NAKANISHI NSK CHK-4.0 Collet Chuck 91540 - 4.0mm, Genuine Part

OVERVIEW

Nakanishi (NSK) CHK-4.0 collet chuck, 4.0 mm bore,

part number 91540. Genuine Nakanishi part, new, from

Japan.

A collet is the part of a high-speed spindle that

everything else depends on. Runout at the collet is

runout at the tool tip, multiplied by the length of the

tool. At the speeds a Nakanishi spindle turns, a few

microns of error there is the difference between a

finished surface and a scrapped part - and between a

tool that lasts and one that does not.

Which is why people buy the genuine collet rather than

a copy.

Nakanishi have built high-speed spindles in Kanuma,

Tochigi since 1930, and the CHK series is their own.

SPECIFICATIONS

Brand            : Nakanishi (NSK)

Model            : CHK-4.0

Part number      : 91540

Type             : Collet chuck,

                   CHK group

Bore             : 4.0 mm

Origin           : Made in Japan

Condition        : NEW genuine

                   Nakanishi part

  [CONFIRM AND ADD BEFORE LISTING: which

  spindle and handpiece models the CHK group

  fits, the part number of the matching chuck

  nut, overall length, and weight. The fitment

  list is the single most important thing in

  this listing - a buyer with the wrong series

  of spindle will return it.]

CHECK YOUR SPINDLE SERIES BEFORE YOU BUY

  NAKANISHI MAKE SEVERAL COLLET GROUPS - CHA,

  CHB, CHC, CHG, CHH, CHK, CHM, CHR, CHS and

  others. THEY ARE NOT INTERCHANGEABLE.

They look similar and they are not. A CHA collet will not seat correctly

in a spindle that takes CHK, and a collet that does not seat correctly at

40,000 rpm is a genuinely dangerous thing.

Tell me your spindle or handpiece model number and I will confirm against

Nakanishi's own fitment data before you buy. I would much rather do that

than process a return.

4.0 MM BORE

This holds a 4.0 mm shank. It is a fixed size - a collet grips over a very

narrow range, so a 4.0 mm collet is for 4.0 mm tools and nothing else.

NO CHUCK NUT INCLUDED

The collet only. The chuck nut is a separate Nakanishi part, and if you

are replacing a worn collet you probably already have one. Ask me and I

will quote the nut.

A COLLET IS A WEAR PART

It is supposed to be replaced. A collet that has been over-tightened, run

on an undersize shank, or had swarf packed into its slots will never run

true again. Keep the taper and the slots clean.

JAPANESE PACKAGE

Japanese packaging with Japanese printed markings.

Shipped from Japan with tracking.