Help with a Number 4T

[Peter Laidler]

Right, once again, lets cut out the crap......... It is all rather academic whether a) it's the front pad that's high or, b) the bracket that's faulty or, c) the rear pad that's low because, cutting out the superflous crap again, you CANNOT alter the geometry of the rear pad because there's a bloody great 1/4" BSF hole drilled and tapped.
You cannot alter the bracket because the mating recess and thumbscrew is where it is - so forget it.
All you can do is to alter the front pad by bringing the bracket mounting spigot - the part upon which the bracket rotates - down so that the mechanical axis of the telescope tube which is (or should be) optically matched to the mechanical axis aligns with the bore of the rifle.

There really is no more to it that that. John, you've been sold a pup and I suspect that you have a bog standard No4 that's been made to look like a T. That is only my opinion I have to say. Others with more experience might choose to disagree and I don't mind at all.

What do you do to correct it................? Mmmmmmmmmm. There's only ONE thing that you can do and that is to listen to Big Duke when he says that a couple of mm's error on the rifle/pad/bracket fiting equates to many yards out at 200 yards when you take accumulative error into account and even then, we're not talking linear here, we're talking logarithmetical curved scales. So all you can do is to
a) make a new front pad that mates up to the bodyside and existing screw holes AND
b) ensure that this new front pad is very accurately machined so that when you screw up the front thumbscrew, the collimated graticle falls in the exact vertical linear plane of the bore of the barrel and
c) That the same accurate machining does the same, but this time brings the point of the collimated grat slap bang onto the horizontal linear plane of the bore.

How do you do that and rectify what you've got? You can't. That is why I say in the paper that tells you all in very simple laymans terms how to make a good repro that the first thing to do is to FIT TTHE FRONT PAD, secure it and work from there. You can tilt the front pad left and right by fine hand fitting before you secure it. But you can't do the same with the rear.

Now, please............ let's not have any more cr............. OK, I've said my piece

Oh, and Jimmie Z. There was NEVER, ever, never a replacement pad in any Armourers kit, never, ever, regardless of what anyone has ever told you. In fact, the pads were NEVER, ever even obtainable even from Ordnance. I appreciate that those more experienced than me will dive into their parts list and gleefully point them out together with the part number, but you tell them that Peter said that the parts list was just that. It was a list of PARTS and not a list of AVAILABLE parts.

And RobD. Look at the geometry of those crap and 'real' front pad photos again. You STILL think that this one is the same height? Go on, be honest!

[john Brandon]

Thanks Jim, I'll let you know how it goes tomorrow

[Ridolpho]

Peter: Just purely as a matter of historical interest, what was the typical armourers procedure for fitting a used bracket from another rifle to a No. 4T in for repair? Were pads often removed and reshaped or was the bracket itself commonly modified? I know from posts on this forum that brackets fitted to two different rifles are fairly common and I own one that has three serials on it, including that of the current rifle (a well used '43 BSA). I can't be certain it's all genuine but I can say for certain that this very well used bracket is perfectly collimated with the bore on this rifle. Were original tolerances in the brackets (and in the pad installation at H&H) so tight that many were nearly interchangeable?

Ridolpho

[bigduke6]

cutting out the superflous crap again, you CANNOT alter the geometry of the rear pad because there's a bloody great 1/4" BSF hole drilled and tapped.

Thats my fault, but have corrected it, what I ment to say was........... anyway its done now.

[jimmieZ]

Ridolfo
I think you might be on to something. I, too, have 4 No.4 (T) rifles and can confirm that I can switch scopes (with brackets) between several rifles and require very little adjustment to re-zero them. The same holds true for the bracket I got from Dr. Payne.

Jim

[jmoore]

I, too, have 4 No.4 (T) rifles and can confirm that I can switch scopes (with brackets) between several rifles and require very little adjustment to re-zero them.

The drama being that the pads were not finished machined until AFTER installation. The spigot OD and front pad face along with the beveled locating cuts of the rear pad were formed whilst the barreled action body was located by a fixture on a dedicated machine at H&H. (A converted old lathe bed, according to Peter Laidler.) So one would expect a high degree of interchangability on freshly converted rifles. I reckon there may have been some minor fitting required from time to time, but only a few thousandths here and there. But that interchangibity would be lessened as the rifles were used and services such as front pad resoldering were performed.

