Author Topic: Main spring  (Read 1040 times)

Offline greyhawk

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Re: Main spring
« Reply #25 on: April 22, 2019, 09:33:58 pm »
Uberti mainspring
Can see here the difference in curve - mine has two distinct bends with a flat area between
full cock pic is as I shoot it - has enough whack for federal primers proly would need another half turn pressure to set off a winchester primer

third pic is the new made mainspring for my 1886 chiappa - 75 thou thick spring and narrowed to .245 width at the front end - only just strong enough for the job! proly could improve it by wedging into the top of the retainer slot rather than the bottom - gun has done about 80 shots without coming undone.   

Offline Cliff Fendley

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Re: Main spring
« Reply #26 on: April 22, 2019, 10:06:32 pm »
OK, I took a pic of the original spring with the action closed. There isn't any difference when closed or open. There also isn't any real room to be cutting a groove in it either. I guess I'll have to send the new springs back to VTI as they are worthless to me, get my $60 back. I wonder if an email to Cimmeron might help? To get a spring from them, or contact Uberti?


What's wrong with the new springs from VTI? I thought they were a bit longer which would be better.
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Offline King Medallion

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Re: Main spring
« Reply #27 on: April 22, 2019, 10:11:19 pm »
Cliff, they are longer, but alot thinner. Old spring is 0.09, new spring is 0.06 on my calipers. I got some shim stock from work, going to fiddle with that before I try Hawk's way. New springs have near zero tension on them.

Offline greyhawk

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Re: Main spring
« Reply #28 on: April 23, 2019, 05:51:54 pm »
Cliff, they are longer, but alot thinner. Old spring is 0.09, new spring is 0.06 on my calipers. I got some shim stock from work, going to fiddle with that before I try Hawk's way. New springs have near zero tension on them.

Thats skinny ! the stock I used for my 86 mainspring is .75 thick and only just enough I reckon.

If you can shim/wedge one of those tightly up into the top of the slot and find a longer strain screw - might work ok. 

Offline King Medallion

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Re: Main spring
« Reply #29 on: April 23, 2019, 05:54:45 pm »
That's the plan.

Offline Cliff Fendley

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Re: Main spring
« Reply #30 on: April 23, 2019, 11:26:42 pm »
Cliff, they are longer, but alot thinner. Old spring is 0.09, new spring is 0.06 on my calipers. I got some shim stock from work, going to fiddle with that before I try Hawk's way. New springs have near zero tension on them.

That may not be a bad thing the old ones were pretty stiff anyway, I thinned and narrowed my Uberti 76 mainspring slightly for smoother action. I know these are not like main match guns and you want a good fast snap to the hammer for accuracy but I still don't like an action that gives a workout.

There may be some that cringe and have a fit when I tell you this but if it was mine I wouldn't hesitate to bend the spring right near tension screw. I trust that more than having shim in there that could pop out.

Look at Greyhawks pictures above, you can see the bend in the spring on his. Some are like this and some are not and I'm almost willing to bet those bends are added when necessary upon factory assembly.

I added a bend like that to the mainspring on a rifle of mine years ago and it's seen well over a thousand rounds since then with no issues. Others mileage may vary but never has given me any issues.

Edit, if you attempt to do that I wouldnt put it in a vice and bend it because you can put a sharp stress area in it. I did it by putting the spring on a piece of pine and using a round brass punch where I wanted the bend and hit the punch with a hammer. You don't want to put any kind of sharp pinpoint stress area and this creates a radius to the bend.
« Last Edit: April 23, 2019, 11:38:11 pm by Cliff Fendley »
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Offline greyhawk

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Re: Main spring
« Reply #31 on: April 24, 2019, 01:05:14 am »
That may not be a bad thing the old ones were pretty stiff anyway, I thinned and narrowed my Uberti 76 mainspring slightly for smoother action. I know these are not like main match guns and you want a good fast snap to the hammer for accuracy but I still don't like an action that gives a workout.

There may be some that cringe and have a fit when I tell you this but if it was mine I wouldn't hesitate to bend the spring right near tension screw. I trust that more than having shim in there that could pop out.

Look at Greyhawks pictures above, you can see the bend in the spring on his. Some are like this and some are not and I'm almost willing to bet those bends are added when necessary upon factory assembly.

I added a bend like that to the mainspring on a rifle of mine years ago and it's seen well over a thousand rounds since then with no issues. Others mileage may vary but never has given me any issues.

