For whatever reason I can't figure this out. I have a sling swivel installed (by the factory) at the 6 o'clock position. I would like to install rails at the 3 o'clock and 9 o'clock positions. I just can't see in my head how to align the rails symmetrically. I do have a calibrated eye, but I'm going for something a little more accurate.
Installing side rails on a round AR style handguard.
- Thread starter weasel1
- Start date
This might work well enough to satisfy you.
Wrap a strip of paper around the tubular handguard.
Mark the overlap point - that will give you the circumference.
Fold the strip in half. Fold it in half again.
This will divide the strip into quarters.
Line up a fold with the center of the swivel. Using fold lines, make reference marks on the sides with a pencil.
Use a piece of angle iron, which will sit nicely on the tube, draw a pencil line along each side.
Lay out the mounting holes for your rails, center punch, drill and tap one hole.
Secure a rail, align the other holes on the pencil line, mark through the holes. Center punch, drill and tap.
If you are careful, your rails will be located within a few thousandths of an inch.
Wrap a strip of paper around the tubular handguard.
Mark the overlap point - that will give you the circumference.
Fold the strip in half. Fold it in half again.
This will divide the strip into quarters.
Line up a fold with the center of the swivel. Using fold lines, make reference marks on the sides with a pencil.
Use a piece of angle iron, which will sit nicely on the tube, draw a pencil line along each side.
Lay out the mounting holes for your rails, center punch, drill and tap one hole.
Secure a rail, align the other holes on the pencil line, mark through the holes. Center punch, drill and tap.
If you are careful, your rails will be located within a few thousandths of an inch.
