R-8 Spindle Accessories
Last updated on Thursday, October 21, 2010 06:30:44 PM Eastern US Time Zone

R-8 Collets, ER-40 Collet Chuck, Arbor, Boring Heads, Fly Cutter, End Mill Holders, Drill Chucks

R-8 tooling is readily available. An extra 5C collet holder modified with an oak insert to hold R-8 sized shanks.

R-8 Collets

Lyndex (Japan) R-8 collet set ⅛" x ⅞" x 1/16"; very accurate & high gripping power.

A rotary collet holder is compact.

 ER-40 Collet Chuck

An ultra-high precision (Maritool USA) ER-40 collet chuck with R-8 shank for RF-25 mill use. Best in class.
Made from alloy steel hardened to 54 - 56RC, balanced to 15,000 RPM, its concentricity is less than 0.0001"
at the collet's face & the rear internal thread is 7/16-20. This chuck allows use of multiple shank sizes of drills,
end mills, reamers, & fly cutters with only one collet system. The ER-40 collets & clamping nut can be changed
out within a smaller space than the longer R-8 collets.  Flats for using an 1¾" open-end wrench.
There are other types of ER-40 collet chucks, e.g., MT-3 shank.

ER-40 collet nut wrench.

Set of ER-40 collets (import) that provides continuous sizes from 0.12" to 1.02"
The sized filler plugs allow gripping short parts without distorting the collet.

Can not measure error using a 0.0005" resolution indicator.

Super low run out. Measured ±0.00015" or 0.0003" total indicated readout (TIR). Within dowel-pin error.

Arbor

One-inch arbor on R-8 shank with various spacers & left-hand nut.

Boring Heads 

Two-inch boring head with ⅞-20 threaded interchangeable arbors MT-2, R-8, & ½" straight type shanks.
Uses ½" boring bars. Steel boring-bar adapter ½" to ⅜". Used a reamer for the ⅜" hole.

Two-inch boring head animation.

The inside diameter is measured using a micrometer or caliper with a self-centering telescopic gage.

This boring head type's dial reads radius so the diameter of the hole increases by twice the adjusted size.
 

A 2½" boring head that uses ½" boring bars. The head has a rigid, integral R-8 shank &
a direct-read dial so the diameter of the hole increases exactly by the adjusted size (USA).


Multiple hole positions, with setscrews, for a ½" boring-bar shank.

Again, this scale reads out the diameter changes; some are the radius. Note the adjustable gib dovetail.

A 3-inch boring head with 1½-18 threaded interchangeable ¾" & R-8 shanks.

The boring head uses hefty boring bars with ¾" shanks.

Mounted in the Rong-Fu mill using the R-8 shank.

A comparison of 2, 2½, & 3-inch boring heads.

Fly Cutter

2½" carbide fly cutter (supplied).

End Mill Holders

R-8 to MT-2 adapter. R-8 end mill holders. Sizes: 3/16", ⅜", ½", ⅝" & ¾". Indexed end mills will not slip.

Drill Chucks

Jacobs ball bearing Super Chuck, ⅛" ~ ⅝" (3mm ~ 16mm) capacity with R-8 to JT-3 ETM Precision arbor (Israel).
Large size shown relative to a US quarter (0.955" or 24.26mm).

Jacobs Super Chuck mounted on the RF-25 Mill & turning.

Keyless ½" capacity drill chuck on R-8 shank. Use only for light duty work.

R-8 Collets, ER-40 Collet Chuck, Arbor, Boring Heads, Fly Cutter, End Mill Holders, Drill Chucks