William B Noble (don't reply to this address) wrote:
aaarrrggghhh!!!

ok, now that I've said it - I have this Abene mill - it has a #40
taper, so I bought a pile of #40 tool holders. Some (about 2 out of
5) work properly, the remainder have the wrong draw bar thread. So,
I'm imagining that I have two different types of holders - it seems by
looking around that BT and CAT are the same except for drawbar thread
(metric for BT, inch for CAT) -- is this correct?

If yes, anyone wanna trade?
Bill

www.wbnoble.com

to contact me, do not reply to this message,
instead correct this address and use it

will iam_ b_ No ble at msn daught com

Also
"There are five distinct inherent differences between BT and CAT tapered
tools.

The first difference is that the BT shank holder calls for a ground ID
in the retention knob cavity. This accepts a retention knob with a
ground pilot underneath the shoulder of the knob. This is important
because it keeps the pulling force of the spindle on the centerline of
the toolholder to minimize any error in the fit between the toolholder
taper and the machine spindle. Also, a retention knob with a ground
pilot will repeat to the same position when you remove it and then
replace it again. A CAT shank retention knob will not. This is a benefit
in maintaining balance in high-speed applications.

The second difference is that the BT shank holder is manufactured for
symmetry. Both drive keys have the same width and depth. A CAT shank
toolholder has drive keys that vary in width and depth, and, therefore,
a correction mark must be made in the smaller keys to compensate for the
difference. This makes the BT shank toolholder easier to balance.

The third difference is that the CAT shank toolholder is governed by the
ANSI standard, which calls for a relief cut under the flange of the
toolholder of 5/8" width. This is a requirement so that there is no
interference with carousel-type tool changers. This specification
unfortunately weakens the design of the CAT shank. Without the relief
cut, in the case of BT, the toolholder can be shortened and a thicker
diameter can be maintained under the flange for increased rigidity.

The fourth difference is that all of the dimensions on the BT shank
toolholder are in metric. This includes the threads in the retention
knob cavity, and the keys.

The fifth and final difference is the slot in the flange of the BT shank
toolholder is off-set, plus the flange is thicker. On the CAT shank
toolholder the slot in the flange is centered."

The preceeding quote was taken from:
http://www.moldmakingtechnology.com/...es/080303.html

Some general information about tapers can be found on
http://www.cox-internet.com/drspiff/...20flange%20dwg

aaarrrggghhh!!!

ok, now that I've said it - I have this Abene mill - it has a #40
taper, so I bought a pile of #40 tool holders. Some (about 2 out of
5) work properly, the remainder have the wrong draw bar thread. So,
I'm imagining that I have two different types of holders - it seems by
looking around that BT and CAT are the same except for drawbar thread
(metric for BT, inch for CAT) -- is this correct?

If yes, anyone wanna trade?
Bill

www.wbnoble.com

to contact me, do not reply to this message,
instead correct this address and use it

will iam_ b_ No ble at msn daught com

On Thu, 05 Jan 2006 23:14:24 -0800, "William B Noble (don't reply to
this address)" wrote:

aaarrrggghhh!!!

ok, now that I've said it - I have this Abene mill - it has a #40
taper, so I bought a pile of #40 tool holders. Some (about 2 out of
5) work properly, the remainder have the wrong draw bar thread. So,
I'm imagining that I have two different types of holders - it seems by
looking around that BT and CAT are the same except for drawbar thread
(metric for BT, inch for CAT) -- is this correct?

If yes, anyone wanna trade?
Bill

Bill..my big old Gorton MasterMill is 30 taper, but Ive got a dutch
mixture of CAT, BT, NNT, and Standard tool holders.

And a nice little rack on the side of the mill I made to hold the 3
draw bolts I made. One for each type of thread, and color coded with
99c a can rattle can paint on the hex at the top.

I got about 6' of .6 Stressproof, and made em up in about an hour.
Threads and all.

Tis quite simple to do. And I did the same for my Clausing 8540
horizontal miller, also 30 taper, so I can use all the various tool
holders on both machines. The Clausing draw bolts were made of
Mystery Metal, .50..cause I ran out of Stressproof.

All work just hunky dorey.

Thread the end of your rod to the right thread. Drop it into the
spindle. Screw it into a tool holder sitting on your table, about half
way. Pull the rod up and hold the tool holder up in the taper.

Make up some hex nuts from hex stock. Slide it over the rod and down
till it touches the top of the quill. Mark with Magic Marker. Remove
tool holder, remove rod, cut off at mark, weld hex stock to rod, or
cross drill and pin.

Repeat as necessary.

www.wbnoble.com

to contact me, do not reply to this message,
instead correct this address and use it

will iam_ b_ No ble at msn daught com

The aim of untold millions is to be free to do exactly as they choose
and for someone else to pay when things go wrong.

