Replacing Meteor hinge pin with Bolt

[Dornfelderliebe]

I am currently seeking engineering advice on installing a Mercury S hinge bolt in my project Meteor.

The potential pitfall involves the folded metal breech jaws being unable to cope with a bolt being tightened due to there being a gap between the two pieces of folded over steel.
The factory pin fits through all four and the breech block, and as new the hollow gap is not a problem but as is known, can wear and create a wobbly barrel.

I have read John Bowkett welded up the gap then fitted an HW style bolt. I have a Mercury S hinge bolt. To fit this I need to enlarge the outer wall enough to pass the bolt head and nut through then clamp it down on the inner wall compressing it against the breech block for a tight lock up.
Done as I envisage the bolt would be flush against the outside of the jaws as per the Merc S

I wonder whether the inner wall will be strong enough with this set up assuming the outer walls are a good interference fit against the bolt head and nut.

Guidance from the engineering gurus warmly welcomed.

[trajectory]

Mmmmmmm...?..

How about drilling through the outer jaw & inner jaw with a drill diameter of the bolt, drill the outer jaw a larger diameter to allow a bushing with the diameter of the bolt in it. Cut to desired length & weld in place. The bolt head would be a bit proud but unless you filled the cavity I cant think of a way to countersink the bolt head unless you make it a bigger job by making a big hole in the outer jaw & use a thick walled bush that gives a bit more meat for machining it out to accommodate the head.

Must be other ways but that's my first thoughts.

[Shed tuner]

you will want to weld up the gap between the jaws on the inside of the holes (and then ream to tidy it).
Or use the bush idea as above.

[look no hands]

Would anything like chemical metal be good enough, you could fill the gaps up with that, it can be drilled and taped if needed when fully hard.

[NickG]

How about, if there is room between the jaws for shims , replace them with a top hat style bush that fits from the inside, and braze it in .

[crowbar]

Drill and tap 10mm through pivot hole ,cut two slugs off a 10mm bolt after drilling a pilot hole and glue into jaws,ream through
and tap to finish .

[evert]

If you fit an oversize pin that actually fits the breech and the barrel (the OEM Meteor bolts ar almost always undersied, I fit cut down Supersport bolts in mine), and then squeeze the jaws gently in a vise, you really dont need anything more.

[Dornfelderliebe]

Thank you Gents considerable food for thought there. I've just been looking at the pin more carefully and this what I did not expect to see.
The whole pin is blued but there are two polished rings at each end where the inner and outer jaw walls are.
Between these, there is a distinct band of unworn bluing corresponding the space between the jaw walls.
The centre part of the pin has almost no wear to the bluing suggesting to me that the pin, which was a very tight fit in the breach block, has not been turning within the breech block and therefore the jaws have acted as bearings.

[evert]

Thank you Gents considerable food for thought there. I've just been looking at the pin more carefully and this what I did not expect to see.
The whole pin is blued but there are two polished rings at each end where the inner and outer jaw walls are.
There is a distinct band of unworn bluing corresponding the space between the jaw walls.
The centre part of the pin has almost no wear to the bluing suggesting to me that the pin, which was a very tight fit in the breach block, has not been turning within the breech block and therefore the jaws have acted as bearings.

That is quite normal. The locking chisel on the Meteor/mercury/supersport pinches the pin/bolt, so it has to fit very tight in the jaws if you expect it to not rotate while cocking the gun.

[Dornfelderliebe]

Thank you Evert as usual the more I think I know the more I realise I don't know.
I think that should be my signature

[lightning22]

On an otherwise sound rifle I think there's an over-emphasis on clamping power, the point of a bolt as opposed to a pin is to stop the jaws spreading in the first place, rather than to force them together.

i do wonder if creating a fixed width via the 1/4" latching pin would create enough rigidity to ignore the much maligned axis pin.

[averageplinker]

Or buy a rifle with a bolt already fitted 😁

[Dornfelderliebe]

On an otherwise sound rifle I think there's an over-emphasis on clamping power, the point of a bolt as opposed to a pin is to stop the jaws spreading in the first place, rather than to force them together.

i do wonder if creating a fixed width via the 1/4" latching pin would create enough rigidity to ignore the much maligned axis pin.

A very good point

[Dornfelderliebe]

Or buy a rifle with a bolt already fitted 😁

But that would stop all my fun. Besides as somebody else said this is an itch I need to scratch.

[T 20]

But that would stop all my fun. Besides as somebody else said this is an itch I need to scratch.

Many moons ago in Sporting Air Rifle, a chap showed how he drilled and taped the ends of a BSA breech pin at 3 mm or 4 mm and fitted countersunk bolts into the ends of the bolt.

The trick is to alter the pin length in order to get the bolts to lock onto the end of the pin just as the bolt head nips the jaws tight.


All the best Mick