Sprocket fastners

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13 June 2012 at 20:33 #34863
Who Boot
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@whoboot
Hi Bob

I am returning to this topic and would like to refer to your thread. Can you tell me please what are the fastners either side of the sprockets called, the top one has a screw sticking out of it presumably to tighten it. Did these come with the sprocket as a set or were they obtained seperately? I ask because i'm looking for suitable fastners that will hold my gear wheel and paddles to their shaft. Would you call these grup screws?
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13 June 2012 at 20:33 #3857
Who Boot
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@whoboot
13 June 2012 at 22:08 #34865
Bob Abell 2
Participant
@bobabell2
Hello Who Boot

The sprockets are supplied by Hobby's Ltd

But, as supplied, the hubs are not strong enough to use in conjunction with 6mm shafts

I made the hubs on a lathe and bolted them to the plastic sprockets

I used 6BA screws tapped into the hub flanges. The shafts have flats filed for the screws to act on.

These screws are not grub screws, but just normal cheese heads screws

If you require any further info, just ask

Bob
14 June 2012 at 07:13 #34868
Paul T
Participant
@pault84577
Bob

I can't see from the photo so can you tell me what you turned the hubs from (brass, gunmetal) and I am assuming that the central shaft is running in a brass tube as it passes through the wooden support column.

Nice piece of lathe work and I like the way you have enhanced the modern materials with more traditional engineering.

I wonder how many people appreciate or even understand how much work is involved in turning, drilling and tapping those little hubs.

I've never used polymer based cogs and chains, are they plastic or nylon and how good are they?

Paul
14 June 2012 at 07:30 #34869
Bob Abell 2
Participant
@bobabell2
Good morning Paul

The photo shows the independent twin drive for Jeannie Deans paddler

The hubs are made from brass bar…….Bronze is very difficult to work with

The centre tube acts as a bearing for both drive shafts and the chain is made from plastic and works well

The sprockets are supplied with a small hub, having a 4mm bore and can't be increased to 6mm, as it just breaks off.

Bob
14 June 2012 at 07:48 #34870
Paul T
Participant
@pault84577
Good morning Bob

I am curious as to why you opted for plastic cogs when brass versions are readily available.

Paul
14 June 2012 at 07:57 #34871
Bob Abell 2
Participant
@bobabell2
I used plastic sprockets because I already had them in stock

And that's good enough for me!

Curly…………(Why do I use this name, sometimes?)
14 June 2012 at 15:29 #34879
Paul T
Participant
@pault84577
Dear Curly.

Perhaps its a hint to the full head of hair that you have under that cap!

Thinly…(guess why I don't use this name at any time)
14 June 2012 at 17:02 #34883
Bob Abell 2
Participant
@bobabell2
In my younger days, my hero was LBSC!…….He was a rough and ready, practical engineer who could build a coal fired steam loco in six weeks!

He used write in the Model Engineer magazine and used the name Curly.

I assumed you may have known this?

Bob
14 June 2012 at 18:24 #34884
Paul T
Participant
@pault84577
Sorry Bob thats to old for me.
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