FrankCrank
Old layabout
I'd say by the time you got to JB the settings were about right. What welding stuff did you do 15 years back? Think it's a bit like cycling - you never forget..............so I've heard
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Yeah I think I'm close with the settings. Need to get hold of some more steel and try to join some bits together next
I did an engineering degree and was taught to weld by one of the workshop technicians. I used their welding gear for a few projects and had always intended to buy my own and keep it up, it's just taken me 15 years to realise
FrankCrank
Old layabout
From finishing my engineering days back there to striking another arc over here was a gap of 25 years. Back there it was mostly stick welding, with a little O/A and MIG occasionally. At Foster Wheeler for a while, and we used robotic gear there, which was TIG. Had to learn proper TIG over here by myself, but easy enough once you get used to using both hands. My apprenticeship was 5 years as a fabricator/welder - happy memories of it all looking back......
rogerzilla
Legendary Member
Supposedly the mark of a good TIG welder is if they can weld two sheets of baking foil together without blowing a hole in the foil. There's a challenge.
steveindenmark
Legendary Member
There is Brompton hacks page on facebook. It may prove useful.I started the strip down this afternoonI've got as far as trying to remove the stem but it doesnt seem to want to budge so I've left it soaking in plusgas and will try again another day
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I've hit a couple of minor snags; I don't have a tool that fits the bottom bracket, haven't seen one like this before so will investigate what's needed to whip it out and get something ordered
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The lower hinge bolts were a bugger to release but I got there in the end! I presume I'll be able to get the bits from my lbs (a brompton dealer) to replace the hinge if needed, probably worth doing if I'm able to repair the cracks.
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Speaking of cracks, I've found a new one and suspect I may have created it while trying to loosen the stem
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I think the forks are now scrap which is a shame but I'll strip the paint off and see if they're salvagable first. I've found replacement forks for sixty quid so it's far from the most expensive error I've ever made
Once I get the stem and forks removed I'll pull those headset cups out and in to the bin, there's no place for rusty chrome on this bicycle
FrankCrank
Old layabout
......baking tins you say............yeah, no problem........
rogerzilla
Legendary Member
No...and not hydrofoils either.
My mini V-brakes arrived today and my impatience spiked 
It's not my finest work but it seems solid as I've hit it with a lump hammer a few times and it hasn't moved The weld wasn't pretty so I've ground it back - I blew a hole in the tube at one point but managed to weld it closed again I didnt take any photos because frankly I didn't want anyone to see it
Mounting the brakes on the underside of the stay was a last minute decision - I noticed the top of the arm was going to foul the original brake bridge unless I mounted the bosses at a funny angle and decided to sling them underneath instead
After I'd welded it on I realised it might be in the way of the chain but a few quick checks show there should be a small clearance
I've just got to do it all again on the other side now, and then stretch the stays out to fit the new hub when it arrives
It's not my finest work but it seems solid as I've hit it with a lump hammer a few times and it hasn't moved
The weld wasn't pretty so I've ground it back - I blew a hole in the tube at one point but managed to weld it closed again I didnt take any photos because frankly I didn't want anyone to see it Mounting the brakes on the underside of the stay was a last minute decision - I noticed the top of the arm was going to foul the original brake bridge unless I mounted the bosses at a funny angle and decided to sling them underneath instead
After I'd welded it on I realised it might be in the way of the chain but a few quick checks show there should be a small clearance I've just got to do it all again on the other side now, and then stretch the stays out to fit the new hub when it arrives
FrankCrank
Old layabout
....hard to see how the brakes will line up correctly without some kind of a jig? Hopefully you're not planning to sell this on when completed - personally I would not want anything like this done on something I ride, unless I've done the work myself. Maybe it's just an itch you've got to scratch, in which case scratch away, it's very entertaining.......
....hard to see how the brakes will line up correctly without some kind of a jig? Hopefully you're not planning to sell this on when completed - personally I would not want anything like this done on something I ride, unless I've done the work myself. Maybe it's just an itch you've got to scratch, in which case scratch away, it's very entertaining.......
I should probably point out that despite my flippant language I'm not just randomly welding bits on without measuring first - I'm also a chartered engineer so there's at least some method behind my madness
I cold set the rear triangle this morning by clamping the seatstay and chainstay bridges and then putting some threaded stud between the dropouts and gradually winding them open. I put some pretty big washers at either end to spread the load and minimise the dropout deformation, I was concerned they would otherwise have buckled excessively rather than bending the stays. It needs some tweaking but I've managed to squeeze the Alfine 11 Di2 gubbins in and check the alignment, all looks good
I went with the nexus di2 servo unit as it's smaller and I'm planning to mount it upside down as shown in the photos. I would have to remove quite a bit of metal from the chainstay to get it fitted right-side up and I don't think it's worth it just to have Shimano written on the top. The connector is waterproof and I've read reviews stating it gets filled with oil and gunk when it's at the bottom so this may have additional benefits. The only downside I can see is the slightly compromised cable routing but I can live with that, the cable routes on a Brompton aren't pretty at the best of times Next job is to tidy the garage up again before I strip the paint off the other seat stay and weld the other brake boss on
Might get to that later today all being well 
Pale Rider
Legendary Member
Wouldn't the brakes normally be mounted on the other side of the tube?
I understood the idea was rotation of the wheel would tend to push the brake against the tube rather than away from it.
I understood the idea was rotation of the wheel would tend to push the brake against the tube rather than away from it.
FrankCrank
Old layabout
....agree it makes no odds to brake function. But, you could have cut out the old brake mount from the frame, then spreading to accommodate the hub would be easier. A new piece of straight tube welded back in it's place, and bosses then welded in a more normal position, if that makes sense. Anyways, would be a dull world if we all did things the same wayIt makes no difference to brake function which side of the tube they are, otherwise the front brake would be on the rear of the forks, and actually sometimes they are
....agree it makes no odds to brake function. But, you could have cut out the old brake mount from the frame, then spreading to accommodate the hub would be easier. A new piece of straight tube welded back in it's place, and bosses then welded in a more normal position, if that makes sense. Anyways, would be a dull world if we all did things the same way
That would have been a nice solution, but I'm not feeling brave enough to weld structural joints just yet
Had another play and am really happy with the results
The rear triangle is close to complete now, someone mentioned it would be worth trying to strengthen the storage/transport wheel bracket up top which I may consider but I think I'll strip the paint, treat the rust and prime it while I decide.