onthebeachalone 18th July 2012, 02:26 PM In helping restore some old trams at the Brisbane Tramway Museum I have been asked to see if I can make up 6 or 8 shafts, like the one in the attached picture, to replace some that have gone missing. It's a bit complicated to explain how this is used but is it basically a ball-race, a bronze bush, some pinned collars and a nut, on a shaft with a sprocket that meshes with a length of bicycle chain.
The issue that is outside my experience is to determine the best approach to getting the sprockets. Are they normally purchaseable, ex stock, in small quantities?
Presumably I could make them by drilling a circle of holes in a sheet of steel at the correct spacing, and then cutting around the outside diameter. If I do adopt that approach, what material should I use?
I would really appreciate any suggestions about how best to tackle this.
Michael G 18th July 2012, 02:46 PM If you phoned up Blackwoods or checked in their catalogue (or firms in the yellow pages under 'power transmission') you'd probably find that they stock something very close to what you want. If you were in Adelaide I'd suggest Chains and Accessories (C&A) - they may be worth an email anyway.
Michael
eskimo 18th July 2012, 02:47 PM they can be purchased from power transmission suppliers
desbromilow 18th July 2012, 02:49 PM You can buy them (Coventries for instance) as singles, but you need to make sure you know the chain pitch, etc
or you can make them - pretty much as you said, but be aware all teeth may require some easing with a file at the tips, plus some tapering
HTH
Des
Grahame Collins 18th July 2012, 05:49 PM It's a bit complicated to explain how this is used but is it basically a ball-race, a bronze bush, some pinned collars and a nut, on a shaft with a sprocket that meshes with a length of bicycle chain.
The issue that is outside my experience is to determine the best approach to getting the sprockets. Are they normally purchaseable, ex stock, in small quantities?
If using bicycle chain its seems to me that a bicycle sprocket would mesh with the bicycle chain.:rolleyes:
If you are on a budget-and isn't everyone ?- the solution would seem to be the quickest easiest and cheapest.Even cheaper, check out the (no its not a pun :D ) recycle centers for old bicycle sprockets.
Grahame
neksmerj 18th July 2012, 06:56 PM If the sprocket is an odd ball size, have the profile drawn up in a cad package, then have them laser cut out of ms plate.
There will be many members on this forum who could draw them up and supply you with a dxf file. All that will be required is the chain pitch, width, No. of teeth and hub details.
Easy peasy I reckon.
Ken
onthebeachalone 18th July 2012, 07:10 PM If the sprocket is an odd ball size, have the profile drawn up in a cad package, then have them laser cut out of ms plate.
Good idea. I can do the CAD stuff myself.
Part of my original question was about material. Is mild steel likely to be OK for a sprocket? It wont be subject to heavy or continuous use.
Thanks to all those who have replied with a range of suggestions. It's been a big help.
SurfinNev 18th July 2012, 08:17 PM Do you have to purchase chain as well? Is there another sprocket that the chain is driven from and do you know the pitch of chain?
If you need chain I may know of some that is cheap but types are limited.
Nev
SurfinNev 18th July 2012, 08:27 PM This will help you work out the type of chain. There's also metric but I would think you have one of these types.
http://www.transeals.com.au/catalogues/files/Transeals_Chain_&_Sprocket_Guide-Imperial.pdf
Oh, and there's Mergard Engineering at Geebung who will probably have what you need. Bought roller chain from them before.
Nev
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