Fitting a new lower fore stock to a no4....what a job!

[ssj]

Well this was unissued...ikky job,

1) The barrel groove wasnt cut deep enough on the left hand side it fouled the barrel....long dremeling and hand smoothing to sort, 20 thousands of an inch clearance all along now..
2) Worst thing the stock was 40thou, 1mm too long...it fouled the foresight I could have used a 4lb hammer I guess
3) The above made me misjudge the amount to take of the draws so I overcut, now I have to put in new draws blocks, damn.
4) There is a 45deg cut at the wrist face to flat that the receiver sits on at the upper rear of the forestock, that was fouling, I needed to curve that to match the curve on the receiver....that caught me out for ages.
5) The wood forestock wood now sits very nicely onto the wrist with good contact both sides but I think it took me over an hour of hand sanding to do...plus I had to keep shortening until I got 0.8mm or 33thou clearance between the foresight block and lower nose cap.
6) Converting it to a 1/2 from a 1 went well, I used a 16mm router bit....and 8mm radius bit I used New Zealand Rimu (oak like).
7) I have 9 1/2 turns to bottoming the king screw (haha Peter couldnt resist) SCREW, guard trigger....5 1/2 with the collar in so some shortening there....off to find how much.
8) When they cut the mag well they over cut on the left hand side there is no support on that side for the Guard, trigger so Im adding a 1.5mm / 60 though sliver of rimu 1inch deep all along that side to restore support, I have some match grade bedding compound coming, I'll use a bit of that as glue.

So much for buying off ebay....not that I has any choice really....

Still Im happy in the man cave, so all good.

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[ssj]

"You MUST have a collar and spring washer. This is what WE used to do. Put the front trigger guard screw into the trigger guard and body WITHOUT the washer or collar. Reverse it (that’s anti-clockwise …..) until you hear it click over the start thread and tighten it BUT COUNT THE TURNS UNTIL IT TIGHTENS AND LOCKS. Say, that it’s 7 ¼ turns to lock. Now do this with the collar fitted if it’s now, say 8 ½ turns, shorten the collar, a smidgin at a time, until the screw tightens up at exactly 7 ¼ turns. That way, you KNOW that the screw is tight, the fore-end is tight between the trigger guard and the screw and you are not crushing the living daylights out of the fore-end."

A bit confused here, I have 9 3/4 turns (after cleaning out the gunk in the threaded hole). 7 1/2 turns with a brand new collar but no forend fitted. Measuring the thickness of the wood between the receiver bed and the trigger guard bed is 21mm or 0.826 inch and measuring the guard to receiver 20.65mm 0,813 inch. So before I start I have 0.45mm crush. New bush is 12.9mm 0.508inch...old bush 9.6mm 0.377inch. Not sure what the pitch is but the above suggests I take about 1.5mm off...seems excessive...?

I might just background shortening this for now until I get advice as i have no spare collars....

[Alan de Enfield]

[QUOTE=ssj;269799.... BUT COUNT THE TURNS UNTIL IT TIGHTENS AND LOCKS. Say, that it’s 7 ¼ turns to lock. Now do this with the collar fitted if it’s now, say 8 ½ turns, shorten the collar, a smidgin at a time, until the screw tightens up at exactly 7 ¼ turns. That way, you KNOW that the screw is tight, the fore-end is tight between the trigger guard and the screw and you are not crushing the living daylights out of the fore-end."

A bit confused here, I have 9 3/4 turns (after cleaning out the gunk in the threaded hole). 7 1/2 turns with a brand new collar but no forend fitted. Measuring the thickness of the wood between the receiver bed and the trigger guard bed is 21mm or 0.826 inch and measuring the guard to receiver 20.65mm 0,813 inch. So before I start I have 0.45mm crush. New bush is 12.9mm 0.508inch...old bush 9.6mm 0.377inch. Not sure what the pitch is but the above suggests I take about 1.5mm off...seems excessive...?

I might just background shortening this for now until I get advice as i have no spare collars....

[/QUOTE]

I had some discussions with Peter (some years ago) when these instructions were first published as I was confused as to how the 'screw' could go from 7 1/2 turns to 'bottom out' without the collar. to 8 1/2 turns with a collar. It turns out that it was a 'typo' and the 8 1/2 should read 6 1/2 turns - you then shorten the collar bit-by-bit until you get back to 7 1/2 turns

Hope that helps

[Peter Laidler]

If it was my rifle/fore-end that appeared to be loo long, with the fore-end cap almost touching the foresight block band or protectors, then I'd just replace the fore-end cap with the version with the almost complete front end missing. You know the variant, with a 'U' shaped void at the front. That variant surely would clear the foresight block band

[ssj]

Gee your a mine for good bits of fasinating info...

