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Reassembling BSA Paratrooper 1st pattern

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Octathorpe

On Training Wheels
Like a lot of people during the pandemic I'm taking some old projects down from the high shelves and getting them in order. Now it's time to reassemble my BSA Paratrooper (Airborne) bicycle, SN R6599.
I bought this in 1997 and rode it a couple times, then stowed it away until 1999 when I began stripping it for refurbishment. The bike had been slathered in red house paint so I sand blasted a lot of it.
Every once in a while as the internet became popular I would do a bit of research trying to find a source for 'correct' paint. Ultimately it became clear that these bikes were painted whatever color the regiment that used them could come up with, and that the British 'standards' for color were "more what you'd call guidelines than actual rules". I'm going to leave it up to the next owner to decide a paint formula and color.

Anyway, I'm taking zillions of photos as I go. I even have hard copies of the photos from 1999 when I disassembled it. The handlebars aren't military spec but seem to be the civilian equivalent. Everything else is right out of war surplus; mis-matched war grade tires, BSA saddle, tool kit. A lot of it is still wrapped up right now, I've put the fork back on and am getting the axles back together with the wheels.

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I loved finding a 35mm film canister with 48 carefully preserved ball bearings in it, labelled "BSA steering head bearings". I've never dealt with loose ball bearings before. I assembled the lower bits and then zip-tied the fork to the frame while I got the upper bits in. There was, of course, one ball bearing left over. I put it in the film canister for the next owner.

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The crank hanger is brazed in some places, welded in others. Here the braze has formed verdegris, cleverly trying to look like green paint.

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I have no idea where or when I got those brake pads, or if they fit. I know there's a BSA owner on this forum who was having brake pad problems. I'll figure that out when the calipers come out in the light again.

More as I go!
 

Octathorpe

On Training Wheels
Not bad. No breaks in the frame. Thats the nemisis to those bikes.
Yes, there was a broken one on display at a bike shop I used to go to. Ugly mess.

This one seems to not have been ridden, from what I've seen of the bearing races. I have a picture of the patent decal before I erased it, and from what I can tell there was no broad arrow on the head tube, though it's possible that came off with the red paint.
I have to wonder how a low serial number frame went unused. I don't know if the early ones broke so swiftly and unanimously that they had to retire all the spares and replace them with the 2nd pattern. I had thought the 2nd pattern was a manufacturing efficiency measure, or that the large diameter tube needed for the 2nd pattern seat tube wasn't available in the early years.
 
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AlfRim

On Training Wheels
I have to wonder how a low serial number frame went unused. I don't know if the early ones broke so swiftly and unanimously that they had to retire all the spares and replace them with the 2nd pattern. I had thought the 2nd pattern was a manufacturing efficiency measure, or that the large diameter tube needed for the 2nd pattern seat tube wasn't available in the early years.
Will it be for sale by any chance? Or, do you have any spares? I’m hoping to buy a twin tube soon but it’s just a frame! Also, my current one is missing some bits annoyingly! Nice bike though, looks great.
They were still being used during Normandy due to pictures, alongside the 2nd pattern bsa’s. I think Arnhem too but not 100% sure on that.
 

Octathorpe

On Training Wheels
Not much progress on the reassembly this week, but here's some close up expository pictures of the thing in case anyone needs them in the future. It was difficult to find information about these when I first acquired it in the 1990s, so I'm a bit of a pedant about publishing the information that I have.

I worked in a bicycle frame factory for a while and in general am just interested in how things are made, so a lot of the pictures I've been taking are pertinent to how these frames were built. There's a mix of welding and brazing on the frames and I haven't tried to figure out just what the order of assembly was. I have a theory that the twin seat tube (1st pattern) design was a manufacturing plan to make the left and right sides on one production line, possibly identical, then marry them to the head tube. Or they just didn't have any seat tubes handy in the early days of the war?

