Double (not Great) bellows

[Nick]

My travelling setup forge is an old Buffalo forge with a large ratchet and flywheel blower driven by a tiller. It works all right for the small ren faires I've been doing, but I want a more authentic setup. As part of that I'm planning on replicating the rest of the Mastermyr tools and making better garb, but I'd like a more authentic forge, too.

A friend of mine is making a small double chambered bellows, but he recreates the early to mid 16th century. I'm more interested in the 14th century, and as far as I know that's before the introduction of the D.C.B. I've seen recreations of Viking forges with two single chamber bellows, pumped by hand. But, I've seen some later medieval illustrations (see below) that show what looks like a lever system so that the smith can pump the bellows one handed, just like the great bellows. The thing I wonder about with a two bellows setup, though, is that when one bellows blows out, the other is sucking in. Is this a problem, or something not to worry about?

[Finnr]

Both those illuminations are new to me. I am only familiar with the double bellows being used by an apprentice while the master forges. But then My time period is closer to the Mastermyr period. I do tenth century Norse.
Finnr

[irnsrgn]

Pardon me for saying so, but those pictures look like an artists rendition of a smithy, not an actual drawing of the setup. Single chamber bellows are possible you just need a very flexible flap valve at the outlet for the intake stroke.

[ApprenticeMan]

It looks simple, probably weighted on top so when you pull the top or bottom up by the handle, it pushes air in.

[HWooldridge]

Our local group restored a 15th century Spanish blacksmith shop at Mission Espada in San Antonio. I was not directly involved in building but have seen their pair of single accordion-style bellows in operation. It takes two people to work this setup, with the helper pumping first one bellows and then the other while the smith does the forging. There is a simple valve in the back and another at the nozzle of each bellows - the rear closes on the pump stroke while the front one opens then vice-versa on the reverse stroke. The forge goes "chuff-chuff" while in operation so it is not a continuous blast but will get plenty hot to weld - the tuyere blows down from the side into a small duck's nest that holds the fuel. In accordance with the period, our members use lump charcoal at public demonstrations.

I'll see if one of our members has any pictures - better than typing 1000 more words...;-)

[Archie Zietman]

until about 15th C. as far as I know it was just two big single bellows, which works fine. All of the illuminations and drawing from 15th C. back have double bellowses in them, great bellows weren't invented yet. I'm going to try and dig up some photos of a very good medieval setup I saw pictures of once.
two single bellows either weighted, or with something that when one goes up the other goes down would be great. I'll think up how it would work, I've seen a few great setups with two alternating single bellowses, worked by pulling a chain which emptied one, then when the other one went down the first filled with air again so that when you pulled the chain again it would be full. You could get a very good continuous stream with it, just have to remember and sketch it up. I'll sleep on it (the design).
Good Luck,
Merry Being,
Archie

ask around on armourarchive.org forums, they do a lot of pre-15thC. viking and norman type stuff and some people there could help I'm sure.

[jake2431]

I've got an idea in my head of how continuous airflow may have been achieved by looking at these photos. It does was Archie was writing about and could have definitely been made during you ideal period. It is hard to tell exactly how the ones in the pictures work, but I will try to explain my idea.

I agree with AMan that it was most likely weighted. The green organic shapes on top if the bellows in the first picture could be weights (but that's just a guess). Anyway, you could make a wooden frame with a bellows on each side of wooden board that acts as a "seesaw" that, on the raised side, extends the lung to its maximum capacity, while the other lung expels air due to the weight on it. Now, in my idea one of the bellows would have more weight than the other, so that when you let go of the lever that you are working the bellows below the lever (the one with the most weight) will expel its air and it must have enough weight lift the opposite bellows to it's full capacity. When you pull on your lever, you will be lifting the heavier weighted bellows. You will also need some simple valves, but I'm not sure what was available in this period. If you are interested in the idea and would like a visual aide to see how it is build, I will draw one up. But if this seems like a bad idea to you, I don't want to take the time. But that' the basic idea for "Jake's Pre-D.C.B Late Medieval Continuous Flow Dual Seesaw-Bellows"! :-)

Seems like it would work, but I may have missed something, as I just thought it up. Oh, plus there may be a better way, but this seems pretty easy.

[Nick]

Originally Posted by irnsrgn

Pardon me for saying so, but those pictures look like an artists rendition of a smithy, not an actual drawing of the setup.

That's one of the challenges of interpreting medieval art. There can be an incredible amount of detail at times, but the way in which it's portrayed (perspective, arrangement, etc) can make figuring it out harder.

The first drawing seems to have a more detailed blower, but it's obscured by the forge. The second clearly shows the bellows but it's more representative than detailed. Still, they both show the bellows attached to ropes on a handle.

Jake, I think I understand what you're saying. The green things in image #1 could be weights. They're absent in #2, but like I said it's more representative. I've found a few pictures of blacksmiths from the period, but not many good ones of forges. They seem to be more common in the later 15th and 16th centuries (I've got a copy of De Re Metallica, it's got a great period exploded view of a great bellows). When I'm in Leeds I'll see what I can dig up.

[jake2431]

Sounds good. Let me know what you find. I am actually really interested in this period also, as well as the later late-middle ages. My interest in blacksmithing actually stems from my interest in medieval/renaissance European history.

[jake2431]

Also, medieval artist try to do pretty detailed pieces. The only thing that should be missing from the images are details that the artist may not have grasped and perspective. Artist of that period hadn't yet obtained a proper understanding of three dimensional space. In essence, there was no perspective. That is why the images appear so flat, and why it is so hard to recreate something seen in the images. You can't really tell what the equipment is doing without it's placement in the room in three dimensions. However, examining the images suggest that it is possible that they could have been using some seesaw type system, and I believe that the bellows setup in the two images is far to similar for it not to be a basic rendering of that particular period setup.