SMK B45-3 Revisit, yet again.

Pleased with the results so far.

Well here we are on a lovely Sunday morning and again i'm stripping the valve, If i've done it once , Ive done it a thousand times, literally.

Breakfast of champions.

 Again it's the seal on air inlet valve, as the body of the valve is machined into the compression tube i can't see much detail of the surface the seal rests upon.

Why i put the scope back on every time i test a new inlet valve seal i do not know.

Two screws and the stock is of, again. We have been here before many times before so i'll sort of skip through this bit.

Handy needle nose pliers for removing the collar screw, Again !

Every thing out, AGAIN! Notice the original seal washer and the O ring above which now replaces it, i now place it out side the valve so the sear doesn't hit too hard on returning after firing.

 I know it has a sharp circular outer edge that cuts into the seals i've been putting in, today i took a mold of that part of the valve body internals with some modelling clay. Now i can see what angle the edge is and how high the collar is, so i can either make a PTFE or Delrin seal or fill the space outside the collar with a washer to go on the outside so only a tiny part sticks up and doesn't cut into the seals.

Mold taken in Fimo and baked, now i can see what i'm dealing with in detail.

This air rifle was sold with instructions and an exploded diagram along with spare seals, so you could replace the seal when it broke.

Advert for the Custom model, still got that ugly pump handle though.

Parts diagram that comes with gun, that should tell you something really.

Instuctions on how to use and strip the bugger. That should have alarm bells ringing by now.

I suppose if you pumped too much air pressure in the valve that would take it over the legal limit and it would cut the seal, that's one way to keep the rifle within legal power. 

Someone else's nice example of the Custom B45-3, last 4 pictures where photo's off the computer screen so thanks and sorry to who ever put the up.

Also the route the air travels through and around the firing pin housing would keep the power down, if it ran direct to the transfer port there would be more pressure behind the pellet.

I have glued some rubber to the air flow channel of the firing pin housing, in the hope of needing less pumps and using the air in the valve more effectively.

 This i think is the reason that no matter if you pump it 6 or 15 times the power doesn't increase, it makes a sort of sense and that is what happens.

Pump arm locks away firmly.

Another thing that is bugging me is the loose fit of the pump arm at the sight base, there is a lot of side to side play when the arm is extended.

But is a bit wobbly when extended.

  I've tried washers in the past which reduce it a little, but have not yet found the right thickness to place either side to reduce it evenly. So i reckon i will make some shims up out of the metal off a drinks can, this way i can add layers till there is as little play as possible. It sure has paid off buying some good strong French coffee for a change, it certainly gets them tired old brain cells kicking in the mornings.

Air rifles i am currently tinkering with, along with tools and spares box, there is a most useful chronoscope in the little white box.

Looking in Halfords the other day i noticed they had some Bio grease for bikes, this i thought might be good for lubricating the piston linkage in the compression tube. So if any gets in the valve it doesn't soften the seals up, which is exactly what petrolium based greases do. Its an idea i will have to research, any way it's back to tinkering.

TTFN

Wing Commander Sir Nigel Tetlington-Smythe.

More caffine and nicotine please, as it takes the same amount of time to strip and reassemble this gun as it does to make and drink a cup of coffee. 

Sharp Innova Breech Repair

Now the Innova is shooting fine and holding air i should at least get get her looking good, and that chip off the back of the breech is not only a spoiler but doesn't allow the bolt catch spring to stay in place. I decided at first to shape a  piece of  8 mm flat bar aluminium and screw it into the back of the chipped section, but first i would need a flat surface to attach it to. For this i used a small circular grinding stone in my Dremel, which is actually made by Draper but i refer to it as a Dremel anyway.The surface was now flat and flush with the back off the bolt catch.

Aluminium plate that held the spring for the bolt catch , after grinding a flat surface.

However i discovered that the bolt i used to attach the piece of shaped aluminium bar was to long and it would press against the sear, so after a shot it would stay in place and let the firing pin move when i gave the rifle a pump. So i cut the bolt shorter and added a drop off abbey SM50 to the sear, now it dropped back down to the firing position and the valve held air again. i used a cut off piece off spring from a clipper lighter to hold tension on the bolt catch, then screwed the shaped aluminium to the flat surface.

The breech is made from a plastic and seeing as i make dread beads and stuff out of Fimo modelling plastic clay, maybe i could shape some Fimo while pressed against the space left by the missing chip then bake it. 

Cardboard in place to stop the Fimo from hindering the bolt catch movement.

 I would glue this with Locktite and drill a hole so the bolt would hold it more securely as well, i cut a piece off thin card board to place over the aluminium and around the bolt so i could not press the fimo to far and impead the bolt catch.I placed the aluminium bar under this then pressed the Fimo into place and shaped it  a little over sized, as i could  grind the Fimo after baking and fitting it so it would be flush with the rest of the breech.

Molding Fimo onto the back off the breech.

Pulling the soft fimo off the back of the breech i cut a notch for the the bolt pin on removal then popped it in the oven and baked it, i left the aluminium in the Fimo so i could drill a matching hole for the bolt.

ready to be drilled after coming out of the oven.

Fimo takes 20 minutes to bake hard at 100 degrees C  and has a little flexibility while still warm, so I quickly drilled a hole and a larger one to countersink the bolt screw on the outside surface. Dabbing a few spots of locktite on all the surfaces that needed joining, i removed the card board and pressed it firmly into place and held it there. Once the loctite had set i put a spot of it on the bolt screw and quickly screwed it into the countersunk hole and breech.

Fimo baked , glued, and screwed in place prior to grinding flush with the breech.

 After leaving the whole thing for 20 minutes or so to harden properly, the fimo was ready to be ground so grinde away i did,so now i'm left with a breech that looks the right shape.

Finished article with breech repair after grinding.

So now i have a complete Sharp Innova short of the rear sights, which i was given but i'm buggered if i can remember where i put them. Besides i dialed in a solid generic 4x32 scope at 12 and 25 yards on 5 pumps and it is so accurate that this one is going to be a keeper, besides i wouldn't get top money if i sold it because of it's original state and my repairs.But they are solid and good enough for me, i would recommend that if someone wanted a multi-pump that they should get one of these. I mean , Sharpsman on airgunforum has loads of Sharp Innova's and he swears by them, if your really lucky he might sell you one, but i doubt it.

These multi-pump air rifles are solid, accurate and a wicked design, it's a shame that no air gun company has taken this 1970's design any further.Webley now do the Rebel which is pretty much the same air rifle. But so far it has only come in .177 and has about 3 sets of ft/lb limits. So you better make sure which one you order or buy, and though some parts actually have Sharp printed on them i'm not too sure if parts are interchangable or if the valve is of the same design.Yeah Man , get a Sharp Innova, it could do with a raised cheek piece on the stock so your head is comftable with a scope. Mine is .22 and i can get pellet on pellet at 40 yards,these air rifles are the dog's bollocks to be sure.

I'm waiting now for some parts from J Knibbs so i can finish off working on other air rifles that i have already start writing the blog for, so it won't be long before some new blogs on some lovely springers will be on there way. 

During the repair of this air rifle i was mostly listening to Heavy Horses by Jethro Tull, Thank Christ For The Bomb by the Groundhogs , and Safe as Milk by Captain Beefheart.

TTFN

Wing Commander Sir Nigel Tetlington-Smythe