Author Topic: pivot pin questions? (Read 1075 times)

bikerbeans · « **on:** January 09, 2012, 04:47:21 AM »

Hi All,
Is the pivot pin splined on one end like the trigger group pins? Also, has any one accurately measured the pivot pin diameters to see how much they vary?
thanks
BB

quickdtoo · « **Reply #1 on:** January 09, 2012, 05:39:33 AM »

It's splined on the left also, only measured them with digital calipers, never measured with a micrometer. But my old Lyman mechanical caliper says they're .370", which they aren't!!

Tim

trotterlg · « **Reply #2 on:** January 09, 2012, 06:55:15 AM »

They are ment to be .375 but will probably measure more like .374 or so. Larry

gcrank1 · « **Reply #3 on:** January 09, 2012, 08:12:16 AM »

As if I dont have enough to do...........leave it to you, BB

........
I will pull my 'handy' ones apart and check all the pins ASAP.

bikerbeans · « **Reply #4 on:** January 09, 2012, 08:27:20 AM »

Thanks for the replys. Was just wondering if they vary enough to play mix and match for adjusting the gun's lockup. Also thinking about d/t on the ends of the pivot pin for a bipod mount that would be isolated from the barrel/forestock.
BB

smokehouserex · « **Reply #5 on:** January 09, 2012, 08:39:00 AM »

Hello Gentlemen:
Without trying to take someone's post, I have a question. I just put a 30-30 topper on a NEF SB1. I put a shim on the shelf and it took all the play out but I also placed a .005 shim on the forward end of the underlug with no effect. The question is, should I continue to shim it until I can get a tight fit on the front also?
thank you
HM

bikerbeans · « **Reply #6 on:** January 09, 2012, 09:00:12 AM »

Rex,

You need to properly shim or relieve the underlug pivot to achieve correct lockup before modifying the latch shelf. Any change to the pivot will effect the latch engagement. To me it sounds like you need a shim on the pivot and the shim you placed on the latch shelf is letting the latch engage but doesn't correct the loose pivot problem. See the FAQs sticky there is plenty of info on this.

Good luck

BB

smokehouserex · « **Reply #7 on:** January 09, 2012, 09:08:11 AM »

Hey BB:
Thanks, this is my first Handi mod. I'll start over and do the pin first.
thanks again.
HM

trotterlg · « **Reply #8 on:** January 09, 2012, 01:42:21 PM »

If you have one (gun) that has gotten slightly loose, just drive the pin out, rotate it 180 degrees and drive it back in, it will tighten up the action. Larry

gcrank1 · « **Reply #9 on:** January 09, 2012, 02:52:02 PM »

FWIW, I like to use a little pin lube on mine; there is high priced stuff for English (and other) doubles, but 'moly' grease works fine; a little dab will do ya!

tacklebury · « **Reply #10 on:** January 09, 2012, 03:12:58 PM »

I use my breechplug grease.

Very sparingly too.

mechanic · « **Reply #11 on:** January 09, 2012, 03:17:32 PM »

I'm thinking the factory might face off one side of this pin to custom fit barrels. I don't know this, but am guessing based on some measurements on mine. Mark the position of that pin if you want the same fit up, so you can put it back the same.

I have one receiver that I rotated the pin to fit a barrel as opposed to shimming.

Ben

gcrank1 · « **Reply #12 on:** January 09, 2012, 03:26:41 PM »

Hmmmm..........maybe they are a little eccentric to dial in at the factory?

trotterlg · « **Reply #13 on:** January 09, 2012, 03:36:01 PM »

No, they start out round, they get egg shaped from wearing out, they grind the barrel underlug to fit the frame at the factory. Larry

tacklebury · « **Reply #14 on:** January 09, 2012, 03:52:09 PM »

Quote from: trotterlg on January 09, 2012, 03:36:01 PM

No, they start out round, they get egg shaped from wearing out, they grind the barrel underlug to fit the frame at the factory. Larry

Perhaps it should be an annual maintenance thing to pop that pin and rotate it to best connection?

