View Full Version : Cutting Tools - What is it, When do I use it, What the heck are these numbers, etc

10-08-2008, 07:48 PM
Well I just stumbled upon a bunch of questions...

First - what's with all the numbers on endmills? I've seen a bunch of endmills that never seem to give their diameter but instead just have some numbers engraved on them. For instance, I've got some 15 cutting tools here that all have TC and then some numbers etched on them. Is there any kind of nomenclature like carbide inserts?

Next, I've taken some pictures of some of the cutting tools I'm a little foggy about. For instance, this guy here:


It has a flat milled 90* from the cutting edge:

It is solid carbide, too. Whats it for and when do I use it? :-D I thought at first that it would be a a boring bar, but the angle on the tip and that flat made me think that maybe it is some sort of trepanning tool. I've got five of these guys. (It might be hard to tell, but the included angle is less than 90*.

I've got several of these little guys too - I figured these were for sure small boring bars, but they have the same tip geometry that the larger carbide ones do.


What about this:


Sort of like a gun drill or "d-bit" but why so short? Whats the advantage to using this for such a short hole?

10-08-2008, 10:02 PM
I second your initial thoughts of the top ones being boring bars. They would be for shallow bores or may have been used for just breaking the sharp burr left after trepanning, even interior profiling.
Bottom one is definately a trepanning tool. I have used such in Acme-Gridley multispindles for hose barb connections with an outer crimp skirt, also in CNC gang lathes for similar parts that needed backwork after the Acmes were done.
Looks as if it is about a 5/8"-11/16" bore and leaves a 3/8" core, that would be if it has a 3/4" shank. Aspect ratios are hard to guess without knowing shank diameter.

10-08-2008, 11:17 PM
Just a thought but they resemble the venturi boring tool form The Four Inch Engine in HSM.

10-08-2008, 11:36 PM
We have lathe boring bars that look like that, for chip clearance in teeny holes.

10-09-2008, 12:02 AM
alright so I threw them in with my box of lathe tooling, but I'm still not entirely sure. Whats the purpose of the flat on the shank for those TiN carbide ones? The boring bar would be rotated the wrong way if that was used in a tool holder.

The trepanning tool is actually 1/2" OD - I know its hard to tell in the pictures.

Anyone know anything about the numbers? Even new end mills from reputable names (i.e. putnam, weldon, niagra, etc) sometimes just have a "serial number" but no other identifying marks. Its hard to find the size you want in a draw full of endmills with no id'ing marks. Have to check them all manually.

10-09-2008, 12:11 AM
Best bet is custom tooling and they are in-house numbers. I have seen tons of stuff like that at Boeing.

10-09-2008, 12:17 AM
LOL - actually quite a bit of the equipment and tooling in one of our shops has been donated from Boeing! Luckily the endmills and other perishable tooling from Boeing got professionally sharpened and then engraved with the size. On the few that were marked, say 3/8, the actual size after sharpening would be .364" or etc.

10-09-2008, 12:17 AM
The bottom tool is for cutting an O-ring recess around a port.Like on a flat face hydraulic fitting or a sub-plate for a solenoid valve.

Allan Waterfall
10-09-2008, 05:23 AM
The top picture looks like the business end of an endmill that I had given me.

The one I've got is for use on carbon fibre and epoxy/glass laminates.Mine then gets bigger in diameter and is formed like a roughing endmill on the larger diameter.


10-09-2008, 01:45 PM
Fastrak...Just a thought but they are probably special tooling for CNC machining centers. The first one kind of looks like a single flute plastics router bit. I think Wierdscience hit the nail on the head about the "plug cutter" style tool being for cutting O-ring grooves. They are probably from some plant that manufactures brass fittings, like Swagelok. I am sure that the code numbers reference a specific style and size, if you had the right list to refer to. Maybe some of the CNC folks can shed some light here.