Picatinny Rails

[dewey-1]

I am making a 3D CAD model of Picatinny Rails.

I cannot locate the following dimensions:

1) Mounting holes diameter

2) Mounting holes center to center

Could some one please measure with a calipers and help me out.

I have a rough "guesstimate", but I would prefer an accurate measurement.

Handguard Picatinny Rails
Short rail is 1-3/8 inches with 2 mounting holes.

http://www.valhallaarmory.com/Picatinny ... ctar02.htm

long rail is 3.5 inches with 3 mounting holes.

http://www.valhallaarmory.com/Picatinny ... ctar03.htm

[jackssmirkingrevenge]

I'd love to help out but what I have is these dovetail adapters (and they're Weaver, not Picatinny) without mounting holes.

It doesn't seem like there's a standard size for these holes either though, have a look.

[dewey-1]

JSR

I used that Mil spec drawing to create the rail profile.

I am guessing the hole centers are on a multiple of 10mm (.394 inches)because that is the center spacing of the "posts".

Can you give a hole size on your rails? Also screw size, 3mm or 6-32 American

I am thinking around 3.5 mm or maybe .140".

Center to center probably varies depending on application.

Some rails have slots for various centers.

[jackssmirkingrevenge]

Can you give a hole size on your rails? Also screw size, 3mm or 6-32 American

If you're referring to the holes at the top of the rails, there are none in my adapters:

[dewey-1]

JSR

Yes, I see what you mean now!

You are mounting to an existing dovetail on the "launcher".

I was thinking the rail was screwed to a flat surface.

I maybe SOL and have to make a wild a$$ guess.

Thanks!

[Demon]

http://www.hawkeoptics.com/us/chairgun/index.php

Could this be used for spudding?

(off topic)

[jagerbond]

Dewey,
What is this going on?

[jackssmirkingrevenge]

Could this be used for spudding?

It's very useful for airgunners who fire consistent professionally made projectiles through consistent professionally made rifles, but in our realm of relatively amateur fabrication, GGDT is a much more useful tool

[USGF]

JSR

Yes, I see what you mean now!

You are mounting to an existing dovetail on the "launcher".

I was thinking the rail was screwed to a flat surface.

I maybe SOL and have to make a wild a$$ guess.

Thanks!

Dewey,
Yep we often buy them blank and machine our own specific hole patterns to mate up with whatever we are affixing this to. #6, 8, 10 and 1/4 SHCS, LHCS, FHCS are most often used. I don't know if you have run into this. We have lying around about 10 different brands or rails. When measured against so called Mil Spec drawings, NONE match. We tried looking at Weaver specs and the same thing. Seems most rails are a hybrid of the two combined? BTW, a lot of rails makers do not stick to the 10mm spacing.

[dewey-1]

So much for a so called "mil standard".

Guess I will just use what fits the application.

I will use M3x.5 SHCS and go with multiples of 10mm spacing.

That way the holes are between posts.




edit: add rendering

[jackssmirkingrevenge]

beautiful as always