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Brake Rotor or Brake Drum?

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I've seen a lot of posts talking about Brake Drum forges. I know the metal is designed to withstand extreme heat and that it has a good shape for serving as the fire pot, but would a brake rotor work just as well?

 

Are there issues that would need to be addressed? 

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Posted · Report post

No

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A forge pot is only a container to hold the fire. Use what is available.

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Sure a rotor will work. It might even work better than some brake drums as many newer drums are only cast iron on the perimeter with rest being stamped steel.

 

Try to get as deep a rotor as possible or gain more depth by building up the top with fire brick. 

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I once used a fly wheel off of a punch press.   I wrapped a ring of steel around the edge to hold the coal.  It worked but it was not ideal. 

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Sure a rotor will work. It might even work better than some brake drums as many newer drums are only cast iron on the perimeter with rest being stamped steel.

 

Try to get as deep a rotor as possible or gain more depth by building up the top with fire brick. 

a rotor is a flat disk. please explain a deep flat disk ?

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I'm pretty sure the front and rear rotors on my truck are "dished" in the center on the back, especially the front ones for the 4WD.

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A rotor from the rear of a an all wheel disk car has about a 2-3"  depression that that acts as a brake drum for the emergency brake setup -- This is what I use as a firepot and it works great, and it sits nicely 'in' my forge table without any mechanical fastening or welding -- just the lip of the rotor. 
 
Even a 'normal' front rotor will have a 1/2 -2'' depression that goes over the wheel hub assembly.  Don't want to create an argument, but the OP posted a legitimate question.....
 
And my answer is -- at least my preference,   go with a rear rotor from a light truck/ sedan, if you plan on setting it in a table like a firepot.  BUT -- -

post-27406-0-24589600-1357857484_thumb.j

If you plan on building one of the brake drum forges without a table (just a drum on a tripod of sorts) then go with the bigger drum firepot.
 
Whatever you choose,  be sure to make the pot more bowl shaped with some woodstove cement or equivalent.....It made fire managment and heating steel much easier for this novice blacksmith.  See my brake ROTOR forge attached.
 
Jon

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Mine uses a rotor disc set into a lawnmower.  There's a slight depression in the middle, but I also used homemade refractory to add to the bowl shape and deepen it into a wide funnel.

 

(Actually, it started narrower, and slight slagging of the edges of the refractory and clinker getting stuck to it led to me widening it.) Lawnmower acts as a table, works well enough for me....probably re-en-ga-neer something better one of these days.

 

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it's not the prefered method, but it would work with some modification. If you can find a disk from a larger truck you'd be better off that say using a disk from a sedan or compact. Anything is possible with a little will power and some enginuity. I used a drum because I had one saying around. I used a rotor to act as a damper when I'm done to same fuel and cut down on clean up time. when you're forging you want enough fuel below the metal to use up all the oxygen before it reaches the metal. The shallower disks wont do that without adding brick or refractory to deepen the fire. from what I've seen, it takes about 4-5" in a coal fire to use up the oxygen.

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cool, as you can tell I am no mechanic , thanks for explaining how a rotor can be used, the only ones I have seen  are like on a motorcycle.

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yeah, those are brake disks, not brake rotors. the OP wanted to know about brake rotors.

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Got it

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Lots of different options, some work better than others, like using rail for an anvil, a drum or rotor is less tha ideal but it can be made to work. Glenn's 55 forge or it's veriants (like the side draft) work very well for the $ a 2" to 8" black pipe reducer is a the bomb for a bottom blast, but I do like my side draft.

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I have a brake rotor which I always meant to try making a forge out of. Several people told me it wasn't deep enough (and that I needed to use a brake drum instead), so I never bothered.

The funny thing is, I've owned a couple of old 'rivet' type forges, which essentially are flat-bottomed.

In retrospect, I'm sure the rotor would have worked just fine for me. I may have to build it just for fun...

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To help clear (or mudy) the waters.a rotor is the disk, in a disk break assembly. The dished part of the assembly is called a hat. The hat provides the offset behind the hub so the caliper has cleriance as not to interfear with the wheel. The part we are talking about is rotor with intrical hat. As indicated the rear rotors on 4 wheel disk assemblies usually have an intrical break drum for the parking break assembly. I know some of you have had lick with them but I don't tink there really deap enough. Even the ones off of heavy duty applications.
For those of you who still insist on break drums, look for traier electric break drums, salid cast, intrical hub, no need to put a plate in the bottom. You can lay hands on mobile home axle drums if you scout around.
I think for the amout of fabrication you have to do (exept for a trailer drum, you can make a nomber of other setups. I would think that a drain pan, clayed like an old rivit forge, wold be less fabrication.

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By the way, the front rotors tend to be be vented, as they do much more work , and get hotter, another reason to use the rear.

