Making an ER collet holder for obsolete mill taper
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    Default Making an ER collet holder for obsolete mill taper

    I want to make an ER 25 holder for an obsolete mill. The shank will fit the mill taper. There is not enough diameter for a stock straight shank ER 25 holder in a mill specific collet.

    Is there a source for a ER 25 plug gauge that won't break the bank?

    The taper could be checked with a ER collet with a ground rod inserted in it to hopefully hold the diameter,, but I do not know if it will be accurate enough.

    Another approach would be to buy a ER 25 holder with a larger shank, and turn it to match the mill taper. I would need to turn the shank to diameter, cut the taper, externally thread the end, then mill a keyway. Seems like carbide might have a tough time with a hardened holder- is this an application for a CBN tool?

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    What is the taper in your machine? I am suspecting that if it is obsolete, it may only be small and an ER25 collet and its holding capacity will be too much for your machine.
    Easy enough to make a new collet holder with the outside taper on it to suit your requirements, harden and grind, then you're away

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    Quote Originally Posted by stoneaxe View Post
    I want to make an ER 25 holder for an obsolete mill. The shank will fit the mill taper. There is not enough diameter for a stock straight shank ER 25 holder in a mill specific collet.

    Is there a source for a ER 25 plug gauge that won't break the bank?

    The taper could be checked with a ER collet with a ground rod inserted in it to hopefully hold the diameter,, but I do not know if it will be accurate enough.

    Another approach would be to buy a ER 25 holder with a larger shank, and turn it to match the mill taper. I would need to turn the shank to diameter, cut the taper, externally thread the end, then mill a keyway. Seems like carbide might have a tough time with a hardened holder- is this an application for a CBN tool?
    What do you consider an "obsolete" taper?

    Can you not get a face mill or shell mill holder for it?

    ER's are sold on plate-mounts as well as on toolholders & straight shanks.

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    I would get a cheap ER 25 straight shank collet holder and attempt to turn shank to the correct taper. My cheap-o CTC tooling ER25 straight shank collet holder can be cut with a file so if you have a reasonably ridgid lathe turning it with carbide should be a non-issue.

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    Quote Originally Posted by thermite View Post
    What do you consider an "obsolete" taper?

    Can you not get a face mill or shell mill holder for it?

    ER's are sold on plate-mounts as well as on toolholders & straight shanks.
    VN "C".
    I have collets, end mill holders, shell mill holders etc.
    It would be nice to have an ER holder for odd ball sizes, drills, reamers, etc. Plus the VN does not have a ton of vertical room under the spindle, the ER would mean less table moving (I think) for tool changes, as the collet is so much shorter than the VN C.

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    I turned a number of ER collet chuck shanks. It can be done quite easily with carbide tooling. I got the final size and finish with a toolpost grinder.

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    Quote Originally Posted by stoneaxe View Post
    Plus the VN does not have a ton of vertical room under the spindle, the ER would mean less table moving (I think) for tool changes, as the collet is so much shorter than the VN C.
    any ER collet chuck will add to stick out from your spindle nose and reduce the head room under the cutter. I don't know the dimensions of the VN C taper, but even if you could get the ER collet (whatever the size) to sit in the chuck partially within the spindle you'd still need space for the wrench flat and collet nut. I dunno, maybe an inch, inch and a half? My R8>ER25 collet chuck sticks out about 2".

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    Quote Originally Posted by stoneaxe View Post
    VN "C".
    I have collets, end mill holders, shell mill holders etc.
    It would be nice to have an ER holder for odd ball sizes, drills, reamers, etc. Plus the VN does not have a ton of vertical room under the spindle, the ER would mean less table moving (I think) for tool changes, as the collet is so much shorter than the VN C.
    You want "short" PQD-Marlin Tool list a "provide your own specs" shank for their VS and S series quick-change system. Shoot them the Van Norman specs. They might even have them in old files, already.

    Quick Change Tooling • PDQ Marlin Tool

    I have some of each on 40-taper and a bastardized DIY #9 B&S modified off 30-taper.

    A VS needs all of one half of an inch clear to get one holder out, the next one in.
    Mind - most of mine are Weldon-style side-locks, but I actually LIKE side-locks, given I don't HAVE no 10K plus-plus RPM spindle CNC-critter.


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    Quote Originally Posted by thermite View Post
    You want "short" PQD-Marlin Tool list a "provide your own specs" shank for their VS and S series quick-change system. Shoot them the Van Norman specs. They might even have them in old files, already.

    Quick Change Tooling • PDQ Marlin Tool

    I have some of each on 40-taper and a bastardized DIY #9 B&S modified off 30-taper.

    A VS needs all of one half of an inch clear to get one holder out, the next one in.
    Mind - most of mine are Weldon-style side-locks, but I actually LIKE side-locks, given I don't HAVE no 10K plus-plus RPM spindle CNC-critter.

    Thanks! This looks like a very useful idea- I will have to do some reading on their site. New to me!

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    Quote Originally Posted by stoneaxe View Post
    Thanks! This looks like a very useful idea- I will have to do some reading on their site. New to me!
    ONE master collet adapted. THEIR proprietary short cone and triangular drive flange, thereafter. High-precision goods, both are.

    Spindle itself no longer a player. Drawbar need not be messed-with. Spanner on the locking ring right in front of yer face, thereafter.

    Advantage? PDQ-Marlin Tool still MAKE their adapters. Brand-New. In the USA, even.

    Just not "for free"!

    Slick system though. Time saver, even. Durable, too. Very! Tasking the cone with precise locating, but off-loading driving force to the triangle is key to why they can outlast other quick-change systems.

    Lasts long enough to pay-back its costs. More than once over.

    Yah can learn to love that combo.



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