How Are Bars Made?

[Davetrials]

How the hell are bars made? they have no join in them, so are they cncd?

Been discussing this with my mate before?

[Mark W]

They aren't CNC'd, 'cos if they were you'd be wasting a LOT of material (in that bars have a typically thin, slender tube thickness, so you'd be machining out a lot of metal).

[Endohopper]

I expect they're drawn from tubing , and the term "extrusion "comes into it the process at some point . Kinda curious too .

[Will Arnold]

it isnt possible for them to be cnc machined i dont think.

i think they start out as double butted tubes, then they are heated up and bent accordingly :)

im probarbly wrong (N)

:)

[Tartridge]

I expect they're drawn from tubing , and the term "extrusion "comes into it the process at some point .

←

Ta-daaa.

The tubing is also usually made by being drawn, as far as I know.

[Davetrials]

they cant be a mould as they would have a join line, unless its painted over?

As there would be no other way to remove the bars from the mould?

[Tomm]

Yes, they are extruded. Extrusion: The act or process of shaping by forcing through a die.

Or, for you Dave:

:S"

[Ben Cox]

Yes, they are extruded.  Extrusion:  The act or process of shaping by forcing through a die.

Or, for you Dave:

:S"

←

waheey, simple terms that even i can understand.

So let me get this straight, bandle bars are made in an industrial sized playdo machine? lol

Ben

[fairy elephants]

but that machine is only making 1/2 a tube... there would need to be a join :S"

[Mark W]

Nuh-uh. That's for making steel girders.

However, not the pic and the other possible options :S

[Davetrials]

Yes, they are extruded.  Extrusion:  The act or process of shaping by forcing through a die.

Or, for you Dave:

:S"

←

My god i wonder how much force is required to do that?

Edited May 12, 2005 by Davetrials

[Tomm]

They melt the metal first :S

[Davetrials]

but how does it harden in the same shape, this is all very confusing :S

[rich4130]

←

I've not seen one of those in years, used to have one just like it... :S

Does all this mean that higher rise bars are probably weaker than flat bars?

[mcajh]

but how does it harden in the same shape, this is all very confusing

The metal is heated but not into a liquid state. Its soft enough to be 'bent/shaped' but hard enough to retain its shape. If you get what I mean.

I think.

Edited May 13, 2005 by mcajh

[theno1woody]

right. the play doh machine is an awesome example, n like mcajh says as the metal comes out of the die it is cooled to a temp at which it hold its shape. Most bars arent the same thickness all the way through, they vary at different points, this reduces weight but also helps a bit with the stress distribution of the massive forces that trials rider inflict upon bars. This thickness variation is done using a special type of extrusion. The red bit on the play doh model creates the outer diameter of the bar, but to make the hole in the middle another tool is used which is positioned in the molten metal, but this metal melts at a much higher temp. This tool can be varied in diameter to make the correct inner diameter for the bar. In some cases the outer diamter of the bar varies so in that case the outer diamter tool would vary its diameter too. once this is all done the bar is still straight, but becuase the tube is still hot enough to be formed it ccan bent into shape using a jig specific to the bar design. To stop the bar from folding or creasing a insert is usually put inside the bar before its is bent to prevent this. The bar is usually left in the jig to cool and to stop it bending back.

Hope that helps

think i covered most pointers

Woody

[oakley]

that is quite interesting, glad i read this topic now!!! :S :P :lol:

joE!

[Trials Tom]

Me too, very informative. I've actually been wondering how it's done myself.

[totaltrials]

I dunno why, but I can smell play doh when i look at that picture (Y)

Phil.