Peter Ross on upsetting a square corner "controversy"

[rockstar.esq]

Last night I watched an old episode of "The Woodwrights Shop" that featured Peter Ross forging a hold fast.

 

http://video.pbs.org/video/2292087803/

 

Peter discusses what he feels is controversial about upsetting to make a square a corner.  Rather than driving material INTO the corner, he argues that he's driving material AWAY from the corner.  I must confess that I didn't understand what he was saying but last night it dawned on me and I think I get it now.

 

If you take a punch and mark the center of a square bar to indicate where you intend to bend a bar (left or right) in a square corner it will end up centered on a line drawn from the outside to the inside corners of a square bend.  The upsetting operation will not move that point from the middle of the bar.  Peter specifically mentions this as the impetus that eventually lead him to his conclusion.

 

The upsetting isn't about adding bulk to the metal section at the bend. If the bend is properly square - the bar will have the same dimensions heading into and out of the bend.

 

I thought of it this way.  If you cut the bar then reattached it as a butt joint the total length of both sides of the bar would still equal the original bar length.  If the upsetting was driving mass into the corner - the total length of both sides would be less.

 

Bending a bar bunches material on the inside of the bend and stretches material on the outside of the bend.  Upsetting in this situation is moving the the legs of the bend away from the outside corner and towards the inside corner. The center mass of the bend is actually staying put - the legs are what's moving. As silly as it sounds - the legs are moving because you're hitting them NOT the corner.

 

I caught myself assuming that upsetting meant more than driving material into itself.  Getting hung up on one application of upsetting like bulking an area for a bolt head - lead me to misunderstand how the term could be applied elsewhere.

 

I thought this was neat to think about. 

[Frosty]

I've listened to Peter Ross explain that very thing in a few "Woodwright's Shop" episodes, the hold fast episode being the clearest I can think of.

 

I don't know if I agree with his explanation as it stands, without him clarifying it more. What I see is the blows are moving the material from the thickened inside of the bend to the stretched outside. When I follow the molecules in my mind's eye, (I take little mental trips, as the iron, to visualize the actual movement) I can see it as either upsetting by driving the iron thicker to the stretched outside of the corner or conversely as drawing down the compressed inside. My little mind rides just tell me it's moving from here to there without really changing anything, call it a wash.

 

I've been getting square corners by over bending a little and driving on the ends of the legs to bring it back to 90, a little fine tuning  over the edge and planishing makes for nice square corners.

 

What I do isn't really much different from Mr. Ross, I'd have to compare the products to decide which I like better.

 

Frosty The Lucky.

[anvil]

I don't think there is any controversy. Its a matter of defining terms.  

There is an inside radius, a square outside corner and two legs. The legs get shorter and the material moves from the inside radius to the outside corner. The legs move inwards and the excess material around the inside radius moves on the diagonal to the apex of the outside square corner.

To forge these to length, meaning no material to be cut off the legs and the cross section to be uniform I follow a rather simple formula.

let's say I am using 1/2" sq. stock and I want to end up with 10" legs measured from the center of the inside radius.

my formula is to add half the thickness of the material to each side of the right angle bend. this is layed out and measured from the center of the inside radius.

so I start off with 20-1/2" of 1/2" a square stock. my centerpunch mark is 10-1/4" from each end. the reason I mark the inside radius is because this point does not move wrt the legs or the outside corner.

when I forge this, the legs get shorter, the inside radius and surrounding area are upset and the outside edge of the parent stock approaches a right angle. I do not at this time use the flat of my hammer to maintain a 1/2" profile around the diagonal. instead I use the crosspeen and move this material from the inside radius on the diagonal to the apex of the outside right anglecreating my 1/2" profile.

I check my measurement from my centerpunch to the outside of each leg as needed. when they hit 10" i dress the forging, check for square and, usually champer the edges, leaving the apex sharp.

the whole process takes way less time than it took to detail the process here.

so you can see the actual movement of material is from the inside radius on the diagonal and from the outside edge of the parent stock inboard to create the sharp apex.

the only difference in this and the Peter Ross video, realizing the video could be a special case as it is not a simple right angle corner, is not using the flat of my hammer on the top surface of the forging and using my crosspeen instead to move material on the diag.

if you use the flat of the hammer you are moving material 360 degrees. the crosspeen controls the direction of movement very specifically on the diagonal to the apex.

hope this helps.

