best approach for face milling alum on small Rockwell mill

helmbelly · Jan 27, 2021

HI

I am a small prototyper about to buy my first face mill to cut Alum/brass/Delrin. I found a Mil-Tec 2" (45 degree) set up for $300 limited by their proprietary and spendy inserts -or I can pick up an import 2" 90 degree mill for $50 with uncoated 1604 inserts that are dirt cheap. Is there a good 45 degree small mill that uses cheap inserts?

I read that 45 will be easier on my Rockwell spindle bearings than 90.
I really like the Mil-Tec but it seems I should be take advantage of cheap inserts since I'm just a duffer. Not production.

Anyway thanks if you have a thought - just want a good clean cut on soft stuff.

EmGo · Jan 27, 2021

helmbelly said:
Anyway thanks if you have a thought - just want a good clean cut on soft stuff.

Fly cutter and a sharp piece of HSS, total cost $35 ?

ripperj · Jan 27, 2021

EmanuelGoldstein said:
Fly cutter and a sharp piece of HSS, total cost $35 ?

This /\. It’s what I did for two decades on my Rockwell. The mill doesn’t have enough power or rigidity to do much with a insert face mill. You could definitely get it to work, especially if you only put one insert in, but that defeats the purpose

Sent from my iPhone using Tapatalk Pro

Bobw · Jan 27, 2021

Here..

45 Degree Square Insert Shell Mill - MariTool

or Here.

ZCC USA FACE MILL

Both of those guys are members here, and they won't screw you.

I'd definitely go with the lead angle face mill. a SMALL one.
The lead angle helps push the cutting forces back up through
the spindle, and makes your machine perform as if it is bigger and
more rigid than it really is. Skip the 90's, only use those when
you absolutely need to.

helmbelly · Jan 27, 2021

Thanks and to RipperJ, I set out to get a Flycutter but don't like grinding tools. I work and work at it - now after some years of trying I can do a few acceptable "things" on a grinder for my lathe. I call them things bc at best they are Frankensteins. So I gave up on flycutters thinking that modern tech inserts would be so much better than an "okay" cut and being sent to the woodshed to try to pull a better grind out of my backsides.

So a face mill was supposed to be my get out the woodshed FREE CARD.

At McMaster a 2" FC is about $30 but none will take a 3/8 tool which I have on hand for my lathe. Shars sells one with 3/8 tool so I should go that way I guess. I'll have to spend an entire day to grind the darn thing!

But thanks for saving me the nearly $200 on a mis direction. THANKS

ps123 · Jan 27, 2021

Glacern has integral shank R8 45 face mills for around $150 (minus the inserts).
I use one on my Rockwell and am quite happy with it.
I would not go any larger than 2" on the Rockwell though, and mine has been "hopped up" to 1HP.

CORONA VIRUS · Jan 27, 2021

For what you are doing I would recommend a 90 degree face mill. It is more versatile. 45 degree is good for production, but it is a one hit wonder.

michiganbuck · Jan 27, 2021

Good to get a bench grinder and by hand, or make a fixture to go with the bench grinder to do sharpening rather than a grinder for your lathe. Grinding on a lathe will do much damage to the machine

Sometimes one may find that a mill cutter may run better with skipping blades/inserts so it acts like a fly cutter or to make more space between blades/inserts so speed/rpm can catch up, but is still in good balance. to do that you put a shim behind chosen blades to make them higher..you don't leave pockets empty.

helmbelly · Jan 27, 2021

I'm not sure if I understand correctly when you say "grinding on my lathe?" Maybe I was unclear- but I do use a grinder with I think a 36 and 80 grit wheels for HSS tool forming. I'm looking at a good diamond dresser (single point) to tackle the grinding for a fly cutter which is prob the best and most cost efficient approach for light removal and good finish in soft metal that I am after for prototyping. I did once try to put an angle on a HSS tool blank on my mill bc I have angle blocks. That idea lasted about 1 second and cost me an end mill.

helmbelly · Jan 27, 2021

ps123, Right I looked at that Glacern. I'm at 3/4 HP with a VFD which helps dial in a good sweet spot. My issue is when squaring stock (alum/delrin) I have to take 2-3 passes to cover the real estate which leaves me chasing the finish. I usually remove less than .125. Having never used a Fly cutter or face mill I thought a Face mill might plow right thru where a Fly cutter would be trying my patience since I hand feed. There is a very cheap asian 90 3 blade insert face mill I might pick up just to see what it does. But I've made my mind up to get the Shars FC just bc it takes a 3/8 bit. I'm going to get a better grinding wheel and dress it real flat. I think my grinding is being effected by not dressing the wheel more diligently. And also a bit because I suck.

Hey do you know where to get a good 1HP motor for a Rock?

ps123 · Jan 27, 2021

@helmbelly: I managed to find a Baldor washdown motor with an extra large/long shaft on ebay and had to disassemble and turn down the shaft to size. The original motor on these has an unusally long shaft for its size so you are unlikely to find an exact replacement. The motor I got is also 6 pole 1200 RPM which gives it more low end grunt.

richard newman · Jan 27, 2021

Whether you get a facemill or not, I think it would be a good idea to learn how to hand grind hss tools, especially as you also have a lathe. Not sure how you've gone about it in the past, but there are all sorts of resources out there. The SouthBend book on how to run a lathe has good info. Do you have good quality wheels on your grinder? If it's an inexpensive import, they usually come with crappy really hard wheels.

