Nothing to lose really.

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That's a big hole you drilled there mister ?

is that the direction you expect the cable to come from ? sort of above and pointing downwards ?

Paul
Yup 32mm. No, the orientation was just for the photo, it can be placed at any angle of course.
I am not quite sure "where" along the axle tube to place these tabs. Right on the lip and then dremel-stone out any buckling of the tube wall, or, further back and behind where the bearing will sit within the tube.
 
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It may be worthwhile having a sacrificial bearing in there whilst welding. Just ensure that sacrifice doesn't get welded in too.
 
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It may be worthwhile having a sacrificial bearing in there whilst welding. Just ensure that sacrifice doesn't get welded in too.
If I go just about 25mm from the end of the tube I will be inboard of the pair of 28x12x8 bearings and the welded in placement "plug" that holds them there and prevents them wandering off down the tube.
I am hoping that the stub of 12mm bar sitting between the backplate tab of the drum hub and the anchoring plate will not be so long as to afford the backplate too much leverage to twist the plate.
It shouldn't really, but you never know until you try it. ;-)
Another question is.....
Should I drill a 12mm hole in the tabs for this bar and weld it in place on both sides or just sit it on the face and only weld it on the side facing the drum-hub backplate?
 
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Yup 32mm. No, the orientation was just for the photo, it can be placed at any angle of course.
I am not quite sure "where" along the axle tube to place these tabs. Right on the lip and then dremel-stone out any buckling of the tube wall, or, further back and behind where the bearing will sit within the tube.
Can they just be clamped around the tube ?

Paul
 
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Can they just be clamped around the tube ?

Paul
I don't think so, their thickness is only 3mm so the friction "footprint" would be pretty small.
 
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Another question is.....
Should I drill a 12mm hole in the tabs for this bar and weld it in place on both sides or just sit it on the face and only weld it on the side facing the drum-hub backplate?
I would suggest drilling and passing it through given it's two pieces. I'd use a surface mount if it was one piece.
 
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I would suggest drilling and passing it through given it's two pieces. I'd use a surface mount if it was one piece.
Ahhh... sorry, its 1 piece. The 2 you see are just tack welded at the corners so I produced 2 identical plates (one for each end) and had one 32mm hole drilling operation to perform.
When I have competed the shaping of them the welds will be ground off and I will have 2 identical plates.
 
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I don't think so, their thickness is only 3mm so the friction "footprint" would be pretty small.
Won't be 3mm if you weld a split collar to it tho ?

Paul
 
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Some ramblings follow...

When I said
I was referring to making the back end of the current project.

My thinking is that I can build a "back-half" that ends in a plug-in stub to which alternate "Front-ends"
can be plugged. Delta or Quad. Sneaky Eh? :)

So the back-end "ends" about where the seat mounts to the frame; it may (or may not) include a suspension component (TBD).
The front part(s) supply their own Chain-ring(s) and chains to be hooked over the input sprocket to the rear-half's IGH hub.
A spring tensioner will be used to keep chains aligned and firmly wound around the rear input sprocket.
All steering componentry will reside on any front half.

Anyway, that's the kernel of the idea/concept. :)
 
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I think you need to move much further up the horse ?

If you make a main boom starting at the pedals and ending at the rear wheels you will then have either a 1 wheel front end or a 2 wheel front end.

Your way will include duplication of the cranks/pedals etc , also I think the loads on the joint will be much less the further forward you put it.

Paul
 
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Today's "Comedy of errors" was very nearly serious. Luckily I have managed to escape the clutches of abject failure.

I have no shame about my many mistakes and cock-ups, as they may serve as a warning to others. :)

I thought it might be good to weld the bearing stops in place inside the axle tube and I set about inserting them square and true with 6mm holes for some puddle-welds to anchor them in position.
First unwelcome surprise after welding the first one was that the filler material looked an odd colour.
When I dressed the puddles down they changed colour to rosy copper colour.
I had grabbed a silicon-bronze brazing rod by mistake. Oops!
Then, to my horror I realised that the length of 1" tube that I had inserted into the axle tube to make a last little positioning adjustment was still in there.
I went to twist it and I could not move it by hand. Argh! Had I brazed it in and now it was a permanent feature and the whole piece would have to be scrapped?
I put a Stillson wrench on the end of the tube poking out and gave it a twist and out it came! Phew!
I did the 'other' end of the assembly with no further issues, welding with steel and all OK.
 
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Dan

Heart stopping moment indeed , luckily the fix was easy [ this time ]

Paul
 
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A tiny bit more progress.
I popped some bearings and a modified SA 90MM drum hub with its half-shaft into the rear axle-tube.
It may all work, but too early to be sure. :)
 
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Dan

Nice , however that is exactly the problem I had with all mine because there is no positive back plate fixing unlike the wheel chair versions.
That play you found can be a beggar when you come to the anchor bolt for the black brake anchor it is only M6 however if the length is wrong then it pulls/pushes the back plate out of square with the mounting bolt/shaft.
Good luck finding a solution you can live with ?

Or take the shoes off drill 3 M6 holes in the back plate and with equal length stand offs mount it more like a car one to the end of the outer axle tube ?



Paul
 
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I managed to get some garage time today and got very little accomplished. :(
I did punch a 32mm hole through a tube to see how good/bad my rear axle assembly would fit. Pretty snug TBH, but I am not looking forward to the fillet welds on the curve of the axle-tube.
I also tried to estimate "how" the 2WD unit would fit in the cage when the central section of the axle-tube is cut away. It doesn't look too bad. But I can already see that weld-cooling has put a bend in the axle tube end-to-end. :(

I messed about trying to determine "how" the drive to the 2WD unit would be aligned and arranged and discovered that it is very unlikely that I will be able to use the recently obtained SA 8-Spd as the IGH mid-drive.

Why? - Well, the SA 8-Spd has no disc brake mount to attach a sprocket to and I would have to affix something to the spoke flange instead. Problem is that the diameter of the spoke flange is so large that I would end up introducing a permanent gear-up to the whole drive system as the Output of any such arrangement would end up being > 25T in order to attach to the flange (probably 34T) and the 2WD unit is 22T. While that doesn't sound like a lot, it matters.

So I may very well have to use the N380 (which does have a disc brake mount) to which I can probably attach a 22T sprocket.
Another challenge will be the mounting of the N380 on a platform without the chain(s) fouling any framework.

It seems that there are problems in all directions. Great fun, isn't it? 🙃


 
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So surely there is plenty of room to do:-
a disc-to-spoke holes
a ring welded to it as close to the middle as possible
another disc
desired sprocket ring



Think how 3 chain rings on front cranks are staggered ?
Big to small inwards and reducing diameter.

Paul
 
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The 380 is going to add some lard over an igh.
Well, yes and no. The XRF8-W is a bit of a beast at (1770g) and weighs only 680g less than the N380.
The XRF8 has 320% gear range, and the N380 has...err....380% so the "lard-factor" as dead weight isn't too bad. :)
 
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So surely there is plenty of room to do:-
a disc-to-spoke holes
a ring welded to it as close to the middle as possible
another disc
desired sprocket ring



Think how 3 chain rings on front cranks are staggered ?
Big to small inwards and reducing diameter.

Paul
Will look at it for sure. 1st glance said not enough room as the plastic end cap on the shell prevents you coming in small enough for the 22T sprocket before your are outside the OLD.
I will look againtomorrow. :)
 
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