What size countersunk screw is this?

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  • What size countersunk screw is this?
  • Premier Icon Northwind
    Subscriber

    A2-70 isn’t the size, it’s the grading- A2 stainless, 700n/m tensile strength.

    At a guess the one on teh left is an M6 (6mm wide thread) and the one on the right is an M5 but can’t tell from the pic. What are they from?

    Important- countersunk bolt lengths include the head, which is unusual and confuses people. Normally to measure the length, it’s the shank only not the head. Guess how I found that out!

    Premier Icon Simwit
    Subscriber

    A2 is the grade of stainless steel. Being a countersunk screw the size is measured as the outside diameter of the threaded section by the overall length.

    Edit, too late

    Moses
    Member

    Can you show a pic of a ruler as well? Scale is important!

    Premier Icon kayak23
    Subscriber

    You should have put them in front of a London bus or something for scale.

    Edit – yeah, or a ruler… ^^^

    whatnobeer
    Member

    I really need to find one the same size as the one on the right (i think) for my mech hanger. Currently it’s being held in place by the qr only and makes taking the rear wheel out a bit of a faff.

    Premier Icon Northwind
    Subscriber

    Oh! Mech hanger bolt might be very small indeed. What bike? and what is the one on the left from?

    Measuring the thread of bolts is very easy to get wrong, do you own a set of calipers by any chance? Or, maybe one of those adjustable spanners with a scale on it?

    Premier Icon scaredypants
    Subscriber

    have a look on here – the guy seems to have a shitload of stock and talks a good game regarding how comprehensive his catalogue is

    (If you have a vernier gauge, it’ll give you the dimensions to compare with as well)

    ackie
    Member

    Yes it’s for a rear derailleur hanger for my Santa Cruz Stigmata.

    I ordered the new hanger (over a year ago) from the distributor but I pretty sure they sent me the wrong one as although the hangers themselves are very similar the new one came with a much larger bolt (M5?)
    When fitted (with the smaller bolt) there is some play (1-2mm)between the frame and new hanger.

    ackie
    Member

    On the left is a A2 70. What is the smaller one on the right?

    Are they measured by head width and thread length?
    If so could it be an A3 50(mm)

    whatnobeer
    Member

    2009 Norco Fluid LT here, just a little bump to see if anyone else can help 🙂

    shandcycles
    Member

    I’m sure the guys at BETD could help :

    BETD

    but I bet it’s M4 x 8 mm

    ackie
    Member

    So the the upshot is. Santa Cruz bizzarrely do not make a M3 bolt version of the hanger (which came fitted to the frame) so my only option is get the frame tapped for M5 bolt so I can fit the new hanger securely!

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