Get the Custom Keyseat Cutter You Need

Keyseat cutters are widely used in the metal machining realm. They are most commonly mounted in either a vertical or horizontal milling spindle, although they can be occasionally used in a lathe spindle to create a feature in a part clamped on the compound. When there’s no other way to create the correct groove in a tricky part, machinists get resourceful! That’s why you need AC Custom Grinding, to help create the perfect tool for such situations. Generally, though, these cutters are used to mill a slot in material perpendicular to the milling spindle. If a groove is needed in a part at 90 degrees to the spindle, a keyseat cutter can be an inexpensive solution.

Square keyseat cutter

Some cutting tool manufactures are now making key seat cutters in a staggered tooth design. This approach allows for greater chip clearance above and below. Stagger-toothed cutters also have a slight ability to remove material in the z plane. As long as the cut does not exceed the depth of the tooth, very shallow slot depth changes are possible.

Optimal Materials

Currently available in HSS (M2) and Cobalt (M42), these cutters are more commonly made out of carbide: solid carbide for relatively small cutter diameters (up to around 3/4″) and brazed carbide tipped versions for cutters as big of diameter as you are brave enough to chuck in a mill. Two to three inches would be a common measurement, but we have certainly made them much larger! Carbide allows for cutters to stay sharper, longer, making more parts for you before resharpening is necessary. While carbide is desirable in almost every scenario, it cannot be ground to as finely honed cutting edge as its tool steel cousin. In instances when a razor sharp edge is required, as in the case of some soft plastics, carbide has to take a back seat. Even if the plastic is abrasive, sometimes HSS is the best solution.

Flute Considerations

Flute count is as varied as the materials we choose for these cutters, with two flutes as the minimum (we could make a single flute cutter, but at that point, we would have to label it a fly cutter. No insects were harmed in the writing of this description!). The ratio between flute count and cutter diameter is important to consider when choosing a key seat cutter. Generally speaking, the harder the work piece, the more teeth necessary. Softer aluminum / brass / copper / plastics are more efficiently machined with fewer teeth, allowing more gullet depth for chips to evacuate and thus yielding faster feed rates. Congruently, the larger diameter of cutter would naturally lend itself to more teeth. It’s easier to envision 20 teeth on a cutter that is 3″ in diameter as opposed to 3/8″. That is not to say that we couldn’t make a 6″ key seat cutter with only 3 teeth, or that we couldn’t make a 1/2″ cutter with a dozen teeth, but at some point the physics of cutting are compromised.

Getting Every Dimension Just Right

A vast majority of keyseat cutters sold in the U.S. market are of standard imperial diameters, from the smallest practical of around 1/16″ (.0625″) on up, graduated in .001″ increments. The thickness of cutters available are basically .015″ and up to whatever a machinist can dream up, in the same .001″ increments.

With the addition of corner grinds and any standard of custom key seat cutter, we can add a whole new dimension of functionality. If you need a tiny .005″ corner radius to satisfy a picky programmer, or a beefy .075″ 45 degree chamfer to hog out some tough stainless, corner work may be just what you are looking for. Radii can be ground on a key seat cutter from effectively .005″ all the way up to a full radius. The same dimensions apply to any chamfers ground on the cutters as well.

Providing neck reliefs just above the cutting diameters is a creative way to allow the cutter to reach around an obstacle in the machining process. the thinner the neck, and the longer we make it, the greater the fragility of the cutter, but even if you need to reach 20 inches down into a recess and cut an 1/8″ groove .500 deep into the wall of a titanium part, we can build you that cutter.

Most key seat cutters have nominal shank sizes, with 3/8, 1/2 and 3/4 probably making up 90% of the cutters we make. The European / worldwide market dictates that we make them with the standard metric sizes, which we do easily.

Need Us to Invent a Design?

We have also designed and ground from scratch double and triple key seat cutters – that is, multiple cutting sections spaced into thin air. This gives the operator the ability to make multiple groove passes in one chucking of the part. It’s not for the faint of heart to grind (or to use!) a cutter of this nature, but when seconds count, spending a few extra bucks on a cutter that you can’t buy off the shelf anywhere else, may make the difference between a profitable job and a cash eater.

That’s why we can manufacture every aspect of a keyseat cutter to whatever the job demands. Use our handy order form to get started with customizing yours, or contact us with any questions you may have.

Keyseat Cutter

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