J. Blanch & Son 12 Bore Damascus: hammer spring replacement required

[fizzbangwhallop]

I've got a nice J.Blanch & Son of 29 Gracechurch Street damascus barrelled hammer 12 bore which has been nitro'd but I've posted this enquiry in here as it used to be black powder and there's probably more chance of someone who knows in this section.

The RH hammer has a tendency to perforate the cap (depending on the make of cartridge) on firing and having looked at it more closely I think this is down to the spring being noticeably stronger than on the left so I'd like to replace it with one to match. The firing pins were replaced a couple of years ago and it hasn't done much work since.

So I'm after someone reasonably local to fit a weaker hammer spring to her or failing that any recommendations as to a source for these springs. I'm quite happy to remove the LH spring in order for it to be matched.

Any advice and suggestions gratefully received.

Best wishes

Fizz

[enfield2band]

The RH hammer has a tendency to perforate the cap (depending on the make of cartridge) on firing.....

Any advice and suggestions gratefully received.

Best wishes

Fizz

Hi,
I think that if hammer is perforating the primer then it will be because the pin is too long. You need to hone it down gradually, or you could try swapping the pin over to the other barrel, and vice versa, and see if it does the same. It is how far the pin travels that is the deciding factor, not the strength of the spring, (unless you get mis-fires).
Primer hardness tends to vary so I would not use that as a guide.

ATB.

[fizzbangwhallop]

Thanks for the reply Enfield, much appreciated.
Having had another look I feel it's possibly a combInation of an over strong spring and a slightly over length pin.

It's not a recent problem and this is it's third set of pins, there is evidence of pitting on the face around the f/pin hole, on the nose of the f/pin and, more significantly, I've noticed the fence is being flattened by the underside of the hammer.

The nipple isn't obviously shorter but I guess it's a combination of several minor things but I would like to start with a lighter spring.

Atb
Fizz

Just had a look at the results from the British Side by Side Championship held at Sporting Targets last weekend and it scored a 72. Pleased with that but it wasn't in my hands.

[enfield2band]

Thanks for the reply Enfield, much appreciated.
Having had another look I feel it's possibly a combInation of an over strong spring and a slightly over length pin.

It's not a recent problem and this is it's third set of pins, there is evidence of pitting on the face around the f/pin hole, on the nose of the f/pin and, more significantly, I've noticed the fence is being flattened by the underside of the hammer.

The nipple isn't obviously shorter but I guess it's a combination of several minor things but I would like to start with a lighter spring.

Atb
Fizz

Just had a look at the results from the British Side by Side Championship held at Sporting Targets last weekend and it scored a 72. Pleased with that but it wasn't in my hands.

Hi Fizz,
There could be more than one problem here?
The pitting, as I am sure you know is caused by the hot gases escaping from the perforated primer.
I am surprised that it has had three pins so far. Is this on the one barrel? If it is then your thoughts on the spring may be right.
But, Could the fault lie with the firing pin or nipple? If the pin is not tempered hard enough it might be getting deformed by the hammer blow which is causing it to protrude too far into the breech. Or, is the nipple too soft and that is deforming and allowing the pin to travel too far?

The fences being damaged by the hammer sounds to me that the inside face of the hammer has worn out. With old blackpowder guns they braze in a small plate or put some weld in. There is a danger that you can ruin the temper of the hammer by doing this but so far I have not heard of any breaking.

I'm clutching at straws here: Is it possible to use a spring balance and and get a reasonably accurate idea of how much force is need to bring the hammer/s to full cock. If you can arrive at an average you are happy with perhaps you could try a hammer gun in a shop and see what pressure they need. It may cast some light on your problem?

Alternatively, on fleabay there are sometimes pairs of sidelocks or pairs of back action locks for sale. The springs might not suit your gun but the supplier might have access to spare parts or be able to advise where you can get new/replacement springs if you need them.
Go to "hunting" "accessories" and select "used" this will narrow down the amount of items you will need to trawl through.

Hope this helps.
Atb.

[RichardH]

Your issue is pin protrusion not spring pressure.

Swap the pins over to confirm this then shorten the bad one in line with the good.

Peterdyson.co.uk is a good source of springs and pins but i suspect a simple shortening will sort things

Rich

[keith66]

Your issue is pin protrusion not spring pressure.

Swap the pins over to confirm this then shorten the bad one in line with the good.

Peterdyson.co.uk is a good source of springs and pins but i suspect a simple shortening will sort things

Rich

J Blanch was a top notch gunmaker, the gun will be how old ? 100years? I cant see for a minute the spring being too strong. Pins have been replaced there lies the problem. Sounds like it needs a decent gunsmith to make sure its replacement firing pins are up to the quality of the rest of it.

[fizzbangwhallop]

Morning all,

Following Enfields reply I've had a closer look.....

The hammer isn't making contact with the fence as I can see daylight although not as much as on the left hammer.

The nipples are not identical and I assume that the RH has been replaced at some point, perhaps the original RH had suffered sufficient wear to allow the hammer to contact the fence leading to the damage there. Quick Measurements: Overall: LH 10.17mm RH 9.59mm. Height of nipple ie 'exposed' height: LH 4.79mm, RH 4.49mm

The inside faces of the hammers do shows signs of peening but are about equal and not excessive.

