Llama Posted November 2, 2012 Share Posted November 2, 2012 So I can make supercool curvy bikes, and play with my welder/solidworks, I've been planning to build myself a pipe bender. Might not be as cheap as I'm hoping, but it should be good enough for all I want to do. It's based on this design I have calculated (yup I'm a nerd) it should be able to bend 50mm OD 5mm wall mild steel pipe before things start to go funky shaped. Obviously that is somewhat overkill, and it probably won't make it that far, but it's nice to have a safety factor. Here is what it currently looks like in SW. Had a play with the simulation part. Was a little shocked when this came up. Little did I realise that dialogue box was covering the deflection scale factor (was something like 300:1) I'm not sure yet how I'm going to do the dies. You might be able to purchase them, else I could try turning them on a lathe or something. I'm just waiting on a 15A plug for my welder, then once I've built and tested it, I'll put forward some drawings and a BoM for anyone else who wants one. Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted November 2, 2012 Share Posted November 2, 2012 you need clearance in the middle of those two lower rollers for the pipe to move downward as its bent.... hard to explain. in your solid works model it looks like this clearance us not there? unless you are limiting yourself to massive radius bends Quote Link to comment Share on other sites More sharing options...
JoKer Posted November 2, 2012 Share Posted November 2, 2012 as in a parabola not a constant radii of say 26mm etc Quote Link to comment Share on other sites More sharing options...
Borgweiser Posted November 2, 2012 Share Posted November 2, 2012 Bearings? Can't see any in the SW drawing, are you going to incorporate them into the rollers or external mount like the one pictured above? Quote Link to comment Share on other sites More sharing options...
Llama Posted November 3, 2012 Author Share Posted November 3, 2012 you need clearance in the middle of those two lower rollers for the pipe to move downward as its bent.... hard to explain. in your solid works model it looks like this clearance us not there? unless you are limiting yourself to massive radius bends I get what you mean, good point. It's not designed to do 180deg or constant radius bends really (the other type of benders are probably better for that), and there would be plenty of clearance for small pipes. Larger pipes I can see getting in the way though, looks like I'll have to extend the subframe down (the jacking point is the mostly likely to fail from what I figure) Bearings? Can't see any in the SW drawing, are you going to incorporate them into the rollers or external mount like the one pictured above? Was hoping to get some input on this. How necessary would they be? External mount flange bearing would be easy enough for the top set, but I don't think I could fit flange ones on the lower two shafts without making the subframe quite large and getting rid of the additional shaft holes. Then I'd have to fix the shaft to the dies somehow (would pressed fit be enough?). Internal on the die is something I hadn't considered, how easy would that be to do? Chur for your thoughts fellas. Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted November 3, 2012 Share Posted November 3, 2012 Internal to the dies easy- just a little more machining time and $ if it were me I'd be going with plumbers blocks/ self aligners just for ease of construction. Quote Link to comment Share on other sites More sharing options...
Llama Posted November 5, 2012 Author Share Posted November 5, 2012 Well, slight progress on the CAD front. Bearings from catalogue and different configurations for the pipe let me check the range of movement quite quickly. I'm unsure at this stage if I want to use pillow blocks or flange bearings for the subframe, will probably make some more mockups. The frame is going to need changing too, but I haven't got around to that yet. /overthinking-yet-cluseless about everything. Quote Link to comment Share on other sites More sharing options...
Llama Posted November 6, 2012 Author Share Posted November 6, 2012 Right so here is the final design. I reverted the top brace for more clearance, and will be using box section for the subframe. This will give me plenty of clearance, and should allow me to easily change the die span if I need to without drilling to many big holes in things. Where do people get their steel from? By the looks of it the only place I can find (aside from scrappers) retail is fletcher easysteel, but surely there must be more around? Plus they don't seem to do bar in the kind I need. Really I'm just mucking around now because I'm still waiting on gloves/helmet/gas and other welding necessities. Quote Link to comment Share on other sites More sharing options...
Beaver Posted November 6, 2012 Share Posted November 6, 2012 Steel and tube? Quote Link to comment Share on other sites More sharing options...
