Re: BT30 taper 7/24

Tim, if you're looking at converting a spindle to a #30 taper quick
change, you might want to consider going with a CAT configuration
instead of a BT. Over the last few years the CAT seems to have
become more and more the de facto standard. Evidence of this shows
up as more than a few tooling suppliers have begun clearance sales
on BT toolholders. While this can mean some good buys for folks
with BT spindles, in the long term it can mean sky high prices as
fewer and fewer of them are produced. BT's are available in #35 and
45 as well as the more common 30, 40, and 50, but hardly anthing is
being built with a 35 or 45 anymore, and the prices of those holders
is thru the roof already due to low demand and therefore low
production. Because of the sheer volume of production and
proliferation of sources, the price of CAT taper toolholders inches
lower and lower over time as well.

Someone please correct me if I'm wrong, but I think the actual taper
dimensions on all #30's is the same, regardless of whether it's an
NMTB, a CAT, or a BT. The differences in a BT and a CAT lie in the
configuration at the area where the toolchanger grips the holder and
at the upper end where the retention knob fits.

Cliff

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Tim" <sspeed@o...> wrote:
> I almost understand what 7/24 means
> just need to have somebody confirm.
>
> I think this means 7mm of taper for every 24mm of length
>
> But not the length of the actual tapered surface but the length
> as if it was straight ?
>
> Like roof pitch?
>
> I am looking into a BT30 spindle conversion.
>
> Thanks for any info,
> Tim