Homemade Parts!

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Homemade Parts!
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flag taquitos
Posted: May 2, 2019 at 7:09 Quote
Mr-Magura wrote:
As for bead blasting, it has generally nothing to do with looks
I blast parts all the time for looks and so do lots of other people. It gives ano a matte look and raw parts become satin. See the difference between the two anodized parts below.

I'm glad someone else has some common sense though. It's kind of funny when your job is designing and making parts all day and someone is trying to tell you your priorities haha
<Photo is private>
<Photo is private>
flag talkingspoon
Posted: May 2, 2019 at 9:14 Quote
*raises shakey hand up slowly* what's the bottom part for in your picture?
flag taquitos
Posted: May 2, 2019 at 9:23 Quote
talkingspoon wrote:
*raises shakey hand up slowly* what's the bottom part for in your picture?
Ball bearing eyelet for a DHX2. Threads onto the shaft in place of the stock one.
flag R-M-R
Posted: May 2, 2019 at 10:03 Quote
Mr-Magura wrote:
I live form engineering and industrial design, and I can assure you that trying to seperate the factors like that, will end up poorly. I mainly develop surgical implants, which brings all the testing you could ever imaging, every time, so there's no guessing as to how things works.

To make a successful component, be that a showel or a space rocket component, the starting point is to define the possible materials. Then the design, based on the cons and pros of the possible materials, with the future manufacturing processes in mind.
This is where most engineers fail, as they have no idea about manufacturing.

As for bead blasting, it has generally nothing to do with looks or fatigue, but simply to remove surface imperfections in a cheap way. In some materials, a simple scratch will initiate a crack. 7075T6 and grad 5 titanium is particulary prone to this, therefore you typically see it on those materials. Same materials are generally sensitive to stress risers, like too small radius in a corner and so forth.


Magura Smile

Engineer here, too, so let's not get into a competition.

No one is saying bead blasting and shot peening are equivalent.

No one is saying manufacturing and materials don't matter. It's a general principle, like the old expression "an ounce of prevention is worth a pound of cure". I hope we could agree, in that example, that it's more efficient to plan properly, rather than rush forward, make mistakes, and fix them. Of course it could be argued that things never go perfectly, it would take infinite planning to absolutely avoid errors, it's important to have processes in place to address problems, etc., but the underlying principle remains true.
flag taquitos
Posted: May 2, 2019 at 10:18 Quote
I think we can all agree that thinking things through is extremely important. I do agree that design is the best way to prevent failure and that masking poor design with materials or manufacturing techniques is not the way to go about things. I think that's what you were trying to get at and I didn't understand. It is definitely true that you cannot separate any of those aspects when designing a part, though. And quite often manufacturing techniques are limited and the hierarchy breaks down. That said peening falls under manufacturing and in my opinion should not be relied on to prevent failure with something like a bike part where it will be subject to random loads you can't really imagine.
flag whattheheel
Posted: May 2, 2019 at 10:35 Quote
Alright bitches. I demand to see degrees and certifications!! Dick compare time!! Whip it out!! Who's got the biggest?? lol lol
flag R-M-R
Posted: May 2, 2019 at 10:36 Quote
taquitos wrote:
I think we can all agree that thinking things through is extremely important. I do agree that design is the best way to prevent failure and that masking poor design with materials or manufacturing techniques is not the way to go about things. I think that's what you were trying to get at and I didn't understand.

Yes, that's exactly what I'm trying to say! Perhaps I could've stated it as the hierarchy I listed is ranked by each parameter's power to make a good product.

taquitos wrote:
It is definitely true that you cannot separate any of those aspects when designing a part, though. And quite often manufacturing techniques are limited and the hierarchy breaks down.

I get what you're saying and I do agree, but we're talking about slightly different things. I was presenting a general philosophy and you're talking about how to implement it. As an example, as much as I like forging as a manufacturing process, we both know some shapes can't be forged. In extreme cases, a 3D printer that produces a material with less optimal mechanical properties can make a better part than a process that would be superior for simpler shapes. These are cases of optimizing a design with manufacturing and / or materials in mind. But even in those cases, once a manufacturing method and a material have emerged as a clear winner, we can go back to the philosophy that, for this given method and material, sound design is critical, while additional optimization of manufacturing or materials produces modest gains.

taquitos wrote:
That said peening falls under manufacturing and in my opinion should not be relied on to prevent failure with something like a bike part where it will be subject to random loads you can't really imagine.

Yes, peening is manufacturing - I thought it's supposed to be you who's arguing you can't separate it from design! Wink No one said it's a design element. Now you're making my point that design trumps manufacturing!

I wouldn't say the loads are random, but I do understand your point. Given enough data on how a part actually fails, we can implicitly account for these loads, even if we don't have a statistical model for them. As Magura mentioned, peening can help with the durability in high cycle, low stress, situations, especially for thin-walled parts. Maybe a handlebar is a good candidate for this. A fork crown probably isn't. Either way, it's a small improvement, relative to the value of a superior design.
flag taquitos
Posted: May 2, 2019 at 11:21 Quote
Long story short we have circled back to the fact that blasting/peening won't really improve the crowns that dude made haha. It could make them look good but personally I think the bright finish looks nicer. Lots of people try to hide poor machining with blasting or tumbling... Dead Horse

whattheheel wrote:
Alright bitches. I demand to see degrees and certifications!! Dick compare time!! Whip it out!! Who's got the biggest?? lol lol
8===D how about you?
flag whattheheel
Posted: May 2, 2019 at 11:47 Quote
8=============================================================D!!!!!!
flag inked-up-metalhead
Posted: May 2, 2019 at 12:26 Quote
whattheheel wrote:
8=============================================================D!!!!!!

we all know youre over compensating...
flag whattheheel
Posted: May 2, 2019 at 13:26 Quote
You still alive?? I'll be damned! How's yo babies Mama??
flag inked-up-metalhead
Posted: May 2, 2019 at 13:40 Quote
whattheheel wrote:
You still alive?? I'll be damned! How's yo babies Mama??

yeah, been trying to sort my life out, and spending pretty much every spare second on here wasnt helping. started a business, hopefully itll actually start making money soon, id say buy some furniture but shipping may be a bit expensive.

getting an e bike soon.

lifes better.
flag Nobble
Posted: May 2, 2019 at 13:43 Quote
yonny10 wrote:
Mr-Magura wrote:
As for bead blasting, it has generally nothing to do with looks or fatigue, but simply to remove surface imperfections in a cheap way.

Shot peening does reduce the likelihood of fatigue failure but only for thin walled spring type components. Agree there would be zero benefit for most MTB components.
thin walled and spring like...

You mean handlebars?
flag Mr-Magura
Posted: May 2, 2019 at 13:58 Quote
whattheheel wrote:
Alright bitches. I demand to see degrees and certifications!! Dick compare time!! Whip it out!! Who's got the biggest?? lol lol

It's much more fun to compare bank accounts.


Magura Big Grin

 


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