belleview washers

[rfair]

A guy came to use my range yesterday and he had replaced the firing pin spring with a sleeve bushing and some belleview washers. He said the lock time was faster and I would say he's right after shooting it myself!
My question is how many of you have used or do use these washers in place of your firing pin spring?

Thanks!

 

[Robert]

A guy came to use my range yesterday and he had replaced the firing pin spring with a sleeve bushing and some belleview washers. He said the lock time was faster and I would say he's right after shooting it myself!
My question is how many of you have used or do use these washers in place of your firing pin spring?

Thanks!

Randy,

Belleville washers, or better Spring Discs, are used on the CGs, RPA Quadlocks, Milleniums, Inch actions, and quite a few Swings and Paramounts have been transformed to the system here in Europe.

The system allow:
-A significant reduction of firing pin mass and travel.
-As the spring discs have no pre-compression, there is no load on them when decocked, hence no long-term fatigue or need for replacements.
-Belleville washers are made to much stricter specigications than coil springs.
-Thhe discs stack need not to be higher than about 1.100 to 1.500 depending on firing pin travel, the movement is also reduced to minimal, each washer having an unit compression of some 0,15mm (.0063 inch).

Not any bolt can be transformed to the system, as washers of the right specification (minimal 250Newton compression force) are to be no smaller than 3/8 or ½ inch OD, this making the ID of 3/16 (already very small a diameter for a FP rod) or 6mm-.250’ for the ½ OD ones, more ideally suited.. The later are the one used in the designs above.

There must be enough clearance in the bolt inside bore, as the spring discs works best when guided by their ID, not from their outside diameter.

Transforming to the system does not allow full advantage if the Firing Pïn travel and eventully mass are not reduced at the same time. This implies a re-cutting of the cocking ramp and Sear alteration to relocate with the Trigger Sear.

For instance, the modification of the Swing-Paramounts were reducing the FP travel from .250 (and over for the former ones) to 5mm (.200) and even 4mm(.160) Re-cutting the cocking ramp is not an easy task.

R.G.C

 

[Moderator]

FYI,

"Robert" is Robert G CHOMBART, chief designer of the RPA Quadlock, Millenium and other actions, and the CG Jackson trigger.

It's great that Robert could provide such knowledgeable advice!

 

[Robert]

FYI,

"Robert" is Robert G CHOMBART, chief designer of the RPA Quadlock, Millenium and other actions, and the CG Jackson trigger.

It's great that Robert could provide such knowledgeable advice!

Mr Moderator,

An honour and my pleasure, Sir

R.G.C

 

[rfair]

I thank you for replying and with all do respect he did do it and took the bolt apart and showed me although I shot it { a 6mm br } and was not impressed with the accuracy.
I was just wondering why I'd never heard of doing it? I read everything I get my hands on!

 

[Robert]

I thank you for replying and with all do respect he did do it and took the bolt apart and showed me although I shot it { a 6mm br } and was not impressed with the accuracy.
I was just wondering why I'd never heard of doing it? I read everything I get my hands on!

Randy,

I would be interested to know what action it was?

Yours sincerely
R.C.C

 

[rfair]

It was a mauser action!
I think he had to turn down some belleview washers to get them inside of the bolt, couldn't get the right size and also reamed the bolt!

 

[butchlambert]

You can get belleville spring washers in all types of sizes and compression. I use quite a few of them.
Butch

 

[Robert]

It was a mauser action!
I think he had to turn down some belleview washers to get them inside of the bolt, couldn't get the right size and also reamed the bolt!

Randy,

The principle of using the Julien Belleville’s invention as an energy pack for a Firing Pin would be to make full use of a given washer speiifications. There is a close relation between their ID and OD, the minimal one being 1 to 2. For instance 3/16 x 3/8 , .250 x .500 , 5 x 10mm or 6,2x12,5mm. I indicate the aboves as they are the best suited in terms of diameters, compression range and force (the later varying with the thickness of the disc, in our case, best being .020’’ or 0,5mm. Those spring discs has a some 290-300 Newtons force at 75% compression, allowing them to be used at some 50% of their compresson range and 60% of their maximum p/f. I have always calculated it for 190Newtons (42lbs) for a 4mm FP travel and a given firing pin mass.

