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Rob Smith

Blower

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Ok I was playing around and designed this blower I have no Idea of the engineering aspects for cfm or anything like that but it might work?? I am thinking I would stack 4 frame pieces to get the cavity then put the left and right cover on and bolt together for the body not sure about impeller but thought you guys might have some ideas. Was thinking small pillow block bearings on either side or just delrin bearings? Oh ya It has a 16" diameter.

 

Rob

frame.jpg

l side.jpg

r side.jpg

Edited by Rob Smith

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I Assume this will be electric? If so the impellers would be secured on the shaft and no bearings would be needed. Unless you are designing a hand crank then you would need a few for the step up gears/pulleys. Just a regular "squirrel cage" impeller is a tried and true method of moving air. You could even build one of those from some round tube. Or use a turbo charger style compressor plate. That might be easier then a "squirrel cage".

 

Pre-bend the vanes then weld or rivet them on. Then balance it before mounting to the motor/crank assembly. Or buy a used cage or turbo charger comp plate.

 

comp_wheel.jpg

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First, a simple MS photo resize tool. It's free, and it works great.

 

Second, if you don't know these folks Lindsay Publications you need to. Somewhere in the catalog there used to be a book all about building and designing fans.

 

Last, for a coal forge? It might work, give it a try and let us know. You're not out much if it doesn't work. The question has to be, why? Anyone of the things discussed in the forge building threads would work, so why build your own, unless building it is the point?

 

Geoff

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did some looking around and found out I will have to offset from center like this picture Making my own tools is all part of the fun :)

b design.jpg

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I am aiming to make this hand crank just working through design out loud

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How's about something like this?

Kitno1.jpg

I posted an announcement yesterday in the Tailgate section. I will have a hand-crank option kit by this weekend. Might save yourself some work, and you could still say that you built it yourself. Your design looks pretty good, by the by, I've got to learn how to do computer drafting one of these days.

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I have a cnc router in my shop that is why I am trying it out in wood. I honestly wish my 3d design skills where much better, would make my machine so much more useful. I really don't have the cash to buy right now or I would love to buy one of your kits they look great!

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Ok here is the new design with the offset let me know what you think

frame.jpg

L side.jpg

R side.jpg

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I will cut the hub for the impeller from the waste in the middle of the frame cut out just have to figure out design

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The impeller of that sheet steel one you posted above is pretty much the standard for hand crank and even power blowers, but the old ones use a cast hub with sheet steel blades leaving it open on both sides. I don't see the need for that, since there's no intake on the back side anyway. As Brent said, be sure you balance it before using. A wonky blower impeller is quite annoying.

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The impeller of that sheet steel one you posted above is pretty much the standard for hand crank and even power blowers, but the old ones use a cast hub with sheet steel blades leaving it open on both sides. I don't see the need for that, since there's no intake on the back side anyway. As Brent said, be sure you balance it before using. A wonky blower impeller is quite annoying.

 

 

That is what I was thinking a six sided hub with paddles attached. I have been working on the gears anyone know what ratio to go with?

 

thank you

 

Rob

Edited by Rob Smith

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My blower has a two-step reduction/step-up drive. One turn of the crank equals something like 30 turns of the impeller. Large gear (~6")on the crank drives a tiny gear (~1") which drives a medium gear (3") which in turn drives another tiny gear (~1/2") on the impeller shaft. It will maintain a welding heat in coal at a crank rate of 3rpm, once you get the fire up to heat at around 10rpm. The impeller diameter is something like 10 inches, 3" output.

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wow 30:1 didn't think that kind of rpm was needed especially when I see hairdryers providing enough cfm

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People who have never used a hand crank always vastly underestimate the output. ;) That's why you don't have to crank very hard or fast at all. A gentle 3 to 5 rpm on the crank will keep you cooking all day long. With your 2:1 step-up drive I'd have to crank at around 45 RPM for the same airflow. No, thanks. B) If they had been that inefficient they wouldn't have taken over from bellows, no?

 

Also, a good hand crank will outwork a hair dryer by a factor of ten. I could use mine as a leaf blower if I wanted a stationary one... :lol:

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The hand crank blowers likely pushed great bellows out of the picture by being more compact. My little, turn of the century, rivet forge (with lever arm and 1/4 cog, the hand crank blowers came a little later) was sold mail order through catalogs from places like Sears and Montgomery Wards. The blower that Alan has is likely one of the top of the line ones and I am curious how many blades it has on the fan. Do you know Alan? Some of the later ones, with sheet metal fan blades riveted on, had as many as 32 fan blades. In contrast the blower on my rivet forge is not "top of the line" and has a cast hub with cast blades, all 4 of them. The blower is 8 inches in diameter and has an outlet of approximately 3 inches (it is hard to tell as the tuyere/ash dump are part of the same 2 piece casting.) The hub that drives the fan is about 1 & 1/2 inches in diameter, this is with a leather belt instead of gears, and the drive wheel is 15 inches in diameter. The photo is not of my forge but, of one similar that I admired and hoped to emulate one day. It is there so that you can see what I'm talking about a bit better.

 

roller base.jpg

 

~Bruce~

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Bruce brings up a good point, not all hand-cranks are created equal. Mine is a big one, as they go. It's a Champion Lancaster #1 freestanding blower, sized to run a large coal fire. The smaller and more common Champion 400 is designed to run a portable rivet forge or farrier's forge, and as such isn't really meant to maintain welding heat.

 

Mine has a 10" impeller with six vanes, and after checking it this afternoon the ratio is more like 1:45. I was wrong about the gear sizes as weel. The crnk gear is 6", which drives a 1" gear connected to the shaft of a second 6" worm-cut gear, which drives the 3/4" worm gear on the impeller shaft. I do not have the tooth count or pitch for the gears. If you want to come measure them yourself feel free, I'm not gonna do it. ;)

 

Here we go:

 

The front- blower 1.jpg

 

The back- blower 2.jpg

 

Gearbox lid removed, showing the crank gear.

 

blower 3.jpg

 

Looking into the gearbox, you can see the small gear the crank gear drives on the shaft for the secondary.

 

blower 4.jpg

 

And finally, a shot trying to look into the front end, but all you can see is the crank gear flanked by the worm-cut secondary.

 

blower 5.jpg

 

There are many brands of these things in this size, such as Cannedy-Otto, Buffalo, Indian Chief, Royal, and so on. Obsolete, yes, but I love 'em. B)

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Alan as much as I would love to visit your shop and measure your gears I would have to take a holiday to do so LOL! but thank you for the offer. I have updated my profile so you can see my location now.

 

Bruce your small forge has got my mind spinning again and I think belt drive might be the better way to go for simplicity and function.

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Bruce would it be at all possible to get some more detailed pictures of your forge thanks

 

Rob

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I found an original Buffalo advertisement catalog with forge blowers in it and it advertised as a 47:1 gear ratio all the gears were helical cut really nice units.

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Yeah, Buffalo and Cannedy-Otto are the best of the bunch. The Cadillacs, if you will, while Champion is the beat-up old Chevy. :lol: And I'm a Mopar guy!

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Bruce would it be at all possible to get some more detailed pictures of your forge thanks

 

Yes but, what do you want to see? These little things are quite simple but, even so, I didn't really go "Aha!" until I'd taken it apart to clean and paint it. A link below to help out.

 

Anvilfire - Lever Forge

 

~Bruce~

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