R8 Taper socket dimensions?

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Has anyone got the correct socket dimensions into which an R8 collet
would sit please?

This is the female socket, not the collect itself.

John S was able to point me to a source for the R8 collect, just need
the other half.
Peter
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Peter A Forbes
Prepair Ltd, Luton, UK
prepair@easynet.co.uk
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Re: R8 Taper socket dimensions?
    --if you can get hold of a copy the dimensions are in Machinerys
Handbood, probably any edition.

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Re: R8 Taper socket dimensions?

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Nope - it's not in there (not in my 26th or 11th editionsanyway)

What can you say about a book that continues to leave out the most
common spindle taper in the world.....

Charles




Re: R8 Taper socket dimensions?
On Mon, 06 Feb 2006 17:24:35 +0000, Charles Ping

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Well it was a one-make type, so not really an open standard, which is
why they probably left it out :-))

I looked as well....

Peter
Peter
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Peter A Forbes
Prepair Ltd, Luton, UK
prepair@easynet.co.uk
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Re: R8 Taper socket dimensions?
On Mon, 06 Feb 2006 17:39:32 +0000, Prepair Ltd

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http://www.forkardt.com/products/toolholders/pdf/FORKARDT_Toolholding_Catalogue.pdf

gives the collet dims, but you have those already :-(

What else do you need? Position of the dowel pin? I can measure that
sort of thing for you if it helps

Cheers
Tim

Dutton Dry-Dock
Traditional & Modern canal craft repairs
Vintage diesel engine service

Re: R8 Taper socket dimensions?
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Can you 'reverse engineer' from sites such as

<http://www.hardinge.com/usr/pdf/collet/2351E.pdf

It came up as first hit from a Google search on the string

"R8 collet tool dimension female"


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Mike Hopkins
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Re: R8 Taper socket dimensions?
On Mon, 6 Feb 2006 17:17:03 +0000, Mike H

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I didn't think of putting 'female' into the search! :-))

They have ER8 on that file, Mike, but not R8 as in Bridgeport that i
could find. Did you actually find it in there?
Peter
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Prepair Ltd, Luton, UK
prepair@easynet.co.uk
http://www.prepair.co.uk

Re: R8 Taper socket dimensions?
Prepair Ltd wrote:
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Well here's the data on the collets..

http://frugalmachinist.com/r8collet.jpg

Thats all I could find..

Wayne...

Re: Re: R8 Taper socket dimensions?

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Yes, there are plenty of sources for the collet, but sod all for the socket they
fit! :-))

Tony Griffiths has a good collet dimension assortment on his site as well.

Peter
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Peter & Rita Forbes
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Re: Re: R8 Taper socket dimensions?

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Am I missing something here? Surely the socket is dimensioned as per the
collet taking into account any positive tolerance allowed on the collet
which on the shank diameter is 0.9496" - 0.0003" (so 0.9496" +0" should
cover it) and on the fattest part of the taper is 1.250" - 0.005" (so 1.250"
+ 0" should be adequate). The longitudinal dims. seem to be + or - .01" so
the socket should be about 10 thou longer than the nominal dimensions.

Am I talking crap or does this help?

Mark



 

Re: R8 Taper socket dimensions and an update
wrote:

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No, probably quite reasonable, but it is nice to have the socket drawn out and
dimensioned, rather than making good educated guesses.

I've been exchanging emails in the interim with Rick Robison at Wells Index, and
we are down to the nitty-gritty of which spindle we have and if they can
actually do this particular machine that we have.

The spindle nose diameter is only 1.437" diameter, so it may be a wasted effort.
He says that he needs 1.3" so we may be OK.

Peter
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Email: diesel@easynet.co.uk
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Re: R8 Taper socket dimensions and an update

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Yes, a picture paints a thousand words. Actually, if you have a propensity
to occasionally slip into buying some of the cheap Chinese tooling as I
have, you may find that accuracy in the socket dimensions is relatively
unimportant. The last piece of crap I bought had to be remachined to fit the
spindle! A strong draw-bar can cure a multitude of sins!

