CCMT recycle face mills

[whateg0]

Like many, I have a bucket (ok, just a small can) of used CCMT inserts. I regrind them as needed,usually just when I need a sharp edge for finish passes. That still only uses 2 of the corners. I know there are other inserts that use all of the corners like the trigons, but per cutting edge, these ccmt usually still cost less.

So, I've long thought of finding ways to use the other corners. Then I see that Adam Booth (I think it was him) was using a face mill that uses the other corners. Look online and they aren't cheap. I'll go through a lot of other inserts before that face mill would pay for itself. I also read other pages where people say that using the other corners produces a bad finish and it's a waste of time. Has anybody here used these?

Dave

[rklopp]

I have Dorian’s take on this kind of face mill that I use on a manual mill. It has a 3/4” Weldon shank instead of a real face mill arbor mount, so the rigidity is not what it could be but good enough for surfacing aluminum in a manual mill. I only use it with polished high-positive inserts meant for aluminum. I use “normal” face mills in the CNC.


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[BadDog]

If your lathe can run them, and you do a lot of steel as I do, CNMG is nearly impossible to beat on cost per corner, plus great deals are plentiful. Years back I bought a box lot of CNMG at a sell-off auction, something like 40 lbs of premium brands, more than I'll ever use. Edges come out to literal pennies each, so that is my go to insert for most things unless unacceptable for some reason. You get 4 cutting edges, and at the price, it's a real bargain.

But I grew up dirt poor (literally single wide trailer on a dirt road in N AL), so I can't stand wasting anything. I've got the meter pegged on "cheap", so I still hated throwing away 4 perfectly good edges.

So I found a "heavy roughing" insert holder from Kennametal (IIRC?) that uses the obtuse corners. Very happy with it. When I have something horrible, I use that one, and it really takes a beating. Stuff like chilled casting skin, rust, scale, heavy interrupted cuts (like Dana 44 front hub I turned down to repurpose, cutting through lug holes), and even cutting off hardened splines on axle shafts (again, repurpose). Stuff like that ruins edges fast, but this obtuse point holds up better than the acute point, AND it lets me use from that can of what would have otherwise been thrown away anyway. That resulting heavy lead angle also makes a handy outside chamfer edge between the points if you don't need a 45 (for which I"ve got an SNMG, but hey, save that edge if not needed).

That holder makes a great addition to the other 4 normal orientation (different presentation) holders I have, and using that one seems to have reached a sort of equilibrium so my pile of discards with 4 good edges has remained pretty stable for the last few years.

[whateg0]

My lathe would happily run negative rake tools, but I generally don't. I guess no real reason other than I don't mind taking lighter cuts, which is why I regrind a bunch of these. With the wear in the cross-slide I couldn't take heavy cuts anyway or the whole thing would tip. Boring and parting has always been a pita because of that. I'm in the process of swapping the carriage with a better one now. It won't be perfect, and the rest of the 10ee is far from perfect anyway, but it should be an improvement. Maybe then I'll try something else.

I'm already planning to make a chamfering tool to get 45 degrees from these inserts. I do a lot of my chamfering with DCMT, but it's not 45. Most people won't notice. The issue I have with them is that the holder sticks out in the way. So, a dedicated chamfering tool would be better. I did buy some SNMG inserts to use for chamfering but never have gotten around to making a holder.

So, if that obtuse edge holds up better on the lathe, it should hold up better on the facemill as well. The TPG inserts don't seem to last very long facing steel. Maybe it's me. Maybe I'm not running at the right speed. I dunno. I would rather use inserts I already have, though, than keep buying the TPG inserts that I don't use for anything else.

Dave

[BadDog]

Yes, I do feel like the roughing tool I'm using for that obtuse angle holds up to the abuse better.

However, I haven't seen or done a side by side comparison or any supporting documentation other than the general position that wider angle points hold up better than more acute angles. After all, that's the whole claim to fame of the popular trigon. But it could be just confirmation bias with me wanting to be pleased with my holder purchase AND using those previously wasted points (K&N Fallacy) Whatever the reality, I'm pleased with it.

Good luck on your 10ee. I would love to add one of those to the collection, but room and cost just doesn't compute for my needs.

[liveaboard]

cutting off hardened splines on axle shafts (again, repurpose). Stuff like that ruins edges fast,

I had this problem; some automotive gears I repurposed were so hard, I couldn't get through with carbide.

Simple solution; anneal it. Just heat it red, then let it cool. It's still pretty hard [hard enough for my purpose] but quite civilized and machinable. Weldable too.

Sometimes you can heat just the area you want to cut and leave the rest, like splined shafts for instance.

[platypus20]

I bought the 2 lathe tools, that use the normally unused edges on CCMT inserts, SCBCR and SCKCR (Tormach #35647 and #35644, from LMS). Because I hated to throw half sharp inserts, I have not seen a face mill that uses CCMT inserts.

[whateg0]

https://www.kbctools.com/itemdetail/1-286A-090

The only pic I've found was in another forum.

Dave

[platypus20]

Thats face mill uses CNMG inserts, the OP, originally asked about CCMT inserts

[whateg0]

I do know what I asked, since it's in the title. I googled for ccmt recycle face mill and that was one of the results. I failed to notice the insert shape was different. It would probably still work, though the insert has less support since the walls would be straight instead of 7 degrees. I just realized that the bigger issue in anything commercially available is that they are probably all going to be for 3/8" IC instead of the 1/4" IC I use. I may just have to make one myself. Worth it? Probably not, but that doesn't tend to stop me.

Dave

[BadDog]

I had this problem; some automotive gears I repurposed were so hard, I couldn't get through with carbide.

Yeah, the one I did was broken in the spline only leaving a little to remove (something less than ~0.200), and it beat the crap out of the insert. But it was able to get it done without annealing, and I counted the insert a freebie since I was using what normally would already be in the trash. They are induction hardened, so once you get a little below the spline they are quite nice to machine. I've also repurposed shafts out of broken transmissions (I literally broke a T-350 K case like cracking an egg for an omelet), which don't seem nearly as hard as the splines on axle shafts. They are hard, but not wreck an insert in less than 30 seconds hard. In fact, most of the shafting/rods from automatic transmissions are really nice high quality free machining steel. I haven't tried to modify the gears. Given their engineered slip-wear in use function, I would expect them to have an even higher surface hardness than splines, which are generally designed more for fixed position (minimal sliding in load) torque shock loading. Shock rods for large HD truck shocks also machine very nicely once you get below the hard chrome.

[SteveM]

I just bought a toolholder that uses CCMT and presents the 80 degree edge pointed straight out.

I figure with some minor milling on the sides of the pocket, I could get the insert to seat 90 degrees and have the 110 degree side facing out.

I just have to do some geometry and trigonometry, which luckily was my best subject in high school.

Steve