In the past few decades, a peculiar and distinctive psychology
has emerged in England. Gone are the civility, sturdy independence,
and admirable stoicism that carried the English through the war years
.. It has been replaced by a constant whine of excuses, complaints,
and special pleading. The collapse of the British character has been
as swift and complete as the collapse of British power.

Theodore Dalrymple,

William B Noble (don't reply to this address) wrote:
aaarrrggghhh!!!

ok, now that I've said it - I have this Abene mill - it has a #40
taper, so I bought a pile of #40 tool holders. Some (about 2 out of
5) work properly, the remainder have the wrong draw bar thread. So,
I'm imagining that I have two different types of holders - it seems by
looking around that BT and CAT are the same except for drawbar thread
(metric for BT, inch for CAT) -- is this correct?

If yes, anyone wanna trade?
Bill

www.wbnoble.com

to contact me, do not reply to this message,
instead correct this address and use it

will iam_ b_ No ble at msn daught com


Its not only the tread is different, the design of the ring that the
toolchanger grabs is different too. Are you looking for BT or Cat 40?


John

According to William B Noble (don't reply to this address) :
aaarrrggghhh!!!

ok, now that I've said it - I have this Abene mill - it has a #40
taper, so I bought a pile of #40 tool holders. Some (about 2 out of
5) work properly, the remainder have the wrong draw bar thread. So,
I'm imagining that I have two different types of holders - it seems by
looking around that BT and CAT are the same except for drawbar thread
(metric for BT, inch for CAT) -- is this correct?

I believe so.

But -- there are also NTMB 40 taper which has a flat flange
instead of the thicker V-grooved ones on both the BT and CAT. All three
should be perfectly usable on your machine (assuming that it does not
have a tool changer as part of it, which given your use of a drawbar
suggests that it does not).

I use 40-taper in my ancient Nichols horizontal mill, and can
use all three styles.

The NTMB 40 has a cylindrical projection from the small end of
the taper. And it can have either of two drawbar threads.

The BT and CAT instead tend to have a ball stud screwed into the
taper threads. (And, these are often retained with Loctite, so you need
to heat them to unscrew the studs.)

I've machined up collars which screw into the CAT-40 or BT-40
holders and which have the smaller of the two common threads at the free
end, so I can use these in my Nichols mill. (The drawbar is
double-ended, with small thread on one end and large thread on the
other.

The nut on the end of the drawbar is also double-ended, with a
female thread on each end to match on eof the ends of the drawbar, so
you reverse both drawbar and nut to switch between threads. You could
duplicate this, or you could simply make another drawbar for the other
size.

Look at _Machinery's Handbook_ (25th edition, page 920) which
will give you the details and dimensions of the taper which I use. (ANSI
B5.18-1972,R1991). (It will be on a different page in later editions of
_Machinery's Handbook_.) This should suffice to tell you how to make
your own extension shanks as I did. (Loctite the extension, so it does
not come out instead of the drawbar when you want to loosen it.)

I can't find the specs for either the CAT or BT tapers in my
issue of _Machinery's Handbook_, but the actual taper is the same. The
differences are in the flange and the drawbar or draw-stud threads.

Good Luck,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On Fri, 06 Jan 2006 17:48:45 -0500, john
wrote:



William B Noble (don't reply to this address) wrote:
aaarrrggghhh!!!

ok, now that I've said it - I have this Abene mill - it has a #40
taper, so I bought a pile of #40 tool holders. Some (about 2 out of
5) work properly, the remainder have the wrong draw bar thread. So,
I'm imagining that I have two different types of holders - it seems by
looking around that BT and CAT are the same except for drawbar thread
(metric for BT, inch for CAT) -- is this correct?

If yes, anyone wanna trade?
Bill

www.wbnoble.com

to contact me, do not reply to this message,
instead correct this address and use it

will iam_ b_ No ble at msn daught com


Its not only the tread is different, the design of the ring that the
toolchanger grabs is different too. Are you looking for BT or Cat 40?

He's actually looking for standard American or NMTB 40. His mill
isn't CNC so the ring doesn't really matter.



Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook/index.htm

According to john :


William B Noble (don't reply to this address) wrote:
aaarrrggghhh!!!

ok, now that I've said it - I have this Abene mill - it has a #40
taper, so I bought a pile of #40 tool holders. Some (about 2 out of
5) work properly, the remainder have the wrong draw bar thread. So,
I'm imagining that I have two different types of holders - it seems by
looking around that BT and CAT are the same except for drawbar thread
(metric for BT, inch for CAT) -- is this correct?

If yes, anyone wanna trade?
Bill

www.wbnoble.com

[ ... ]

Its not only the tread is different, the design of the ring that the
toolchanger grabs is different too. Are you looking for BT or Cat 40?

