Face milling with a small mill.

[Ken from ontario]

For the past 2 days I have been using the search function here on what tools to use for face milling Aluminum and mild steel, especially when the milling machine the tool goes onto, is a mini mill.
I found out a few important points and now I'll bring them up and ask you guys to please correct me in my findings :
1= with a 1/2 HP mill, It is best to use a smaller size indexable face mill.
2= the size of the indexable face mill should not be bigger than 1.5" you may get away with a 2".
3= the best type of inserts for a small mill (which does not have a very ridgid mill head) is, TPG32.
4= the indexable face mill head should have at least 2 inserts but 3 is even easier on the machine, less vibration.
5=If possible,It's best to use a collet than an R8 EM holder , less chance of the tool vibrating .
6= Adjust your feed rate and RPM to get a chatter free operation.
Am I missing any other important point? how about using compressed air for chip evacuation? or maybe using coolant(spray?),I do have the option to use a fly cutter but find it a bit too slow,overall I'm not comfortable using it but regardless of using that option,I still want to learn which indexable face mill is best for my mill. your comments as usual are important to me and very much appreciated.

 

[ch2co]

Ken,what do you mean by its is a 'Small Mill"? What brand and model are you using?
I just have a bottom of the barrel Grizzly 8689 mini mill that came to me used but at no cost when I bought a lathe.
I'm amazed at what I can do with the little thing IF I'm careful and take my time. I do want to move up several levels
at some time for a larger table more headspace more power and greater stability. For facing I just use what came
with my mill, a fly cutter and have had good results. I do use lubricant when milling steel and just a few sprits
of WD40 at times with aluminum. I don't have a face mill so I don't know if I 'need' one.

 

[TORQUIN]

As far as size goes, first you have to decide if you need the entire face of the work piece to have a seamless cut across it, or if you can stand to have little ridges at the edges of where your smaller cutter was overlapping previous cuts. If you need seamless, you need a bigger cutter. Adjust your speed, feed and depth of cut for this. Your worry will be if you have the rigidity in the machine you are using, but most of the time you can compensate for this with the slower feed and smaller DOC.
While I have a Bridgeport, it is only 1hp, and when I need to face something big I use a big cutter. The biggest I normally use is a 6" with 10 inserts in it. I run it slow with slow feed and small depth of cut. I have had no problems getting a nice, seamless finish on the parts I had to face like this. It has not caused a problem with the mill of the parts.



I have a 10" cutter also, if I ever need to face something that big.

Chris

 

[Ken from ontario]

Ken,what do you mean by its is a 'Small Mill"? What brand and model are you using?
I just have a bottom of the barrel Grizzly 8689 mini mill that came to me used but at no cost when I bought a lathe.
I'm amazed at what I can do with the little thing IF I'm careful and take my time. I do want to move up several levels
at some time for a larger table more headspace more power and greater stability. For facing I just use what came
with my mill, a fly cutter and have had good results. I do use lubricant when milling steel and just a few sprits
of WD40 at times with aluminum. I don't have a face mill so I don't know if I 'need' one.

Hi CH2co, The mill I have is LMS 3960 mini mill,is has a brushless motor and higher torque than the classic motor , I'm quite happy with it and you're right it can handle quite a bit for it's size.
For facing Aluminum I usually use the largest end mill I have (7/8") but as you can imagine , it get tedious facing a let's say 3"x6" plate with such a small end mill (going back and forth ) , I thought an indexable end mill/ face mill could do that surface in a fraction of the time .
I have not tried my fly cutter with this mini mill yet.

 

[Ken from ontario]

Chris, now that's a nice size cutter.
you mentioned if I could stand those ridges an end mill would leave,the truth is I can't stand them, and I get plenty of them ridges currently with my the end mill I use.
BTW, I would love to own a Bridgeport even if it came with a single horsepower.

 

[mikey]

I would use a flycutter, Ken. I have a Tormach Superfly and it works okay. I also have a Sherline inserted carbide flycutter that I use on my Sherline mill and my RF-31; it is only a bit over 1" OD so bigger pieces have overlap marks but if the mill is trammed well, they are visible but not palpable. Finish with that single insert is excellent; I get a near mirror finish in aluminum while running at max speed of 2800 rpm. It also cuts to a shoulder so I can make ledges with it. Because it holds only one insert, I don't have issues with getting other inserts to line up. I can take a 0.020" deep cut in steel without slowing the motor down at all. That little Sherline cutter is one of my most useful tools.

 

[Ken from ontario]

Mike, the fly cutter I have comes with 3 bits,2 of them are carbide, one is HSS,I'll give the HSS a try, I just have to grind the cutting edge and get it ready.
I'll let you know how it turns out.
Thanks.

 

[Bob Korves]

An ordinary cheap or shop made fly cutter with a sharp HSS lathe style tool will work beautifully doing light cuts in aluminum or mild steel on a light mill.

 

[Ken from ontario]

I guess I wasn't clear in my original post about what I'm trying to find out , I should not have mentioned the option of using a fly cutter since it has nothing to do with what I was asking, I'm sorry for causing the confusion.
Anyhow I figured it out myself and found out the answers to my questions right here on this site.

All I wanted to know was what was the biggest end mill I could use with a small mill, an end mill bigger than the widest in my set which is a 7/8", I am limited in choosing the size, can not go too big without sacrificing RPM or feed rate so 1.1/2" is the size I finally picked, I think 1.5" is somewhere in the middle that I can be comfortable with .what I should have asked in my first post was your opinion on these two types of indexable end mills:






They both are described as (1.1/2") end mills and both are capable of face milling but which one demands less torque for face milling? My search lead me to believe that the one on the left with TPG32 inserts is more suitable for a less powerful mill because it only has 3 points touching the surface(needs less torque to operate) and also less prone to create vibration than the one on the right with APKT inserts.


If you do have any opinion on these two end mills and don't mind sharing, please do so(I.E. are they both equally capable of side milling?, or R8 vs straight shank in a collet?)I always enjoy reading about cutting tools in general but also respect your views and base many of my purchases on them .
Thank you all for your help so far.

 

[T Bredehoft]

I found one very similar to the one on the left, uses triangular inserts. Instead of a shank, has an R8 mount. My PM25 handles it nicely in steel and aluminum, I don't have the other to compare with, though, probably never will. I do not use it for side milling. Chuckle, that's what end mills are for.