R8 Taper socket dimensions?

--if you can get hold of a copy the dimensions are in Machinerys Handbood, probably any edition.

In message , Prepair Ltd writes Can you 'reverse engineer' from sites such as
It came up as first hit from a Google search on the string
"R8 collet tool dimension female"

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

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 -- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk

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 -- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk

Well here's the data on the collets..
Thats all I could find..
Wayne...

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

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 -- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

One would assume that taking the collet dimensions and using 0.950" instead of 0.949" for the diameter would be pretty close. 61/64" would be far too sloppy. The key location looks as if there is quite a lot of leeway.
Presumably John has pointed you at this:-

Mark Rand RTFM

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
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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 -- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

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

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.
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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How does one tell the difference?
Pete
-- peterseage ----------------------------------------------------------------------- peterseager's Profile: this thread:

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

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.
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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)
-- peterseage ----------------------------------------------------------------------- peterseager's Profile: this thread:

"peterseager" wrote in message news: snipped-for-privacy@no-mx.themodelzone.org... > > I bought a set of 10 R8 collets to hold metric and imperial endmills up > to 20 mm. There were two makes, both Chinese, one make fitted OK but > the other had to have the keyways ground deeper before they would fit > my mill (Warco VMC). > > > -- > peterseager > --------------------------------------------------------------------

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