If you make a sharp rake angle and keep it very short, it works as a modereatly decent chip breaker. I often do this and make it deep and keep the rake area only about 3/16" long at most.
Gunner
"You cannot invade the mainland United States. There would be a rifle behind each blade of grass." --Japanese Admiral Isoroku Yamamoto
If I want a chip breaker, I take the geometry I mentioned, and put a narrow groove across the tool, a tiny bit in back of the edge. No longer easily sharpenable, though.
Jim
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There is one exception -- which is already taken care of in the quick-change tool holders for Aloris style toolposts. That is the parting tool, which is mounted in its holder with a built-in rake angle. Since the parting tool cuts purely on its tip, this makes sense. (And you can grind a chipbreaker notch just behind the front edge on top, if you so desire. (And for deep parting cuts, it is a good thing to have, depending on the workpiece material.)
This is the only Aloris style tool holder that I have used which introduces rake angles, other than the Aloris 16N, which holds triangular inserts directly, and introduces a *negative* rake for those inserts designed to use that rake. The 16P (I believe) introduces *no* rake, depending on the design of the proper insert to provide the clearance and rake.
Enjoy, DoN.
[ ... ]
The screws are particularly bad.
I've never had such a problem with the tool holders (or the toolpost), but I replaced the setscrews *before* putting the holders into service, since I had already been warned about them. I actually replaced them with the imperial screws of very similar size, and had to use a good HSS tap to clean up the threads to make up for the slight difference between the metric and imperial ones. One benefit of this is that the same T-handled Allen hex key works on both the Phase-II and the genuine Aloris tool holders.
I really crank down on those setscrews, so if the holders were likely to break, they probably would have by now. And I sometimes put a significant cutting load on the machine (a Clausing 12x24" machine.)
Enjoy, DoN.
O.K. I've never seen the Phase-II version of this, and did not know that they made that style at all. I have a genuine Aloris for that style, and a few other special styles as well. I'll agree that a discrepancy in heights of the pockets on either end is a "show-stopper".
But, for the normal turning and boring style tool holders, I'm still using the ones which came with my Phase-II (wedge style) toolpost. The one which I am *not* using from that set (at least, not for its intended purpose) is the knurling tool, which I consider to be close to useless. I do use the other end of it from time to time to hold a facing tool.
I have used a scissors style knurling tool quite a bit in a standard Aloris tool holder, and later got an Aloris one which has the two knurling rolls held in two arms on dovetails on a BXA style base. This works quite well for my needs.
But for most of my knurling, I use a T-headed one designed for turret use -- as long as I don't need to knurl too far onto the workpiece.
Enjoy, DoN.
And yet, even there it's hardly essential.
I have one of those Enco toolposts with a quick change position. I think somebody even sent me one of the holders at one time.... but no matter. Anyway, I wanted to put a cutoff tool into play one day, and did not have the proper QC holder for it. So I did a horrible cheat, I put the cutoff blade into a turning boring holder, the one with the V-notch at the bottom - the notch typically used to accept a round shank boring bar.
The square bottom of the cutoff tool lined up with the notch, but the top - what to do about the top? One could imagine a small piece to adapt the setcrews to the top of the blade, a narrow strip with a slot on its underside.
But I was in a hurry, and I knew that the cutoff blade is a bit wider on top than on the bottom. So I just brought each of the four setscrews to bear on the top of the blade, and carefully tightened them in turn to keep the blade vertical.
Consider - there's hardly and side force on a cutoff blade. And it worked so well, I did my other one that same way. I like to have a square-tip cutoff, and also and angle-tipped one. Never hand one pop out under cut, never had any trouble with the crazy setup. So I keep using it.
And, because the tool holder has a flat bottom, the blade has exactly zero rake. And they seem to work as well as the genuine aloris cutoffs I have here at work.
Jim
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That sounds familiar. The Enco toolholders do not fit the Emco toolpost on my Compact-5/CNC. :-)
How tall was the cutoff blade? Mine are too tall to fit in the
1/2" slot for the Emco toolholders, and I don't remember the Enco being that much taller. [ ... ]
IIRC -- the holder for the Emco designed for parting tools has no rake, either.
One of the disadvantages of the rake on the Aloris style holders is that if you loosen the blade to extend it for deeper parting cuts, or pull it in for more rigidity for harder materials (or even just sharpen it by re-grinding the tip), you have to re-adjust the height-setting nut.
Enjoy, DoN.
Just a half inch tall. But because I used one of my home-made boring/turning holders, the V-grove in the bottom allows the blade to drop enough so that the setscrews are dropped below the top of the 1/2 inch slot before they touch down on the blade top. I always use the (soft) home made tool holder blocks because I don't think the factory made ones, which are hard, would be compliant enough when the bottom of the HSS blad is forced into the slot. I'd be worried about cracking the bottom of the blade in that case.
That is a real annoyance, I agree. And my zero rake holders seem to do every bit as good a job as the aloris ones. Go figure.
Jim
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