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Help identifying a cutter found in toolbox

M

Megar arc 5040dd

Super User
I was going through my toolbox of old cutter that came a mill I had a few years ago and came across this. Any idea what it is? Is it supposed to be a face mill? There are no markings on it and it kind of looks homemade or maybe its just really old. The cutter diameter is 2 3/4" and the shank diameter is 1 1/4". With the cutter sitting on the piece of granite it has the slightest wobble. Two cutters opposite each other seem to stick down ever so slightly lower than the other two. Or would this be more like a slot cutter for a horizontal mill? It's been in my toolbox for years and I have never really looked at it twice since I have never had a collet big enough to fit the shank.

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Yeah a slot cutter. This is the type of cutter to mill the slot in lathe chuck jaws, for instance. The staggered teeth aids in chip clearing. The deeper the slot, the more important chip management becomes.
 
Dabbler said:
Yeah a slot cutter. This is the type of cutter to mill the slot in lathe chuck jaws, for instance. The staggered teeth aids in chip clearing. The deeper the slot, the more important chip management becomes.
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Is this type of slot cutter common or is it more of an old school type thing? Would anyone have a use for it, I mean other than for adding weight to the toolbox like I use it for :cool:
 
Sure. It is a specialized cutter.

Normally you can do all top operations in the mill, and even do planar milling on the sides with a good setup. In the rare event that there are overhangs or slots on the sides, this cutter keeps you cutting without making a new set (or possibly 4 setups). Not changing the setup contributes to improved accuracy.

Often people use woodruff key cutters or t slot cutters for these purposes. Slotting mills are available, but they are hard to source and are a little pricey :)
 
Im not convinced it is a slot cutter, although the outside face of the cutters appear 90 deg to the face of the mount, the sidewalls of the cutters appear in one photo to be at an angle considerably off 90...it would cut a sloped side on one side of the groove and a very rough undercut on the other side would it not??
 
historicalarms said:
Im not convinced it is a slot cutter, although the outside face of the cutters appear 90 deg to the face of the mount, the sidewalls of the cutters appear in one photo to be at an angle considerably off 90...it would cut a sloped side on one side of the groove and a very rough undercut on the other side would it not??
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To be honest, I cannot tell. None of the pictures are shown at the right angles for me to determine that with any certainty. The camera would have to be positioned on a right angle to the axis of rotation with the cutting edge of each blade positioned at a right angle to the same axis. One blade does not define the full profile unless they are all identical and they don't have to be. The blades can be staggered like saw blades are.

It's an interesting tool.
 
Shop-made facing tool with silver soldered or brazed on carbide for the cutters.

You can see in the photo that the trapezoidal carbide segments are set to cut out at the periphery of the tool, and if you look at the profile of the 'upper' edge of the tool, it shows a definite angle, not something you would find useful on a tee slot cutter.
 
trevj said:
Shop-made facing tool with silver soldered or brazed on carbide for the cutters.

You can see in the photo that the trapezoidal carbide segments are set to cut out at the periphery of the tool, and if you look at the profile of the 'upper' edge of the tool, it shows a definite angle, not something you would find useful on a tee slot cutter.
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Yeah it has that feel of a facing tool.
 
Tom Kitta said:
Yeah it has that feel of a facing tool.
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Ayup. Has the look of a tool that was likely needed or wanted to try out the process without much of an investment, or perhaps it was simply a solution to a harder than average surface that needed to be dealt with. Carbide tooling has come a LONG way in the last 30-40 years, but I have magazines dating from between the WW's that mention the stuff.
 
The cutters are indeed angled and would not produce a flat if used to make a tee slot however would it work for a face mill if it doesn't sit flat on the cutters? wouldn't 2 of the four cutters be doing all the work? If anyone wants photos from other angles of with parts against a square just ask I am happy add more photos if needed?
 
The thing that makes me lean away from a home made face mill is the top contour. That thing has the cutters proud of both the bottom and the top surfaces. It seems more likely to me that it was also designed / intended to cut on the top edge too.

Not saying I think it's intended to cut T-slots though. I really don't know that. But I don't think it's a face mill.

I have several old home made face mills that I acquired at auctions, in bulk Kijiji buys, and in one case it came with my old mill/drill. All have home-made hss inserts or silver soldered carbide cutters. None of them are made that way on the top surface. Why go to all the trouble of making a top cutting edge if it was not intended to be used? And why make the cutters proud if they were not intended to cut anything?
 
Megar arc 5040dd said:
The cutters are indeed angled and would not produce a flat if used to make a tee slot however would it work for a face mill if it doesn't sit flat on the cutters? wouldn't 2 of the four cutters be doing all the work? If anyone wants photos from other angles of with parts against a square just ask I am happy add more photos if needed?
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Do a little reading on Tool and Cutter grinding and sharpening, and have a CLOSE look at a decent sized two flute end mill with the end resting on a flat surface or with a rule against the end edges, and you pretty soon find that it is really common to have all the cutting occurring right at the outer periphery of the cutter. Limit your feed rate to something near half the tip radius of the insert, and you get a pretty slick finish.

In the simplest form, look at a fly cutter, with a single cutting edge, doing laps around the center of the spindle axis. This tool is set up as essentially a four toothed fly cutter. Post-manufacturing grinding on an appropriate jig or tool and cutter grinder, takes care of the problem of getting the teeth even.

FWIW, if the maker had mounted the carbides with one pair angled down, and the other pair angled up, it WOULD serve quite adequately as a Tee Slot Cutter, for essentially the same reason as a fly cutter works, in that the surfaces are generated by the path of the tool tooth tip, rather than by it's form.
 
Megar arc 5040dd said:
Yah I only have ER32 collets up to 3/4" and the shank is 1 1/4". I'm sure I could probably make a holder for it just to play around with.
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ER32 doesn't go to 1.25. Er40 does, but who spend all that money just to test it. I'd make an adapter for it. Say something that fits it on one end like a Weldon Shank, and then fits your biggest ER32 on the other end.
 
trevj said:
FWIW, if the maker had mounted the carbides with one pair angled down, and the other pair angled up, it WOULD serve quite adequately as a Tee Slot Cutter, for essentially the same reason as a fly cutter works, in that the surfaces are generated by the path of the tool tooth tip, rather than by it's form.
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I agree with that Trev. The top cutters are proud, but they also angle up toward the root. So it would cut a sloped top on a T-slot. Maybe on purpose?

I'm convinced that the top is intended to cut too. Too much trouble to make it like that if it wasn't needed. But for what?

It's definitely a weird tool!
 
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