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LuckyDave
09-02-2012, 06:42 PM
I've been out riding the Spirit.

My Bottom Bracket is about 3-4 degrees off square. My Bad. And it's too far over to the right from the dérailleur. The BB sleeve is distorted from welding so the bearing caps won't go all the way in. Basically I cannot get the front gears to work properly without fixing this.

The BB sleeve is already distorted from welding it without the caps in place. I have ordered a new BB sleeve. I will rebuild this.

I also need to move the chain pulley inboard about 1/4 of an inch, possibly more. I will wait till I have the new Bottom Bracket Assembly made up before I do that.

I am going to brace the seat tube. It probably does not need it. But given that I'm learning to weld, it will make me happier.

Practice helps a lot with riding it. I can now turn circles in one road width, and start of without doing the scoot-scoot-peddle-wobble thing. I'm now happy to ride it in the park and on quiet roads.

The seat is squeaky. I need to sort that. The bracket that holds the seat is not directly under my weight. That should be a small fix.

I got a cheapo bar end mirror. It was not convex. Complete waste of money. I've ordered a decent one now.

Planning a trailer for the kids. Half thinking of a Roman Chariot sort of thing.....

Dave

Ticktock
09-02-2012, 07:45 PM
Hi Dave,
THe derailer tube position is a common problem, as the location depends on the combination of derailer, axle, and chain rings that you are using.
If you use all the parts from one bike, it will be dead center on the BB shell. But if you change something, it may not be dead center!
Best to fix the BB and set up the cranks, then check where the derailer tube should be.
I still have to do this on my LWB, but I have not found ahill here where I need to change, so I keep forgetting to do it!
It is possible to get BB cups here in China that have no threads, and simply bash in. These would have been an alternative for you, but in view of the other problems with the BB I thinkyou are right to make a new one.
As you say, good welding practice.
Thanks for shareing,
Steve G

Radical Brad
09-02-2012, 09:15 PM
Sounds like you will have it all worked out on the next trip to the garage. Hope to see the photos soon.

Brad

LuckyDave
09-09-2012, 10:10 AM
Some pictures are up in the other thread, I've added a panier rack.

My frame is 2x40x40mm box section, all I could get easily, (somewhere between 12 and 14 guage), so I just drilled some holes, tapped them and bolted on some 10 mm steel tube. (You can bend that with a cheap plumbers pipe bender and some handle extensions).

I tried welding some 1.5x20x20mm box section. That's way harder. Melting through all over the place. I managed to get some good but welds with 1.6mm electrodes at 40amps. But the fit up had to be perfect. Any caps and I melted through.

Also, with 1.5mm the when welding a T shape, the end of the box section needs a LOT less heat to burn through than the side of the box section needs for penetration. It's going to take a lot of practice to get to the stage where I can weld 1.5mm properly.

D

darnthedog
09-09-2012, 12:15 PM
Hey Dave
Just a question on your Arc welder- is it an A/C welder? It has been mentioned here and on some welding sites I've that DC provides better control. And there are a few plans online to convert AC welder to DC for few $ and much cheaper than a new welder. Might allow for better penetration without the burn through. Just a thought. When I was in welding class my instructor mention that 7018 rod was much easier to strike an arc. I cannot say as I never got to use it and use Gas shielded mig now. But again these are things I have picked up on and willing to share with you and the group. Good luck.

Ticktock
09-09-2012, 01:04 PM
The hardest part about welding is learning to recognize where the problem is.
Sounds like you have started to do this--so just keep on welding!
Electric is much harder to do this with than gas welding, so you are well on the way to getting it right.
Steve G,
Beijing

LuckyDave
09-09-2012, 04:30 PM
It's a pretty decent DC welder. I got it second hand. A pico 140.

Basically the main problem seems to be that an edge on 1.5mm steel melts in an instant at the same current that
will penetrate a corner.

So if you imagine making up a T with box section, you have 2 fillet joints with close fit up. This needs a higher current as the heat is being drawn away by 3 faces. If you put the T flat on the table, these are the vertical joints.

The two horizontal joints are however more interesting. I think they are called flared bevel welds. You have an edge, a corner and a gap. So you really need to focus the heat on the corner, or it does not melt, and your weld sits on top and is as strong chocolate, and you need to build up a lot of metal, which adds a lot of heat. You barely need to touch the edge or it will melt back.

I will practice a lot more.

I also read that you can lap weld thinner material more easily, so I'm considering joining the top by putting 1.5mm flats across it and lap welding them onto the box section. Less pretty, but a lot easier. (And probably stronger than a poor quality butt weld)




Hey Dave
Just a question on your Arc welder- is it an A/C welder? It has been mentioned here and on some welding sites I've that DC provides better control. And there are a few plans online to convert AC welder to DC for few $ and much cheaper than a new welder. Might allow for better penetration without the burn through. Just a thought. When I was in welding class my instructor mention that 7018 rod was much easier to strike an arc. I cannot say as I never got to use it and use Gas shielded mig now. But again these are things I have picked up on and willing to share with you and the group. Good luck.