Thread: Mainspring, Re-holing
09-08-2013, 03:50 PM #1
1. Cut off old hole
2. Clamp the spring in a vise for a heat-sink. Anneal about 4 inches of the end of the spring. Heat to cherry red, then withdraw flame slowly. If it cools too fast it may air-harden. Let it cool on its own; don't quench it.
3. Round the end of the spring.
4. Center punch the location for the hole.
5. Drill the hole.
6. Re-shape the hole with a Dremel. As you can see, I use a flex shaft, diamond bit.
7. Re-shaped hole should look something like this.
8. Make a sharp, straight bend at the front edge of the hole. The corner of the bend —and therefore the front edge of the hole— will press against the inside of the barrel, making it easier for the barrel hook to grab it.
9. The final product.
Last edited by bangster; 09-09-2013 at 01:06 PM.
09-09-2013, 02:05 PM #2
Re: Bang,s tutorial on re holing a main spring. (By: bangster)
You know, Bang, before I had that spring catch in the drill bit, I probably would have been OK with just using the drill press and a drill bit. But many of our new members don't have a lot of shop experience, and may be more likely to have the drill catch the spring than you and I are.
Here's a few pictures showing how I make a new hole, using a punch, and a pair of tin snips.
1. Trim and round off the end, using the snips and a bench grinder.
2. Select hole size (I used a 9/32" bit).
3. Line up punch to put the hole where you want it.
4. Punch the hole.
5. Dress the hole to as close to the shape of the old hole as you can make it. A dremel, or a hand file can be used for this. Also make sure the hole and the end are free of burrs.
Have a close look for any cracking on the spring, then lube and install in the barrel.
Thanks Harold; this contribution is more valuable than everything presented in the discussion thread.
Last edited by bangster; 09-09-2013 at 10:07 PM.harold bain, Member ch 33
"If it won't "tick",
let me "tock" to it"
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