The pins are in good condition having actually been replaced in Sept 2009 (Time flies ) the tops ends are still chamfered with no signs of wear, the ones they replaced had taken on the 'rivet' effect showing signs of thickening and peening over.... more so on the right with the heavier spring.
Quick measurements: Overall length: LH 20.4mm, RH 19.78mm. Above skirt LH 8.10, RH 7.67. Below skirt LH 9.57, RH 9.25 which suggests that they were tuned to the barrel/nipple.
The difference of .3mm matches the rough n ready measurement of the difference in the exposed height of the nipples.

I also measured the pin protusion from the face with the (non-rebounding) hammers in the fired position and the LH actually protrudes more at 1.89mm than the LH at 1.69mm - it's only the RH that occasionally perforates the primer. The RH pin does have some play in it.. perhaps it is stroking across the face of the primer rather than a straight forward strike?

The barrels a nicely tight to the face closing with the perfect click, various makes of cartridge including some 40/50 year old Eleys sit perfectly in the chambers with no difference in headspace.

Which brings me back to to the hammer spring pressures.... using a spring balance held in the nick between the hammer and the ear, the LH spring starts to move at about 9lbs but the RH starts at around 18lbs!!

So, I can only really conclude that the root of the problem lies in work done, however many years ago now, to replace the spring and the nipple on the right hand lock. Possibly the stronger spring was fitted first, that flattened the original nipple leading to the damage to the fence. I'm happy that the work done replacing the pins has been done with care to get an equal strike (I did measure the pins at the time to allow for less development work next time and there were differences between them).

I'm still open to suggestions but a new and weaker spring in the right would be a good place to start methinks.

Many thanks for the replies, watch this space.

Cheers

Fizz

[enfield2band]

Morning all,




Which brings me back to to the hammer spring pressures.... using a spring balance held in the nick between the hammer and the ear, the LH spring starts to move at about 9lbs but the RH starts at around 18lbs!!

I'm still open to suggestions but a new and weaker spring in the right would be a good place to start methinks.

Many thanks for the replies, watch this space.

Cheers

Fizz

Hi Fizz,
It does seem that you have narrowed down the problem and confirmed your original suspicions.
The difference in spring pressure is enormous!

Is the RH spring thicker than the LH one?
I would definitely get a weaker spring like you intended to do.

Atb

[fizzbangwhallop]

Hi Fizz,
It does seem that you have narrowed down the problem and confirmed your original suspicions.
The difference in spring pressure is enormous!

Is the RH spring thicker than the LH one?
I would definitely get a weaker spring like you intended to do.

Atb

Hi Enfield,
Yep, I was surprised by the difference and although I haven't had the locks off I think that's a good way to go for a start. I'll give the gunsmiths who did the pins a ring in a bit and go from there.

atb
Fizz

[fizzbangwhallop]

Well, I've just taken the locks off and the RH spring is a lot more substantial than the left as expected.

Just tried to add a photo.... but not the easiest thing in the world to do here!!

Interestingly the locks are marked "J Stanton"

atb
Fizz

[enfield2band]

Hi Fizz,
It looks as though you have solved the problem.

Gunmakers out-sourced some parts which is probably why the locks are stamped J.Stanton.

When I can find my spring balance I will try the hammer on my muzzleloading Enfield. The spring on them are very strong. I suspect it will come out at about 18lb like the RH spring on your gun.

Atb.

[DJS]

It should be possible to thin down the stronger spring to bring its strength down to match the other one. If you were closer I could do this for you.
Daz

[fizzbangwhallop]

Morning all,
Thanks for the offer Daz, that's an option I hadn't known about - it is a bit of a cart spring in comparison.
I did speak to Ladbrook & Langton's who've done all the work on it since I inherited it from my dad - the quick n easy solution w'be to shorten the pin a touch.

I also spoke to a helpful lady at Peter Dyson re- a new spring but it w'be expensive.

Then I found J Blanch themselves over in Cheddington, Beds/Bucks. That's not far from me n worth a visit to see if they can do anything. Just waiting on the email response. My other option for a quick spring fix c'be the gunsmith over at Broomhills SG where the Aitken Grant & Lang label is/was.

That's me for now, more next week no doubt.

Ath
Fizz

[fizzbangwhallop]

Just spoken to the chap at J.Blanch and will be popping over to see him in the morning.

He did raise an interesting point which I hadn't actually thought of..... that the travel on the pin might be excessive.

So, out with the digital vernier again.. on full travel the pins protrude from the face by approx 2.77mm on the left and 2.75mm on the right.

With the hammers down and the pins resting back against them, the measurements were RH 1.89mm & LH 1.69mm.

The difference between these is LH .88mm and RH 1.06 so the RH has an extra .18mm of travel.

Overall length of the pins is 20.40LH and 19.78RH. Maybe, although it doesn't protrude any further than the left, the RH pin has the ability to travel further gaining more momentum along the way.

My brain hurts.... but I still get the feeling that the stronger spring is the root cause.

We shall see........

atb
Fizz

[enfield2band]

Hi Fizz,
After exploring all the possibilities I think you are on the right track about the spring. If it is much thicker and the pressure need to pull the hammer back is almost twice as much as the LH hammer then I think a new spring is the answer.
I am not well up on metric but is .18mm about .008" thou? If it is that is not much of a difference.

I hope your trip to the gunshop solves your problem so you can use the gun again without any worries about the primers being pierced.

It will be interesting to know how you get on. Please keep us informed.

Atb
e2b.