psycholist Posted December 18, 2009 Report Share Posted December 18, 2009 The section labelled 'Still not convinced this is possible to machine will be the first place the frame cracks in use. Reentrant corners, especially when they're located directly on a load path will produce crazy high stresses. I'd merge the chainstays flush with the end of the BB shell. Quote Link to comment Share on other sites More sharing options...
trialsmax04 Posted December 26, 2009 Report Share Posted December 26, 2009 alex, your brake mount idea, its been done. no idea of what frame it is. but the begining part of this video you get a sneaky peak at the mountclicky Quote Link to comment Share on other sites More sharing options...
indianatrials Posted December 27, 2009 Report Share Posted December 27, 2009 Ok, this is a real random question. How do yuou get the geometries right? and everything square? im sure you couldnt just lay it on the ground????? Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted February 2, 2010 Author Report Share Posted February 2, 2010 Ok, this is a real random question. How do yuou get the geometries right? and everything square? im sure you couldnt just lay it on the ground????? make a frame jig to hold each component of the frame. The solidworks model is built around a virtual jig so will give me all the tubing lengths too Okay, Topic bump. I now need to start ordering materials....has anyone got any other improvements for the frame? I'll put up some renderings tomorrow of the finished seat tube and reinforced brake mount area. In the mean time, I DESPERATELY need wall thicknesses for my frame. If anyone could shed any light on this, it would be a great help. Like the tubing thickness of a koxx, say, and an Adamant. I can then cad model this and get the weight to the target. Mainly I need to know the approximate ratios between wall thickness on different parts of the bike. Also, when a bike is reduced on weight...are all the tubing all over made thinner? or just specific areas? Cheers Alex. Quote Link to comment Share on other sites More sharing options...
Revolver Posted February 2, 2010 Report Share Posted February 2, 2010 Also, when a bike is reduced on weight...are all the tubing all over made thinner? or just specific areas? Often tubing is double butted, meaning it's thinner in the middle. Quote Link to comment Share on other sites More sharing options...
isitafox Posted February 3, 2010 Report Share Posted February 3, 2010 This may sound a bit gay but I'm quite excited about seeing this all come together and really hope it works for you! Quote Link to comment Share on other sites More sharing options...
Matt Vandart Posted February 3, 2010 Report Share Posted February 3, 2010 alex, your brake mount idea, its been done. no idea of what frame it is. but the begining part of this video you get a sneaky peak at the mount clicky Saw it on a weird bike that was sorta just one thick tube also. Not long ago, on here. Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted February 3, 2010 Author Report Share Posted February 3, 2010 This may sound a bit gay but I'm quite excited about seeing this all come together and really hope it works for you! Haha I'm excited to actually...ordering materials soon, I'll be starting work just after half term. Saw it on a weird bike that was sorta just one thick tube also. Not long ago, on here. Yup, that was a Koxx prototype and a Hoffman Bikes frame. Has anyone got any info on wall thickness? Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted February 3, 2010 Author Report Share Posted February 3, 2010 Here is the frame so far.....I'm thinking now it could do with pitbull 06 style "wings"? or do we think that would be a bit OTT? Quote Link to comment Share on other sites More sharing options...
craigjames Posted February 3, 2010 Report Share Posted February 3, 2010 Nah a bit of 3-4mm plate machined up nicely would be a smart idea Alex, increase the stiffness in the brake and rear end area. Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted February 3, 2010 Author Report Share Posted February 3, 2010 Nah a bit of 3-4mm plate machined up nicely would be a smart idea Alex, increase the stiffness in the brake and rear end area. Righto So worth the slight weight penalty? The frame is currently 2.2KG with no gussetts, although I'm sure the tubing is currently too thick. Ill design one up now then....Cheers Craig Quote Link to comment Share on other sites More sharing options...
craigjames Posted February 3, 2010 Report Share Posted February 3, 2010 What diameter and gauge tubing to you have? Think the main reason will be where its plain gauge. Headtube is a very easy on to externally butt although it will make mitring the top and down tubes harder. Thinner top tube and seat stays? Quote Link to comment Share on other sites More sharing options...
