So what thread are the screws?

bobt

Well-Known Member
I have a couple of damaged screws on my scope mount, I got a couple of spares from the gunshop, but they are too big, just called into the local engineering supply place,

they had a 4mm screw that wouldnt go in, but the 4mm nut fits the old screw perfectly as well as the 4mm.

is there a 3.9mm?
 
Errr what mount is it?

European?

American?

British?

Have not got a clue as to what you have so cannot even begin to think what size the thread might be.
 
there is the problem,
its a Tikka 595 with a Leupold scope, not sure what mounts I bought from Bradford shooting supplies,

so the gun would be metric, the scope may be imperial.........
 
I have asked my other half and he says to try 3/16 UNF (24TPI) whatever that means
 
Could also be a ba screw thread. If you can get a screw for metal sheeting (The bolts with the big flat heads, or the screws from an electric junction box both have slightly off metric values. Once you locate the thread it is easier. Pity yo were not clser I have boxes of odds and sods,
Jim
 
they are almost certain to be 4mm, and probably cheap chinese ones at that, they are well known for being undersize on the shank, it sounds as if the pins have been overtightened at some stage, go back to engineering shop and ask for an electricians 4mm tap, if they haven't got any go to electrical wholesalers they'll definately have some, these taps have a moulded plastic handle attatched to them and are generally used for cleaning threads in conduit boxes and are reasonably priced, next size down is 3.5mm and these screws are used for fixing switches and sockets to back boxes, it may be that these fixings are spurious b@st@rd threads, no, not swearing it's just what they are called, they won't be anything other than ISO metric unless they are of american origin, so borrow, beg or buy a 4mm tap and you'll find that will cure your problem.....callie
 
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