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I Forge Iron

Figuring out a blower. Electric or dual power?


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I'm just getting started building my smithy tools up. I've joined a local blacksmithing group that meets weekly, and it's a great bunch of guys sharing all they know.

I really really need my own coal forge. And I've got one about halfway built. Like most things I do, it's going to be way overbuilt. I currently have a table made, and I've just received a coke firepot. (Heavy duty, with dumping ash gate).

For my next step, I need to figure out what I'm going to be using as a blower. I like both hand crank, and electric (even though I've never used electric) and was seriously thinking of putting both on my forge so that I could switch back and forth using a valve. Then I saw THIS POST and I gotta admit I really love the idea of a switchable manual / electric blower.

First question. How do I build something like that, that's not going to beat me senseless with the handle when running under power? I considered using a one way sprag from an auto transmission. Or I could have a gear that can be pulled out of engagement to disconnect the gearbox, and just let the motor freewheel when it's being hand cranked. Thoughts?

Second question. What to build it out of? The fan could be a repurposed dust collector fan. I could modify an old handcrank blower, and that would get me a gearbox too. Or I could build entirely from scratch, at which point I'd probably need one of the Gingery books on fan design / building.

Also the weird stripes on the pic is where the paint isn't dry yet. It's 2" square tubing, and the flat of the table is 1/4 steel ~ 2.5 x 3.5 feet, with 6" wide strips angled 45 degrees on 3 sides, and one side with it straight up and down. Still needs side notches, and a hole cut for the fire pot. All the forges I've worked on have little bitty table tops, and invariable a long piece will launch like a glowing hot catapault / spear. I wanted a big table to have a place to rest things safely.



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So I'm thinking.....


What if I got one of commercial link removed or something very similar. Then mount it on a simple shaft instead of a motor. Connect that shaft to both an electric motor, and the output of a handcrank gear box with a roller chain going around all three. Both the electric motor, and the gearbox would get a one way sprag / clutch sprocket.


In theory when the motor is on, the handcrank/gearbox would freewheel, and vice versa. I'd probably have to build my gearbox from multiple shafts / sprockets too. I can't find anything like a 40:1 gearbox in a sane price range. The fan is for 3600 rpm. But I'm thinking more 1750 rpm with a speed controller, and if I can do 50 rpm (not all the time) on the crank at 40:1 then that's 2000 rpm. I won't need to max out the fan RPM to get good results, I think, maybe, kinda/sorta.

Edited by Mod30
Remove commercial link per TOS
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In our group’s shop, there is an electric blower mounted onto the intake of a hand crank blower. Doubt it’s an original setup, but I couldn’t get a clear view of it to see how it’s connected. Pretty basic I imagine… It works just fine under electric or hand crank and the hand crank can give a little (or big) boost of air if needed when the electric blower is running.

Keep it fun,


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The blower in the link is probably ten times the blower needed a Dayton like this one would attach to the hand crank blower intake and give more air than needed at a fraction of the cost. I used one of them before going to strictly hand crank Champion Lancaster blower. A Google search will bring it up.

Dayton Model 1tdn7 Blower 50 CFM 3030 RPM 115V 60/50Hz

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I've seen those recommended, and also dismissed. My understanding is that a squirrel cage style like that, while moving plenty of air, lacks the ability to build significant pressure. Hence the use of the straight blade radial style fans. Most of this I've picked up from reading various threads here on the forum, but it makes sense to me.

The firepot I'm using is a coke firepot. The recommended blower for it is 500cfm in free air, with a straight blade radial design, so assumably at least a little bit of w.c. pressure. Obviously you wouldn't run it wide open all the time, but I'm basically trying to duplicate that fan's parameters without paying the 728 dollars just to tear it apart for a dual drive conversion. Besides, I can always run it slower.


1 hour ago, Goods said:

In our group’s shop, there is an electric blower mounted onto the intake of a hand crank blower.

I actually thought about this, but the other way around. That way I could have the hand crank out in the open, and the electric mounted under the table and out of the way, and out of sight. The electric seems just a touch out of place. I'm glad you brought it up, I may revisit it. It'd certainly be simpler.


Also, sorry about the commercial link in my previous post. If anybody's curious, it is, or was, a Dayton Model 6YG63.

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I have two Dayton blowers (using one currently, other is a spare) similar to the one Irondragon suggested.  I agree with him.  Works a charm.  Anything 50 to 80 CFM is all you need.  I can burn the ends of a set of tongs with either!!  FWIW, 500 CFM could blow the coke or coal right out of your firepot....

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