I *think* that his mill is not CNC, and thus does not have a
toolchanger. For that, just making alternate drawbars should be
sufficient.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

well, I went out to my garage after a good night's sleep and did some
more experiments trying to understand what fit and what did not - this
is very odd, but I think I'm understanding it now. So, some more
"facts", such as they a

1. this machine has a captive drawbar, so it's a realatively bigger
deal to change drawbars for a different tool holder.

2. a 5/8X11 bolt fits into every tool holder - the ones that fit and
the ones that don't fit.

so, my conclusion is that this is a thread tolerance problem, the ones
that don't fit have the female threads undersized compared to the ones
that do fit. So, I will see about enlarging the threads in the "don't
fit" tool holders a little bit and then if I am lucky, all will be
well.

I've never seen this happen before, but then again, there's a lot of
things I haven't seen. I know it's theoretically possible....

I intend to modify the offending holders rather than the drawbar on
the theory that the Sweedish machine is probably more accurate than
whatever made the holders and therefore should remain the standard.

remarks anyone?

(yes, this is an interesting learning experience - thanks for the
commentary and advise)
Bill

www.wbnoble.com

to contact me, do not reply to this message,
instead correct this address and use it

will iam_ b_ No ble at msn daught com

On Fri, 06 Jan 2006 22:41:53 -0800, "William B Noble (don't reply to
this address)" wrote:

well, I went out to my garage after a good night's sleep and did some
more experiments trying to understand what fit and what did not - this
is very odd, but I think I'm understanding it now. So, some more
"facts", such as they a

1. this machine has a captive drawbar, so it's a realatively bigger
deal to change drawbars for a different tool holder.

Actually this is easily fixed. There's just a threaded collar
holding it in place. Mine never had it in there from the first time I
saw it. While nice in some ways it's not totally necessary and would
be a hinderance in some cases like this.

2. a 5/8X11 bolt fits into every tool holder - the ones that fit and
the ones that don't fit.

so, my conclusion is that this is a thread tolerance problem, the ones
that don't fit have the female threads undersized compared to the ones
that do fit. So, I will see about enlarging the threads in the "don't
fit" tool holders a little bit and then if I am lucky, all will be
well.

Possible though another possibility could be slightly buggered
threads on the drawbar. It might not hurt to take it out so you can
get a good look at the threads.

I've never seen this happen before, but then again, there's a lot of
things I haven't seen. I know it's theoretically possible....

Definitely.

I intend to modify the offending holders rather than the drawbar on
the theory that the Sweedish machine is probably more accurate than
whatever made the holders and therefore should remain the standard.

The holders might be to hard to modify but you won't know till you
try.


Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook/index.htm

On Fri, 06 Jan 2006 22:41:53 -0800, "William B Noble (don't reply to
this address)" wrote:

well, I went out to my garage after a good night's sleep and did some
more experiments trying to understand what fit and what did not - this
is very odd, but I think I'm understanding it now. So, some more
"facts", such as they a

1. this machine has a captive drawbar, so it's a realatively bigger
deal to change drawbars for a different tool holder.


AH!! major difference...

2. a 5/8X11 bolt fits into every tool holder - the ones that fit and
the ones that don't fit.

so, my conclusion is that this is a thread tolerance problem, the ones
that don't fit have the female threads undersized compared to the ones
that do fit. So, I will see about enlarging the threads in the "don't
fit" tool holders a little bit and then if I am lucky, all will be
well.

They may..may be hardened, so proceed carefuly and use lots of earl
G

I've never seen this happen before, but then again, there's a lot of
things I haven't seen. I know it's theoretically possible....

I intend to modify the offending holders rather than the drawbar on
the theory that the Sweedish machine is probably more accurate than
whatever made the holders and therefore should remain the standard.

remarks anyone?

If the Cats are too short..its maybe possible to make up an
extension..though ID of the quill may prevent this..or not.

How is the draw bar held captive? I dont think Ive ever seen one that
couldnt be easily removed.

(yes, this is an interesting learning experience - thanks for the
commentary and advise)
Bill

www.wbnoble.com

to contact me, do not reply to this message,
instead correct this address and use it

will iam_ b_ No ble at msn daught com

The aim of untold millions is to be free to do exactly as they choose
and for someone else to pay when things go wrong.

In the past few decades, a peculiar and distinctive psychology
has emerged in England. Gone are the civility, sturdy independence,
and admirable stoicism that carried the English through the war years
.. It has been replaced by a constant whine of excuses, complaints,
and special pleading. The collapse of the British character has been
as swift and complete as the collapse of British power.

Theodore Dalrymple,

following up, for those who chimed in - I removed the drawbar (held in
place by a LH threaded nipple - took a while to figure that one out) -
took drawbar and holders to a friend who had a good thread mic and we
found that the drawbar thread was about 1.5 thousandths too large -
turned it down with a nice sharp 5/8X11 die and all is well.

thanks for the help and advise.
Bill

www.wbnoble.com

to contact me, do not reply to this message,
instead correct this address and use it

will iam_ b_ No ble at msn daught com