Chopped up some old bikes and put this together:



Curiosity spared my cat this time...

I know it's not pretty, but it works. At least until the top chain broke. Ah, the joys of rust. So aside from a new chain, other changes that need to be made are tensioners for either chain, as well as putting a smaller sprocket on the jack shaft. That won't be hard since the other side of that hub is unused, with a 3/8 threaded end (it just dawned on me that in cleaning up after I was done, I may have thrown out that accompanying nut, hope its nothing wierd!) Right now I have roughly 4:1, which is definitely not enough. The fan is 11 1/2" diameter, 2" wide, vanes attached to the rear wheel assembly of a single speed bike. I meant to take a picture of it before it was enclosed, but I forgot, so this is all you get:



This was all pretty much improvised, so I was worried it wouldn't put out enough air. Luckily it does, just at a higher crank speed than is comfortable. I was originally going to have a 14:1 using a sprocket off the back of another bike, but removal proved difficult. Since it's so nice out tonight, I may go back out and try to get that off.

In retrospect, if I had just worked some overtime instead of doing this, I could have bought a pretty nice manufactured blower. But where's the fun in that? :lol:

I LIKE IT!! it's always more satisfying to use tools you've made yourself, even if they take more time. when you make stuff yourself the little flaws become quirks that you wouldn't do without.

Thanks! Something I forgot to ask above, does anyone know the proper ratio (even just as a general rule, I'm sure it varies on the blower design) of the intake to the output openings? I oversized mine, since it's easier to cover up than to recut. I would figure that 1:1 would be fine, right now I have 20 to 8 sq. in, 2.5 in. radius opening on the side (I'm discounting the sprocket side, since the sprocket is close the frame and almost covers the hole), which is nearly half of the radius of my fan interior. That seems large to me, but I don't have any objective way of measuring airflow, so when I cover part of the hole it's hard to tell if I'm making any difference.

Dan, I like it. Since blowers can be so hard to find and the wife usually doesn't want to give up a hair dryer the best thing to do is to make a blower yourself. You can fine tune it as you go and you will learn so much by making it yourself.
Good job and have fun perfecting your blower. Teach the cat to turn the crank and you'll be set.

Mark<><

After I replaced the chain today, I got fed up with the high crank speed really quickly. So I changed the gearing, and made it so the top chain could be tensioned. The bottom chain doesn't have that luxury, but it hasn't slipped yet, so I'll cross that bridge when I come to it. Here's it mounted to the forge. The oddities in the pipeline are from last night, when I was really excited to get this hooked up but didn't have a lot on hand besides some 2" tee's, two 6" nipples, and a welder. And lots of duct tape.

Hi Dan
nice design for a blower. one question i have is i see you have a bunch of duct tape around it. is this all you used or did you use some wood filler or bondo? i would think if you went to a 1:1/2 ratio for the pulleys you would not have to crank as hard or fast. not sure on that ratio. so if your first sprocket was 6" make your blower sprocket 3" you would be turning your blower sprocket faster then what you would be turning your crank sprocket. less arm cranking with more blower action. again not sure if that would be right or not. but i believe it is.
good luck