Cheap frame material

[nick_ish]

a singular weak weld is a weak frame and there fore a danger or so they say haha
i'm terrible at welding but with practice and maybe a quick google or youtube search and i'm sure you will have the skills to put your knowledge to the test!
good luck

[herku1004]

Hehe! Ok nick! I think I'm gonna give it a try.
Hoewever, I still have a problem: How do I know that the tubes will actually sorta hug each other? How do I cut them right before the welding?

Also: How big does the hole where the mechanism for the pedals go in? And how on earth do you call it???

I may have to apologize but English is not my native language. I'm still learning the parts of the bike.

[wimpy]

Depends on what you want. In my case,I took a donorbike and cut off the complete bottombracket. I marked it with the blue lines in the pic.
Later,it was welded onto this frame. Keep in mind,you use the same material. Iron and aluminium don't mix too good in welding,I think.

[wimpy]

Handlebars or just bars.

[Uncle Stretch]

Not wanting to burst your bubble , and anything is possible , but it requires a little skill to build a frame from scratch.
The ability to weld is one of the things that you will have to know. Whether you learn it before you start or as you go along.
Most people start with throw away frames and modify them. Then after a little trial and error you build what you like...or what works. There is a safety factor involved too. If what you put together isn't stable you could be hurt. The people that scratch build frames here have some knowledge of how to build things out of metal. Well most do.
Saying I want to build a house , tell me how , but I don't have a hammer or know how to use one will make the task quite a bit harder. I know your not trying to build a house , but the concept is the same.

[gcrank1]

Can you take a tech school class in welding, or even go to talk to the local high school shop teacher about it. If there is a motorcycle shop for chopper guys near you go see if you can hang out, guys there have lots of skills and somebody might think what you are trying to do is cool.

[herku1004]

Sure. I just wanted to give it a try. I was thinking, once this is gonna be my first bike, maybe I should use a donor bike to extract some parts I may find difficulty in making myself. Such as the place where the pedals go, the front fork and the rear place for the wheels. What do you think? Is this gonna turn out well?

[herku1004]

OK, I think it would be easier, to use a donor bike to extract from it some parts I may encounter difficulties on making.
That includes the pedal part (can anybody tell me how is that thing called???), the front fork and the part where the rear wheels go.
Would I need to do the same for the tube where the seat goes just to be sure? Also the steering wheel? Or is it easy enough?

Speak, bike gurus!

[gcrank1]

Your 'Mark I' version probably wont quite match your vision, Mark II will be better for sure. Its just metal, adapt, adjust, re-weld, Rat On!

[herku1004]

I'm soorry gcrank1, it may be my english but I don't understand what you're saying. Paraphrasing? Please?

[gcrank1]

'Mark I (as in 1)', the first version
'Mark II, III, etc.,' subsequent versions with modifications, but the same basic assembly
The use of this helps denote the progression of developement, but is a bit formal, I suppose.

[herku1004]

OK gcrank. However, I only have only one scetch. So, only MarkI existing? I guess you consider planning to use a donorbike as MarkII. So yes, I may need to change some angles where I will weld the ready parts.

[herku1004]

OK, I have a new Idea, tell me if I'm right. Like in the first scetch I posted, the tube where the seat goes will actually begin from the pedals. This way the distance between the seat and pedals could be adjusted to fit any riders liking. Is it a bood idea or will it turn out hard to reach the handbars?

[nick_ish]

The part on the frame where the pedals/cranks go is called a bottom bracket
and i would recommend getting yourself a donor bike and take the head tube (place where the forks slot through) forks, bottom bracket and rear drop-outs ( little slots that the back wheel slots into)
these are the basic corners of your bike ,kinda

so you can have these parts and then do whatever you wish with the tubing in-between them! also measure your self (arms, waist to shoulders and legs) the try to draw yourself onto the bike you want to build and make estimations of how long the tubing should be (: if you do get it wrong first time you can re-cut and weld again!
best of luck

[gcrank1]

"Is it really important to have welded before?"
Well, considering that the welds are what holds your frame together, keeping the the bits in place and from you doing a header into the pavement, yes, it is. Welding is a learned and acquired skill. Ive seen some naturally talented people catch on pretty quick to the basics, but nobody Ive seen has done really well without some training and practice.