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Peter, by any chance do you have a scaled drawing of the No.7 extractors or if you have them in hand make a pencil tracing that I could use to get a start on making them ? Do you know the screw size that is used to attach the spring steel case holder on left side of the bolt head . I can not find any listing for it anywhere. Any help would be appreciated, John
TR63. Suggest you contact DaveN on this site as he probably has the parts you need.
Anyone contemplating following your No4 bolt converting scheme should hold fire because to be honest, it's NOT as simple as you are suggesting. The fluidity of the thread start position in this bolt (and the No8 bolt incidentally) that dictates that there are 8 sizes of bolthead. That is to ensure that you can achieve CHS
Quote:
Originally Posted by Peter Laidler
Two words stand out "Readily available" this just isn't the case anymore, as for de-act, still a lot life left in it yet (specially as a .22) and it was worth saving, again its not meant to be a No7, just intended to use a No7 bolthead and go from there. If it was a commercial venture I,d be bankrupt, but as its for myself and always been attached to it then no problem apart from time.....
Geoff
If your Nr 7 doesnt work out I would go for your idea of a Nr 9.
I bought an ersatz Nr 9 (Maltby Nr 4/2 with AJP .22 barrel liner, bolt head and empty magazine made by a father and son naughty boys in Derby?) a couple of years ago. Having added a tailor made magazine ramp, spare cheekpieced butt, PH target sight, tunnel foresight and canvas and Springfield slings this rifle enables me to play squaddie/sniper/target shooter and general tinkerer without altering the original rifle and its story.
The sole disadvantage is that its a single loader.
And it gives me more enjoyment than almost any other rifle I own.
John
If I was going down the No7 route, for the magazine, I'd forget about the original over complicated 3 part No7 magazine and just use a bog standard unserviceable No4 mag, accurately place into it one of the cheap and cheerful 5 or 10 round off the shelf .22" magazines, available aplenty from the US, accurately fix it in place within the No4 mag with putty at the base area and then fill the rest with a resin. I know it's fixed, but it'll work and if you damage it, like I have already done with a couple, then what the hell..... Just make another. And I've still got the original to boot!
I did try it using the readily available L1A1 and SA80 H&K sub cal magazines inside the No4 mag but while they were cheap, they were far too long!
Thanks Peter for the lead for the parts. The head space is obtained with any No.7 bolt head size used ,by how much you shorten the main body of the No.4 bolt that is being cut down to fit an existing barreled action . When I said the bolt is cut by 1.6" that was to provide the approximate amount the that the builder will take off to insure that you start long and then shorten in increments untill the the shortened body and bolt head of what ever size you have locks into place against the face of the chamber on the barrel . My bolt head was marked as a No.1 . In my case the bolt body was cut to 3 and 11/16'' long measured from the rear of the bolt to the first cut . You then rethread the bolt so you can screw on the bolt head. Then with the bolt head screwed on and placed in the action you see how much more is needed to be taken off untill you have the correct head space . My bolt body has a finished length of 3 and 5/8' measured from the rear of the body to the front. In the normal way the the head space is done you have bolt bodies of more or less the same length and some one has 8 sizes of bolt heads to fit untill one comes close the correct head space . But you will lucky to find a bolt head in any size or a original bolt body for that matter in today's world !Quote:
Originally Posted by Peter Laidler
tr63,Quote:
Originally Posted by tr63
I,m thinking you had a lot of luck on your side, The thread start on the bolthead and boltbody are timed threads, so you cant headspace on the bolt body, and unless you have some fancy way of timing the thread for the body then it will be a mile off, this still can be corrected but you still cant head space this way, only way to get the timing of the thread is to continue the original thread of the bolt body by running a tap down before chopping, even then it needs chopping at a certain point then needs a recess machining or counter bored (Like the original boltbody) then machining or precision ground to enable the bolt head to fit correct with the correct amount of overturn and even after all this it doesn't guarantee correct head space, but will guarantee the load is transferred from face to face (and not thread to thread).
Couldn't have put it better myself Big Duke. TR's idea seems good, even perfect, but it was/is based on fuzzy logic for a standard No7. Mind you, if you were starting from scratch where you could adjust the barrel to suit the bolt head and bolt that you have just converted, it'd work. But not if you've already got the fixed body and barrel. Well, not if you wanted to get it mechanically correct.
It's all to do with the bolt head being supported on the main diameter of the bolt shaft and NOT the threads at the moment of highest load that matters
I wasn't go to mention Barrels, but the barrel I,ve produced can be adjusted to suit so CHS not a problem.Quote:
Originally Posted by Peter Laidler
Yes,you need to extend the threads in the bolt before you cut it off to insure the threads are kepth in the same relationship as it was made . This will insure the bolt head will clock when it's screwed in . On page one of this thread I indicate that you must counter bore the front of the bolt the same amount to allow the bolt head to enter so it can be timed or turned in to the same standard as it would be when fitting bolts on the production line. The bolt and the bolt head with out the firing pin or the cocking picec attached is placed into the barreled action and you will try to close the bolt . the bolt head is houzontal the bolt handel will not fall into the locked position or cam .This is because it is still too long , withdraw the bolt and remove a few thousandths using a fine single cut mill file . reassemble the bolt and try to close the bolt. Repeat this operation untill the bolt handel will close with a small amount resistance . YOU will now have a bolt correctly time with the bolt body and head spaced .You can pull the bullet and the powder from a 22 round and use it as fail safe as not to remove too much from the bolt and creat to much head space . I did not want to spring for a .22 head space gage. Yes, I know, you will find the empty 22 case a problem as it is still live. The tools I used to do the bolt work are a hack saw with a high speed blade 32 teeth per inch, 10 inch fine single cut mill file, a 6'' steel rule , a 3'' steel machinist square, my bench mounted 6'' vise , tap handle , and the various sizes of taps and dies I mentioned earlier. I have done this two times now .The first was on my No.7 the second one for a friend that he built a .22 on a No.4 using a No.7 bolt head . The first one took me about 12 hours over 2 days. the second one was only 4 hours .The first time I was not sure the best way on how to maintain the bolt head and the bolt body to clock correctly. Than after the light came on it was clear that I needed to run the bolt head thread all the way before cutting anything off the bolt body. You do not need a milling machine to make a true square cut or surface a try square and a good file can this work.