welding feet to stand and making boss for shift lever and adding rectangulr tube to stay front wheel

I bougtht shift lever for road bike.
However, I can't get the boss in japan. I know I can buy it from U.S.A..
But I wanted to try making it.
At first, I measured the shift lever to know the form of boss to needed.

 The boss has square part.

I noticed that Campagnoro's boss may fit these shift lever.

 I made two bosses and 1 screw handle. I used M5 tap for Boss.

 3.1 mm from top are filed.

 Bottom square marked like this.

 Narrower parts of top  and bottom square is parallel.

 Cutted and filed. It's good job.

I have not known I can make these parts.

 I had a mistake to welding feet to stand. Why didn't I do it well ?
yesterday, I welded the other parts well. Ofcourse, I tried again. but bad work again.

 Now, attaching stand. I wonder how the stand stops. with only screw, it's hard.

I added stopper of front wheel. but, How do we  take it a parts ?

My welding technique is bad now. sometimes I can weld so so. May be I need sensible work because I use 1.6 diameter rod for welding.

I tried solderling, but I can't yet. when I make flute and oboe keys, it's easy to solder. But on this bike, I can't yet. what's is problem ?
I guess, maybe more higher temparature is needed. But I have just 1 handy gas torch. how can i heat the pipe of bike.
That's problem.
not fine.