Face mill for a bridgeport

I am looking at getting a new face mill for my bridgeport and I was looking at the 2.5" "freedom cutter" from Mil-Tec. It's a 4 insert cutter that will take octagonal, square, or circular inserts (GP, NP, PS, SS, and SA geometries).

MIL-TEC USA Products

Most of what I use for tooling is high Cobalt HSS and it works great for most things i need, however I am sick of fighting with fly cutters and it looks like this will take care of 90% of what I use a fly cutter for.

Does anybody have any experience with this face mill from Mil-Tec, or any general comments on the inserts that it uses?

Ethan

I happened to have been given a nice Ø2-1/2" Widia cutter, and bought the R-8 shell mill adapter for it from Lovejoy Tool down the road from you in Springfield.



It's turned out to be a fantastic cutter, taking on everything I've thrown at it with aplomb. The chips on it are from 954 aluminum bronze, but I've just as easily milled hardened steel tool holders and other tough stuff. I've yet to rotate the inserts, but they're getting close. The high-shear angle and 45º lead angle work exceptionally well to keep loads light on the 1HP Bridgeport motor while still being capable of heavy cuts or light finishing.

I'm running a SEHN43 AFTSN in the now-obsolete Valenite SM245 grade, but they still offer the same insert in a newer 5142 grade.

I don't know much about the "Freedom Cutters" from Mil-Tec other than that the name sounds corny and I'd wonder where the inserts come from. You have Lovejoy Tool down in Springfield offering a nice cutter, why not call them and see what they can do to compete with the Mil-Tec and support your fellow Vermonters?

229 Series Face Mills

You can get a kit of cutter, 10 inserts, wrench, spare screws, etc from Lovejoy for a fair price (and don't be bashful about telling them you're considering the Mil-Tec), but later on you can get replacement inserts from a number of different sources as they are ANSI/ISO standard SPEX/SPEW/SPET 32.5x style. I like that their little Ø2-1/2" cutter take 6 inserts, allowing you to get nice finishes with a decent feed rate.

I'm not sold on the "interchangeable insert" style of cutter. I can't see where the inserts would be securely seated. That matters a lot when it comes to process stability and tool life. There's not much in the way of detail on the Mil-Tec site.

My last job had lots of cutters from Miltec. They kick ass and take names. One cutter body can do many things with different inserts. The bodies are not hardened (something to do with harmonics said the guy who started Miltec when I asked why), but if used properly that won't be an issue. And the last time I bought inserts they were made in the U.S.A.

We have a three tooth cutter at work like the one Pixman has. Ours is integral R-8 shank, but it otherwise nearly identical. We had nothing but chinese 3hp Bport copies for the first couple of years I was there. When it came to moving stock out of the way, this was the tool of choice. You can literally bury it as deep as the inserts will cut in the work, crank as fast as you can running about 700rpm and it just slings chips everywhere. Would never have believed it had I not tried it myself. Very impressive metal removal rates for a Bport type machine.


Anything of larger diameter, or with a straight tooth profile is asking for chatter on a Bport. I agree, the high shear inserts and 45 degree lead is what makes this work so well.

That is useful to know. I have a 2-1/2 diameter shell holder with inserts for the horizontal and it works great (40 taper).

I've thought about getting one with R-8 shank for the vertical (Taiwan 8 x 30) but figured it would be too much for a small vertical mill. The main application would be smoothing welds, is that an unreasonable expectation ?

Cheers,
Randy C

These 45 degree lead mills mow down weld like it's cheese. I am not at all a fan of the Birdgeport type machines, and would not have believed you could run a mill this hard in one without it chattering and/or stalling. I think one big factor is that the cutter is practically pulled up to the spindle nose. There is VERY little overhang. Also a disclaimer... I run a Bridgeport with the quill fully retracted and locked down for this type work, feeding up with the knee.

