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Coupling, How would you build it?

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  • HWooldridge
    replied
    Real Swiss chocolate, I hope...

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  • Black Forest
    replied
    Originally posted by dave_r View Post
    Now you will find out it's a 1" shaft...
    No problem! It is then called a press fit. He asked for 25mm. That is what he got. If it doesn't fit it is his fault not mine. If he wants me to bore that .4mm it will cost him another chocolate bar. That will double the cost to him.

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  • dave_r
    replied
    Now you will find out it's a 1" shaft...

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  • hermetic
    replied
    Originally posted by macona View Post
    Rigidly coupling the motor and the pump us usually not a great idea unless you can get them perfectly aligned on their mounts. It can kill bearings. A gear coupling would have probably about the same shaft to shaft spacing: http://www.lovejoy-inc.com/products/gear-couplings.aspx

    For your design I would have made it from two split collars with a third split collar that clamps the two together.
    +1 Without perfect (impossible)alignment, it will kill the bearings.
    Phil

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  • Black Forest
    replied
    I made another one today. I made it in two pieces. One side 25mm inside bore with a 8mm keyway. The other side 20mm inside bore with a 6mm keyway. Then I turned a mandrel with a shank 25mm and 20mm with a threaded end for a 20mm nut. When I turned the two parts I put a bevel on one end of each of them. These bevels formed a V and then I mounted the mandrel in my welding positioner and TIG welded them together and finally turned down the outside diameter to 40mm. Came out pretty good and looks clean. As you can see in the picture I offset the keyways from each other as per a suggestion on here.

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  • Norman Bain
    replied
    The coupling is to join an electric motor to a hydraulic motor; hence the direction of rotation (torque) is all in one direction.

    How about:
    * Turn the part and bore both the 25mm and 20mm holes.
    * Broach (or shaper cut) an 8mm keyway all the way thru.
    * Create (mill) a custom key for the 6mm end.


    Cheers,
    Norman

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  • Carm
    replied
    Life imitates machining forum

    Originally posted by Carm View Post
    Mr.Alciatore raises very good points.
    I would make two parts, each with their respective keys, and threaded holes for setscrews.
    The interface of each would have two projections @ 180 and two notches 180 apart but 90 from the projections.
    Leave clearance between the tang/slot. Assemble w/ high durometer urethane caulk.
    This morning I went to pick up an Amish neighbor, we were going to see a mutual friend who is in the hospital. While I was at his house his 14 year old son walked in, hands completely black. I kidded him, what, you're digging coal? No, fixing the log splitter.
    On the way to the hospital I quizzed the Dad about was ist los mit der holzspalter?
    It's the thing between the motor and the pump, the third one in as many years.
    Oh? When we get back, show it to me. He described what sounded like a Lovejoy, I'm thinking there has to be massive misalignment, especially when I hear it's a lash up with an old vertical shaft lawn mower engine.

    Nope, somehow nobody installed the spider, it was running essentially as described in my first post, #10. After heavy use (he burns and sells firewood) the tongues were chewed off.
    Therefore I apologize for my poor design, it will not last, although possibly longer with electric vs. gas.

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  • Edwin Dirnbeck
    replied
    Forget about the keyways ?
    You say its for a friend,so what about no keyways. Consider 3 plus 3 modified set screws . Start out with the apropriat sized High quality CUP POINT set screws,now grind the front OD to be a slight clearance to the sides of the shaft keyways.This will now look like a DOG point set screw with a CUP point,When you tighten the set screws the cup points will dig into the FLOOR of your shaft key ways. I have done this a few times on pulleys when I had bad or mismatched key ways. good luck . Edwin Dirnbeck
    Last edited by Edwin Dirnbeck; 03-17-2016, 08:04 AM.

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  • oldtiffie
    replied
    Originally posted by awemawson View Post
    Two hubbed chain sprockets, face to face, with a piece of double roller chain around them, makes a good coupler that gives just a bit of mis-alignment tolerance

    Has the advantage that you can work on each hub independently then slip on the double chain and its joiner after the event.
    That is my default/preferred method as well for the reasons given.

    I'd prefer to use the keyway cutters using a press. Make a guide bush/mandrel to suit the job/key-way cutters.

    https://www.machineryhouse.com.au/Keyway-Broach-Sets.

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  • awemawson
    replied
    Two hubbed chain sprockets, face to face, with a piece of double roller chain around them, makes a good coupler that gives just a bit of mis-alignment tolerance

    Has the advantage that you can work on each hub independently then slip on the double chain and its joiner after the event.

    Leave a comment:


  • boslab
    replied
    I must admit the last one I fitted was one of those rubber throwing star ones (don't ask, but they do hurt when they are thrown at you by idiots! ) it was on a bobcat between the hydraulic pump and engine
    Mark

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  • macona
    replied
    Rigidly coupling the motor and the pump us usually not a great idea unless you can get them perfectly aligned on their mounts. It can kill bearings. A gear coupling would have probably about the same shaft to shaft spacing: http://www.lovejoy-inc.com/products/gear-couplings.aspx

    For your design I would have made it from two split collars with a third split collar that clamps the two together.

    Leave a comment:


  • becksmachine
    replied
    Originally posted by Black Forest View Post
    There is no room for a LoveJoy type coupler.
    This space constraint may invalidate this suggestion also, but here it is anyhow.

    I would have suggested a two piece assembly, each piece having a hub and flange, with hubs bored and keyed to fit the respective shafts.

    The flanges would each have a matching bolt circle, the mating faces of the flanges could also have a shallow counterbore and matching shoulder to ensure concentricity.

    Each flange/hub would be installed on it's corresponding shaft, the two assemblies shoved together and bolts inserted to secure the two flanges together.

    Dave

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  • Carld
    replied
    I too would have cut the keyways with broaches 180 deg from each other. If you just had to use a shaper to cut blind keyways just drill a hole at the end of the large keyway for cutter clearance.

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  • boslab
    replied
    The drawing shows the key ways meeting, I would rotate them 180 degrees apart and run them right through.
    Easier as you can then broach them or shape them as clear cuts instead of blind keys, much more difficult
    Mark

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