Any "as new" pads with spigots already machined are not from British military stores. Israeli, possibly. Fakes and forgeries for the most part.

A gross misalignment of the front pad to the rear in any direstion than straight fore and aft would mean that the rear pad's mating surfaces would not be fully engaged without some distortion of the bracket. Which is entirely possible, and unlikely to be noticed by most folk. Try "bluing up" the mating surfaces sometime to see what precentage contact is achieved.

I have had to "scrape in" a couple of well worn L42a1s. Although matching, they had only about 20-30% contact without really bearing down on the thumbscrews.

[CINDERS]

Sadly I have to agree with Peters view, from my limited experience with the T owning one and having brought Skennertons book and the No.32 by Peter the pads are the issue.
If it is a genuine BSA Shirley then some one who put those pads on was probably shot at dawn.
To give you an idea of the WW II tolerances they worked to at H & H when doing up the T's it was 2 thousandth of an inch, the front pad is done first and then the rear.
This is so the scope is exactly over the centre line of the bore and the horizontal axis of the bore and bloke yours is canted up at a fairly stiff angle.
I see the screws were not staked either on the front pads as on the T's they have multiple stakings so the front pad did not work loose as happened in trials conducted.
Which was an issue with them initially till they slotted the screws so the silver solder would lock in the screws.
Interestingly they kept the heat on the front pad whilst doing up the screws a bit each at a time so when it all cooled it acually tightened the pad harder to the reciever.
As well as permanently locking up the screws though the staking still took place Skennertons book and Peter Laidlers book are well worth the monies to procure.
A word on scopes mine is fitted with a Kershaw Mk III this was an improvement on the Mk II's as it has slipper drums so you do not need the tool that requires 3 hands to adjust the elevation and windage drum though all the scopes are now are fairly pricey.
I sincerely hope things work out for you.

[Peter Laidler]

I'll answer the question of 'they all fit' for the very last time on this forum. Look...... It's not a question of whether each bracket will fit each rifle..... Some will, some won't. It's a question of whether when it does fit, does the tip of the graticle post is EXACTLY upright and aligns EXACTLY with the vertical and horozontal bore of the rifle. EVERY time!

And to do this, the bracket has to be accurately fitted at the factory or subsequently at the Armourers shop so that the front and rear pad fit with no twist or strain or other deviation. That is to say when the front thumbscrew is tightened and the rear thumbscrew is removed, then the rear longitudinal ribs sit comfortably against the rear pad. And when the rear thumbscrew is tightened up and the front thumbscrew is removed, the front mounting sits comfortably on the spigot. No twist or strain..........

Now, here is a realistic scenario. Imagine if you could just swop brackets and telescopes and.......... I'm tempted to say stop asking stupid questions and get real. But imagine a group of snipers sat on the range for a day - as they do - and after a day zeroing the rifles go back into the armoury. Next day, out on operations and the rifle you get issued with just gets another telescope 'that fits'. Oh yes, it fits OK just as Jimmy says but do you really think it'll be zeroed when he really needs it.

That's why that are fitted, numbered and all cross referenced between rifle to telescope to bracket. This is why later in its life, probably after a series of mishaps, that the REME Inspection Board decided and issued the decree that if the need arises to remove a telescope from a bracket then the bracket WILL be numbered to the rifle because if not, then the unbreakable numerical link between rifle bracket and telescope will be broken. Think about it.

[bigduke6]

Going back to the rifle itself , is it the real deal as in the receiver/body ? any thoughts or is someone forging the inspectors stamps? ( post 1, top row of pics, picture No2 going from left to right)

[john Brandon]

Well I must say, not realising it at the time, but this thread I started has certainly given rise to a few questions, and forum members have provided some outstanding answers.

Anyway the long and short of it is, I took it to the range this morning, and could only manage 5 sighters, which was enough, because after the first 3 landed and I adjusted the rings, the next 2 went smack in the bull.(nearly)

So the different front pad I fitted made the world of difference, and I can only say, that if it is a pup, then it's a thorough bred one, It handles and shoots like a dream (100yards)
But then I'm easily pleased