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  1. #1
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    Default More from Switzerland - an Erlach Drill chuck

    About a month ago, a fellow was selling some of his father's gear on eBay and amongst that gear was a 1/64 - 3/8" No.2A Erlach chuck. It was Swiss and unused and I was interested. A Google search revealed a suggested association between the Swiss firm Bergeon and Erlach, an eBay seller reckoned that Erlach chucks were supplied by Bergeon as accessories for their beautiful watchmaking lathes, and another seller said that Emco offered Erlachs as a more accurate drill chuck option for their Unimats than whatever their standard chuck was. And that was it.

    The auction started at 20 dollars with a "buy it now" of thirty. I hummed and harred about dropping 30 bucks on an unknown so I placed a bid not long before the auction's end. I'd been outbid so another bid four seconds from the end made it mine. I mentioned the acquisition to my friend and fellow forumite, Piers and it was " ...k me!, you were the other bidder!! ". Had we both known a bit more about the chuck the seller might have been happier.

    6 (Large).jpg

    My enquiries continued and after a post on the Schaublin Lathes Yahoo Group's site, I received some replies, one from William Brem who posted photos of a number of his Erlachs and suggested that Erlach may have been the original supplier of drill chucks to Schaublin.

    William's chucks -

    IMG_0059.JPG

    The chuck arrived in the mail and it would not open. The application of some 3 in 1 oil managed to provide some movement but it was rough. I dismantled the chuck, cleaned, regreased and reassembled it and gave it a test mounted on a 1/2" straight shanked J2 arbor. The results looked promising, less than ''0.001 TIR with the arbor mounted in a 1/2" P20 collet in the 13's dividing head.

    DSC_9657 (Large).jpg DSC_9662 (Large).jpg DSC_9676 (Large).JPG DSC_9678 (Large).JPG

    To gain the greatest advantage from the Erlach, it needed to be mounted on a 12mm straight arbor which would allow its insertion in an ISO 30 collet. These collets do not project beyond the 13's spindle nose thereby saving precious Z. I toyed with the idea of making an arbor from 4140 but ended up pursuing the lazy alternative of modifying the 1/2" arbor. The downside of that option was the mutilated centre hole in the J2 end.

    To remove arbors from chucks that won't accommodate wedges, Jacobs suggest drilling through the soft centre of the chuck and punching the arbor out with a drift through the hole. Invariably the arbor's centre hole is damaged. To reduce the shank diameter to 12mm it needed to be turned between centres because it would then be possible to grind it between centres. The mutilated centred required reboring. I used a Borite boring bar which has a cutting edge about 1mm in length. Worked well.

    IMG_20180719_135403082 (Large).jpg Capture (Large).jpg

    Whilst I could grind the arbor, a comment Peter Fou made about it sometimes being easier to get close with the lathe then finish off with abrasive paper rather than fool around with the grinder stuck in my mind ( Peter sold me the Hercus tool and cutter grinder ) and that's what I ended up doing. The arbor is 12.00mm in diameter. The M6 tapped hole in the arbor's end is to facilitate its removal should the need arise.

    IMG_20180719_160202759 (Large).jpg IMG_20180719_160215723 (Large).jpg

    With the arbor securely mounted and the chuck in the 13's spindle , TIR is a hair over 0.0005". Not too bad for twenty nine dollars plus postage!

    BT

    IMG_20180719_161136403 (Large).jpg

  2. #2
    Join Date
    Apr 2009
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    Ballina N.S.W.
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    Default

    Hi BT
    Another nice piece of Swiss precision tooling to add to your collection, and at a great price as well. I am surprised that the knurling outer has not cleaned up better. I recon that will not sit well with you, I know I would not like it.
    Bob

  3. #3
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    Default A Homage to Toblerone !!

    Hi Bob,

    The brown isn't rust. The key body has the same finish. The well greased chuck came in its original cardboard box and was wrapped in corrosion inhibiting paper. The body showed no signs of corrosion. I just used a brass bristled brush and kero to clean it as I did with the sleeve.

    Bob.


    DSC_9673 (Large).JPG

  4. #4
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    Default

    Hi BT,
    That explains it,thanks. When I saw the picture of William Brem's chucks that you showed I thought the knurled body's looked liked a bit dark, I suspected that they had originally been blued and were just showing a bit of age. I have never seen a brown finish like that before. I assume it is some sort of rust protection.
    Bob

  5. #5
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    Default

    Hi Bob,

    Erlach weren't the only ones to use that brown finish. The photo below is of the 13's drawbars. Close to identical colour.

    Bob.

    IMG_20180720_091503635 (Large).jpg

  6. #6
    Join Date
    Aug 2011
    Location
    Melbourne
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    Default

    Bloody hell Bob. You never cease to amaze me how you sniff out a beautiful piece of work!

    Thanks for sharing. I never realised there were such things as precision drill chucks. They look very unassuming to the untrained eye!

    I also like the way you tell a story. Makes reading your posts so enjoyable.

    Simon

    Sent from my SM-G900I using Tapatalk
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  7. #7
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    Default

    Simon,

    Precision chucks exist but at a price 1st Drill Chucks The best please.

    I do have a beautiful little 0-1/8" Albrecht chuck that I purchased second hand from the States on eBay. It is accurate but probably not as accurate as the Erlach but it will close to zero. I also have a collection of Jacobs Super Ball Bearing chucks that aren't as accurate but do not slip. A problem with buying second hand chucks is that you never know if they have been the victim of a crash. Two of my ball bearing chucks and another Albrecht have bent bodies. Outwardly they look good but their excessive run out suggests a major collision and probably explains their appearance on eBay.

    The photos below show the Albrecht mounted in a Jacobs 14N, a combination used to successfully drill a 0.57mm diameter hole 8mm deep in a piece of 1214. An example of using the run out in the two chucks to arrive at a pretty well centred drill. Took some fiddling though!

    Bob.


    IMG_20180623_112206119 (Large).jpg IMG_20180623_114658761 (Large).jpg

  8. #8
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    Default

    Using two chucks to cancel out the runout similar to mounting precision bearings. Now thats smart!

    Simon

    Sent from my SM-G900I using Tapatalk
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  9. #9
    Join Date
    Nov 2008
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    Perth WA
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    Default

    No Simon, just lucky.

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