Home Forums Hunting & Shooting Gunsmithing NECG barrel band front sight install question

My barrel diameter is .805. Do I just buy the .827 inside diameter model and use an epoxy to install or do you buy the next smaller size? They mention you can stretch them to fit, curious about how you do that and what tools are required. Thank you

You buy the size closest without going over. You can use a lathe to bore it to size, or you can make a mandrel for which to forge or stretch it a little through the use of red heat and a hammer. I prefer the lathe method myself.

When I purchase a banded front sight, I take time to measure the barrel as to the small/large diameters on the ends of the band position on the tapered barrel. Of course, if the barrel is straight tapered, then life is somewhat easier.

I try to buy on the order of 0.020" undersized to what my smaller measurement told me. If there is a good sale, then I do wonder into somewhat smaller sizes and do more work to stretch them. Keep in mind, that stretching way too much can cause the metal to fatigue and split; so there are some limitations to......too small.

I have heard/read of the mandrel and lathe methods in fitting these sights. I have used the mandrel and flat faced hammer many times to fit the band to the barrel. For a mandrel, I either make up one that is the taper of the barrel or use an old barrel with that taper. One drives the banded sight onto the mandrel, then applies hits to the band with the flat faced hammer. This is done several times usually in iteration. One plus of this method is that the front and back of the sight band fits very closely. I use either Brownell's 44 soft silver solder or Loctite 620 for affixing. I find that either is very strong, and stands the bluing tanks; with the nod for ease of cleanup to the Loctite retainer. After a bit of hammering, one learns how/where to hit to get the desired movements in metal. I have not found that heat is necessary for stretching as the bands are pretty soft.

I have read about the lathe method but never could come to grips with that method on my own. I was always afraid of crushing or slippage, but read that it works ok, just never done it that way.

The banded ramps are all straight bored, to include the undersize of the ramp itself; so one cannot just cut a straight relief on the front of the tapered barrel. With the hammer/mandrel method, one can apply hits to the band to move the ramp around easily, as well as stretch the band itself. Obiviously the flat hits have to be draw filed out etc for appearance.

Perhaps someone will post about how to do the boring in the lathe in more detail sometime for me to learn more about how the ramp's underside is handled.

Have to admit the working time and cleanup ease of the Loctite 620 takes some of the hassle out of the affixing to the barrel. 620 wipes up easily with acetone.

Just some ideas to consider, the working of the straight boring of the band as it comes is the main effort for a nice fit on a tapered barrel.

Remember to measure fore/aft on the final positioning on the barrel.

Malm,
When you use the lathe method are you using a 3 or 4-jaw chuck? One would also presume that the ramp portion of the banded sight is facing inwards and not out.

I too would be interested in the specifics of the lathe approach fitting on these banded sights to a tapered barrel.

The metal in these bands and ramps is pretty soft and malletable, works fairly easily with a mandrel and hammer in my case, but the clean up is a bit laborious. It would be nice to get rid of the cleanup work.

I was always tense about the taper on the ramp end of things and how to hold etc. Guess smallish cuts with a boring bar? The folks requesting the work seem to always want a very fine fit and straight on the barrel etc........

I will say that I have used adjustable reamers in the past. Depending on the ID of the band and the desired ID, more than one adj. reamer may be required.

I use the 4 jaw chuck and adjust the compound to match the taper you need. I just use a boring bar. Take a light pass and test fit the barrel into it without removing the sight from the lathe. I just put a mark on the barrel and keep taking light passes until it fits.
Don

I have been trying to think about the methods mentioned here for banded sight fitting.

The red heated band over a mandrel kinda bothers me, as that is the storied method of Ruger's fairly permanent application of banded sight to muzzle of their rifles. Does one have to worry about getting it on the mandrel and not getting it off? The mandrel or trial barrel is a pretty good heatsink one would think.

I read with great interest the posting about the lathe approach. It seems prudent to mount the sight in the lathe with the ramp mounted outward from the chuck, otherwise a lot of reindicating.

Question on the indicating, one would think that a few different indications down the band's interior would be ok to see if it was really concentric. Obivously done without power, but only a partial revolution can be done. Same indicator run down the ramp's undersize as well? NECG says straight bored, I have not used the lathe method before, but getting ready to try it.

Since the ramp is unsupported, a real light cut is probably the way to approach. It is an obviously interrupted cut out there on the ramp, and the ramp is flexible, can one achieve the fine fit that the customer's demand? Many fine passes with the manual compound movement to get it down to slipping to position on the muzzle?

I suspect that the actual barrel is used to set the angle on the compound, ie indicator mounted on the toolpost and the stylus run on barrel surface.

Just curious about the lathe method and getting rid of the labor in the mandrel/hammer stretching method in fitting/finishing. The front bands do not grow on trees here, so trying to be careful before I make an expensive piece of scrap. Just trying to think out the detailed methodology.

I do appreciate the posting on the lathe approach, something to start with. Just trying to pick up things to learn/do.

Red you have a PM

FWIW, I just finish installing a NECG banded front sight. In lieu of using adjustable reamers, I used the lathe. For reference purposes, the band had an ID of .650, and the OD of the barrel was .665.
I indicated the band, ramp towards the spindle, in a 4-jaw chuck. To avoid marring the band with the chuck jaws I 'wrapped' it with a small aluminum strip cut from a 'beverage' can. Then I used a boring bar, hand turning the chuck initially, to take out the required amount. I then turned the process over to 'power' - very slow feed, and about 300 rpm. After each cut I stopped and inserted the barrel thru the spindle into the band to check for fit, as well as from the front. When I got the point where the barrel would just enter the band from the front, but not when inserted thru the spindle, I took a .002" cut. At that point I removed the band and checked for fit, again, and again. With a little effort, some light heat, and a little tapping with a rawhide mallet, was able to get the band positioned where I wanted it, and the ramp resting properly on the barrel. With the band press fit on and aligned, I made an index mark thru the hole for the allen-head screw. With that done, I let the barrel and band cool. After cooling I masked the barrel to mark the rearward position of the ramp, as well as placing an index mark on the ramp and masking tape for alignment. From there I set-up the barreled action in the mill, and drilled a .125" dia, .015" deep pilot for the allen-head screw.

After all the machining was done, the barreled action was set in a vice, the band and barrel degreased, and band aligned and affixed with Loctite 620 (acquired from the local Fastenal), and the allen-head screw tightened. Cleaned up the excess 620 with acetone and that's how it sits as of now. I'll have to wait to see if my effort paid off.

As a second thought, and I may try this on a piece of scrap, but I'm wondering if one could mask off the band and ramp, apply a release agent (Brownells, One-Shot, paste wax, etc) to it, remove the band, clean and degrease the band again, and reinstall using the 620 and see if release agent will work with the 620.