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Sporting Pattern BSA Improved Model D restoration  


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Sporting Pattern BSA Improved Model D restoration

This description and pics from 'KWK' on Airgun Warriors forum:

Got this BSA recently. Improved Model D Sporting Pattern. I think I have 5 Sportings now. This one needs help.It's going to be a carry around gun. Truck gun. I can take it with me and let people shoot it no worries. I especially enjoy letting young people shoot airguns. So many of our 3 son's friends have nobody to introduce them to shooting sports anymore.

I got it in pieces and several are missing. Some parts I have. Others I have to make. The compression tube was seperated from the Stock and trigger block when I got it. The spring is missing. Ok, I have some springs for it. The piston was a little stuck(100 year old gunk) so I had to pull it out by the piston rod. Carefully so I didn't damage the bent. "Bent" is what Brits call the sear notch in the piston rod. Something was rattling in the chamber so when the piston came out look at all the round lead shot that fell out! The pile on the left of the crosman .22 pellet. To the right of the pellet is the shot that was pounded into the bottom of the chamber. Had to be scraped out. Packed/pounded in there so tight. The piston washer screw survived! I've had to make so many of those. Not this time.

The problem with guns with loading taps is that people sometimes load the tap before cocking the spring. Anything in the tap gets sucked into the chamber. And sometimes it's not even a pellet! Then gets pounded by the poor seal and/or screw. Very often it's a steel BB and it wrecks the screw and brass washer, then gets imbedded in the leather seal. Any time I get a new prewar BSA I open it up to see what's inside. Over half have ruined seals and screws.

I'll post each time I make a part. Rebuilding this gun. I can't wait to shoot it.

My next post regarding this gun will be making the missing cocking lever screw. Thank you for looking

Making the cocking lever screw. The screw diameter is .280. Looks like a metric, right? 6mm right? Nope, it is 26 tpi pitch. They say BSA used their proprietary bicycle threads when making guns. Odd diameters and Imperial pitches. That's ok with me. I don't have to use metric transposing gears in the end gear train. Just select the pitch from the chart on the quick change gearbox.

The first pass turning the screw is about .060 metal removal. Then .040 and I'm down to about .300 diameter. .010 more give or take and I'm at finish diameter. Cut a step to .400 for the screw head. About .040 something first pass and the remainder in the second cut. Time to run the threads. Zipped through a few threading passes and I'm trying it in the rifle. I go pretty quick as I don't use back gears for finer thread pitches. About 220 rpm. Don't blink! Gotta be quick with the halfnuts. Pretty good reflexes at 60 years old? The thread was too snug. One more pass. Now it gets just a little snug when the screw head bottoms in it's counterbore. Perfect. Cut off the screw with a hacksaw. Turn it around in the chuck an face to the desired head thickness. Used the same 29.5 degrees compound slide setting to start shaping the screw head dome. Filed the rest of the dome profile. Polished it some to remove file marks. Cut the slot with aa hacksaw. Done! Took about 35 minutes. Done for now.... I still have to cut a little crescent for the keeper screw. Next time. Then I'll make the grip screw. Brits sometimes call the trigger a "grip". The trigger is also missing but fortunately I have a spare one. Thank you for looking

Last night I milled the place on the cocking lever screw for the keeper screw. I just clamped the barrel in the vise with a Vee block. Wasn't worried about scratching the rust. LOL! Not a real rigid set up but ok for what i'm doing here. The existing hole for the keeper screw was about 9/32. So who would have a 9/32 end mill handy? Looked around a little and guess what? I found a 2 flute 9/32. Hey, this is going pretty good. Would have preferred a 4 flute for this but it worked ok. Plunging down on the edge of the new screw with a 2 flute on this setup was a little sketchy. Using the quill to feed down I was tentative. It didn't feel "happy". Import mills like this Enco don't have a precisely fitted quill like a Bridgeport has. They're really just a big drill press quill. You could certainly never be able to bore an accurate hole with a boring attachment this way. Best you can do there is raise and lower the knee for an operation like that. So, slowly, carefully plunged the quill down and could see I was close. I hadn't set the depth stop so I was looking for the end mill to just scrape the keeper screw existing counterbore. Got it. It's done. Next will be that missing trigger screw.

Would someone like to suggest a plum brown formula for these parts?

Thank you for looking

BTW look close. I found a loading tap in my spare parts. See it in the barrel? I bought it on UK eBag last year for about $2.00!! I forgot I had it. It's from a post 1919 Standard a guy parted last year. I got several parts he had listed and added them to my stash. Shipping for all the parts was about $10. Royal Mail Standard Post International(Always ask for this). NOT eBag Global Shipping Program. Too expensive! It's a little different than the Improved Model D tap so I have to use a later tap retaining plate too. And I know where to get one in UK for 20 pounds. But I really want to make that.