Milling Chuck Vs Endmill Holders

What is the decisive difference between Richmill's Milling Chucks and Endmill Holders? It's that Milling Chucks can hold and turn the cutting tool at their center-something that Endmill Holders cannot do. By turning the cutting tool at their center, Milling Chucks are able to produce a smooth, truly beautiful finish. Let's take a closer look at the finely balanced internal structure, the strong gripping force, the extraordinary accuracy, and the other advantages of Richmill's Milling Chucks as compared with Endmill Holders.



Milling Chucks


Life of cutting tool,
precision of finish

Since Milling Chucks hold the cutting tool at their center, the cutting tool's TIR is good. During processing, moreover, all of the cutting edges uniformly cut the processed object, which effectively extends the life of the cutting tool. In addition, the internal diameter of Richmill's Milling Chucks is finished with extraordinary precision:-0, +0.0003 inch.

Endmills cannot hold the cutting tool at their center.Therefore, when the processed object is cut, the problem of single-edge cutting occurs, shortening the life of the cutting tool.

Gripping Force

Richmill's Milling Chucks have extraordinary gripping force: 1,800 ft/lb for a Milling Chuck with an internal diameter of 3/4 inch, and 5,100 ft/lb for a 2-inch internal diameter.

When making a heavy cut with an Endmill with an internal diameter of 3/4 inch, 300 ft/lb of gripping force is required to prevent slipping; with an 8-inch internal diameter, 600 ft/lb is necessary.

Can the cutting tool be moved
and adjusted along the Z-axis?

With Richmill's Milling Chucks, needle bearings uniformly hold the gripping area, so the cutting tool can be moved and adjusted long the Z-axis.

The cutting tool can only be gripped when in a fixed position, so it cannot be moved or adjusted.

Total indicator runout (TIR)

Through slanting of the needle bearings, the operation of screws has been replaced with the turning of a lock ring. This makes possible both the uniform elastic deformation of the cutting tool's steel and the uniform tightening of the Milling Chuck's inner diameter. As a result, the TIR of a 4-inch edge has been found in tests to be 0.0004 inch.

Endmills use set screws to hold the cutting tool, from its side, in the center of their holder. Consequently, they are incapable of uniform elastic deformation of the cutting tool's steel, so that the TIR with a 4-inch edge is 0.0008-0.0010 inch (according to JIS data).

Suitable or not for high-rpm machines?

Since Richmill's Milling Chucks hold the cutting tool at their center, it has been possible to design for them a well-balanced structure that does not cause chipping. Accordingly, they are extremely suitable for high-rpm machines.

There are no problems up to 3,000 rpm's, but beyond that, since the cutting tool is not held at the center, an imbalance occurs and chipping readily takes place. Thus, Endmills are generally not suitable for high-rpm machines.

Attachment and detachment
of cutting tool

With Richmill Milling Chucks, the cutting tool can be attached and detached with the accessory wrench alone. Its installation is thus extremely easily.

Attachment and detachment are by Allen wrench.

Finish "Surface" Smoothness

Richmill's Milling Chucks can be used from rough processing to final processing, making them highly economical. They also provide a smooth, exquisitely beautiful finish.

Endmills can only be used for rough processing.


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