Webley Junior Air Pistol - help needed.

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zooma
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Webley Junior Air Pistol - help needed.

Post by zooma » Sat Jan 25, 2014 7:07 pm

I bought a Webley Junior air pistol some time back - it worked well enough but the barrel joint screw ( part number J19) had been replaced by a large spilt pin :snooty: (!).

Since then I have found a new joint screw and checked that it fits OK on another Junior but it will not to screw into the spring guide (part number J4) on this Junior - presumably the use of the split pin for an unknown period of time has damaged the screw thread inside the spring guide. :doh:

The barrel joint screw will turn into the spring guide about two turns but then it stops dead.

The usual tricks of trying to follow the screw thread grooves inside the spring guide by hand with a hardened point have failed , and easing the screw in and out trying to make small progress and then reverse to "break the chip" have also failed as the joint screw still stops dead at the same point every time so I need to find or borrow a "tap" of the correct size to run through the spring guide to clean-up the damaged thread.

The thread used by Webley looks to be a very fine and I have nothing like it in my workshop and I have no idea what it is.

Does anybody know what type of screw thread Webley used to cut these threads please? (about an M5 size). :pray:

Once I know what the thread actually is I can then start to try and find a tap of the correct size to fit it - unless anyone has a correct size tap that I can buy or borrow to clean-up this thread?

Please let me know if anyone has a suitable tap I can buy or borrow or even advise where I may be able to find one.
Feinwerkbau P40 Tricolour wanted.........still !
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RobinC

Re: Webley Junior Air Pistol - help needed.

Post by RobinC » Sun Jan 26, 2014 11:30 am

Hi Bob
If you have a spare screw I find that sawing a slot down it and grinding a lead often works as a one shot tap.
Robin

zooma
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Re: Webley Junior Air Pistol - help needed.

Post by zooma » Sun Jan 26, 2014 2:37 pm

RobinC wrote:Hi Bob
If you have a spare screw I find that sawing a slot down it and grinding a lead often works as a one shot tap.
Robin

Hi Robin,

I only have the one pivot screw and I was considering the same technique as being an option if I cannot find out what the correct thread should be.

It is surprising that with so many knowledgeable Webley enthusiasts and collectors out there we have that nobody knows what thread was used on this component as it is probably universal on all Webley spring powered air pistols.

The best guess so far is that it is some sort of cycle thread.
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bellringer
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Re: Webley Junior Air Pistol - help needed.

Post by bellringer » Sun Jan 26, 2014 3:22 pm

zooma Hi please see my post under Webley and Scott I have an answer and solution for you. [Ray] bellringer

zooma
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Re: Webley Junior Air Pistol - help needed.

Post by zooma » Tue Jan 28, 2014 9:31 am

bellringer wrote:zooma Hi please see my post under Webley and Scott I have an answer and solution for you. [Ray] bellringer

Thanks Ray,

With a bit of luck ( and the use of your tap) I should be able to get the Junior back together and working again quite quickly.

ATB - Bob.
Feinwerkbau P40 Tricolour wanted.........still !
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zooma
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Re: Webley Junior Air Pistol - help needed.

Post by zooma » Sun Feb 02, 2014 12:10 pm

The Junior is now back together again and the action feel smoother than a smooth thing and the trigger is match grade - maybe I over-cooked the polishing so I had better start looking for a new sear :whistle:

Meanwhile the piston washer has fallen apart so I need to get another one :doh:

I like working on Webley air pistols :lol:
Feinwerkbau P40 Tricolour wanted.........still !
http://www.bobsairguns .com - proud to host the RMTC site since April 2011.

zooma
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Re: Webley Junior Air Pistol - help needed.

Post by zooma » Sun Feb 23, 2014 12:48 pm

The tap I used to recut /clean-up the pivot screw thread on my Webley Junior was actually an M5. :o

I had a set of these taps for years ( originally bought during a visit to the Harrogate Model Engineers Exhibition). The "taper" ( no 1) and "intermediate" (no2) taps were not needed as the "plug" tap ( no 3) was a nice easy fit that pulled itself nicely into the damaged thread.

The "correct" Webley supplied tap was sent to me by Ray to use for this repair ( thanks Ray - now safely returned).

This tap had been broken at some point in it's life and had the end of it ground-off square. I established a slight taper on the tap so it could enter the damaged thread hole correctly but it just did not "feel" right so I stopped and gave it "a good coat of looking at" . :ugeek:

I checked that the tap was now cutting OK (no problem) and so I looked again at the thread form and to my old ( and knackered) eyes it did not seem right and so I started digging out all of my old English taps to see what they may have used. BSW (British Standard Whitworth), BA (British Association), BSF (British Standard Fine) - nothing looked right.

Surely Webley never used any of that "foreign" metric stuff in their manufacturing just after the war I thought to myself - but I had nothing else to choose from so I looked any way and imagine my surprise when it was the perfect fit :doh:

A new Webley pivot screw went straight in to the new thread so I checked this in another Junior pistol and also fitted the old pivot screw and everything was easily inter-changeable so the M5 thread works perfectly.

I mention this as it may be a good tip for others that may have problems with a damaged pivot screw thread as special "rare" or "unavailable" taps are not needed to make the repair. M5 taps can be found and bought easily from local engineers suppliers, model shows and "online" from a number of outlets.

I think I just "got lucky" with this repair as I know the threads usually used on the old Webley air pistols are some sort of "cycle" thread but an M5 will certainly work on the Junior pivot screw.
Feinwerkbau P40 Tricolour wanted.........still !
http://www.bobsairguns .com - proud to host the RMTC site since April 2011.

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