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I Forge Iron

A bone-headed mistake!


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While trying to loosen the nut holding the blower blades in place, I inadvertantly bent one of the blower's circular gears! I put the screwdriver handle through an opening on the side of the gear to keep the gears from turning as I pushed on the socket wrench. I didn't think I was applying all that much force but apparently I did because it ended up putting a wooble in the gear. Here's a mock up picture:
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The damaged gear has a brassy color and isn't nearly as hefty as the primary blower gear. Could it be made of a softer metal, and if so, why? It sits on top of the "spiral gear" that the blower blades attach to. Did the gearing cause the force of my action with the socket wrench to amplify and thus bend that gear? What would be the correct way to remove that nut without damaging anything? The damaged gear has the red markings.
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I want to remove the damaged gear, is there a special tool needed to remove these type nuts?
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The Champion #401 is really cool and I hate to scrap the restoration project.
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The forge pan was rusted out so I put in a new one of a heavier gauge metal.
tmpphp1AQcup.jpg

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An impact wrench is the easiest way. If you don't have one, you can still use impact. Hold a wrench on the nut to be loosened and strike the end of the wrench a sharp blow with a hammer. This way, you don't have to jam the gears. Inertia holds them for you.

Your new pan should be lined with clay to protect it.

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Thanks for the info, arftist, that makes a lot of sense. The original pan was either rusted through or the forge heat over a period of time destroyed it. I don't know anything about lining a forge pan with clay but I'm assuming it is mixed with water first? Any info about that would be appreciated. Thanks, Alan.

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Why were you taking it apart in the first place? Was it seized up? did it turn free? did it coast at all? I see too many people who want to "restore" a piece of equipment that works just fine, or at least it works. My thought on old rusty equipment- if it works don't fix it. I do not spend a lot of time cleaning up and painting something like this, I would clean up the gears and bearings with brakekleen or solvent, blow it out with air and re-lube with ATF, no disassembly required. most of these blowers have a dust cover over the bearings that can be popped out from the out side

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That looks like a bronze gear. Why not try to straighten it?

Keith, thanks for the input and you are right, I will definitely try to straighten it! I'm thinking of using a strong piece of metal as a "backer" on the concave side of the bend and clinching it with a large C-clamp. That way the pressure exerted can be gradual and somewhat controlled. I should be able to do that without removing the gear. I wish I had a pair of sheet metal crimpers, the small, hand-held variety. They might prove very handy for what I'm trying to do.
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I'm getting ready to line a big old "RR forge". I'll just be using the adobe mixture left over from my bloomery. Take the stuff that didn't calcine add a bit of water and pack it in place.

Thomas, your "senior moment member" made me chuckle! Also, it's nice to meet a master curmudgeon; I qualify as a journeyman in that department. I'm familiar with adobe, and have access to some adobe bricks, but what exactly is a bloomery? Alan
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Why were you taking it apart in the first place? Was it seized up? did it turn free? did it coast at all? I see too many people who want to "restore" a piece of equipment that works just fine, or at least it works. My thought on old rusty equipment- if it works don't fix it. I do not spend a lot of time cleaning up and painting something like this, I would clean up the gears and bearings with brakekleen or solvent, blow it out with air and re-lube with ATF, no disassembly required. most of these blowers have a dust cover over the bearings that can be popped out from the out side

Clinton, the blower turned smoothly and worked fine. I took the blower cover off to clean the blade housing which was covered with a thick layer of old grease. I wanted to remove the blade assembly to make it easier to do this.

tmpphpgnKc0h.jpg
I'm not an obsessive type that needs to tear something apart just for the sake of doing it. Had I used an impact wrench to remove that nut, nothing would have been damaged. I plead quilty to being mechanically challenged. Thanks for your input and info about cleaning blower gears, etc. Alan
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Through a gear system torgue times RPM is constant (neglecting friction). For my blower and I assume most are similar in speed ratios, the RPM increase from crank to blower is about 50 fold. With two equal gear increases this would be about 7 fold from the crank to the intermediate gear and another 7 fold from the intermediate gear to the fan (7 times 7 is almost 50). Going backwards, torque would increase that fast. If you put 30 ft pounds on the fan nut, it would have been about 200 foot pounds on the gear you bent.

I suspect the mfg built the gear on the assumption that input from the crank should not exceed perhaps 45 ft - pounds (30 pounds force on a 1-1/2 foot handle) or about 7 ft-lb on the intermediate gear. With high multiplication gears, it's risky to apply force backwards.

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Through a gear system torgue times RPM is constant (neglecting friction). For my blower and I assume most are similar in speed ratios, the RPM increase from crank to blower is about 50 fold. With two equal gear increases this would be about 7 fold from the crank to the intermediate gear and another 7 fold from the intermediate gear to the fan (7 times 7 is almost 50). Going backwards, torque would increase that fast. If you put 30 ft pounds on the fan nut, it would have been about 200 foot pounds on the gear you bent.

I suspect the mfg built the gear on the assumption that input from the crank should not exceed perhaps 45 ft - pounds (30 pounds force on a 1-1/2 foot handle) or about 7 ft-lb on the intermediate gear. With high multiplication gears, it's risky to apply force backwards.

Jack, I think you are spot on about "applying force backwards"! The info about RPMs in a gear system is very helpful and enlightening, thanks for the input, Alan.
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Remove the gear and pm me. I will straighten it for no charge if you can't get it yourself.

Highlander, I tried to pm you but was told you could receive no new messages. That is a generous offer, but I would feel better paying you something for your trouble. I'll see if I can get the gear out and try to pm you tomorrow. Thanks again for the offer. Alan
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mate a lot of good advice above ,have restored a heap of frozen blowers by putting them in the forge and getting them bloody hot,never had a failed attempt(some had to get realy hot,just keep an eye on them and dont cool em quick,heat is the ultimate loosner

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It can be tricky to get that gear out, does it have a set screw? I would apply a good amount of Kroil to the whole thing, if you do not have any Kroil get some http://www.kanolabs.com/google/
You will probably have to drive the shaft though to get that gear out, use a socket or a piece of pipe to support the housing (find something that fits on the shoulder well) then use a drift to drive the shaft though, if it does not move stop before more damage occurs
I have made bone-headed mistakes as well (too many) continue with caution and chalk one up for experience

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Highlander, I tried to pm you but was told you could receive no new messages. That is a generous offer, but I would feel better paying you something for your trouble. I'll see if I can get the gear out and try to pm you tomorrow. Thanks again for the offer. Alan


I deleted a bunch of PMs but I don't think my inbox was full... Try again when you read this.
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