1870 Trapdoor Front Sight Removal

[school of mines]

What is the best method to remove and re-install a front sight for an 1870 trapdoor springfield? Any advice would be appreciated!

[StrawHat]

Al Frasca would be the fellow to ask.

http://www.trapdoorcollector.com/m70.html

I am not sure if they are soldered or dovetailed in place. Don't have one handy to check but Al will know off the top of his head.

[oksmle]

The front sight on my carbine consists of a blade pinned into a slot, cut into a base which is soldered onto the barrel. Simply apply heat to the base & it should pop right off.

[KCSO]

The front sight base is brazed on and should not POP OFF with a little heat, you will need to get the barrel red hot. The blade itself is pinned in place and the tapered pin can be drifted out. The blade can then be removed. In the old days Marbles made a bead sight tat replaced the trapdoor blade but now you will have to make one by working down a dovetail type sitht. The blade can also be replaced with a silver or brass blade to center the sights at 100 rather than 300 yards. I tapped the front hole in the base and use an eyeglass screw instead of the pin and I can now switch sights by undoing a screw.

[oksmle]

KSCO .... I'll stand by what I said. On both my Springfield carbines it only took a small amount of heat from a propane torch to remove the bases. Were mine "oddballs?" Maybe....

[docone31]

A propane torch can loosen brazeing, depending on how thick the item(s) are.
If the barrel was thin at that point, where the front sight was, then the heat from the flame would be able to melt the brazeing and the sight pop off.
Propane can be amazing to use.
When I have large items, I sometimes go to propane to do the silversoldering. If it is a large bezel, the large heat of a propane torch will work, where my smaller Little Torch will not.

[KCSO]

Bronze brazing alloy melts at about 900 degrees F, a propane torch will put out a maximum of 1900 degrees, but is a little lacking in btu's to actuall braze anything but the smallest of parts. If you use a propane torch to POP off the front sight you are having to heat the barrel for a long time and you end up with the whole end of the barrel almost red hot before the braze gives. By contrast a air assisted or a Mapp Gass torch gives out about twice the heat and best of all a regular Oxy acetelene not only gives more heat but it will do it quick enough that only the sight and the metal underneath gets real hot. In addition before I ever heat a barrel to braze on a sight I coat the inside with lamp black to avoid oxidation of the inside.

So, Yes a propane torch CAN do the job, but a good cresent wrench can do it too. I tend to think in terms of doing a job in the best professional manner and I make my recommendations on that basis. I prefer to braze on a sight by heating just enough to do the job.

[13Echo]

If the sight bases on your carbines came off easily with a propane torch then it is likely you have a cut down rifle rather than a true carbine that had the front site bases soldered on. Also I think the 50-70s and the early 1873s had a one piece sight base and blade. Later models had a pined front sight blade.

Jerry Liles

Jerry Liles.

[school of mines]

Thanks for all of the input! I tried to use a Mapp gas burner, but didn't get it hot enough. I like the idea of the oxyacytlene torch to re-install the sight, since I don't want to heat any more of the barrel than I absolutely have to. Brazing the sight back on would be very durable and I think I'll use that method.

Again, thanks for everyone's input. I'm rebuilding a project 1870 trapdoor in 50-70. I've replaced the rusted in place/frozen firing pin, extractor, extractor pin and spring! The breech bolt is ready to go. I had to cut the barrel down and recrown it since it was bulged about 2" from the muzzle. Now I will remove the old front sight and then re-install it. After this is complete, I'll be after a new stock!