[rockstar.esq]

Anvil,  I'm not sure I understand.  It sounds as though you're saying that you take a rod of some length, then upset and form a square corner resulting in two legs on either side of the bend that sum to shorter length than the original bar.

 

A "perfect" square corner out of bar stock should look like a perfect butt joint or a perfect miter joint.  There's no waste, and there's no extra.  If the legs end up shorter it seems to me that the corner must be thicker than stock entering and leaving the corner.

[anvil]

I think I understand your question.

sorry, but I can't do pictures at the moment, so will try word pictures, and my wordsmithing needs work!

let's say we are using 1/2" square as in the first example in the Peter Ross video. the one he did not finish. think of your perfect butt or miter with two legs running at rt angles to each other.

the diagonal of your miter is the diagonal of a 1/2" square. the outside edge is sharp and crisp. this is what we want to end up but with an inside radius not a sharp inside corner. otherwise you will end up with a cold shut. so my example is a bit different than your perfect butt/miter.

now take your 1/2" sq bar. heat it and bend it to a tight right angle bend. I use bending forks for better control.

now look at the area we defined above. the inside radius is upset. the outside radius is radius'd drawn out, and no longer 1/2" along the diagonal in thickness and the length is shorter than your original diagona

on your perfect example we would not need to add any material, but because we have an inside radius, we need to add material to get our example(with inside radius). the greater the inside radius, the more material needs be added. because of the beautiful, large inner radius in the video, Peter Ross started with larger material and thus avoided a major upsetting experience. ;) .

so for my "normal" tight inner radius'd right angle bend (like the first example in the video) I add 1/2 the thickness of parent material on both sides of the bend to fill in the needed extra caused by the inner radius, then move it by upsetting and using my cross peen to move it from the inner radius to the outer sharp edge.

so to forge to length, I need to add 1/2 the thickness to each side of the bend.


do you see the difference between your perfect butt/miter and what I'm doing, and what Peter Ross did to both in the video?

two good sources, and most likely way better understood is

Francis Whitaker's cookbook. and

Schwartzkopf's book. elemental forging? can't remember the name of it.

[KYBOY]

I have that episode saved on my dvr. Peter Ross is a smith of the highest caliber. Ill admit it didn't make much sense to me either at first but now it kinda does..Regardless the man knows what hes talking about. Take a look at his tools sometime, what he makes like the calipers and such. He did a fine episode about making hinges too.

[anvil]

absolutely, one of the best.

[anvil]

I don't see any controversy. Peter Ross said, as I understood it that material moves away from the centerpunch Mark. his centerpunch marks the inside of the bend. material moves sway from the centerpunch mark.

it was confusing to me and sounded like material moves out towards the legs, making them longer. but I don't believe this is what he meant, so stated it moves on the diagonal away from the centerpunch and tried to make it clear this applies to the first piece he demonstrated, not the big piece he finished.

[Frosty]

Anvil: You're trying to explain away something that doesn't exist and not doing a very good job of it. You can find the correct rules of length allowances in a sheet metal bending book.

 

Cold bends, subtract the thickness of the stock.

Hot bends, subtract half the thickness of the stock.

 

From personal experience, forging a square corner requires no (zero) length correction.

 

The only discussion was about how Mr. Ross worded his explanation and folk trying to see if he meant something other than most of us understood to be the working facts. I'm thinking he fell into the trap many folk do when trying to explain things to "intellectuals." The intellectual tends to want a deeper understanding to some philosophical element that just doesn't exist. Mr. Ross being a pragmatist in every sense of the word I've seen demonstrated exercised the age old adage, "if you can't dazzle them with brilliance baffle them with BS."

 

I used to work with guys who had to have multiple degrees to even apply for their positions and very few could accept a basic answer from a guy with dirty hands. So I HAD to add a raft of BS so they'd be baffled enough to accept what I said. Demonstrating I could do it was almost never enough.

 

Anyway, I believe Mr. Ross had to explain things to intellectuals like his bosses at PBS for too many years and fel into the habit of making them more confusing than necessary to "sound" learned to the . . . educated.

 

Anvil, you might ask yourself why you're trying to explain something so basic to us and in such convoluted language.

 

Of course that's just my take, I could be wrong.