Use of Belleville allow to reduce considerably the length o the spring: For a .250 inch FP travel, each disc being used at, say, 0,12mm compression, the total amount of washers fitted in opposite would be some 53. This gives a stack height of 1.770 inch for the range of washers indicated above

In the case you mention, reducing the spring washers outside diameter reduces also exponentially their compression capacity and increases their force same, up to the point of making them almost incompressible plain washers..

I see it difficult to increase the Mauser ID of the bolt without impairing the Shroud threads. The Firing pin diameter could have been reduced from its original 8mm, but, then, how to fix it again in the sear piece?. The 10mm travel of the FP and the limited capacity of the modified washers meaning a considerable amount of them being installed all the way long the (long) firing pin.

If the transformation cannot result in:
-Reducing the springs stack height.
-Hence the mass of the spring (and those of the whole firing Pin BTW)
-Also reduce the Firing Pin travel…
I do not see the point worth the effort.

The range of target actions using the Belleville spring discs were specifically designed for it, with very short and light firing pins and travels.
R.G.C

 

[AJ172SBCT]

I just love these technical discussions, especially when they come from somebody as knowledgeable as you are Mr. Chombard, thank you.

Jacques

 

[Kenny474]

Is there a site I could go to so I could see an action that uses these washers, and how they are assembled inside the bolt? I am very curious as to how it all works, and I understand the concept, but would like to see it so I can have a greater understanding. Thanks to any that help.

Kenny

 

[butchlambert]

The way they are stacked make a difference. You can go to Century Spring www.centuryspring.com to see a variety of them and the tech specs.
Butch

 

[Robert]

Is there a site I could go to so I could see an action that uses these washers, and how they are assembled inside the bolt? I am very curious as to how it all works, and I understand the concept, but would like to see it so I can have a greater understanding. Thanks to any that help.

Kenny

Kenny,

http://www.actionclear.com.au/docs/6-2,FIRINGPINASSEMBLY.pdf

Under this link there is a cutaway of a bolt specifically designed to be equipped with a Belleville system.

I have photos if different fittings, but I should be particualrily idiot as I mm unable to post a picture here...

Any question, please, ask.
R.G.C

 

[habu]

FWIW, - MSC has a huge selection to choose from.

http://www1.mscdirect.com/cgi/nnsrhm?&KNC-T7L391316886

ron

p.s. robert, a true story will be coming your way soon.

 

[woody_rod]

Here is a picture of the belleville system in exploded view:

Posted on Robert's behalf.

 

[Robert]

The way they are stacked make a difference. You can go to Century Spring www.centuryspring.com to see a variety of them and the tech specs.
Butch

Butch,
The way they are stacked makes a difference, yes, but not in the positive direction in this case.
The Belleville can effectively be stacked:
-Opposite by single pairs. In this case the ‘power’ value is the one of the single unit, but the deflection is the addition of each of the washers in the stack, and this is what counts in this specific application, in which we have to try to obtain the maximum of travel with the minimum of washers compressed at no ore than 60%. In the picture kindly posted by Woody, the number of washers is 33 (16 in opposited pairs +1) ID 6,2mm x OD 12,5mm x Th. 0,5mm. Nominal force at 75-80% compression = 298Newton. Force at cocking compression = 205 Newton. FP travel 4mm. Total weight of the spring = 11,8 grames or .416 ounces. Total weight of the firing unit when assembled; 52 grammes (1.834 ounces)…I leave it to you to weight any ‘conventional’ assembled FP ……

-The washers can be stacked in multiple pairs, as you state (2x2 , 3x3 , etc) but, In this case, the force adds, but the compression capacity remains those of a single washer. It would then be necessary to increase the number of washers therefore the length of the stack by 2 or 3.. to obtain an equivalent total compression.

As I said, those imperatives limits the choice of useful Bellevilles to very little:
-Inside diameter, dependant of the FP diameter. This can hardly be under 3/16’’
-Outside diameter, dependant of the available bore diameter in the Bolt. This can hardly be much over ½ inch in most cases, but some march actions allows more eventually.
-Thickness corresponding to the required specifications.

Quickly looking into both imperial and ISO specifications, I see 2, maybe 3 only possibles in each one.
R.G.C