Hybrid_From_Hell Posted July 21, 2006 Share Posted July 21, 2006 Hello all, Ok sort of semi tech Q here. I am thinking of making some sill bars fer meself and the 90, ..... I have a design drawn out and in mind, they will be 'tube' based. Now, I could make them from say 48.3mm Blue band (3.2mm wall) stuff (have it handily lying about), or I could be a flash s*d and use Aluminoium tube..... Questions are as follows. 1. Can I actaully get 48mm ??MM wall thick tube, and is it a fortune ? 2. If I can get it then will my tube bender thingy do the bends or a.) will the tube collaspse under the bending b.) if it will collapse then will it then bend ok if I say go "Up" a wall thickness or 2 sizes ? c.) I know there are grades of Ali - some will not bend ie 5083 vs 6024 etc etc which grade should I look for for tube to shove through a bender ? 3. Anyone know say on a 2 metre length 48.3mm x 3.2mm wall how much would each weigh,(steel vs Ali) or another way of saying IF I have to go up in wall thickness to get the strength and the ability for the tube not to crush on be4nding is there really any saving in weight overall ? Why Ali ? Well as a mature "Studunt" I have been advise that I can "have a project" to work on during the course ...........one bloke is bring in a Motorbike frame, and 2nd a lump off a traction engine and and another a lump of Model T.... ...its "Nutter Time" So discuss please and post up ! Nige Quote Link to comment Share on other sites More sharing options...
Astro_Al Posted July 21, 2006 Share Posted July 21, 2006 HFH: >"I am thinking of making some sill bars fer meself and the 90," - cool, what're you gonna do, bolt them to the sides of your wellies...? Ok, enough with the carp gags... 1. Can I actually get 48mm ??MM wall thick tube, and is it a fortune ? Yes, and yes. You can get it from BSS. Andy (Moglite) has used it for his links and bent it with the Tubela bender (now residing in my garage if you need it). It strains the seals 'a bit', but you can bend it. Special order, so you'll need a whole 6.5m length. Looking at the best part of 100 squids I think. Personally, I'm gonna try regular wall (3.2) blue band with another length split in half length-ways welded over the lower half (so kind of doubling up the lower half of the tube thickness with a C-section of the same stuff). Savvy? Maybe you could try this, so I can see how easy it is? a.) will the tube collaspse under the bending - no, it's ok - damage done also depends on bend angle (I'm still talking about the thick wall steel here - schedule 160?) ... c.) I know there are grades of Ali - some will not bend ie 5083 vs 6024 etc etc which grade should I look for for tube to shove through a bender ? No idea, check the specs of different alis on Matweb.com. With the weight of your truck, I'd just say stick with steel. You probably won't save much weight by the time you've made the ali strong enough - it's a bit like ali wheels I expect (more amterial = heavier = less advantage over steel than originally supposed)... Plus steel is easier to fix / replace etc, and it is a part that'll see some action! Unlike mine, which will never leave the damn garage. 3. Anyone know say on a 2 metre length 48.3mm x 3.2mm wall how much would each weigh,(steel vs Ali) or another way of saying IF I have to go up in wall thickness to get the strength and the ability for the tube not to crush on be4nding is there really any saving in weight overall ? mass = density x volume... see above ref for values of density. You're a student - break out the calculator! (You may need to steal a VCR from the 'Common Room' in order to fund this bit) It's not 'crushing on bending' that's a prob (you could always mandrel bend it), it's 'crushing while hung up on an annoying rock' that's gonna kill it (point load). There is no way an ali tube 48 x 3.2 is gonna be man enough as a sill bar on your truck. So, yes, you'll need thicker ali alloy (but which one??? It'll affect the density, cost and weight!). What do you have access to - that'll give you some idea of what's possible, it's all very well picking the ideal alloy from a list, but you've got to shell for it and source it, and these factors will instantly rule the truly blingy alloys out I guess... If you want a project - how about a new lightweight truck? Hope that helps? Sorry to sound a bit negative. Al. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted July 21, 2006 Author Share Posted July 21, 2006 Kin 'ell Al Either I iz getting more technickal like, ................. or u iz getting softer with us mortals in yer old age - cos I could almost understand your post 100% Seriously ta for this it has sort of confirmed me thoughts ie Mit big "Nudgette" on tree Ali is going to maybe not bear up as steel might, up the wall thickness on the Ali ...and then the weight is the same or even more.... Ok Thought No 2. Is say 60mm CDS with a 1.6 or 1.8 wall going to have the impact resistnace of say 48mm 3.2 wall seamed tube ? I know where there is the above going free, and I have a former for 60mm too, but CDS can be odd to bend / wel / work with ? Nige PS ......NOW wot iz I the 'matuaurer studunt' gonna take into me class to TIG up Nige Quote Link to comment Share on other sites More sharing options...
