Anyone know the thread size count gamo

[shady816]

i ordered a new barrel for my cfx but i will have to thread the reciever end of the barrel, does anyone happen to know what thread count size this is ,it does not match anything i have.

[Truman]

It will be metric for sure! Check the diameter of the thread then you can look it up here! ie, an M18x2.5 will have an outside diameter of 18mm (or a tad under) and a pitch of 2.5mm! The thread will be a 6o deg 'V' type thread where as I think your American threads are all 55 deg 'V? type threads! (I may be wrong on the American threads though!)

Just noticed you want to thread your barrel!! OK, with a vernier, check the inside diameter of the thread! Now look on the link for the drill size that matches! Note what thread that refers to and buy a metric bolt of that size! Try the bolt in the receiver to make sure it is correct, then you need to cut the same thread on the barrel! I'm just a little worried about concentricity and thread tolerance if you are going to use a die to cut this thread! You will also need an undercut at the end of the thread to get a decent mating of the two parts!

http://www.engineershandbook.com/Tables/tapdrill.htm

[Truman]

Buy the way, There are also special metric threads which have different pitches, for example M18 can be 2.5mm course pitch, or 2.0 or 1.5mm fine pitch! Just be aware of that!

[shady816]

Thanks Truman i will be using the lathe to thread it if mine is capable of making a metric thread . i spoke with gamo tech today and he said he would talk to the gun smith and give me a call back but we all know how thats going to go. the od measures 12.75mm i do not see any thing that relates to that measurement.   i think i have it at 13mm x 1.0 i will get a bolt to test.

[Truman]

Typical of Gamo to use an obscure thread, next thing you know it will be left handed!!! Good luck chasing it anyway.