R8 Taper Dimensions

I bought a cheap R8 collet for use in my neighbor's equally cheap vertical mill. Surprise of the ages, it doesn't fit. I'm trying to figure out whether the issue is collet or the mill. The problem seems to be the groove depth. The tooling that came with the mill has a groove that is 0.104" deep where as the collet has a groove 0.060" deep. The collet groove is slightly wider, by less than half a thou.
What's correct? I Googled "R8 dimensions" (and standard, and drawing, and every other combination I can think of) without luck. I'll RTFM if I can find TFM.
Oz

I've had a similar problem with 5C collets from Enco. I was able to mill the groove deeper on the worst ones but filing the pin slightly shorter seemed the best fix.
jw KB1DAL

The standard size for the groove should be 0.060- you will find that some imported mills will have a key made for a deeper groove and in some cases a wider groove as well.
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    Note that at least on a Bridgeport, the key is the end of a dog-point Allen screw (which can be accessed through a hole in the back of the quill). You'll probably have to rotate the spindle until the screw lines up with the access hole.
    There are actually *two* Allen screws in the hole. From what I have read, it is often the case that the outer one (which serves to lock the inner one with the dog point at a proper level) is one with the hex hole all the way through. So -- you loosen the outer one, pass the Allen key in to access and adjust the inner one, set the depth correctly for that worst-case collet, then back the Allen key out so it is only engaging the lock screw, and tighten that to hold the lock screw at the proper depth. Then -- make sure that the one with the dog point has not moved, so you can get that worst-case collet in and out without problems.
    I don't know that the mill which your neighbor owns has the same system, but it may be worth checking for that, so you can adjust it (if he so allows).
    This is also good to know about so you can replace the dog point screw if the key happens to get sheared off by a mishap at some time in the future.
    Good Luck,         DoN.

http://www.oldengine.org/members/diesel/Tables/Clarkson3.htm

wrote:
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Which shows it to be 5/32 wide, 3/32 deep, and 3" long.
Take care.
Brian Lawson, Bothwell, Ontario.

The machinery's handbook has all the dimensions for nearely every taper device ever made. You should be able to find it at your local library.

wrote:
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XXXXXXXXXXXXXXXXXXXX Hey woodworker88,
Yep, but R-8 is not shown under "Taper", but rather under "Collets". And in my three MH books, only the basic info is given, and does not include any reference to the key slots in any.
Take care.
Brian Lawson, Bothwell, Ontario.

Guys..as a machine tool repair tech..Ill put in my .02 worth. Its VERY common for import collets to not fit American made machines, let alone import machines. You get what you pay for.
Your two options are:
Take your trusty Dremal tool (or equiv) and a small stone..and make the slot a smidge wider and deeper, which takes all of about 2 minutes per
Or thin/shorten your pin. Which takes about 30 minutes or longer.
Its not rocket science. And its strictly due to piss poor quality control of imported (and occasionally domestic) tooling
Ive seen even (Barrummmm) Hardinge (Barruummmmm) collets be a bit sticky because of a burr etc. Often times..cramming the slot into the face of a spinning soft wheel will open the slot enough for it to work thereafter.
Shit happens. Deal with it and drive on.
Gunner, who is fasinated that a Very nice SB Heavy 10, well tooled, with collet closer, didnt sell at the Visalia show, for $1000, probably because the paint wasnt perfect and there were lots of tire kickers looking for perfect machines for nearly free. "Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.
Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Gunner wrote:
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Yup, understand and agree with all of this. That's why I got a $6 collet rather than a $60 one to use with this $400 Rong Wei mill. What I'm wondering though is which (or both) is out of spec, and by how much. If it's the mill, I'll correct it so I have fewer future problems.
Back to the original question. Does anyone know how I find the specs on an R-8 shaft, specifically the index groove?
Oz

The 3/4' collet for Segway's Bridgeport measures 0.160 wide by 0.063 deep. (I'll take any excuse to zip around the factory, which is laid out like a race track.)
jw, who seems to have become the toymaker here. Not sure if that means elf or troll.

snipped-for-privacy@segway.com wrote:
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Thanks!

Sorry about that. I seem to remember looking up some information about r-8 stuff before, although that was a diameter dimension if I remember correctly. I'll look more carefully in the future.

Seems to be a common problem with Shoptask 3in1. Common cure is to set up a boring bar in your vice and lower the spindle of the mill onto it while spinning.
cheers T.Alan
Rich Osman N1OZ wrote:
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The Shoptask machines use a Morse taper #3 spindle- maybe you are thinking of Smithy which has R-8 models.
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