Thanks for the info and your patience!

[ssj]

I had some discussions with Peter (some years ago) when these instructions were first published as I was confused as to how the 'screw' could go from 7 1/2 turns to 'bottom out' without the collar. to 8 1/2 turns with a collar. It turns out that it was a 'typo' and the 8 1/2 should read 6 1/2 turns - you then shorten the collar bit-by-bit until you get back to 7 1/2 turns

Hope that helps

Im still not getting this.

lets try a different way.

So my forestock wood is 21.90mm thick at the mainscrew point (as in pics below). With the Collar in place and the screw tightened but with no wood I end up with 21mm distance between the receiver bottom face and trigger guard top face. So when tightened up to the collar Im going to compress the 21.90mm of forestock wood to 21mm....

0.9mm crush, Is this enough?

If not how much more?

otherwise if you say you want 1.6mm crush, I know I need to shorten my 12.90mm collar 0.7mm.

Or can someone point me at another method please?

[ssj]

Attachment 45606 new bush length

Attachment 45607 new stock thickness

Attachment 45608 receiver to trigger guard dimension

[Peter Laidler]

I don't think this needs a vernier caliper SSJ! And what's this about wood crush? All you need to do is nip it up. It is the nipping up of this screw that gives you the reinforce bearing, the underside of the body bearing and the muzzle bearing. We're not talking thousandths of an inch here - modern Armourers wouldn't understand those sort of tolerances! We're talking, say 1/8th of a turn of the front trigger guard screw tolerances

I have tried to explain the method of calculoating the correct length of the collar in relation to the fore-end with my clearest physics teacher hat on and can't really elaborate any further. Can anyone else

[ArtioZen]

I'll have a go, as I am on a break at work and have recently completed this op:

The new forend will “tell you” how thick it is when sandwiched correctly between the knox and trigger guard plate - using a “count of turns” of a naked front trigger guard screw (no washer no bush). Find the start of the thread (turn it backwards until you hear/ feel the click of the thread ratchet over each other) and then turn the naked screw forward and count the turns. Screw should be a light hand tight - no wood crushing! ("creaking" gives that way = too far! – practice hand torque if necessary on wood screws and fire kindling…) I got about 6.5 turns as an example.

Then reassemble and repeat with the washer and spacer around the front trigger guard screw and to the same tightness. Count the turns - should be a little more - I got 4 turns which indicates the bushing is too long and the wood is not sandwiched.

To have a fully assembled (with washer and spacer) and correctly assembled and torqued front end, you need to shorten the spacer to achieve the 6.5 turns again.
Now it’s time for the caliper if you wish to measure how much to shorten the bush by! If you know the screw pitch in thousandths of an inch times that by the number of turns to remove. Using the example above 2.5 turns X screw thread pitch.

I could not find the front trigger guard screw pitch from a brief internet search, and cannot remember what I measured (maybe a note at home). So you can establish this by running the front trigger guard screw into the knox thread 2-3 turns - measure the gap between the knox and head of the screw. Turn the screw in exactly one turn and re-measure - the difference in these measurements is the thread pitch . Those with OCD can turn in additional turns, measure each one and take an average.

Other thoughts:
I found the screw collar to be quite soft and quickly shortened down using a fine file (flat and square). I used to have access to a lathe so it’s up to you… Knowing how soft and tub- like the real bushing is, making one from scratch using steel tube should be acceptable in a pinch. Choose a target bush length a little longer than required and try, adjust, try, adjust.... until the number of screw turns matches the number found with the bare screw that is hand tight. As Peter indicated the accuracy required is about 1/8 of a screw turn (pitch) – not a small amount for a caliper, file or lathe. I’m thinking the thread pitch will be somewhere between 0.040”and 0.060” so an eight of this could be a large target of around 0.005” through 0.0075” for bush length control purposes.

I hope this helps!

[ssj]

ah now I follow you I think...I was making the screw bottom in the blind hole in the receiver without the forewood in the "way". I have some 30 odd year old baco files I bought in my apprentiship years, best ones I ever brought, they will do the job fine, plus I have dry and wet stones so im happy on shortening it. Ive always wanted my own lathe but I lack the space....until I build my shed.....wife insists on kitchen first though.

I think the threads are all BA? Im trying to find my wee pitch gauge set....I have a feeling Ive put them safe somewhere, found my mics but not much else...

Peter, 1/8th turn is a good indicator....thanks

PS Im used to working on metal, so I kind of over do the accuracy with wood I guess.....I have this huge problem, if it doesnt look good it will irritate the hell out of me....