Steelies Posted November 6, 2012 Share Posted November 6, 2012 ^yeh, at 5M lengths. or local machine shop, almost the same price for just the small bits you want also, not sure how el cheapo you're aiming for, but that looks like about $400ish worth of bearings and blocks.. possibly why there are only two in your example pic. just got two bearings and blocks the other day to suit 15mm shaft, $130 odd. that was straight off the shelf, screaming retail. pillow or flange may depend on how you want to stress the mounting bolts? watching this project with eager anticipation! Quote Link to comment Share on other sites More sharing options...
Llama Posted November 6, 2012 Author Share Posted November 6, 2012 Ah, S&T. Being young I only looked online, and S&T don't have a website catalogue. Suppose I'll resort to the good ole' phone. I'm not toooo worried about purchasing extra steel though; I still have to build myself a bike carrier/towbar, welding table, bike jig and velobike at some stage (although I do have designs for a bamboo one...) I downsized the two lower shafts to 17mm, so I may be able to get internal bearings in there now. Will get some quotes today, then have a fiddle tonight based on what I see. Quote Link to comment Share on other sites More sharing options...
Beaver Posted November 6, 2012 Share Posted November 6, 2012 also, not sure how el cheapo you're aiming for, also this. you can buy them for under 200/300 bucks on tradme (pipe benders). obviusly they wont be perfect but surely it sbetter then spending heaps more building one that is bullet proof but used for bike frames and bike racks? just my 2 cents Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted November 6, 2012 Share Posted November 6, 2012 great design. I would worry about strength of the centre shaft- there is much unsupported shaft between bearing and die. may not be an issue- but might be? how's it cope with your stress analysis? Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted November 6, 2012 Share Posted November 6, 2012 also the flat bar that the ram pushes up on is piss weak- needs larger gussets that create a beam through there Quote Link to comment Share on other sites More sharing options...
Steelies Posted November 6, 2012 Share Posted November 6, 2012 also the flat bar that the ram pushes up on is piss weak- needs larger gussets that create a beam through there bent pipe clearance issues i think. increase overall height and replace said plate/gussets with capped RHS full width up under current RHS? Quote Link to comment Share on other sites More sharing options...
Ned Posted November 6, 2012 Share Posted November 6, 2012 I bought Chinese pillow block bearings for the ride on chilly bin (30mm or somthing like that) got both for $30 or something and seem sweet! Quote Link to comment Share on other sites More sharing options...
Llama Posted November 6, 2012 Author Share Posted November 6, 2012 I was planning on making the gussets bigger, just had some issues when it came to extruding the sketches. There will be plenty of clearance if the gussets meet in the middle. Had bar calculations somewhere... hold up. I bought Chinese pillow block bearings for the ride on chilly bin (30mm or somthing like that) got both for $30 or something and seem sweet! Where?!? It's not like they are going to be high load or high speed or anything. The upper ones are the only important ones really. also this. you can buy them for under 200/300 bucks on tradme (pipe benders). obviusly they wont be perfect but surely it sbetter then spending heaps more building one that is bullet proof but used for bike frames and bike racks? Ones like so ? http://www.trademe.c...n-529355147.htm Looks like the dies are pretty limited in scope though? Plus I'd rather build my own. Quote Link to comment Share on other sites More sharing options...
Ned Posted November 6, 2012 Share Posted November 6, 2012 Bearing Supplies in Henderson. Nicer and close(ish) to you even probably? http://goo.gl/maps/BWPgd My friend Bo used to work there and may have gotten me a slightly better deal, but still shouldn't cost much. I think they may even have been $24 for the lot or something. Was way cheaper than expected thats for sure! Quote Link to comment Share on other sites More sharing options...
Steelies Posted November 6, 2012 Share Posted November 6, 2012 dayum, cheap! Quote Link to comment Share on other sites More sharing options...
peteretep Posted November 6, 2012 Share Posted November 6, 2012 that top design looks like it was made in a university for an example? a cheap bender would be a bulldozer with dies made to suit. it would only require a few heavy plates and no bearings. eg http://www.carellcorp.com/horizontalpress.html , http://machineryhouse.co.nz/Horizontal-Benders-Bulldozers and you just make dies when you need them from aluminium or something easy to make that wont damage what you are working with. also easy to change the ram later to bigger/longer/more powerful depending on your design basically IMO I think what you are basing your design off is not as good as it could be Quote Link to comment Share on other sites More sharing options...
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