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New FAQ August 2020

For section "Milling"
QUESTION
What is "stepover" and what is "stepdown"?
ANSWER
In multi-pass milling, "stepover" and "stepdown" refer to the distance between two adjacent passes. "Stepover" relates to this distance when, after finishing a pass, the milling cutter moves sideward and then performs the next pass. By contrast, if at the end of a pass the milling cutter moves downward to start the next part, the distance is called "stepdown". Sometimes "stepover" and "stepdown" are referred to as "sidestep" and "downstep" correspondingly although this is less common.
QUESTION
What is the difference between "gang milling" and "straddle milling"?
ANSWER
Straddle milling is a type of gang milling.
In gang milling, an assembled tool comprising two or more milling cutters mounted in the same arbor, machines several workpiece surfaces simultaneously. In straddle milling, two or more side-and-face milling cutters, mounted in one arbor, machine parallel planes of a workpiece. The planes are perpendicular to the arbor axis and feature an exact distance (distances) between them. To ensure the necessary accuracy of the distance (distances), the milling cutters are spaced apart with the use of bushings and spacers.
For section "Profile Milling"
QUESTION
What is ISCAR's "rule of 12" for ball nose cutters?
ANSWER
"The rule of 12" is a rule of thumb that may be useful for quick estimation of the relation between a depth of cut and a width of cut (a stepover) when milling ISO P materials (soft and pre-hardened steel, ferritic and martensitic stainless steel) by ball nose cutters. In accordance with the rule, if a depth of cut is the half of a cutter diameter (D/2), a recommended width of cut (a stepover) should be no more than D/6; for the depth of cut D/3 the maximal width of cut should be D/4 etc.
It is not difficult to see that 2×6=3×4=12.
For section "Solid Endmills"
QUESTION
Is it possible to regrind ISCAR's lens- and oval-shape solid carbide endmills?
ANSWER
The lens- and oval-shape solid carbide endmills features a complicated cutting shape and therefore they are not intended for regrinding.
For section "Holemaking"
QUESTION
When should a carbide guide pad in a deep drilling tool be reversed or replaced?
ANSWER
Even though the guide pads do not cut material, they, like carbide cutting inserts or heads, are subject to wear. A damaged or worn out guide pad causes unacceptable roughness and scratching of the machined hole surface.
The pads should be thoroughly examined visually before applying a drill. If a pad is damaged or the pad working corner wears out approximately 70% of the corner width, the pad should be reversed or replaced.
For section "Shop Talk Professional slang"
WORD
PH
MEANING
precipitation hardening stainless steel.
WORD
Ruthenium, ruthenium grade
MEANING
a cemented carbide alloyed with ruthenium .
WORD
Superfinish
MEANING
this word is used for the extremely high surface finish that a cutting tool can ensure. The tool may even be referenced by as a "superfinisher".
Not to be confused with superfinishing - a fine abrasive machining process!
WORD
Barrel
MEANING
a barrel-shape milling cutter.
WORD
Chip mouth, chip throat, chip slot and chip gullet
MEANING
these terms relate to the area of a cutting tool designed for chip flow during machining. The chip mouth and chip throat are usually shaped holes, and the chip gullet is a groove. In rotating tools, the terms "chip mouth" and "chip throat" are more common in hole making, while the terms "chip slot" and "chip gullet" are used more in milling.
WORD
Weldon
MEANING
the cylindrical shank of a tool (usually a milling cutter) with one or two side flats for clamping and driving. This type of shank was originally introduced by Weldon Tool Co. in the 1920s.
WORD
Whistle notch
MEANING
the cylindrical shank of a tool with an inclined side flat for clamping and driving.