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Bicycle grinder ?

PostPosted: Thu May 15, 2008 2:48 pm
by Robin Fawcett
Did anyone take a photo of the very ingenious grindstone at the Bodgers Ball?
I think it was on the stand of Tony Bryant who came over from France (He also had some interesting old tools for sale including a set of clog carvers gouges). It was basically powered by a 5-cog bike sprocket with a piece of bike chain connected to a treadle but now I come to think about it I can't remember the actual details.
I meant to take a pic but then got distracted by a thousand other things.

PostPosted: Thu May 15, 2008 8:13 pm
by monkeeboy
Robin,

I do have a picture of the grinder.
It's a good old fashioned analogue film picture tho and so it might be a wee while before I get it scanned in.
Maybe by the middle of June...

I'll get on it.

Mike

PostPosted: Thu May 15, 2008 9:10 pm
by Mark Allery
Hi Robin,

not sure if this shows the details you are after. It looks to me as if the stone is attached to a mandrel driven directly from the rubber tyre in the way that we used to use dynamos.

Image

Image


sorry I just can't seem to get either of these image inserts to work (perhaps somebody can tell me what I am doing wrong) so here is a URL instead

http://www.flickr.com/photos/25543273@N07/2495637190


cheers

Mark

PostPosted: Thu May 15, 2008 9:24 pm
by monkeeboy
Not bad....you get the idea.

My pic is slightly better than that but might not shed much more light.
I have a friend who has made similar devices for grinding, band saw and lathes out of bikes and sewing machines.
I'll have a chat with him and see if i can get you some ideas.

PostPosted: Fri May 16, 2008 12:43 am
by Robin Fawcett
Thanks for that Mark . . .
Is there some kind of spring in there somewhere ?

Monkeeboy . . . analogue is Stone Age now !

PostPosted: Fri May 16, 2008 12:47 pm
by Mark Allery
Robin,

now you mention it there is something protruding just under the mandrel alongside the tyre - I can't see what it is unfortunately. However, given the rubber grip of the tyre I would have thought that it would provide enough friction just from the weight of the stone/box and maybe a little bit more if the coachbolt locks the angle of the box off correctly.

Interesting - but I'm not sure how much use it would be in practice? It's a very small wheel in comparison to the old pedal powered waterbath stones that were favoured by smiths?

cheers

Mark

PostPosted: Sat May 17, 2008 1:00 am
by Bob_Fleet
Here's another image of it.
Image
I was fascinated too and thought the image would help make one.
At the rear the chain is attached to a bungee cord which acts as the return.
It also jumps around a bit as the tyre is patched.

PostPosted: Sat May 17, 2008 6:17 am
by Robin Fawcett
It reminds me of one of those French Solex mopeds where the drive from the motor turns a rubber disc which turns the front wheel. Maybe that's where he got the idea - he does live in France.

The tyre does look as though it's seen better days.

Could the sprocket be fixed directly to the mandrel of the grindstone and get rid of the wheel ? or wouldn't this give enough revs ? Mechanics was never one of my strong points.

Also couldn't you make a treadle lathe on a similar principle?

PostPosted: Sat May 17, 2008 9:36 am
by Bob_Fleet
It needs a bit of weight somewhere to act as a flywheel and in this case it's the bicycle wheel.
It's still a bit light and the stone is jumpy mainly because of the tyre.
I think it would need a bit more engineering than woodwork skills though to mount the sprocket on a wooden flywheel and also the wheel would get in the way of the stone on the same axle.

Now how about using the freewheeel on a bowl mandrel so it doesn't have to be reciprocal - megabowls.

PostPosted: Sat May 17, 2008 10:05 am
by Mark Allery
It's got potential. If you put a mobile phone or battery charger on it at the same time I might be more tempted to sharpen my tools ? What about phone charging, tool sharpening and bowl turning all off the same wheel?

Mark

PostPosted: Sat May 17, 2008 12:43 pm
by Bob_Fleet
Tesco value wind up radio £7 ish.
Music while you work too.

Bicycle treadle lathe

PostPosted: Sun May 18, 2008 4:42 am
by Steve Martin
In the August, 2007 edition of Popular Woodworking magazine, Don Weber, a Welshman living in Kentucky, describes a treadle lathe for bowl making he designed and built as part of an effort to assist Hondurans in improving their economy. According to the article, the lathe is based on a design Don saw in "Woodworking with Kids" by Richard Starr (Taunton Press). It uses a bicycle sprocket and chain to transfer the power from the treadle to the bowl blank. It also has a flywheel for momentum. The chain is also attached to a spring. I haven't been able to locate a copy of Starr's book. Quite a machine. The magazine has a site, popularwoodworking.com, but I'm not sure if you can actually access the article on the site. Don has a site handcraftwoodworks.com which tells more about him.

PostPosted: Sun May 18, 2008 9:57 am
by Bob_Fleet
Starr's article was in Fine Wood Working Techniques Jan 1979 # 3
p 125: Freewheel lathe drive; bicycle parts convert muscle power. author: Starr
Can't find a picture yet.

I have a pedal driven Union lathe which I hoped to use for demos but it has a cast iron flywheel which weighs about a hundredweight on its own.

PostPosted: Fri May 23, 2008 6:02 pm
by riptoff
Oui, c'est moi! I am the perpetrator of this infernal machine.
I have plans for Mark2: Take off grindstone and pulley wheel, then:

1. Cut emery strip and join ends; deflate tyre, fit band, then reinflate.
Problem- how to join emery band.

Possibliity 2. Cut ring of ply and screw to side of rim then glue emery onto edge of ply.
Problem- cutting ply accurately. Maybe true up with turning gouge after fitting ring.

Possibility 3. Take off tyre and tube and fill rim with plaster or car body filler then glue emery strip. Problem- plaster would prob fly off with centrifugal force, and body filler would be expensive. Possibly fill rim mostly with rope then finish with body filler.

PostPosted: Mon Jun 02, 2008 10:12 pm
by Bob_Fleet
You could fill the tyre with fine sand then water to give it weight.
I think it also needs a bit of weight in the wheel resting on the tyre.

Nice meeting you at the BB and glad you got home

Bob