I'm no expert, just a wooodworker who drifted into metal machining to make jigs, tool, and rebuiild machines. I find it absolutely necessary to be able to grind tools offhand.

L Vanice · Jan 27, 2021

I bought my Rockwell vertical mill new in 1974 and still use flycutters frequently. I use brazed carbide tool bits in them, mostly 1/4" but have some other sizes. The brazed tools are sharp and ready to use when you get them. After some use, they can be sharpened or the radius modified by grinding with a diamond wheel and one bit may last for years before the carbide is gone.

I have APT brand lathe tools with 1/4, 3/8 and 1/2" shanks that use TPG or TPU 221 or 222 inserts and use them in my lathes rather than in the flycutters. The diamond wheels can sharpen these inserts to get more use out of them. Maybe 40 years ago, I bought a couple hundred of these inserts for about $1 each and am still using them.

Maybe 25 years ago, I did buy an expensive APT brand R8 shank 2" or 3" face mill that uses three inexpensive TPG or TPU 321 or 322 inserts. Tried it a couple times and went back to flycutters.

Larry

michiganbuck · Jan 27, 2021

helmbelly said:
I'm not sure if I understand correctly when you say "grinding on my lathe?" Maybe I was unclear- but I do use a grinder with I think a 36 and 80 grit wheels for HSS tool forming. I'm looking at a good diamond dresser (single point) to tackle the grinding for a fly cutter which is prob the best and most cost efficient approach for light removal and good finish in soft metal that I am after for prototyping. I did once try to put an angle on a HSS tool blank on my mill bc I have angle blocks. That idea lasted about 1 second and cost me an end mill.

Sorry but I thought you mentioned a grinder for a lathe, might have been someone other than you.
Fly cutters sometimes give the appearance of a great finish, because the light reflection and lines are even but then with a profilometer check, may check not better. No, I'm not knocking fly cutters as have often used them. a small with clearance flat or a radius often makes the finish better

helmbelly · Jan 27, 2021

I could not agree more, I grind a lot but my learning curve does not keep pace with my needs! I made a grinding bench at the far end of shop kinda tucked away. It has 3 grinders tactically laid out for access and also a nice old Shopsmith belt sander thats built like a lathe. Grinder 1 is very old belt drive I restored. it's low power but with very stout tool rests. Got a green wheel for Alum and a scotchbrite deburring wheel on that antique. I have a wire wheel and buffer beside that on an old Thermotron AC motor that runs like a top. Next over an 8" bigbox POS and i can't recall whats on there for wheels but I think 36 and 80. I wall mounted a nice little 5" McGraw Edison for quick deburring between drill press and lathe.

I've spent hours reading and watchign youtubes and just making things I have to have. I can make serviceable lathe tools but the bits I buy cut cleaner than the ones I grind. They just do. I figure at 5-10 bucks a pop for an insert, it makes way more sense to go that route. That said I would prefer to rely on my own skills- of I had them. I'm buying a good diamond dresser and a new white wheel today. Maybe it's the tools not the craftsman after all. (hard swallow)

Got two 3/8 M2 HSS blanks in my drawer to get ready for this Flycutter.

helmbelly · Jan 27, 2021

L Vanice, wow thats super helpful. At Macmaster they dont sell factory made bits for a fly cutter - only blanks. I love brazed tools for my lathe. I'll google up flycutter bits again - I was having trouble finding them.

I just got my Rockwell vertical last year and love it, I do light work and its very accurate. I paid 3K for it and I know that is too much but its what i wanted in cream puff shape and for the amount I use it now - the money dont matter. I have not pulled trigger on Shars 3/8 fly cutter i may wait and get a 1/4 version if I find the right brazed bits.

crossthread · Jan 27, 2021

"Got a green wheel for Alum and a scotchbrite deburring wheel on that antique."

I don't think you should be using a green wheel for aluminum.

helmbelly · Jan 27, 2021

HOLD THE PHONE will just a left hand lathe cutting tool work in a Flycutter? I just saw a photo online that looks like that's what they are using.
I also see people are using round ended lathe tools. I guess I'll just have to mount it up and try some cuts with brazed lathe tools. Also I did not realize the geometry was nearly the same as a lathe - the motion seems diff somehow. But if their using lathe tools ....

helmbelly · Jan 27, 2021

Crossthread, I went green (silicon carbide)based on Norton's literature. It's been working well for a couple years. I only use it for brass and alum

DDoug · Jan 27, 2021

helmbelly said:
HOLD THE PHONE will just a left hand lathe cutting tool work in a Flycutter? I just saw a photo online that looks like that's what they are using.
I also see people are using round ended lathe tools. I guess I'll just have to mount it up and try some cuts with brazed lathe tools. Also I did not realize the geometry was nearly the same as a lathe - the motion seems diff somehow. But if their using lathe tools ....

You really, really need to read & understand what cutting tool angles & clearances are.

Then you can grind up a tool that will work, or pick one out of a line up, which
one will doo what you need.

best approach for face milling alum on small Rockwell mill

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