Need metric thread help

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BEARMAN

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A friend has a PEDERSOLI ROLLING BLOCK all drilled and tapped for a tang sight. My friend has the tang sight but no screws. The catalog says 4x10mm and when he ordered them they turned out to be the plugs to fill in the holes when you don't have a tang sight.. I believe 4 is mm and the size of the screw. Is the 10 the pitch of the thread or the length? I am unsure of the metric method , if it was 1/4 x 28x 1" I would have an idea ,with metric I am at a loss. Any one know where to look ,only need 2 of the little devils to see how well this .45-70 shoots.
 
Could be 4mm x 1.0 4 is the diameter 1 is the pitch in mm (1 turn = 1MM) is the way I believe it works. Quick google says 2 common threads are 4.0 x .70 and 4.0 x .75. Sounds like the screws are 4mm diameter and 10mm long, so you need to find out the pitch.

Andy
 
I had the same problem when I ordered my rear sight. Bring it to your local gun shop and let them try to match it up.Just because it say's the thread doesn't mean it actually is that thread pitch.

Second would be a well stocked fastener supplier, i.e. Brafasco or the bolt bin's at Canadian tire or Home depot.
 
Metric thread call out is not the same as imperial. In metric the pitch is not specified in the call out so typicaly you would see something like M4 x 10mm. Major diameter is 4 mm and then the pitch is determined thru the metric charts if it is fine, course ect. and anything after that would be the length of the fastener.
 
Had the simuliar problem finding metric screws and found them at a hobby shop called pms hobbies supplies here in calgary . They specialized in radio conrolled cars and planes and such and had all the right size metric screws and bolts that i needed . The local bolt supply houses where rather useless.Hope this helps.
 
BEARMAN:

The major diameter is 4mm, the pitch is .7mm and the length of the bolt is 10mm not including the head. Post here what head type you are looking for and I will look for some at work. If I can find what you are looking for, I'll send a few out to you in an envelope - no charge.
 
Threads

Rather than torture yourself trying to find a metric screw with the correct size blued fillister head go to the local gunsmith or machinist and have him run a standard 8 x 40 tpi tap into it and you will find screws at any decent gun shop to mount the tang sight. D.H.
 
You can get metric screws at just about any industrial supply store and even Home Depot or Canadian Tire. Look in the liitle bins.
If you are only looking for 2 button head cap screws places like Fastenal may even give them to you. It is not worth the paperwork for 40 cents.
 
Thanks everyone, I managed to get some at HOME DEPOT, M4-6, M4-12, AND M4-16 in 3 different lengths and 2 different head shapes . I will try them on his gun this weekend, we may need a finer thread but we have something to start with. Thanks again.
 
#8 X 40 cannot be found in a machine shop... trust me, I tried several. We have no gunsmiths in this town so I ended up ordering several taps online. They are a hard tap to find.
 
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