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Thread: How Large a piece can be held in a chuck?

  1. #16
    Everything i have read says not to use countersink screws with faceplates and to only use pan head type screws. Have you had any problems with heads breaking?

  2. #17
    Join Date
    Mar 2018
    Location
    Melbourne Australia
    Posts
    79
    Quote Originally Posted by Chris A Lawrence View Post
    Everything i have read says not to use countersink screws with faceplates and to only use pan head type screws. Have you had any problems with heads breaking?

    I take your point and have used this work action when working in railway line systems around 45 years ago. Also, when fabricating steel, I've used rivets, nothing countersunk with them.

    However, the face plate that came with my Revo Laguna 24-36 lathe that I bought last year, came with countersunk holes; suggesting that countersunk bolts or screws were the go.

    The Vicmarc face plate rings that I have, are all countersunk and I have had some pretty big pieces of timber hanging off of them.

    Another thing to remember is that of the various chucks I have seen and used, all of them had countersunk retaining holes for their respective bolts to hold the chuck jaws in.

    Attached are my Vicmarc chuck face plate rings and the OEM face plate that came with my lathe; which I have never used.

    To specifically answer your question; no.

    Mick.



    Face_Plate_IMG_20190426_132249_Web.jpg Face_Plate_IMG_20190426_132411_Web.jpg

  3. #18
    These allfastener pine screws are ruspert coated, which is basically a fancy (but excellent) galv like coating over carbon steel. The research I have seen here shows that stainless screws have the best longevity for CuAz and ACQ timber treatment, and ideally 316/A4 not 30, see:

    Stainless Screws in Copper treated Timber

    And a range of stainless decking screws

    Quote Originally Posted by Mick Fagan View Post
    "Originally posted by John K Jordan" What kind of exterior screws? Do you mean what is sold as deck screws at Home Depot, etc?


    John, I used what is virtually a generic term in Australia, for external use construction of treated pine timbers. Decking screws are usually different as decking is in this country usually hardwood, sometimes really hard hardwood. Stainless steel is often used for these and in the case of our own decking, required pre-drilling to prevent any timber cracking and to allow the stainless steel hob nails used, to work correctly.

    I did a small bit of research on the matter, eventually contacting a major supplier for advice. Their advice was to use treated pine screws as for my intended purpose they would suffice, they directed me to their appropriate web page for more information. Scroll down past the first text and pictures to the bottom of the page text, where some clearer information is available.

    https://www.allfasteners.com.au/prod...ed-pine-screws

    Eventually I was able to find some good gripping screws for green wood, compared to normal screws. I have found that green wood can at times be quite flexible, with fibres moving a bit over time and with the forces used by turning making the screws sometimes come slightly loose. This can be seen with the attachment where there is a standard 80mm wood screw alongside a 76mm long treated pine screw. The treated pine screws that I eventually found and use, have a greater holding capacity in very wet wood.

    As for the type of driving head, my preference in descending order is Square drive, Pozidriv and lastly, Phillips drive.

    Mick.


    Attachment 408665

  4. #19
    Join Date
    Mar 2010
    Location
    Quorn United Kingdom
    Posts
    536

    Phillips screw heads are designed so that the screwdriver will cam-out (slip) if too much torque (power) is applied. The reason is that this prevents the risk of the screw head being twisted off by a power tool. This can be helpful, because if the head breaks off, a screw is very difficult to move.
    The Phiilps design is often criticized for its tendency to cam out at lower torque levels than other "cross head" designs. There has long been a popular belief that this was a deliberate feature of the design, to assemble aluminium aircraft without overtightening the fasteners Extensive evidence is lacking for this specific narrative, and the feature is not mentioned in the original patents. However, a 1949 refinement to the original design described in US Patent #2,474,994 describes this feature.

    Pozidriv screws, on the other hand, are designed specifically so that the screwdriver head does not cam-out.

    https://www.accu.co.uk/en/p/126-what...zi-screw-heads
    Last edited by Brian Deakin; 06-03-2020 at 9:53 AM.

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