Author Topic: Tang sight for rolling block (Read 880 times)

JCP · « **on:** January 28, 2004, 02:03:57 PM »

I am building a 45/70 on a no.5 remington rolling block action and would like to drill and tap the tang to accept an origional sight . The screw spacing is 1.940, could anyone tell me the screw size and threads per inch for the mounting holes?

John Traveler · « **Reply #1 on:** January 28, 2004, 05:42:09 PM »

I just installed a tang sight on a RRB recently.

The screw size all depends on the exact make/model of tang sight you are using. It would be best if get the sight in hand before you mark and drill the holes. It would also help assure that you get the hole spacing correct. Also, your sight screws made be metric, and you would have to either find new American standard screws or metric taps (ugh!).

I used 6-48 screws and drilled with a Number 31 drill. You can also use 8-40 screws and drill with a Number 29 drill. Some sights use two different size holes, combining 8-40 and 10-40 screws.

The smaller diameter screws can be used because the screws and the holes in the sight base are countersunk and center themselves. The larger screws are stronger, of course.

HTH
John

JCP · « **Reply #2 on:** January 29, 2004, 08:14:20 AM »

Thanks for the info John but I would like to use the same size screws that the origional had.

marlinman93 · « **Reply #3 on:** February 07, 2004, 02:46:57 PM »

The original Rolling Blocks were a 10-40 screw. Be sure to use a very strong drill bit when drilling that tang! RB's have some of the toughest metal anywere! You'll wear out a lot of standard drill bits, before you get it drilled. Also, be very careful tapping, and use lots of cutting oil, or you'll break a tap.
I annealed my tang before drilling, to allow D&T for a tang sight. A Mapp gas torch does this easily, and will prevent an incident with a broken bit or tap.
Hope this helps.

ssdave · « **Reply #4 on:** February 08, 2004, 07:09:45 AM »

I have to respectfully disagree that the original rolling block tang sight uses 10-40 screws. All I have ever seen use a 10-28 screw. I have heard of 10-32, but have never seen one. The 10-28 tap is expensive and hard to find. Victor Machinery Exchange (http://www.victornet.com/cgi-bin/victor/index.html) has them and the best price. MSC also carries them. I would recommend using whatever screws come with the sight you select, since you're starting with a #5 action anyway so there's no real question of authenticity. If you want an authentic sight, try the Axtel Riflesmith sight. It's an exact copy. BTW, it uses a 10-28 screw.

dave