Re: Spindle dimensions & tapers

--- In CAD_CAM_EDM_DRO@y..., Bill Vance <ccq@x> wrote:

> On Sun Jun 9 14:13:03 2002, Jon Elson, <elson@p...> wrote:

> Ok, then, here's a question: I've been told that R8 is the taper

one usually

> wants to go for

No. Today, Horsepower determines the spindle taper more than
anything else. R-8 is effective up to about 3 hp.(about the same
range as a 30 taper) It is usually much less expensive than the 30
taper holders, and much more prevalent at shop auctions, industrial
suppliers, ebay, etc.

Over that up to about 10-15 usually becomes a BT or Cat 40
toolholder (primary difference is the metric mounting thread on the
pull stud). THe R-8 will slip and the threaded drawbar is
insufficient for powerful cuts. The only positive drive is the 3/16
or so tool alignment pin, and most people remove those as they are a
pain to position the collets/holders. The taper tool holders
generally have a positive drive on the flange slot in addition to the
drawbar pressure on the taper.

For R-8 you need to have the spindle bore, ground to the correct
geometry. The system can handle spring collets, Colleted and quick
change tool holders, or solid holders. The most common addition is
the quill clamp accy. This would include the angled heads, and the
horizontal adaptors. Most of the horizontal adaptors also have a
support bracket that slides on the Dovetail of the turret. The quill
clamp is a bored split casting that has clamping screws that attach
it to the spindle quill. Since the quill is only 5 inches or so,
adding a 2-3 inch clamp severely restricts the quill travel and
usually the quill is just locked in position and the table is
positioned. If you anticipate using these kinds of accessories, that
could be a deciding factor between CNC-ing the table or the quill.

Best Regards,

Fred Smith
IMService