counter sinking on ali

Discussion in 'Engineers' Talk' started by dvddvd, Jan 9, 2006.

  1. dvddvd

    dvddvd Well-Known Member

    Want to counter sink some screws in 2mm thick aluminium flat pieces, will be fixing the ali with 4 gauge screws, will the screwfix HSS 12mm counter sink bit be o.k or is it to big ? many thanks
     
  2. britishblue

    britishblue New Member

    It's fine. Just take it slowly, and check regularly with a screw as you progress, until it reaches the correct depth. With such thin sheet, if you go too fast, you could end up with a huge hole instead of a countersink.

    Before you start, have you checked the depth of the countersunk part of the screw to make sure that it can be accommodated within a 2mm thick sheet.

    BB
     
  3. jasonb

    jasonb New Member

    Yes,it will be OK but the Ruko ones give a smoother finish but the smallest they will do is a 3.0mm hole as the tip is 2.5mm .

    Use a slow speed when countersinking, and a bit of parafin is a good cutting fluid for ali.

    Jason
     
  4. Hitch.

    Hitch. New Member

    As jason says, a little cutting oil will work a treat on ally.
     
  5. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    Use a 6 or 7mm HSS drill-bit and you will make the clearance hole less big than you will will a countersinker, normally.

    Tad more care needed not to go right through.


    Mr. HandyAndy - really
     
  6. Hitch.

    Hitch. New Member

    Yeah that will be cracking on 2mm ally.... as soon as its bit you through and ****** :)
     
  7. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    Yeah that will be cracking on 2mm ally.... as soon as
    its bit you through and ****** :)



    Some of you really do need to get a bit more experience.



    Mr. HandyAndy - really
     
  8. Hitch.

    Hitch. New Member

    Yes, good job you reminded me. I will do some practice tomorrow.
     
  9. problem

    problem New Member

    Handy-andy you daft knob, im sick of your idiotic comments, Hitch is clearly correct. A drill bit is not a countersink. This poster wants to do the job properly not a bodge like you recommend.

    Passy - Really
     
  10. Bob Property

    Bob Property New Member

    Yeah that will be cracking on 2mm ally.... as soon
    as
    its bit you through and ****** :)



    Some of you really do need to get a bit more
    experience.



    Mr. HandyAndy - really

    Handy - I think you need to buy some new HSS drills - yours are obviously blunt.
     
  11. problem

    problem New Member

    Handy-Andy you complete fool, Hitch knows what hes doing, yes i am aware he spent one year as a sheet metal worker and 80% of the work was ally you ****!

    Now, **** back off to B&Q at your own pace.

    Passy
     
  12. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    You idiots. If you don't know how to control a drill and a drill-bit, you shouldn't be touching the stuff.

    In all my living years I have NEVER used a countersink on metal.

    I have ALWAYS used a HSS drill-bit of the appropriate size.

    As I said before, it makes the clearance hole smaller because of the lesser angle on the drill-bit.

    There is need of more control but a little practise(you don't push the drill with your foot to get the most pressure), piece ofpis.


    More practise, boys.




    Mr. HandyAndy - really
     
  13. problem

    problem New Member

    Its not the correct method is it?

    Thought not you idiot.

    Passy.
     
  14. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    A countersink countersinks.

    A drill-bit countersinks.


    What's not correct ?



    A pencil sharpener sharpens pencils.

    A stanley knife sharpens pencils.


    What's not correct ?

    Which one do you use. A stanley is not the correct tool.


    Mr. HandyAndy - really
     
  15. Bob Property

    Bob Property New Member

    Handy - at the start of this thread 3 different posters gave what to me seemed very reasonable advice. I don't know the skills of the original poster but he seems to have some idea what to do and was asking a sensible question in the circumstances. Your post about using a 6-7mm drill seems to be a retrograde step when the OP was already talking about buying a countersink.
     
  16. Bob Property

    Bob Property New Member

    A countersink countersinks.

    A drill-bit countersinks.


    What's not correct ?

    Using a countersink to drill holes with...and vice versa


    A pencil sharpener sharpens pencils.

    A stanley knife sharpens pencils.


    What's not correct ?

    Which one do you use. A stanley is not the correct
    tool.


    Mr. HandyAndy - really

    You obviously don't own any carpenter's pencils which says it all really.
    Goodnight.
     
  17. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    It's fine for people to recommend the use of a countersink.

    What I'm saying is that the job can be done equally as well, if not better in some cases, using an ordinary drill-bit that dvddvd may already have in his toolbox.


    I would challenge anyone here to make a better job with a countersink than I would with a drill-bit.

    The ONLY differences in the drill-bit method are that you have to exercise a bit of restraint not to drill through, AND the clearance hole will not be made as big as it would with a countersink(which is more than likely a benefit).



    Mr. HandyAndy - really
     
  18. jasonb

    jasonb New Member

    Handy, do you re-grind your drill bits to suit the csk angle of machine screws? the head will not sit correctly in the "flatter hole" produced by a twist drill and will leave a gap around the edge. This can affect the pull out strength of the fixing as well as looking unsightly.

    Jason (O level grade A - engineering theory & practice and 20 odd years Model engineering experience)
     
  19. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    Handy, do you re-grind your drill bits to suit the
    csk angle of machine screws
    ? the head will not sit
    correctly in the "flatter hole" produced by a twist
    drill and will leave a gap around the edge. This can
    affect the pull out strength of the fixing as well as
    looking unsightly.

    Jason (O level grade A - engineering theory &
    practice and 20 odd years Model engineering
    experience)



    As a matter of fact, I do. Mainly with wood bits though, as I find they drill better with slightly more angle.

    But for machine screws, I have always found that the countersink on them is at slightly less of an angle than woodscrews, so a drill-bit does work quite well with them.

    The main reason I use drill bits is because a countersink is not easily sharpened, but a drill bit can be sharpened until there is only shaft left, so economy and convenience really.

    You are correct in pointing out the angle though, but I must admit that the problem has never really arisen for me, as I have found that on tightening the screws the angle difference disappears.

    I do concede that it is not the perfect solution, but it's always worked for me.




    Mr. HandyAndy - really
     
  20. Mr Kipling

    Mr Kipling New Member

    A few basic rules,

    1) The counter sink angle is totaly different to that of a drill.

    2) To get a neat cut the counter sink MUST be have an odd number of cutting faces. Same goes for reamers. Otherwise you don't get a round sink.

    3) A drill should be ground at the correct angle for optimum cutting but, A drill should not break through the other side until it is cutting its full diameter. Where this is not possible you should counter drill first.

    Thats the facts, not gonna get drawn into being ****** though.
     

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