Mark



Re: R8 Taper socket dimensions and an update
On Tue, 7 Feb 2006 19:37:24 -0000, "Mark_Howard"

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Ok we need to look at a bit of history here to get the full picture.
The R8 collet was devised by Bridgeport back around WW2, before that
they were using the B&S collets or sometimes the Morse.
All this is rather hazy due to licensing agreements.

Because the R8 was classed as a proprietary taper it was never listed
in places like Machinery Handbook, to my knowledge unless it's in V27
it still isn't.

Many people have listed various drawings for the R8 some very crude
and some with a few major dimensions on them as a guide.
many of the collet manufacturers have them on line.

The first recorded entry I can find on the FULL specs is in a 1952
edition of the National Machine Tool Builders manual.
This was a professional body of interested people who went about
setting various standards, machine noses and tapers being one.

Incidentally the initials NMTB is still prevalent today as a standard
taper although it has also been superceded by the term INT

Here's a copy of that drawing hosted by Scott Logan of Logan lathe
fame.

http://www.loganact.com/tips/r8.htm

So now we had a standard and all was fine - until.............

Sometime with the last three of four years with the import of tools
from the far east a certain American manufacturer who was building his
version of a machine with an R8 taper sent a sample to China for
collets to be made.
Unfortunately due to a lack of published standards his spindle wasn't
standard so the Chinese working with what they had made collets up to
fit this spindle.
The Yank was pleased as he now had a supply of collets but in the
process had pissed up the whole shooting match.

So what has now happened is that in certain provinces they are making
collets to the Twonk spec and in other provinces they are making
collets to the correct spec.

The importers know this problem but it depends on where they are
buying from whether they admit to knowing about this.

Over the last couple of years I have bought about 12 pieces of R8
tooling from collets to boring heads, all have fitted my Adcock and
Shipley built Bridgy with no problems so watch where you buy from.

--
Regards,

John Stevenson
Nottingham, England.

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Re: R8 Taper socket dimensions?

>So what has now happened is that in certain provinces they are making

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How does one tell the difference?

Pete

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Re: R8 Taper socket dimensions and an update
John Stevenson wrote:
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Missed this for some reason. It sounds like the orientals could
have ended up grinding the collets to 30 NMBT taper of 3-1/2" per
foot, it only has a few minutes difference in taper to R8. In
actual fact, people have been known to use 30 Int in R8 machines.
Requires a longer drawbolt and the some of the more "fussy" even
fit an extension to lengthen it to fit the R8 upper register..:-)

Tom

Re: R8 Taper socket dimensions and an update

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They could have made this mistake, it's hard to measure a couple of
minutes of a degree by hand but the biggest difference is in the
0.9490 / 5 diameter.
They have probably rounded off this to 0.950 /5 and if the collet has
been made to suit, and  on the plus side it's a whack in fit into a
correct spindle.
--
Regards,

John Stevenson
Nottingham, England.

Visit the new Model Engineering adverts page at:-
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Re: R8 Taper socket dimensions?

I bought a set of 10 R8 collets to hold metric and imperial endmills u

to 20 mm.  There were two makes, both Chinese, one make fitted OK bu
the other had to have the keyways ground deeper before they would fi
my mill (Warco VMC)

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Re: R8 Taper socket dimensions?

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up
but
fit
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Yes I've had the same experience - all other dimesions seemed ok, just
the keyway.

AWEM



Re: R8 Taper socket dimensions?
On Thu, 9 Feb 2006 21:51:12 +0000 (UTC), "Andrew Mawson" 475
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And lots us us don't use the keyway - to no great disadvantage.

Regards

Charles

http://www.homeworkshop.org.uk

Re: R8 Taper socket dimensions?

Andrew Mawson Wrote:

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Figured out tonight why the keyway was shallow. I happened to stand on
of the collets on its drawbar end and it wobbled. When I looked close
you can see a slug with the drawbar thread has been inserted into th
end of the collet. I wondered how you open out the centre cavity an
now I know how this bunch did it. I had wondered why there was a coupl
of stake marks in the bottom of the keyway. Again I now know - to sto
the slug turning out. Grinding them deeper has exposed what I now kno
to be the tops of the thread on the outside of the slug. Fortunatel
most of the metric sizes are better made. I thought I was shopping wit
a reputable dealer.

In case of any missunderstanding in view of my last post, can I make i
clear that these were NOT supplied by Warco.

Pete

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