Insert facemilsl, correct use on hardened Steel.

Nothing to regret Steve. We all learn something new everyday, and everyone has their own experience with their purchase.

Ketan at ARC.

Ha ha. No problem. Since watching your video, sparks are no longer a concern. I did set fire to a tissue sat on the tray though.

Steve.

I think Jason just posted a screenshot of my video. I do not think he put up the whole video, which I would not like uploaded, because I was potentially abusing the tool and the machine to test out Andrews theories. It was me playing with the shell mill, milling away some stainless steel I had acquired for testing from the late JS.

Ketan at ARC

Entertaining video, and turns out Steve sounds just like my Brother-in-Law!

Anyway, I think the sparks are because the inserts are rubbing as much as cutting. The polished look of the job suggests rubbing too.

Steve's Tom Senior has a ½HP motor, which is very much on the small side for driving a whopping big 5 toothed cutter through hardened steel. The depth of cut and feed rate available to Steve are well below optimum. Lack of grunt obliges a shallow cut producing small, fine swarf at high temperature. Most of the firework display is due to swarf burning, not the cutting operation. The swarf is catching fire.

If the depth of cut were increased to 1 or 2mm then the improved cut to rub ratio would make less frictional heat. Also, bigger chips can absorb more heat without their temperature sky-rocketing. And their smaller surface area to mass ratio makes them less likely to catch fire or keep burning.

Steve mentions he thinks his inserts might be going blunt. Worth checking them with an eye-glass. It's possible; if most of the mill's motor power is converted to bright red heat due to rubbing the inserts narrow edges, then the carbide may well suffer. Again, lack of power and speed are relevant. Carbide inserts aren't designed to scrape metal off a surface, rather the point is meant to penetrate deep under the surface and then wedge chips off. Working properly, the delicate edge of an insert isn't in contact with the job at all. As with getting a speedboat to hydroplane though, quite a lot of power is needed to start the process properly, especially with the blunt inserts recommended for steel.

For this job: bigger motor (not a good idea), much bigger mill (yes please!), or sharp inserts and fewer teeth on the face-mill. Be interesting to try a fly-cutter with a single carbide insert and a deeper cut. I think the job would take about the same time, leave the insert in good condition, produce bigger chips, a milled finish, and less fireworks. It's how best to apply that ½HP to this particular job. Probably not a real problem for most work: the mill and cutter might perform well-enough on mild-steel, and the pair are only struggling because the tool-holder is made of something extra tough!

Dave

Dave one moment you say Steve's machine does not have much power and then you suggest he takes off upto thirteen times as much metal off in a pass, I doubt it would do that in mild steel let alone hardened, I know 2mm on a similar width of mild steel would have the X3 popping it's trip and the SX2.7 would not be happy doing half that. What type of cuts can you do on yours with a similar facemill?

I put it badly Jason, I'm explaining the fireworks, not suggesting they can be fixed by hammering the Tom Senior. I meant if Steve had a machine powerful enough to take heavy cuts, then he could go deep and hard without fireworks. I'm suggesting his relatively small machine scrapes hot thin swarf that catches fire, whereas big chips produced by a more powerful machine driving the same face-mill into the tool-holder wouldn't burn. Smoke and blue, but less likely to flame.

I think the combination of carbide face-mill and that steel is too much for the small motor, and Steve might do better with a fly-cutter. My 1100W WM18 wouldn't take 2mm cuts in hardened steel either!

Dave

I use a 50mm diameter Ceratizit shell mill with 5 round 12 mm inserts for machining harder types of steel. Not really hard, but the shanks of indexable lathe tools. The life expectancy of the inserts is about one tool reduced from 20mm to 17.53mm, the centre height of the lathe. This is not as bad as it seems, as the round inserts are indexable in 8 positions in the holder. The Ceratizit is designed for die machining for stainless steel, so the insert grade is not ideal, but I have amassed a good quantity at an average of £2 per insert.

It is easy to see when the inserts are going off, the sparks increase and the workpiece heats up. New edges put very little heat into the workpiece.

.

Indeed he might ... but:

With a six-insert face-mill, it would seem simple enough to try using three, or two inserts ... maintaining balance but reducing load on the machine.

MichaelG.

You are not the 1st to say that, so I will give it a try maybe tomorrow & report back.

Steve.

I have done quite a bit more milling with the facecutter. I have tried 4 different types as you can see in the video I have posted. Spent half the night uploading it. It may be a little long for some of you.

But if you have the patience it is quite informative. Probably not for the pro members but definitely for any amateurs, like myself.

Using the Chinese cutter was not a comparison but purely just to try it out. The price of the inserts alone in the best cutter were far more than the whole tool on the Chinese version.

Cutting hard steel with a facemill.

Steve.

Think I said when you first got them that with the right inserts and a moderate depth of cut they would work and the round insert one would not be that good.

The 63mm is cutting well, the slight mark you were getting when taking those additional cuts off to get down to the line may have been as the work was higher in the vice, would be better as low as you can get it.

Like me you found the very cheap one was quite poor, if you have the time it would be interesting to set it a few mm below the top of a block and do the feeler gauge test against the side of the inserts, as the tool is moving sideways that is where the chip load will alter if the inserts are out, You could also put a DTI on the holder as I found mine was a loose fit on the cheap arbor that resulted in it being eccentric, tapping it true may help get a better cut. However the real difference will be seen if you swap out the supplied cheap inserts with the ones you were using in the 63mm cutter. You should be able to see the difference even on mild steel as you can't have many hard holders left!

I will try that Jason. Never thought of checking the side. Also correct I have finished the tool holders now. So I will have a go with some En1A. I also do have some ISCAR inserts that will fit & I am sure the results will be different. Regards.

Steve.

Steviegtr,

Have you tried removing the insert that is not in line and trying other inserts from your stock? Is it the insert or the pocket?

A brass or steel shim can be stoned down to whatever works. Alt, the pocket might need an irreversible stoning. Note: DaveM of YouTub MiniMachineShop.com had success with a shim, but he is willing to pursue any problem to a resolution, no matter time invested, patience required or difficulty.

Even name-brand inserts have been known to have "slumped/shifted" after baking!

Paul

That is a good point. I was pondering that the other night. Holder or just a bad insert. As Jason pointed out I think the best way is change the inserts for some known good ones. Remount & do some measurements taken from the underside as done before, plus on the side edge.

Steve.

It may not be the pocket that is bad. M tolerance inserts have a .002 to .005 inch variation. Check the inserts as well as the pocket.