landrover598 Posted July 21, 2006 Share Posted July 21, 2006 I know that you can get aluminium scaffy poles (48 x 3) which would do the job fine i reckon Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted July 21, 2006 Author Share Posted July 21, 2006 <pikey Mode On> Yeah, any clues as to sites in surrey wot have them "Available" Geezer <Pikey Mode off> Its a thought (BUYING them not nicking them before you all jump on me ) Nige Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted July 21, 2006 Share Posted July 21, 2006 If you go down that road ………….my neighbour is a scaffolder ………… wot length is required ? Alternately a nice pair of galv tree sliders from Mill services cant be beaten for the money. IIRC about £130 a pair................. and the quality is fine. Ian Quote Link to comment Share on other sites More sharing options...
bishbosh Posted July 21, 2006 Share Posted July 21, 2006 Nige, Ali is a waste of time for this application IMHO. You will save very little weight and loose massively on strength. Steel all the way for this one I think. Smaller diameter and thicker wall = more point load capacity. Obviously there will be a larger diameter tube with certain wall thickness that is as robst as a smaller tube with thinner wall. Don't fancy the maths though. Whilst people may laugh, scaffold tube is probably a good way forward as material will be very cheap. My 2p. Oh, and I second Mill services.... Quote Link to comment Share on other sites More sharing options...
freeagent Posted July 21, 2006 Share Posted July 21, 2006 Ally has a slightly better strength to weight ratio than steel (typically 0.25 the weight of steel, but 0.33 of the strength...) But.. its not quite as good at deflecting/ resisting localised damage, and as others have said, its not as good when subjected to a point load... i'd stick to steel, you give your truck quite a bit of abuse, and ally rock sliders will have to be absolutly enormous to do the job you want them to do... if you do want to go with it, i've got loads of stuff on different ally specs, as just used a load of it in my disertation... as far as tube sizes in steel goes.... if you want it to deflect/ resist local damage (such as getting whacked on rocks and denting the wall) you need a tube with a thick wall, if you want to resist bending along the length of the tube, then a larger diameter will help enormously, if you want some more techy info on this, ask Astro al, he's a 'proper' engineer..... Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted July 21, 2006 Author Share Posted July 21, 2006 Oh B******s I give in, .......................OK I'l do steel If it helps ...........................I'll do 48.3mm and a 2mm ID mm It was a thought but I did wonder and you have all confirmed. Pics as and when, .....it will be after the rear winch mount .......so its job No 2, .................but planning is everything ( Gengis Khan ) Nige Quote Link to comment Share on other sites More sharing options...
MogLite Posted July 22, 2006 Share Posted July 22, 2006 Don't give up so easy Nige Ali tree sliders are quite common in the Ibex world, because they've already got the roll-strength built into the spaceframe. Take a look at Red Ibex It was an absolute sod of a job - you'd love it I can measure the spec of tube I used if you are interested, but scaffolding is not an option. Scaffolding is designed to resist bending, this ali is designed to be bent. I got my tube through Maddison 4x4, but I know where I can get it in Dorset too. If you do ali - call Patrick at Maddison 4x4 - they do this work all the time Do ali - learn something - be different, failing that buy Scorpian Quote Link to comment Share on other sites More sharing options...
northernchris Posted July 22, 2006 Share Posted July 22, 2006 Andy Do you know what grade of Alloy it was that you used??? i.e 7075 t6 etc etc Chris Quote Link to comment Share on other sites More sharing options...
Astro_Al Posted July 24, 2006 Share Posted July 24, 2006 Kin 'ell Al ... I could almost understand your post 100% Yeah, hanging round here is making my brain soft... Ok, I'm confuzzled: are we talking 'sill bars' like a Series owner would think of - down below the doors which could potentially see the full weight of the vehicle (or half or whatever), or are we talking tree-slider type 'sill bars' up above the doors? I thought it was the low ones when I read your post, but now people are talking about trees and stuff...??? I think it's all been said for the lower bars, but if making uppers, then I also would vote for some decent ali alloy. Al. P.S. Man - one day I'll do those flippin' graphs I promised of tube diameter vs. wall thickness. They're somewhere on my hard disk... Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted July 24, 2006 Share Posted July 24, 2006 Unlike mine, which will never leave the damn garage.Place your bets now Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.