At work I use a 5-insert cutter with integral R8 shank from Ingersoll tools. It's quite similar to what Pixman showed, but with inserts with holes in the middle (can't remember the type). Really, they are beautiful things, the 45 degree lead combined with the aggressive rake and minimal overhang. Definitely my facemill of choice.

Mike C. said:

I run a Bridgeport with the quill fully retracted and locked down for this type work, feeding up with the knee.

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As any operator should. Roughing hard with the quill extended is abuse of the machine.

I have used Miltec cutters almost exclusivly for 15 years .
The PS inserts are great for lower horsepower machines .
McMaster carries inserts if you need them fast .
I found out a while ago that the 8 sided inserts cost about the same as the square ones .
About $13 each . So half price per corner is a good thing .
I don't know about the round ones though .
I have a 3" freedom cutter , an 1 1/4" 2 insert cutter , and a 2" 45degree cutter ,
The 2 smaller ones in a 3/4" shanks . These fill almost all my milling needs and get swapped between the CNC and BP .
As a bonus I discovered that the square inserts can easily be reused on several boring bars
I made ( easy to mill a sq pocket on the BP ).
Just mill half the bore bar away , plus .177" thickness of the insert for the seat ,
McMaster has the special screws , but you have to call to get the part number.
Inserts are SPG type so there is clearence built in the sides . Top clearence on the PS is provided by a dished grind on the top surface .
TIALN coating runs best dry , and make sure to feed agressivly to maintain a heavy chip load .
It took me a while to get optimum life out of the cutters until I believed the advice to run dry and heavy !
See if your distributer offers the Miltec madness sale : $10 per inch dia for the body IF you buy 3 packs of inserts . Lotsa moola up front , but a good deal if you use them up .
PIXMAN : that does look like a great cutter and I admit the insert mounting clamps are a lot more robust on the Widea .
It is true that the MT cutter has a bit of a propriartary insert , but they are made in Florida USA
FBBob

That's a good cutter and a Bridgeport is a good milling machine but the cutter is capable of about 12 x more depth of cut than the Bridgrport can handle. No fault on either side but you have to consider the BP's limitations.

The cutter if mounted in a machine with an honest #40 MMT keyed drive spindle could run mild steel at 500 ft/min 0.3 depth of cut and 0.008 feed per tooth. In a BP other things being equal, you can expect about 0.025 depth of cut. That's the way it is with an R8 spindle. With no positive drive they are torque limited by the tension on the taper. In a BP a carbide face mill is a skim cutter. Real stock removal takes lot of passes.

By the way, if you haven't already, remove the 1/4-32 collet index pin from your BP spindle. If you run this cutter to ratings you may very well spin the cutter in the spndle.

Miltec rocks

I have several Miltec cutters with an assortment of inserts, and they work very well.

And they're American made.

- Leigh

"The cutter if mounted in a machine with an honest #40 MMT keyed drive spindle could run mild steel at 500 ft/min 0.3 depth of cut and 0.008 feed per tooth. In a BP other things being equal, you can expect about 0.025 depth of cut."

That's exactly what I thought, too Forrest. I fired it up, droped it full depth, giggled and laid into the crank. My jaw fell open as it just cruised through a hunk of mild steel like it was plastic. This thing will take ten times that depth of cut (.250) in a cheap, worn out chinese 3hp Bridgeport copy with ease. Only reason it won't go deeper as that's all the cutting edge you have before getting into the body of the cutter. Plenty of power left. The servo type powerfeed died on that mill, so I have no idea what exact feed rate I was running, but it was about a rev per second on the crank. Estimate 12" per minute, but that's an approximation.

Halcohead, I started with a VN6, so it only made sense to me to mill with the quill of a Bridgeport type up and locked. Only exception to this is my VN 2G bridge mill, which has a rough adjustment of 8" range by moving the head and a fine adjustment via a quill with 6" travel, that quill is huge, though (almost 6" in diam). One thing I wish mills with quills had, and that is a clamp of some type to bind the spindle spline to the pulley so it doesn't rattle under heavy cuts. I think the rattling spline really contributes to chatter in some circumstances.