Phatmike Posted February 4, 2010 Report Share Posted February 4, 2010 The reason being that by default the back of the fork legs will be in tension at all times except while you're endoing, so the fork will fail more quickly all other things being equal with the mounts on the back. Just thought I'd pick up on this; the forks will be under tension at the back when 'just riding along', however hardly any stress is put there then! The big (fork-breaking) forces come into place when the forks are being bent back, which is why most forks break from fatigue caused by high stress on the front of the legs/crown/steerer. Quote Link to comment Share on other sites More sharing options...
Matt Vandart Posted February 4, 2010 Report Share Posted February 4, 2010 alex, your brake mount idea, its been done. no idea of what frame it is. but the begining part of this video you get a sneaky peak at the mount clicky Is that a hoffman frame? Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted February 4, 2010 Author Report Share Posted February 4, 2010 Is that a hoffman frame? Yes Siree... Here is a rendering of the latest revision of the frame. I need to get the design all sorted by MOnday...so any pointers would be brilliant Cheers Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted February 4, 2010 Author Report Share Posted February 4, 2010 If anyone's interested....a predicted weight from solidworks ( excluding welds ) is 1.613kg 1.5mm tubing used pretty much all over. The brake area is constructed from 3mm plate. Material is 6061 t6 aluminium Quote Link to comment Share on other sites More sharing options...
Luke_zoo Posted February 4, 2010 Report Share Posted February 4, 2010 If anyone's interested....a predicted weight from solidworks ( excluding welds ) is 1.613kg 1.5mm tubing used pretty much all over. The brake area is constructed from 3mm plate. Material is 6061 t6 aluminium Would love to see it work/ ride! If it worked, Would you make your own frames then sell on... worth a go though. Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted February 4, 2010 Author Report Share Posted February 4, 2010 Would love to see it work/ ride! If it worked, Would you make your own frames then sell on... worth a go though. I'd quite like to do that in the future...who knows though...just going to see how this turns out Quote Link to comment Share on other sites More sharing options...
Luke_zoo Posted February 4, 2010 Report Share Posted February 4, 2010 (edited) I'd quite like to do that in the future...who knows though...just going to see how this turns out I've been thinking about making frames ect... my mums mate is a welder, I spoke to him and he said I could do it and He will weld it But really dont fancy doing it my self really... Edited February 4, 2010 by Luke_zoo Quote Link to comment Share on other sites More sharing options...
Mikee Posted February 4, 2010 Report Share Posted February 4, 2010 Here is the frame so far.....I'm thinking now it could do with pitbull 06 style "wings"? or do we think that would be a bit OTT? I have been looking at this pic for about 5 mins now and I can't see where the crossover for the brake would go. Is this just me being silly? Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted February 4, 2010 Author Report Share Posted February 4, 2010 I've been thinking about making frames ect... my mums mate is a welder, I spoke to him and he said I could do it and He will weld it But really dont fancy doing it my self really... Well youve got material to think about, milling, heat treating etc.... I have been looking at this pic for about 5 mins now and I can't see where the crossover for the brake would go. Is this just me being silly? Well i'll be running a custom splitter, but I'm thinking about drilling that spline in between the two horseshoes... Quote Link to comment Share on other sites More sharing options...
Mikee Posted February 4, 2010 Report Share Posted February 4, 2010 Well i'll be running a custom splitter, but I'm thinking about drilling that spline in between the two horseshoes... Ah I see. Looks good . Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted February 8, 2010 Author Report Share Posted February 8, 2010 Wall Thickness has no been decided at 1.7mm. Materials ordering will commence tomorrow Any more improvements to the frame, let me have 'em The final design is shown below, minus the headtube gusset Quote Link to comment Share on other sites More sharing options...
davey1991 Posted February 8, 2010 Report Share Posted February 8, 2010 Cut out the danger and go for regular magura mounts, or bottom mounted, i can see those killing the frame quickly. Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted February 9, 2010 Author Report Share Posted February 9, 2010 Cut out the danger and go for regular magura mounts, or bottom mounted, i can see those killing the frame quickly. Hm maybe...the whole idea of the project was to be relatively innovative hence the interesting mounts. The design is fairly tried and tested in Hoffman bikes, albeit with some modifications in my design Quote Link to comment Share on other sites More sharing options...
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