Steelwork help, please

[Thistle]

I'm trying to think of a way to join two metal rods of slightly different diameter (21.4mm / 20.0mm) end-to-end in such a way that the joint can be made and taken apart in the field using hand tools. The joint must be able to withstand a shear force. Any ideas, please?

(It is boat-related: part of a pontoon access ramp.)

 

[colhel]

Get a bit of barstock, bore one end 21.5 the other end 20.1 tap the barstock radially into each bore and fix with a screw, or drill through with the peices you want to join and pin. OD and length and material choice depends on application

 

[prv]

Could you just drill the end of the larger rod and tap a thread into it, then turn down the end of the smaller rod a little and cut an external thread onto it. Then screw one into the other.

Pete

 

[NorthUp]

How permanent or pretty does it need to be?
You have had two elegant solutions- now for quick and scruffy, overlap the bars, or add a joining bar, and secure with bulldog grips.

 

[philip_stevens]

I'm trying to think of a way to join two metal rods of slightly different diameter (21.4mm / 20.0mm) end-to-end in such a way that the joint can be made and taken apart in the field using hand tools. The joint must be able to withstand a shear force. Any ideas, please?

(It is boat-related: part of a pontoon access ramp.)

I would try to get a piece of steel bar - round or hex - about 24mm or so, and drill out to 17.5mm and thread both bar and ends to 20mm x 2.5 thread. That is about the nearest you will get to 20mm bar. Then screw both ends into the bar.

 

[jerrytug]

Just weld flanges on the ends with holes for nuts and bolts-this would be good in shear and could be dismantled an infinite number of times with 2 spanners. Easy- peasy !

 

[Thistle]

Many thanks for the ideas so far, guys. Keep them coming.

Perhaps I didn't put quite enough information in the original post. There are actually two stubs of the 21.4mm galvanised steel rod which are fixed and are pointing at each other. They are intended to take the wheels on which the ramp runs. Getting wheels which don't wear away at the centre in a season or so is a problem. A suggested solution is to fix a length of 20mm bar (for which we can get wheels with decent bearings) between the two stubs. We would want to be able to dismantle it occasionally to replace the wheels.

With a few folk on the ramp there could be a load of 3-400kg on that end of the ramp. Say 500kg for safety.

As I say, keep the ideas coming. I can feel a solution just around the corner.

Many thanks.

 

[NorthUp]

So the stubs are to mount the wheels on?
Get bearing fitted to the new wheels with a bigger inside bore, have sleeves machined to suit the existing stubs, to make up the difference. Retain on shafts with split pins, or whatever exists at present.