Just read this interesting post on a recent JOHANN FANZOJ thread:

quote:

Originally posted by 505G:

Re Bolsters on the Boxlock, I think it has to do with
1. Width of the action / water table and
2. The type of locking mechanism / Dolls Head.

I do like the "moustache" type bolsters (on H&H and Heym side-locks), rather than the more "geometric" type bolsters (on Purdey and Hartmann & Weiss doubles). Westley-Richards doubles don't seem to even have them (but I may be mistaken).

So are bolsters really 'needed', and is the action 'strengthened' with their presence?

Peter

PD

I look at it this way.


Early Holland Double Rifles (Royals)
like the 500/450's etc didn't seem
to have them.

Then a bit later - not sure of the date
but I think post 1910 - 12 - Holland started
putting bolsters on all Double Rifles above 375 (And maybe even 300H&H Fl but will need to look
at a photo to confirm that).

So it seems H&H determined they were needed
BUT that may be because on H&H guns they don't
have a big dolls head like on a Webley.


Also, I am sure I saw a comment about a new Heym or something on here
where they talked about the width of the action / water table
and this negated the need for Bolsters.


I also prefer the H&H style over Purdey's style.

Anyway, look forward to a good discussion.

quote:

Originally posted by 505G:

I also prefer the H&H style over Purdey's style.
Anyway, look forward to a good discussion.

Thanks 505G!

Way back in the day when all gunmakers had to work with was wrought iron, or low carbon steel, they added bolsters to strengthen the frame. Nowadays, we have alloy steels which are far stronger even in their annealed state than the old stuff. Some makers still use them, some don't.

According to Ken Buch and the fellows at VC, the width of the action on the round body is exactly the same as the width of the action WITH bolsters. Therefore, they are not needed as the action actually has more steel than the traditional action with bolsters. Certainly a different look, especially how the stock mates into the action.

Todd

Thanks

That was the comment I was referring to.

quote:

Originally posted by PD999:


So are bolsters really 'needed', and is the action 'strengthened' with their presence?

Peter

Peter

I would suggest they are there to strengthen the corner of the action where the water table meets the breech face. As you know any sharp corner under stress can develop stress risers which form cracks. To avoid this happening you try to design a radius corner so there is nowhere for the cracks to start ( similar to drilling a hole at the end of a crack to stop it travelling any further), and add extra material around the corner for bracing/strengthening. This is basic engineering and isn't limited to guns. On high performance engine blocks they grind smooth any sharp edges and round any sharp corners to limit stress risers. I have a friend who built a 55ft ferro cement yacht which was lost in a storm two years after it was launched. He was hit by the loss however he admitted that he had made this mistake when he built the yacht and that cracks were beginning to develop in the corners of the structure.

As to whether the bolsters are needed with todays actions you would have to confirm with somebody else. I would say they would help to limit flexing and so limit metal fatigue over time so they certainly wouldn't hurt.

Hope this helps.

Rhodes
DRSS

Rhodes, thanks for that, I have no engineering knowledge so this is all good stuff!

With bolsters at the corners where the standing breach, and the water table meet it is not only the thickness but the shape of the bolster that counts most. A bolster needs to have twice as much surface that compresses than it has that stretches when the bending of what it is protecting tries to bend.

This is why the part of the bolster that meets both surfaces of the breach face, and water table always gets thicker as it’s surface moves away from those two surfaces, then angles sharply back to the outside surface of both the bar and fence, and tapers in toward each end of the bolster. This works to supply several surfaces that require compressing more than the surface that stretches. Steel is much easier to stretch than it is to compress. So the shape of the bolster is far more important that how large it is! Any double rifle can benefit from a well shaped bolster.

I hope this si at least as cleer as mississippi mud! Without pictures this is hard to explain!

..................................................................

Well said, Mac!

quote:

Originally posted by MacD37:

... as clear as Mississippi mud!

It sure is
Mac, you are truly a fountain of DR knowledge!

quote:

Originally posted by PD999:
Mac, you are truly a fountain of DR knowledge!

............... There are those who would disagree with that opinion!

There is a pair of H&H Royals in .275H&H on GI with the bolstered frames.
I think they are somewhat an H&H trademark these days.
The earlier 375's and 465's with bolsters seem to command a bit of a premium over those that don't.

Never mind the bolsters ♫

If, as someone here pointed out, big rifles from a certain famous maker come off face after 30 rounds, I'd be looking for something 'Brummy' with a top fastener.

quote:

Originally posted by Huvius:
The earlier 375's and 465's with bolsters seem to command a bit of a premium over those that don't.

Very much so. Have always said it.

Especially the rebarreled 450's and 500/450's that became 500/465's.


I would like to know the date that Holland's
decided that Bolsters were needed.