A work from Alfred Habermann - How does it hold together

[LeMarechal]

Hi to all out there,

There is a book named - Alfred Habermann - Blacksmith and Designer. It is a kind of an portrait and I think a friend of him wrote this book. There is almost no information about the techniks he used for the pieces shown in this book. And there is one thing Habermann made I evertime wonder how this all helds togehter:

 

 

Does anyone know this gate? Or had it seen in nature?

How does Mr. Habermann prevent the parts from slipping apart? As you can see on the photos, you can´t see anything there. They are not detailed enough.

What do you think?

Did he weld it at a few points from below, where it is not visible?

Did he rivet the crosspoints and ground the rivets leveld with the edge of the holes?

 

Grettings Sascha

[anvil]

No welding. It's all traditional joinery. Your bottom pic actually answers your question.

Using slit and drifted holes, to dimension and passed thru pieces peen'd over it can't go anywhere.

Pretty cool, huh?

[Frosty]

Slit and drifted to size and then heated to around 400f when the male piece is pressed through they'll shrink very tight. Also if you look at the first pic, you'll see a bit of sag from the hinges down to the far end. This will wrack the joints, they CAN'T move. 

Frosty The Lucky.

[LeMarechal]

I thought too, that it must be this shrinking thing. But the upright bars have to cross the horizontal bars 5 times. Must be a very fiddly job, not?

 

 

[ThomasPowers]

I remember a set of bars, I believe it was on the Federal Reserve Bank, NYC, where to get an "impossible interpenetration they had cut the back of the eyes open and then forged them back closed.  Blind rivets/pins would be a possibility.

[LeMarechal]

Hi Thomas, I'm totally with you. It must be something like riveting or some welding points.

Shrinking is in theory possible but I can't imagine that it will work here.

I made a little bit of math about changing in length by heating up a bar with a 25mm hole in it.(see the photo)

 

If I'm not too wrong with that calculation, you can see that the diameter will only grow about less than 1/64"...

 

This kind of measurements is a very unusually one in blacksmithing

Ok let's say if your drift is well dimensionsed and you drift at the right temperature each time, each hole...the next challenge would be, the distance between the holes must be exact 0,0000mm the same!

Ok let's imagine that someone can do this... now it comes the moment to assemble all parts together. You have now to bring up all 5 joints/holes to nearly orange-heat and slip one upright bar after an other thru all 5 holes into the right position .... and all the clearance you have about the 5 holes is that fraction of a millimetre . 

Ok, what I heard about Alfred Habermann was that he was an amazingly good blacksmith, who knew all techniques and I won't say anything against that.

But I think everyone can see what I'm meaning

(Hope my english makes sense)

[Glenn]

There were 5 blacksmiths from Alabama that made this project in 2018.  Travis Fleming, Ronnie Howard, Dustin Patterson, Saxton Reynolds, and Al Stephens. Click here to go to the IFI thread

Kuhn Ring Notebook PDF.pdf

[LeMarechal]

This is really a nice job. And a cool project. A very impressive example of what is possible if people with visions work together. Thumbs up

 

greetings

Sascha

[twigg]

1/64" is too much shrinkage for an interference fit. IIRC it only takes a few thousandths to get a snug fit with steel on steel. I don't know how this gate was assembled but I wouldn't call heat shrinking implausible. I've seen people hot fit bearings with a toaster oven. If anything a forge is probably overkill. 

I agree on the difficulty of alignment, but that problem applies to every method not just hot fitting. 

[LeMarechal]

Hi twigg,

 

yes absolutely too much for shrinking, but also much too little for assembling. :)

Alignment is always one difficulty and for that a little clearance is necessary. But far more than what is needed for an interference fit...

I tried to make two more photos to show a little detail I found after looking at the original photo with a magnifying glass. Sorry the poor quality of the pictures but the originals in the book are not better

Above you can see a crop of one of the photos out of the first posting... can you see this round shadow where I marked it. For comparison I copied the area without markings.... Maybe a blindrivet?

 

 

This is realy poor in quality but I guess you can see, that there is "something", a little irregularity could be a little welded region perhaps?

 

 

[Frosty]

7 hours ago, LeMarechal said:

bring up all 5 joints/holes to nearly orange-heat

Just for the purpose of discussion and until someone comes up with the proper term, I'll refer to the female half of these joints as the "collar" half.

Even red heat is too hot for interference fitting, the collaring half will stretch as it cools and not produce an interference fit. 

However this doesn't need an interference fit, just snug. 1/64" is almost close enough to use other methods to "set" the joints. Methods that are easier than hidden rivets or more cosmetic than tack welds. 

I agree though the evidence you highlight sure looks like it could be a rivet. Could it be a punch that just swages that point in the collar half of the joint tight? I've done that many times when hammer marks aren't bad things. I've made V blocks to swage square collars on the diamond.

Another technique I've used is to use a chisel to make a couple marks within the area to be covered by the collar half of the joint. I warm the collar a LITTLE with the smallest brazing tip on my oxy propane torch because I can heat the smallest area with it. Even though the collar is a little too snug to slide easily on the shaft it won't pass over the chisel marks until warmed up. Once cooled it's stuck tight. By warmed up I mean a couple hundred degrees. 

The complexity of the gate would have me making a swage to tighten the collar or even pinning it, drilling and tapping the collar for a set screw, then cutting,  peining ad grinding it clean sounds like the least work for nice results and would really aid assembly.

Frosty The Lucky.

[twigg]

LeMarechal, sorry I think I misunderstood the point of your calculations the first time around. I see what you mean now. I agree with Frosty that swaging/crimping the collars with a punch sounds most reasonable, and agrees with your first set of photos. Hard to tell if the welds shown in your second set of photos was part of the alignment process or a fix.

[anvil]

Working to a 64th is standard for this work and you don't need a heat shrink to fit. Iron/ steel has memory and if forged to dimension they will slide in easily with the light tap of a hammer and will jam fit between the many joints when hung. For the few that may be loose than frosty hit it on the head, so to speak, just use a small chisel on whichever side is the back and bottom and do as you see in your pics. With a small chisel you can drive in a small divot and do it on the inside of the round roll around the slit and drifted holes and most will never see it.

Again, and most critical, because when forged gates and railings are built, they are not built quite square. When they are hung they"rack"  to square and literally every joint is put into a hard imovable bind.

Heating and swedging tight is not an option for many reasons. Too difficult to do when assembled and most important, every time you swedge them hot, your lengths will change and your piece loses its symmetry.

That doesn't mean a sloppy fit, it means all pass thru' s must be done to a tolerance of a 64'th.

So, do like blacksmiths do and keep it simple at every detail, then the most complex of projects will fall together as they should. And never forget the "rule of rack".  . (Lol, I just made that rule up, but rack and roll still rules.  ) 

[LeMarechal]

Hi,

Thanks to Anvil, Twigg als Frosty and all the others.  Sometimes I tend to bit on such details and as long I can't find an answer it could make me crazy...

So thank you all for the patience! Nit at least because English is not my mothers language and so it maybe sometimes a little bit hard to find the right words to subscribe what I mean... I'm sure that, what I'm writing, often sounds a little bit clumsy for natural english speakers:)

 

I think we found a few very good points here so far. I will find a projekt where I will try out the tipps I got here and then I'll show it here...

 

At Anvil:

 

Rack and roll is a good sentence for a Blacksmith-TShirt I guess

 

Greetings from Germany

Sascha

[anvil]