Good afternoon!
I have some box section stainless steel, which needs to be cut and electrically welded to make a lifting frame work. I am not concerned about rusting of the weld, so will ordinary mild steel welding rods weld this OK?
A length of mild steel 8mm galvanised threaded rod, is this capable being used to lift and safely supporting say around 250kg?
It is a single post type motorcycle lift I am building by the way.
Get it properly welded by a person with a good TIG welder.
No again.
Find a suitable D shackle and bolt or weld it on. Studding is inherently liable to break at the weakest point in the thread, which might just be the point you are using to lift with
Unless you have access to some for nothing that is ;-)
Personally I'd use 50mm square 3mm thick MS Box section, a good arc welder, some Eutectic(sp?) rods, and a portable chop saw for metal to cut accurately. As for the lifting part I stand by my shackle approach or alternatively a
13mm re-bar bent to shape then passed through the main frame and welded each side. I made a heavy duty engine hoist attachment for a single post lift a while back like this ( Lorry engines) and it worked very well. For private use there's little point in having it tested, although testing it to double the weight expected to lift would be a good idea before using it even for your own peace of mind. If being used in a "shop" or commercially it is subject to the Loler regulations.
Being a little pushed for time - I've just built up and tested the lifting frame part. 1.75" square for the end bits, 2" square for the main spar, all 3mm wall - It's basically a frame which slides under the wheels like an 'F' at each end linked by the 2" x 2". I managed to test load the frame up to 2.25 tons, at which point my welding snapped, rather than the box section. So I'm reasonably satisfied with that first part.
It has to be a self contained screw lift of some sort - I'll have to rethink that part.
It is some stainless I acquired before it was taken for scrap.
Thanks...
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You might consider something like this:
You might also look at this for some ideas:
Cic.
Cicero used his keyboard to write :
I did consider using one, but there is just no room to get one in.
bike via its frame, but they don't work at all with a sports bike due to the lack of under frame members and lack of clearance. The table lift type needs lots of room to enable it to be used and stored - which is where a compact single post lift wins.
So it's an end lift not an entire lift the bike from the top styleee. At least the welding held out to 5 times what you needed
So is it sort of looking like a car spectacle lift with a centre mounted lift ?
I reckon a "Hi-Lift" (Landrover clubs use em a lot) would be good for this with a little adaption on the base for stability See EBay item
120104386063
Heh....always worth saving stainless even if just to weigh it in later
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35( Y8PF[#H)QTG$N>SIH5@``.P`` ` endOn 2007-04-08, 11:09 Z, in news:mn.42d97d7402f2403b. snipped-for-privacy@tiscali.co.uk, Harry Bloomfield wrote (paraphrased):
Harry: An M8 x 1.25 mild steel threaded rod (property class 4.6) subjected to only axial tension, with no applied bending moment nor applied shear load, can withstand a static, allowable, applied tensile load of 4400 N, with no onset of yielding in the threads, if the nut isn't torqued beyond 5.5 N*m. This means it can support a gently-applied (not bounced nor suddenly dropped) allowable mass of
448.7 kg in tension.An M8 x 1.25 mild steel threaded rod (property class 4.6) in axial compression, having an unsupported length of 635 mm, constrained against rotation at one end and free to rotate and translate laterally at the other end, can support an allowable, concentric, axial compressive load of 522 N. This means it can support an allowable mass of 53.2 kg in compression.
To support a concentric compression load of 2450 N, a mild steel threaded rod of length 635 mm would need to be an M20 x 2.5 thread, which would actually support an allowable, concentric compressive load of 2918 N. This means it would support an allowable mass of
297.5 kg in compression.It happens that R formulated :
That's the sort of idea, except the specs are open at one side to allow them to be pushed under the wheels prior to lifting. The vertical post sits alongside the bike at around the mid point, with its frame passing both under the bike and under the specs.
The other post about the specification for 8mm rod, suggests using that might well be possible after all.
David H. Neumann wrote on 10/04/2007 :
It would be in tension supporting and lifting the bikes weight of 200Kg plus around 30Kg or so for the frame part which moves. A welded on to the rod nut at the top, passing through a bracket at the top of the main lifting post, then a captive second nut pulling on the actual lifting frame with the bike sat on it. Turn the top nut and the rod screws into the lower nut pulling up the frame. The only loading apart from the weight is that of turning the rod to achieve the lift.
It sounds as if 12mm would be a more suitable size to give an extra margin.
On 2007-04-10, 17:15 Z, in news: snipped-for-privacy@tiscali.co.uk, Harry Bloomfield wrote (paraphrased):
Harry: Now that you described the design details, if we combine the torsional shear stress on the threaded rod (due to repeated torquing) with the tensile stress, and look at fatigue strength of the threaded rod at the thread root (instead of static strength), my current calculations in this scenario indicate an M14 x 2.0 mild steel threaded rod (property class 4.6) can withstand an allowable, applied tensile load of 2570 N for a long lifespan. An M12 x 1.75 might also work, if well greased, but the M14 gives you extra margin.
I assume your stainless steel rectangular tubes are perhaps AISI
304L stainless steel, or comparable. Welding these with common mild steel welding rods isn't recommended. I recommend using AISI 309L welding rods. And this same welding rod (309L) can be used for welding stainless steel 304L to mild steel.David H. Neumann has brought this to us :
Thanks, but I managed to get hold of a threaded rod of about 20mm OD complete with nuts. Obviously well over the top for the load, but found in a scrap yard so quite cheap. The same place had one of those manual type hydraulic fork lift trucks to dispose of really cheap (£100). Had I known about it before I started on this it would have saved me a lot of effort. All it would need is a 'spectacle' frame added to the forks to lift a bike with ease.
I have made a start now on the base and the vertical post, but I have had concede defeat on cutting out the sliding part which fits around the post and onto the 'spectacle' part to actually lift the bike - I asked a steel fabricator to cut these for me.
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