Forrest apparently you have not used one of these type cutters,.125 deep,25- 30 ipm,750 1000rpms,ur B.port becomes a mini B.mil.

My Anilam readouts shows feedrate as well as location,a blessing for a chip load per tooth guy.
Respect
Gw

I have also been VERY surprised at how much of a depth of cut and how hard I can push the feed rate with the 45º lead/high shear face mills.

I am well-aware that the cutter I have would be more at home on a 10 to 15 HP machine than a 1 HP Bridgeport. I do expect there to one day be at least a 7.5HP CNC in the shop, and I'm well prepared for that day.

My preference is to use (when practical) cutters that take ANSI/ISO standard inserts. This has afforded me to stock some pretty good inserts in a wide variety of grades & geometry when the deals some up. I have everything from those "general purpose" to shiny upsharp edge for aluminum. I haven't paid more than $4 an insert yet. Heck, if I had the speed and volume of work to justify it, I could even get PCD inserts.

I'm sure the Mil-Tec product is good, it's just not for me. The "Freedom" cutter with it's interchangeable shapes is going to be good for some home shops. If I were tooling up a commercial shop and productivity was important, I'd be going with the bigger name-brand stuff to get the research and development of grades and coatings that a tiny company like Mil-Tec doesn't afford.

Productivity of a milling cutter is measured in cubic inches or millimeters per hour. That includes a balance of tool life, insert change time, and overall cost of tooling for the amount of material removed in a given time. I'm sorry, but I just can't believe a Mil-Tec cutter would ever be competitive with task-specific cutters developed with complete research and extensive testing.

Of course, even with the money behind them, the big companies have put out some real dogs too.

BTW Forrest, I have never spun a tool in the Bridgeport, and the pin is definitely staying in there. I prefer to have it there.

PixMan, You suggest staying local and that's just what I'm doing. When I was talking to Ken at Springfield Tool he wasn't able to get any of the parts for that old Valenite I got my hands on and he suggested that I pick up one of these from them with the R8 shank and a set of inserts for $175 or so. As far as I've seen, that's a kick-ass price for any sort of face mill and I figured so long as nobody has anything bad to say about it I'll pick one up.

As far as insert retention is concerned, I assumed that the octagons and the squares were the same size and as such they would locate on the edges of a square pocket, while the circular inserts simply need to be centered around the lock screw... Without actually seeing one that's just a guess, but am I far off?

And Forrest, I'm with PixMan on keeping the pin in the bridgeport, I'd rather stall the mill than gall up the taper any day.

Clews Machining said:

PixMan, You suggest staying local and that's just what I'm doing. When I was talking to Ken at Springfield Tool he wasn't able to get any of the parts for that old Valenite I got my hands on and he suggested that I pick up one of these from them with the R8 shank and a set of inserts for $175 or so. As far as I've seen, that's a kick-ass price for any sort of face mill and I figured so long as nobody has anything bad to say about it I'll pick one up.

<snip>

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Ken Millay @ Springfield Tool Supply is a good friend of mine, THANK YOU for doing business with him!

So which cutter & inserts are you going with after all? I assume it's the Mil-Tec Freedom cutter.

charlie gary said:

The bodies are not hardened
(something to do with harmonics said the guy who started Miltec when I asked why).

Click to expand...

Harmonics?, man that's called cost savings in my world, nothing to do with harmonics. Sorry but I couldn't miss that. I agree with Pixman that SEKN style is the way to go, high positive insert that will work in all type of materials at low cost due its an AISI standard insert easy to find everywere and with multiple grades.

PixMan said:

I happened to have been given a nice Ø2-1/2" Widia cutter, and bought the R-8 shell mill adapter for it from Lovejoy Tool down the road from you in Springfield.