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For those of you who still insist on break drums, look for trailer electric break drums, salid cast, integral hub, no need to put a plate in the bottom. You can lay hands on mobile home axle drums if you scout around.
I think for the amout of fabrication you have to do (exept for a trailer drum, you can make a nomber of other setups. I would think that a drain pan, clayed like an old rivit forge, wold be less fabrication.

That is what I used for mine. Another cool thing about using it was that a 2" black iron pipe fits perfectly. Mine is about 3 1/2" deep. I have it set flush into a metal table I had sitting in the shop. I am really happy with it for the time being. Will probably weld up a rectangular firepot with sloped sides sooner or later, but for now... I'm doing ok.

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I have 4 electric trailer brake drums I could have used for my forge build, and didn't because the drum has a inside flange for the bear assembly that would have stuck up into the fire pot. I would have had to clay the drum in order to get it to work and that would have made the fire pot about 1/2" deep. I Think you're better off sticking to a car/truck brake drum vs a trailer brake drum for that reason.

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TH, you had the wrong type of drum ;-) most of the ones that have intrical hubs are flat on the inside, wile those with pressed hubs have a pilot. But like aiutomotive there are different types. With an electric breaking axle, the face of the drum is thick and machined. It's where the electromagnetic "puck" rides.
I think they're better than automotive ones, but I think you'd be setter off with a popcorn tin, a peice of pipe and some dirt in the first place.

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I'm not sure how I could have the wrong one... as all the electric brake trailer brake drums I've ever come in contact with have all had that. They have to have it to hold the drum on the spindle and bearings. unlike a traditional truck axle where there is an axle shaft that spins inside a housing, the trailer axle doesn't spin and the drum spins around the spindle. because the "puck" as you called it, rides on the rotating face of the drum they can't have a separate hub to mount the drum on like you'd find in a none drive axle on a car. on on a hydrolic trailer axle. but those drums wouldn't have the thicker machined face that an electric brake drum would have.

 

theses are examples of the older style trailer brake drums that use electric brakes and lug bolts instead of lug nuts.

 
These are examples of the newer style trailer brake drums that use wheel studs and lug nuts.
 
As you can see both have the "pilot" for the bearings and do not have a flat bottom like an automotive brake drum would have.
 
now, you could cut out the "pilot", but without the right tools you'd have more time and effort trying to do that than you would just using an automotive/hydrolic brake drum. the hydrolic brake drum forges can be built by bolting a pipe flange onto the bottom of the drum, and don't require the use of any special tools. Just a drill and some wrenches.

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If that is what you have, then use it. Ash will fill the drum up to the top of the hole, so the only issue is that it may be a bit shallow. This can be overcome with putting the drum into a table and using brick to build up the sides.

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I used a regular automotive brake drum. It was far easier to use and no need to wait for hollow below the "pilot" to fill up. I was just trying to illistrate why I think a brake drum for a hydrolic system would be a better choice than a drum from an electric brake system. Especially for someone with minimal tools and fabrication abilities, let alone funds.

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I don't fallow you TW, how is cutting a 1/4" plate and drilling holes in it easier, less expensive than the trailer drum? Now I have has a torch and a 1/2" drill forever, but a Lott of the young smiths don't. More do they have cash to buy 2" black fittings for the "no weld" twere.
Now, I'm not a fan of the drum/disk fire pot anyway, but it has started, and works well for a lot of smiths.
It seems we have several collage and high school students starting up. Little or no tools, cash or experience. How can we help them? Lots of "how to" books points you to the break drum. So that's what they ask after.

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thats what I'm saying. my brake drum didn't require any drilling, at least it wouldn't have if I'd gone that route. It had the center hole open already. it was from the rear axle of an 86 chevy s-10 pick up. lets face it, unless you're really good at scrounging, have a decent tool selection and plenty of scrap (my case), or are given you're equipment. You're going to have to spend some money. It was cheaper for me to use scrap and the tools and equipment on hand than to do a threaded pipe twere, but if I didn't have that stuff $50 in pipe fittings isn't all that bad. and a good days worth of manual labor should net you that much at least as a teen these days. I was making $10 an hour for manual labor in my teens. Thats why I can't afford to pay a neighbor boy to do my work for me now. but I'm getting off the point. a little bit of money and common tools can get you a working forge for around $50. and even with the electric brake drums you're still going to have to put money into a twere or you're going to have problems with ash in you ducting. so why not use a regular brake drum that already has the center out of it and gives you a deeper fire pot. I mean if thats all you've got it will work, but so will a brake rotor if thats all you've got. Maybe I'm just working on the wrong vehicles/equipment, but I can't recall ever seeing a brake drum that didn't have a hole in the center. so what's wrong with drilling a few holes? how many people do you know who don't have access to a power drill?

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