Hinges, Pivots, Joints - How?

  1. TheJoker Member

    Guys,

    I'd really appreciate your insights on this. Currently my head is designing all sorts of contraptions. Some of them have moving parts, such as a motorcycle lift, for example. Other ones I'd like to fold up, etc.
    Now, inside my head, where the party is going on :laughing:, this is all quite simple, but then I start thinking about how to actually do it, I don't have a clue on exactly what to do.

    The simplest thing my head can think of is two box sections with a hole drilled through and then a bolt through. But this isn't a very good construction, especailly if weight is being applied. I'm assuming that there's better ways of doing "movable" things. Things that hinge, things that have joints, things that pivot, etc..!?

    I've seen that you can, for example, buy ready made hinges for making steel gates. Is there similar "kits" for smaller more delicate projects?

    Any insight appreciated! :hug: :welder: :welder:
  2. GrahamGKD

    GrahamGKD Forum Supporter

    Not sure if this is what you are looking for but I bought some weld-on barrel hinges for my workshop doors. Have a look at

    http://www.calmorehinges.co.uk/

    These people are just up the road from where I work and they were happy to supply in small quantities. I imagine there must be other suppliers?

    I think for your box section/bolt idea you would need to weld some sleeves through the box section to spread the load and increase the wear area. These are the kind of jobs where a metal turning lathe comes in really handy!

    Graham.
  3. TheJoker Member

    Thanks for the link, Graham! Very useful for hinges. Will most likely come in handy one day!

    What I'm also looking for is these types of "pivots" (I don't really know how to explain).
    [​IMG]
    http://www.proppa.com/300kg-motorcycle-scissor-stand-6096-p.asp

    [​IMG]
    http://www.proppa.com/550kg-motorcycle-and-quad-lift-6085-p.asp

    [​IMG]
    http://www.burtonbikebits.net/medium-lift-2.jpg

    And finally this scissor type lift;
    [​IMG]
    http://www.biketek.co.uk/Shop/index.php?act=viewProd&productId=25

    I don't really know what the correct term is, but they all feature "things that hinge". :whistle: How do I make those? Do's, Don'ts?

    :welder:
  4. peterd51

    peterd51 happy to be here!

    Hi,

    box section with plates welded on two opposite sides so they overlap a second box section and can be bolted through. You can then weld a spacer inside the second box to strengthen it.

    Either use a bolt with locknuts or weld the nut in place leaving it loose enough to move, or use a rod with a big washer welded on each end as the pivots.

    Or make your own longer pivots with rod and tube selected so that they provide a smooth, sliding fit, etc.

    You might want to design in some locking pins/bolts to be installed when it's up to full height to stop it collapsing on you!

    That lower picture with the trials bike on the lift looks a bit unsteady!

    Regards
    Peter
  5. Drains

    Drains Yeah, nah.

    Posts: 7,670
    Soggy Sefton, NZ
    Hey Joker. For pivots, hinges etc, it all depends on what they have to do. For simple things like the stuff in your photos, it's all holes in plate, bolts (some long ones), and bits of tube. All this can be in similar metals, without much, or any, lube. A dod of grease never hurts though. The heavier the load, the more bearing surface you need (to avoid holes opening out over use)

    For harder working joints, either taking constant heavy load load and movement, or high speed stuff, you're onto bearings - nylon, oilite, roller etc. All depends on how it has to be used.
  6. GrahamGKD

    GrahamGKD Forum Supporter

    Maybe if you could find some thick walled tubing with an inside diameter which matches a common bolt/stud size you could weld to that as the female bearing of your pivot? Maybe you could get a machine shop to knock up some sleeves for you?

    There's allways plummer blocks - not sure how much they cost as I have never used them but they are all over the kit at the gym I use.

    http://www.ashleypower.co.uk/PDF/SelfAlignCstIrnPillow.pdf

    Graham.
  7. TheJoker Member

    That's really good stuff, Gents! :clapping: Very good! Thanks! Those bike lifts are only one type of project that's bouncing around in my head, and yes, that last scissor lift looks quite unsteady. Only does 130kg too.

    One would think that there's a market for weld-on "kits" consisting of tubes, bolts, washers, pins, etc.

    I guess my first port of call is to buy a few tubes that have an inner diameter matched to common bolts (M6, M8, etc), then shouldered bolts, washers, lube, etc. :welder:

    Good stuff! :clapping:
  8. pedrobedro

    pedrobedro Man at Matalan

    Drill a hole through your box section to the inside diameter of your tube then enlarge one side to the outside diameter. You can cut it to length and weld it in but if you put the bolt through it with a washer under the head it will hold itself in. It's a crush tube to stop your box section wall pulling in like the ones used through car chassis for draw bar bolts.
  9. TheJoker Member

    Thanks pedrobedro! That's just the sort of stuff that I want to know. Those tips and tricks! :) Brilliant! :clapping:
    :welder: :welder:
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