It's turned out to be a fantastic cutter, taking on everything I've thrown at it with aplomb. The chips on it are from 954 aluminum bronze, but I've just as easily milled hardened steel tool holders and other tough stuff. I've yet to rotate the inserts, but they're getting close. The high-shear angle and 45º lead angle work exceptionally well to keep loads light on the 1HP Bridgeport motor while still being capable of heavy cuts or light finishing.

I'm running a SEHN43 AFTSN in the now-obsolete Valenite SM245 grade, but they still offer the same insert in a newer 5142 grade.

I don't know much about the "Freedom Cutters" from Mil-Tec other than that the name sounds corny and I'd wonder where the inserts come from. You have Lovejoy Tool down in Springfield offering a nice cutter, why not call them and see what they can do to compete with the Mil-Tec and support your fellow Vermonters?

229 Series Face Mills

You can get a kit of cutter, 10 inserts, wrench, spare screws, etc from Lovejoy for a fair price (and don't be bashful about telling them you're considering the Mil-Tec), but later on you can get replacement inserts from a number of different sources as they are ANSI/ISO standard SPEX/SPEW/SPET 32.5x style. I like that their little Ø2-1/2" cutter take 6 inserts, allowing you to get nice finishes with a decent feed rate.

I'm not sold on the "interchangeable insert" style of cutter. I can't see where the inserts would be securely seated. That matters a lot when it comes to process stability and tool life. There's not much in the way of detail on the Mil-Tec site.

Click to expand...

I just bought a 80mm face mill with similar inserts. The top is completely flat while the sides are angled, square but with angled corners. I have no idea what the insert is called but it's about 16mm in diameter each. Mine has 5 inserts. When I bought it (I paid 15 dollars for this including NT40 arbor) 2 of the inserts, wedge clamp, and carbide pad was missing. The screw for one of the carbide pad was broken inside and the pad missing. I ended up buying replacement parts (which cost the same as what I paid for this cutter) and tried to just wedge the insert in with the pads... well it came loose during use (cutting 3mm of Chrome Moly steel) so I brazed it in so it would not come loose (the insert itself is not brazed in, just the pad so it doesn't come loose).

My mill takes NT40 cutter, not built at all like a Bridgeport Series 1 at all but more like a heavier machine even though the table length is the same as a Bridgeport. When I cut 3mm of chrome moly with this the mill shakes like crazy and the mount for the vise looks like it could come off anytime. But I cut at about 400 RPM which I think may be too low. When I tried to cut aluminum at 700RPM the cut quality was terrible and then one of the insert took a huge bite and came off (it broke one corner), that was when I decided to braze the pad in (the screw hole had a piece of the original screw stuck in it). When I made the same aluminum cut, DOC 3mm and at 3000 RPM the machine cut much smoother and the cut quality was vastly improved.

if youre talking to Ken in Springfield Vt ask him about Lovejoy Tools facemills running on a bport type of machine. octagon inserts for 8 edges, very high rake and hold up well. Lovejoy is in Springfield as well. Lovejoy also makes indexable emills and other things, their tooling has always been great for me.

This is some hard core necroposting.

Forrest Addy said:

That's a good cutter and a Bridgeport is a good milling machine but the cutter is capable of about 12 x more depth of cut than the Bridgrport can handle. No fault on either side but you have to consider the BP's limitations.

The cutter if mounted in a machine with an honest #40 MMT keyed drive spindle could run mild steel at 500 ft/min 0.3 depth of cut and 0.008 feed per tooth. In a BP other things being equal, you can expect about 0.025 depth of cut. That's the way it is with an R8 spindle. With no positive drive they are torque limited by the tension on the taper. In a BP a carbide face mill is a skim cutter. Real stock removal takes lot of passes.

By the way, if you haven't already, remove the 1/4-32 collet index pin from your BP spindle. If you run this cutter to ratings you may very well spin the cutter in the spndle.

Click to expand...

I was taking a .200 depth of cut yesterday on a small Bridgeport with a 4 tooth facemill with SEAN inserts. Both off of Amazon. Worked like a dream on steel. Lead angle makes all the difference