Recent content by dave-b

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    George Daniel's Watchmaking understanding!

    Thanks. I had completely forgotten wobble sticks. ( have a dedicated mandrel lathe which seems very accurate .I must do some comparative tests)
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    George Daniel's Watchmaking understanding!

    If the pump centre cannot be relied on, how is perfect concentricity achieved?
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    Levin thread cutting

    Mike, on a geared set-up, all you do for a left hand thread is to add an idler gear. Admittably, mine is on a Unimat 3. I probably rotate at about 60 rpm, torque is not a problem, I use a standard thread cutter for any size external thread. I do think yours is a great set-up, and probably the...
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    Levin thread cutting

    double post
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    Levin thread cutting

    Hi Mike, I am a bit confused (not unusual),but you say 25 - 100 rpm gave acceptable surface results under power, but surely that rpm is what you would get by hand cranking the spindle? dave.
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    Levin thread cutting

    Thread chasing ?
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    Pivot drilling lathe question

    Sorrry - fat fingers.
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    Help needed with Wolf Jahn tailstock

    Wefalck, I meant the flat pivoted link that joins the lever to the body has been renewed.
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    Help needed with Wolf Jahn tailstock

    I understand you now, but I still have to disagree. The sleeved tailstock is the historical interest. Once the cam hole is milled, all evidence is covered up.One example of a sleeved tailstock is shown in post 33. Here it is obvious why. Intuitvely I also assumed that all tailstocks were made in...
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    Help needed with Wolf Jahn tailstock

    You confuse me. The first picture show the collet holding spindle in place. It fits the sleeve, and holds 8mm collets.The drawbar is not present. Pics 2 and 3 show with the spindle removed, to illustrate the problem, which is that there is no cutout for the camlock. Or are you crticising the...
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    Help needed with Wolf Jahn tailstock

    Thanks Jerry, while I believe this to be un-altered and original, it has become for me of purely historic interest. I shall be doing nothing more to it. Thanks for everybody's help. Dave.
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    Help needed with Wolf Jahn tailstock

    double post
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    Help needed with Wolf Jahn tailstock

    No, what you see is the smaller bore for the collet meeting the slighly larger bore for the drawbar. There's no loose tube, but it's not a bad idea for clamping.
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    Help needed with Wolf Jahn tailstock

    Please see first post
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    Help needed with Wolf Jahn tailstock

    No problem Betzel. I am a great admirer of all things Boley, and can find no measurable difference in spindle position, locked or free. Same goes for other makes. It just shows that theory does not always apply to real life. Re. the original post, while I could easily find some way to lock the...

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Hard Life for Wristwatches by Roy Gardner