Project idea: Pedal grinder

[mrcairney]

Just wondered if anyone has any references so I can put together a pedal grinder? When I say pedal, I mean a foot board that only needs one foot.

I *think* I've got the idea right (just in my head) but I'm sure if there's anyone who can put their hands to the plans it's you lot.

Ideally I'd like the stone horizontal, not vertical.

Thanks!

 

[Retired Member southey]

what use the pedal, chain system, rear spindle and the bits of frame there attached to then you would just need to move the power from the spindle to the shaft of the stone either with a gear box to take it through the 90 degrees or a pinion type gear(I think)

 

[mrcairney]

I've seen dave budds here: Though how it works is MYSTIFYING. That's the kind of light-weight idea I'm after. Portability!

http://www.davebudd.com/IA_knife_web_12.jpg

 

[launditch1]

That grinder in the pic works using gears that mesh together at right angles.You press down on the pedal and it rotates the vertical shaft with the stone.It kinda works a bit like bike pedals...it will turn one way providing motion when you stop pedalling it free spins.I have one just like it.
*this makes sence in my head!*


In fact.Just wot Southey said....Combine the two for demystification!

 

[mrcairney]

Hey launch, any chance you could help me out with some pictures of yours? I'm getting frustrated hand filing this axe I'm restoring. Solution? Make a tool!

 

[launditch1]

Yeah, sure.Give me a half hour or so and ill dust it down and post some pics.

 

[mrcairney]

Thanks mate, show us the workings for ultimate kudos

 

[launditch1]

Hah, Yeah...Well ive just been to my workshop and tried to take the thing to bits to see how it works...No joy im afraid.My grinder needs a 'c' spanner to get it apart and thats the one tool i dont have!
I took a picture but it just looks like a tube with a grindstone on top.

As far as i can tell my last explanation was totally wrong.

It looks to me like when the pedal is depressed this pulls down a rod thats attached to ???? making the stone spin.
A bit like an archimedes drill but the type that keeps spinning in one direction, not backwards and forwards.

 

[mrcairney]

Hmm. I hate having brainstorms at work. Luckily I sit at the back, like all the naughty kids.

Keep ideas coming, I'm sure it will reveal itself in time!

 

[mrcairney]

Right, back at home and so far my google-fu is failing. Everything I've found so far would require you to sit and use two feet to pedal

@launditch1: you know your grinder, did you buy it? Capitalism is always the fallback from failed ingenuity

 

[launditch1]

Yes i did.It was made in Redruth Cornwall.

 

[mrcairney]

I wonder if that's where Dave bought his too? He's not far (ish)

Do you remember the name of the shop / person that made it?

EDIT: Brain has kicked in. Look at the visible mechanics of this http://www.flickr.com/photos/tomswyomingauction/5805360642/in/photostream/

Working the pedal must turn the crank that's attached to the stand, which in turns the horizontal axle. The far left of the axle must have a vertical cog on the end. There must be another rod in the far left upright with a horizontal cog on the end that in turn spins the business end. The big wheel (fly wheel, right?) provides momentum.

I think that's right?

Question is, what provides the momentum in Dave's and Launditch's? Bearing / bushels?

 

[mrcairney]

Also, just found this which is quite nice should I want to make a pedal lathe eventually

http://www.vintageprojects.com/machine-shop/woodlathe-treadle.pdf

 

[ged]

The posted link to a photo showing two guys working at a vertical axis wheel brought several things to mind that I think might be worth a mention.

Guards. Conspicuous by their absence in the photo.

Eye protection. Again conspicuously absent.

Inrunning nips. Grinding wheels love to get hold of loose clothing and use it to pull parts of the wearer into the machine.

Wheel design. Grinding wheels rotating fast enough to throw sparks experience large 'g' forces which are trying to make the wheel fly apart. Wheels all have a maximum safe operating speed, which assumes that they haven't been misused. Most wheels are designed to be used with the work piece in contact with the curved outer surface of the wheel, not the flat surface. If you wear away part of the flat surface of the wheel it may no longer be safe to rotate the wheel at speed because the wheel may no longer have the strength needed to prevent itself from flying apart.

I've had a couple of wheels explode. It's no fun at all. On both occasions I was wearing eye protection and on one of them it probably saved my eyesight.

There are regulations governing the use of grinding wheels in industry. This might be worth a look:

http://www.hse.gov.uk/pubns/books/hsg17.htm

 

[mrcairney]

Safety noted.

I think I've actually found the original model. It's called the Hayden AllBall and seems to run with ballbearings. I doubt I'll be able to recreate anything of that calibre. You can see the diagram on this page: http://manlist.treadleit.org/Heyden

Annoyingly, one went for £7.50 on ebay last month.