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Hi. My name is Colin.   I would like to fabricate some turn off the century metal chairs.  I have restored a few of these classics and would now like to replicate them.  I have attached a pic.   I assume I simply start from stock flat iron.  The chairs are designed to 'bounce' like a rocking chair.  Is this something I can take to a blacksmith or do I need to transfer the design to paper/computer?  I'd like to make several of these chairs.

 

Any suggestions would be awesome!

 

Colin.

 

Chair_Apartment_front.jpg

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Research the history and try to find out what the material used at the time.  No doubt carbon steel  but what were they calling it?   http://www.admiralsteel.com/  has a category of products they call spring steel strip.   The alloys in that category are of lower carbon content but can be heat treated and to retain extra spring with out becoming too hard

Turn of the century or not they were using steel.  Further research on you part is necessary

 

Knowing the material a blacksmith could reproduce what you show there.

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think its time for you to get an anvil, forge and a good hammer. Need an anvil? Read the stickies, need a forge? The stickies can help with that too, as well as a hammer. 

If you have a modericum of mechanical ability (wich end of a hammer do you hold?) and a willingness to learn, experimant and fail but true again you can make those chairs.  Scrolling, heattreating, of sets, punching riviting...

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Other than peining rivets that's a straight up fab project. Cutoff saw, drill press, torch and a couple bending dies. Jig to assemble and a rivet set. I'd make one from mild first and see if one of my BIG friends and mean old Mr. gravity could damage it.  300+lb. repeated plunks should show if it needs to be spring.

I have a commercially made steel Adirondack chair that's similar, VERY similar and it's not spring stock. Deb hates it so it lives in the woods now. <sigh>

Frosty The Lucky.

Edited by Frosty

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On a closer look at the picture, is there a hinge at the junction on the seat and the back? if so are there any other hinges on it?

 

Russell

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I have a couple of those chairs at camp and they are comfy. Please keep us posted if you find out anything about the materials, I might just have to try making one myself.

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If I was trying to do an exact copy I would probably spring for two tests:  One a spark spectroscopy to determine the alloy and the second a hardness test to give an idea about how it was processed.  Both do little damage to the item---got any friends at a University with a MatSci/Metallurgy department? 

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I have a couple of those chairs at camp and they are comfy. Please keep us posted if you find out anything about the materials, I might just have to try making one myself.

Would you be able to take a few pics?  I'm trying to sort out why my chairs have a hinge where the seat assembly joins the backrest.

hinge.jpg

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Mine are exactly the same. My guess is it allows the seat and back to pivot just a bit while "bouncing". You've got two pivot points (seat to back and seat to arm) with the fixed point at the front of the seat.

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as the seat flexes the shape of the upper section between the seat and the back compresses and expands.  The weight of the person is carried in the back 2/3 of the seat.

 

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Two hinge points one where the back meets the seat and one where the arms meet the back. This turns it into a compound lever arrangement sit down and the downward motion of the seat wants to lean the backrest forward and the arms resist with the added force of the seat pulling the arms towards the back.

Lean back and it pulls the arms back and pushes the seat downwards drawing the backrest bottom forward. The hinge points make it a smooth, sensitive, responsive action.

Sorry, that doesn't sound clear at all and I have to say it's been a long time since I sat in one and watched it work. Every time I read what I wrote the less sense it makes, please feel free to disregard what I just said.

Take a look at the fold up Adirondack chairs, they have a similar compound lever action that might explain how they work. However they work they're comfy chairs.

Frosty The Lucky.

Edited by Frosty

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When you look closely at it there is a lot of sophistication and elegance to the design.

Too bad that we tend not to expect those things in a made in china era.

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So, I requested a quote from a local testing lab here in Chicago in an effort to discover the composition of the metal used in creating these chairs.  It's very important to re-create the 'bounce' and also, I'd prefer the chairs not snap in half in someone of 'size' sits in one and decides to test out the limits of the spring action.  If interested, you can follow my progress on my new site.  www.steelglider.com  

 

There is a blog section where I'll post results of my activities.  Thanks again for all your help!

Colin.

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Please keep us posted. I know what you mean about someone of "size" testing the limits. I've seen our chair flex all the way down to the floor without breaking, yet spring back to it's original shape/position when unloaded (although getting them up and out of the chair is a challenge in itself).

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I would be a little worried about the rivet where the seat joins the armrest at the front end. It looks like a weak point. I would put in a short supporting piece there to relieve the stress concentration at the rivet hole. Just four inches of the same material ground to a taper at both ends and held by the same rivet.

Maybe I worry unnecessary the chair is obviously OK in the pic.

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