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Making a frame thread


Blake

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If i had a brain i´d think over what i´m about to post,because the post to which i answered this bollocks was helpful and the tubes marino has used are a good example,people have seen them and can imagine what familybiker means...

:wink:

Edited by FamilyBiker
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^beat me to it. Or recycle some old mtb or road frames, chromo should ideally be heat treated during and after the weld process. If your using tungston always purge the tubes, it helps cool the weld but more importantly you get hendrix style penertration.

Agree with recycling an old frame- definitely the best way in my opinion.

Don't worry about purging tubes, but do make sure you clean up the bore as best you can.

Also wouldn't worry about heat treatment, CrMo or otherwise. Expect there's a bit too much specialist equipment involved there anyway!

Without sounding like too much of a twat, I get the feeling you're not really getting into the "engineering" of a frame here. You mentioned what diameter to use for the tubes which was a start. Look into which tubes are in compression or tension, different ways the frame might break that you need to design against (yielding, buckling, fatigue), advantages of different materials, ways of joining tubes together, effect of different shapes of tube (moment of inertia?) etc..

Good luck- there's a lot of effort gone into frame design!

Adam

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Without sounding like too much of a twat, I get the feeling you're not really getting into the "engineering" of a frame here. You mentioned what diameter to use for the tubes which was a start. Look into which tubes are in compression or tension, different ways the frame might break that you need to design against (yielding, buckling, fatigue), advantages of different materials, ways of joining tubes together, effect of different shapes of tube (moment of inertia?) etc..

Good luck- there's a lot of effort gone into frame design!

Adam

I agree with everything here, but you should also be looking at the minimum loadings and such that it states in the MTB regulations, they will give you a rough guide of how strong the frame has to be at a minimum. You have to consider the loadings involved with trials and the direction of the forces on a frame for each move, like how much twisting the frame will have under hard loading to the pedals for instance. I also agree that fatigue needs reasonable consideration, there is high and low cycle fatigue, both affect different materials in different ways. For good materials analysis you can find a program called CES on download and it is a massive database of every material and its properties, so direct comparisons can be made.

I found this very difficult to get these loading from recorded data, but accelerometers are probably the way to go. and strain gauges

For an excellent guide to really understanding the science of cycling keep a look out for the book Bicycling Science, it is a bit out of date, but the principles are there.

.

Also, my advice, make the prototype weaker this will give you minimum loadings to yield when you want to stress test the frame till destruction. Then you can be confident that the final one you produce for yourself to ride should support you.

Then you can try and loose some weight once you have looked at all these things and taken everything into consideration and fancy maybe making another frame, should be much easier.

Hope I helped.

Ash

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Cheers ash.

It's fairly certain now that this frame won't be ridden properly for trials, as in I am not going to build it up and go do some drop gaps on it, it's probably going to be more of a wall ornament than anything.

However, to address what ash and BionicBalls have mentioned, this is my second year of level 3 engineering, so I am no way near an engineer yet. This is our first real project of the course and what you mentioned is part of the process of the project.

We have to produce a thick booklet to have on the final project day, it will contain our diary entries that we must do weekly about the project and also a shit load of other stuff. As part of the shit load of other stuff I will have what you two have mentioned, different material properties and different forces and the appropriate joining methods.

Cheers for both of your help though, I appreciate the time you've donated to my cause.

George

xx

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Cheers ash.

It's fairly certain now that this frame won't be ridden properly for trials, as in I am not going to build it up and go do some drop gaps on it, it's probably going to be more of a wall ornament than anything.

However, to address what ash and BionicBalls have mentioned, this is my second year of level 3 engineering, so I am no way near an engineer yet. This is our first real project of the course and what you mentioned is part of the process of the project.

We have to produce a thick booklet to have on the final project day, it will contain our diary entries that we must do weekly about the project and also a shit load of other stuff. As part of the shit load of other stuff I will have what you two have mentioned, different material properties and different forces and the appropriate joining methods.

Cheers for both of your help though, I appreciate the time you've donated to my cause.

George

xx

FIrstly this is an opinion.

Secondly i have done the course you are currently studying.. also i did it while in a work place and operating 5 asix milling & millturn machines and had the opertunity to considerably alot more processes than you probably currently have.

Now, if you plan on making a frame for your ONC project, let me say. Good luck.

Making the frame in throry would be easy. But to pass the course in question, I cant see how it would satisfy the paperwork over the whole course of he year.

My project was was actually on developing and installing a new manufacturing Jig for my machine for when we produced a particular product. The hardest part was compiling the data for the evidance and providing usefull and relevent information to satify the grading module. Pictures, Quotations for steel, Testing figures, technical drawings, graphs etc etc.

Should you require any help on the course, just ask, as i still (Paper copies) have all my work saved. I walked away with a distinction in my work based project and a Double distinction with distinction for the overall year. I also got the same grade in my HNC and passed with merit for my HND. So im not just chatting shit.

Doing a frame for a UNI project is probably alot better idea..as you can follow everything Ash has said above. But for ONC.. i think it would be trying to much and dumb it down.

That being said,

Good Luck!

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  • 3 weeks later...

If that's all you've done so far, I want your life :P

A bunch of boring write ups as well, got to do a whole load of shit like what we want out of the project and stuff. Basically guff for people to read on the project day.

Still not a lot though, college is pretty f**king slow and boring.

EDIT: I still am behind on all my work because I'm slow and lazy

Edited by DrStix
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