trotterlg · « **Reply #15 on:** January 09, 2012, 06:40:46 PM »

Remember, these guns are built for the bottom end of the price range, every thing they do building them is based on the cost to build, so when you are thinking about how they are made just think about how to make it with the least investment and cost of production and you will know how it was done. Larry

keith44 · « **Reply #16 on:** January 09, 2012, 07:13:25 PM »

This makes me wonder if an aftermarket pin could be made from "drill rod" or another hardened round stock. So that when a pin wears down a new one could be fitted.

trotterlg · « **Reply #17 on:** January 09, 2012, 07:22:43 PM »

The pins are not made from any thing special, just a good steel. An offset pin could be made to adjust the lockup, but you would need to ream the frame to a larger pin diameter to match it. It is simply easier to shim the barrel. Larry

bikerbeans · « **Reply #18 on:** January 09, 2012, 08:36:09 PM »

Larry,
What are your thoughts on trying to drill & tap the ends of the pivot pin? An 8-40 thread, blind hole about .12" deep?
BB

quickdtoo · « **Reply #19 on:** January 10, 2012, 04:59:38 AM »

Quote from: bikerbeans on January 09, 2012, 08:36:09 PM

Larry,
What are your thoughts on trying to drill & tap the ends of the pivot pin? An 8-40 thread, blind hole about .12" deep?
BB

That can be done, I have one that's drilled and tapped that I got from from another member here, ya want it?

Tim

bikerbeans · « **Reply #20 on:** January 10, 2012, 06:40:08 AM »

Quick,
Yes I would love to have that pin. I want to try to make a bipod setup for my 308x444 in the hopes I feel good enough to chase antelope out west next fall.
thanks
BB

quickdtoo · « **Reply #21 on:** January 10, 2012, 08:12:10 AM »

It's 10-32 threaded, are ya still at the same address? In the mail today.

Tim

bikerbeans · « **Reply #22 on:** January 10, 2012, 12:07:14 PM »

Same address, thanks Tim.

BB

gcrank1 · « **Reply #23 on:** January 10, 2012, 01:50:05 PM »

Kind of a 'swivel gun' pivot mount, BB?

; put it on the 45-120 for the 'wall gun' at the fortress.......

bikerbeans · « **Reply #24 on:** January 13, 2012, 02:12:15 AM »

The reason I asked about the spline on the pivot pin is I had a pivot pin move on an SB2 while at the range last month. I tapped it back into the place and forgot about it till later when it dawned on me it was protuding from the right side of the receiver. So I figured it must not be splined since it is exiting the receiver from the wrong side. Then I learn the pin is supposed to be splined so I go investigate and it is splined, but it will fairly easily move the wrong direction in the receiver. It will move all the way to the right side until the splines touch the rightside hole in the receiver and then it stops. Any thoughts on this?

gcrank,

No bipod on the 45-120, it already weighs too dang much!

BB

gcrank1 · « **Reply #25 on:** January 13, 2012, 04:44:37 AM »

Gunbearer....oh, gunbearer,
where art thou.......
(poetic license encouraged)

keith44 · « **Reply #26 on:** January 13, 2012, 05:19:10 AM »

so the splined end of the pin moves inward and the pin is freely moving until the splines reach the other side of the reciever

IMHO the splined hole has become enlarged and needs to be sleeved if this is even possible with these guns.

quickdtoo · « **Reply #27 on:** January 13, 2012, 05:31:29 AM »

I'd check with Brian, he may have some oversize hinge pins, another member had the same problem with the 3/16" pins.

Tim

bikerbeans · « **Reply #28 on:** January 13, 2012, 10:21:29 AM »

Quick,

Got the d/t pivot pin today, thank you very much. Will install it over the weekend and then start building an adapter to mate it to a Harris type bipod.

I decided to Bubba-Engineer the loose pivot pin on my one SB2. Quick set epoxy.

Will up the anty to JB weld or Loctite Black Max if the epoxy doesn't work. If the glues all fail then I will try silver solder.

BB

quickdtoo · « **Reply #29 on:** January 13, 2012, 02:06:39 PM »