Edit, if you attempt to do that I wouldnt put it in a vice and bend it because you can put a sharp stress area in it. I did it by putting the spring on a piece of pine and using a round brass punch where I wanted the bend and hit the punch with a hammer. You don't want to put any kind of sharp pinpoint stress area and this creates a radius to the bend.

Cliff
To keep that spring in mine needed enough strain screw adjustment the trigger pull was atrocoius - soon as I backed the screw off enough to make a decent trigger, the spring walked forward out of the slot, took about ten to fifteen cycles, best fix I could figure was what I did with the dremel at the back end of the spring, could have got the same place by a different route by narrowing the spring I guess - that would have kept the geometry the same at the notch end - seems like this gun needed a lot of upward force to hold the spring in place - I figured those couple little grooves and shaping gave it a reason to stay put. Its nice now and a darn fine barrel in it .     

Offline Cliff Fendley

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Re: Main spring
« Reply #32 on: April 24, 2019, 01:07:31 pm »
Cliff
To keep that spring in mine needed enough strain screw adjustment the trigger pull was atrocoius - soon as I backed the screw off enough to make a decent trigger, the spring walked forward out of the slot, took about ten to fifteen cycles, best fix I could figure was what I did with the dremel at the back end of the spring, could have got the same place by a different route by narrowing the spring I guess - that would have kept the geometry the same at the notch end - seems like this gun needed a lot of upward force to hold the spring in place - I figured those couple little grooves and shaping gave it a reason to stay put. Its nice now and a darn fine barrel in it .     

Gotcha, yeah whatever it takes sometimes that works.

What I was referring too was his new springs had no tension at all so he needs to add some tension in order to use those longer springs. Hopefully being longer they would stay in but rather than being like yours I would put the bend in the spring behind the strain screw so the hump would have to climb the strain screw in order to walk out. 

I personally haven't had any issues with mine coming out even when I thinned and narrowed the spring and backed off the screw.
« Last Edit: April 24, 2019, 01:10:37 pm by Cliff Fendley »
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Offline greyhawk

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Re: Main spring
« Reply #33 on: April 25, 2019, 12:46:55 am »
Gotcha, yeah whatever it takes sometimes that works.

What I was referring too was his new springs had no tension at all so he needs to add some tension in order to use those longer springs. Hopefully being longer they would stay in but rather than being like yours

 I would put the bend in the spring behind the strain screw so the hump would have to climb the strain screw in order to walk out. 

That makes sense - I was too chicken to mess with my spring in case I snapped it
When I made the new one for my 1886 Chiappa - used your technique - ball pein hammer on the dolly hole in my anvil - to get the correct curve into the stock I used (a recoil starter spring from an old lawnmower I think) - I cheated this - ground and cut the fingers with a dremel to fit the stirrup (cheap set of diamond burrs for the Dremel have been really useful - can drill a hole in a piece of spring without messing with temper.) 


Offline King Medallion

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Re: Main spring
« Reply #34 on: April 25, 2019, 04:00:28 pm »
So, I cut a couple slivers of .20 shims and put them under the tension screw. 1 shim didn't seem to be enough, but 2 felt good. Action is smooth and trigger isn't bad at all. This is with one of the VTI springs, I sent the other back. Next time out will see how things go. I levered and dry fired multiple times, so far so good. Will report after next outing.


Offline King Medallion

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Re: Main spring
« Reply #35 on: July 04, 2019, 02:19:30 pm »
Took Thumper out today. Action and trigger pull is very smooth. Did have a couple misfires/light strikes tho. But the spring stayed in place. Was shooting imr 4198 with laser cast 350'so today fireforming for uberti chamber. Must be a dandy load as there were zero misses in 50 shots. Milk jugs became mist. Rocks became gravel. Walking target became flying target.  Very very good shooter.

Offline dusty texian

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Re: Main spring
« Reply #36 on: July 05, 2019, 08:18:29 am »
Hello KM , sounds like you had a good time shooting your 1876 . Make's me want to get out and do some shooting . ,,,DT

Offline King Medallion

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Re: Main spring
« Reply #37 on: July 05, 2019, 10:29:51 am »
It was fun, despite the heat and humidity, and the occasional misfire. I tightene up the main spring tension screw a 1/4 turn, all the way in now. hope that helps. Did you get my PM?

Offline dusty texian

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Re: Main spring
« Reply #38 on: July 07, 2019, 10:51:56 am »
Just seen it and sent you a reply . ,,DT