Shaun H
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Posts posted by Shaun H
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Something happened today between me and the missus this morning, mostly sorted but won't know for sure until in a few weeks time. But since this morning, she hasn't spoken to me much at all and just wants to be by herself. I'm just worried about her. I can't tell you what happened but it was my fault and I have apologised and she said it's fine.
Do I just let her be for a while? It just feels horrible between us today.
I think we've all heard that one before
Obviously it's difficult for us to give advice if you can't tell us what it is you've upset her with. I'd suggest making sure you're there for her if she wants and being VERY careful about pushing the issue. I think it may be Skoze who is best experienced in dealing with a missus who doesn't want to talk about something difficult? Either way like he said, we're all friends here, we'll be able to help better knowing the whole situation.
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If you're weight inclined it may be worth noting white parts will be slightly heavier since they have to be painted rather than being anodised.
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Thanks to everyone who replied, especially Shaun. That was the kind of answer I was looking for!
As soon as I first glanced at the depth part I immediately had thoughts that a 12mm thick booster like the old Echo Control or Heatsink ones would be stiffest. The Tensile is 10mm thick, though seems an overall larger booster? It's interesting that you say the Tensile is stiffest of them all. Guess that works out pretty well as they're the cheapest too!
If you look at the equations for second moment of area for a beam you'll find the general formula:
So looking at a booster, making it taller has a much bigger effect of making it deeper although it is important to point out that is theoretically!
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To generalise, the deeper and taller a booster's cross section is, the stiffer it will be. Stiffness is a function of a materials' modulus of elasticity E, and the geometry's second moment of area I. Since boosters require stiffness driven design, out of the two popular 6061 and 7075 alloys, 6061 tends to be used since there isn't a large difference in their moduli (6061 about 69 and 7075 about 72) and 6061 is a bit lighter and is cheaper.
I sort of agree with Adam that you don't necessarily want the extra stiffness offered by heavier boosters since increasing the cross section of a booster (and increasing weight) won't return a similar increase in stiffness for some dimensions. Increasing the width of a booster's cross-section is the most efficient way of increasing stiffness however there's little scope to do this when working around rims, tyres, brakes etc. Failing that increasing the booster depth increases stiffness but this also considerably increases cost, since a larger amount of material has to be machined away in the webbing (pockets), hence, some boosters sticking with a thinner shape and simple, minimal machine operation profiles that (should) make for a cheaper product.
EDIT: In answer to your question, the Tensile booster is the stiffest one I have ever used, however I found it couldn't be run with unworn brake pads.
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They aren't 7075 and infact they are exactly the same as Trialtechs. I bought them thinking they were 7075, but was later told by tarty that apparently its impossible to forge 7075 cranks the way they are made.
Anyone want to send me one to cut up and stick on the Uni tensile tester?
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It's at Becton Dickinson in Plymouth.
Looks well interesting! I quite like engineering that really benefits people's lives, big responsibility in it too.
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Just applied for a job as a design engineer, got a good referee who studies with me who is already a design engineer so hopefully I'm in. If I haven't settled down by June I'm moving to Nepal for the simple life
Where's that at then?
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If you know anyone with access to a lathe get them to turn the mashed threads off for you. I did the same for a V!Z BB which I put into a frame that I didn't realise had wonky threads.
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Not sure I agree with that. He had the best car of the year by a long way (from everyone except perhaps Webber, and even that appears to be debatable) and only just scraped over the line...
If it wasn't for numerous mechanical failures Vettel would have walked it this year.
Still, I'm a bit disappointed Webber didn't make it his year but at least Alonso didn't win!
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Cheers for the advice. It's a 42 mile journey.
I like the idea with cheaper tickets in advance though, that'd be cool. I'm sure she'd come and see me too, she's very dedicated once she has a boyfriend from what I remember from her last relationship. which is good
I've been with my missus over 5 years, the past 3 have been spent living about 50 miles apart!
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So much power AND precision. Impressive.
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Thank you, you have just rephrased my question in the form on an answer and given no information to help. I know that it is up to me what properties the frame requires, but i thought it would be quite obvious that like a bike frame a rickshaw needs both strength and stiffness, what I was asking was if anyone could give me a starting point for what tube wall thickness and diameter i should be looking at
I was trying to give you the thought process to decide for yourself. It's pretty unlikely that someone here will have designed a rickshaw before and even less likely that they're going to be able to give you tubing specifications.
To rephrase what I was originally trying to get through; If you believe you are limited to just those 2 alloys, then you need to compare all their properties. You are correct, it is obvious a rickshaw needs strength and stiffness, but which is more important for your application? Does the rickshaw need to last a long time, if so you need to consider corrosion and fatigue limits. Is one considerably more expensive than the other? Is one more difficult to work with?
If you aren't familiar with these kind of design processes and you can't find some one with experience, then I'd advise you play it safe and use tubing around twice the thickness of standard cycle tubing.
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Well depending on whether or not you can get comprehensive property data then you should be considering what you need from the material. Strength? (Yield stress) Stiffness? Endurance limit? (Fatigue strength) Corrosion resistance? Cost?
It's down to you the designer to decide on which properties are most important in the application. I'm not familiar with either alloys so I can't give you my thoughts, even so it should be your own decision as it's yourself (and maybe your friend?) that need to decide on the specification.
Square tubes are probably used in most rickshaws since it is easier to work with than round tubes and therefore cheaper in labor (could also use cheaper mitre equipment).
EDIT: Although I should add, square and round tubes have different mechanical properties which will also impact on the design.
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Fernando Alonso could pretty much wrap up the drivers titles this weekend at Brazil if both Redbull drivers don't get their sh*t together and work as a team. Or maybe Jenson Button will get the kind of luck that gifted 'ICEMAN' Kimi Raikkonen the drivers title back in 2007.
Do you honestly think that's going to happen?
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Please ignore my lack of MTB knowledge but why does it cost so much?
Like, what makes it so special from a.. say.. £600 frame etc?
Is it build quality, weight..
It's a full carbon fibre downhill frame. As such there will be a very small number of them produced at a very high cost per unit.
If CF stuff didn't have such a stigma attached to it I'm sure it'd be more popular and therefore cheaper.
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Dont pussy out this time! Bloody Brummies!
Looks like we're going somewhere else now
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You heard the boy, we want a modstock 24
Like this?
I'm pretty sure you already have a photo of a certain Limey breaking Mike?
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It would make carbon fibre even more amazing but, even better, more isotropic! (CFRP analysis is the current bane of my life
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Really liked that Ben
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evening all, browsing tartys today looking for a bashring for my limey, then remembered i had a oldschool echo one in my tool box, so i thought f**k buying one i'll make one haha. after about an hour this is the end product:
[pic]
Comments?
Precision angle grinding engineering?
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Fair play squire - she looks nice. Who owns those jugs on the right? (Sorry if it's your sister or something haha)
Nah his sister's fitter than that, me and the Brummie lads were perving on her when his Dad came to pick him up at the DJ Pompy ride
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If it's cracked where I've highlighted that wouldn't seem unusual if that's where you're trying to describe. It's the member which will be carrying the load from the brake caliper to the hub and the highlighted areas is of minimum cross section. The "small arm" as you described it will just be stiffening the central area and won't carry much force.
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The Ashima/Rockman rotor seems to be pretty well designed, but it's also very light. Where has it cracked, it's either a material failure or a not so obvious stress raiser.
EDIT: It's probably worth mentioning that one generation (maybe the first) of Hope Mono Trial rotors had a problem with premature cracking which seemed to be down to an unforeseen stress concentration in the design.
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Can't believe no one has mentioned Trashzen yet!