The picture in an earlier post showed the brazing medium (on the aptly called 'crank hanger') all covered in verdegris, here it is scrubbed down. The brazing rod seems to have been highly cupric, if not just pure copper. In real life it's deeply red. This is not a repair, there are brazed joints and welded joints all over the frame; in fact one end of the crank hanger struts is welded to the downtube, while the other is brazed. See?




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Here's some of the fork going back onboard. The head tube is flared at top and bottom, not machnined. The races just snuggle up as they feel comfortable in the raw steel. The alignment of the whole upper and lower bearing assembly is referenced off the fork steer tube, frame be damned.

In this frame, the upper race came out with the fork, while the lower race stayed in the head tube. It's still in there, undisturbed, despite what I've done to the rest of the bike.

What do we have here in this picture? Starting at the top right there's the fork with the crown race still installed (waiting to meet the still installed lower head tube race), a film canister with 48 ball bearings (diameter 0.155"), some proper English bicycle grease, and (out of assembly order, sorry) the upper-inner bearing race, the washer (not a tab washer, though the fork has a keyway for one), the knurled upper-outer bearing race for adjusting, and on top a chrome plated lock nut (probably not correct for a war department bike, but who knows?)

It's interesting to me to see that the inner crown race is machined with a radiused cutter, to match the ball bearings. The other races are grooved; a much simpler machining operation with a short service life. Like the not-a-tab-washer washer, this was a war effort.

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With the frame inverted I installed 23 ball bearings (I lost track of one, but I know where it is now) in the lower head tube race by sticking them to the race with Phil's proper English bicycle grease. I greased the crown race and dropped the fork in. Then I zip tied the fork to the frame so nothing went rouge on me when I reverted the frame to put the upper bearings in.

(I'm not Superman, I dropped a couple ball bearings in this operation and was just lucky to find them again. My new procedure is to coat the damnable ball bearings in grease BEFORE picking them up; if they fall on the floor the grease keeps them from bouncing into oblivion.)

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Next installment: Wheels!
Well, axles into hubs. More fun with ball bearings. I swear that'll be the end of that.
But Hey! Check out this eighty year old rubber.

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Octathorpe

On Training Wheels
Progress!
(The bike is upside down because there's a rowboat in the shop with it.)

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Axles went into hubs; tubes & tires went onto rims; wheels went onto frame.

Now for some nitty-gritty...

The rear axle measured 3/8" (0.370", actually) at the threads and was in the neighborhood of 26 TPI, but IDK if Whitworth threads were in use on these. There were 9 1/4" ball bearings on each side.
The front, curiously, measured 0.305" diameter and used 10 3/16" balls on each side. I didn't try to thread the front axle nuts on the rear axle or anything, and I may have mis-measured so don't take it as gospel. If you have a bike with the same measurements then I guess that's how they made them; axle nuts not interchangeable. I guess that would keep the bearing cones from getting on the wrong axles, too, but why not have everything the same thread and ball diameter?

Rear axle assembly. One cone is fixed in place and has no flats to adjust the position, the other is where the adjusting is done so that will go on the non-drive side for ease of access. You're going to need that access because there's no lock nut on the adjusting cone.
Each side has a pair of flanges ( beveled washers? I don't have a word for them) and one will fit on the inside, over the shoulder on the adjusting cone. The other won't fit over the cone so that's how you know it doesn't go there.

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Front axle assembly. These pictures are deceptive, after I took them I realized there were 2 washers on each side but that they were well stuck together. It doesn't matter, because when it went into the fork all the washers ended up on the outside. In other news, there's a lock nut! Bearings aren't shown but again, they're 3/16" and ten each on each side.

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And here's a silly picture of all the shiny steering head bearings ready to greet the world and whatever it throws at them. I may need to re-do this, they look dry and I left one out on the lower race. I added an incorrect tab washer to take up some space under the (also incorrect, non-BSA) headlamp mount.

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