that could cut 2" wide X 24" through


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