 

Frosty The Lucky.

[anvil]

 I watched his video and enjoyed it. I've watched him in person and enjoyed it. I heard him talk of a controversy and tried to see what it was. No luck. So I worked my process backwards and still see no controversy. 

 

Sorry for not being good at writing. I warned of that in my post.  That's why I'm doing this, trying to bring back lost skills.  Is that a problem?

 

As far as adding material to a right angle bend, I'll just recommend you look at Francis Whitaker's book and Schwartzkopf's " plane and ornamental forging". Sorta cuts to the chase.

[Frosty]

Ah, I get carried away sometimes and should be smacked with a rubber chicken or a cyber sock. I took another look and he did indeed say something about controversy. I don't see it myself but I miss a lot. My bad.

 

Frosty The Lucky.

[anvil]

No problem, and thanks for that.  If you get a chance, do check my sources.

[Frosty]

I reread what you were saying and I get you. The closest you can get to pre measuring for a bend without an allowance is down the center line. As I recall that was covered in shop class too, it was always just easier to make the allowance and avoid having to try taking other factors into account. Number of bends, degree, simple, compound, etc. It gets to be such a hassle we'd just guesstimate and trim as needed. Always figure to trim, it's Sooooo much easier than adding a titch.

 

Frosty The Lucky.

[anvil]

sometimes its easier to trim it a bit. sometimes not. thinking of a closed piece like my tulip, or a square where you close it with a forgeweld. of course you can always trim it and use the welder, do a bit of grinding, then reheat it, hammer it and wire brush it to get rid of the grinder marks and take a good heat to get rid of the mismatched colors. its all choice.

however, for me the feeling I get when I forge a complex piece, and the only drop is,,, feeling that little "snick" when it drops into its place is second to none. :).

but hey, to each his own. the beauty of a piece of iron comes from the heart.

[rockstar.esq]

Anvil,  thank you for your patient replies - you made a lot of sense.  The difference in the before, during, and after perspectives really play a role here. 

 

My background is in conduit bending - you can't "get back" anything you lose in bending (take-up) without adding pipe.  

 

I didn't mean to frustrate anyone - I have a book by Alexander Weygers that shows upsetting a bar considerably for forging a 90 degree turn. It's kind of a bulk up - draw down situation where surplus material is brought to the corner to allow it to be forged back down .  He made  a point of upsetting the stock while the bend was fairly open to avoid a cold shut on the inside corner.

 

 Peter Ross didn't approach it the same way so I sought to understand his example better - he certainly seems to be getting it done quickly.

 

Thanks to everyone for their replies.

[anvil]

thanks for that. my technique is almost identical to Peter Ross. I've done it like Weigers and found it takes longer and is less precise, but it works as well!

3/4" and smaller is a one heat operation or one heat and a bit of cleanup.

[Ten Hammers]

Peter Ross is an incredible teacher.  I sat within 10 feet of him for almost 2 days at the BAM conference last weekend.  One hammer ( likely 1 1/4 lb ) and a few BAM tools ( tongs, top tools ).  He did incredible work including steel and wrought.  ZERO use of a brush and the pile of scale on the floor was almost nothing.  VERY clean work.

[Benton Frisse]

I've seen one of those episodes from the Woodwright's Shop on upsetting. Really great work, the guy has an INSANE amount of hammer control. I think those episodes can really help clarify upsetting for people who are new to the trade. 

I just thought it was really funny that if you noticed, he kept giving the Woodwright guy a look like "would you shut up so I can explain what is going on here?" lol 

[rockstar.esq]

Benton,

 

I agree - Peter was waiting for Roy to hush quite a bit.  From what I understand Peter does a lot of demonstrating - it would be tough to break your rhythm. 

[Frosty]

I've seen one of those episodes from the Woodwright's Shop on upsetting. Really great work, the guy has an INSANE amount of hammer control. I think those episodes can really help clarify upsetting for people who are new to the trade. 

I just thought it was really funny that if you noticed, he kept giving the Woodwright guy a look like "would you shut up so I can explain what is going on here?" lol 

 

Ayup, Roy talks too much in those episodes by half. It is however HIS show and he MUST be the main talker, his producers, director and writers kind of demand he do the talking.

 

I've watched the Peter Ross episodes of Wood Wright's Shop as far back as I can remember and have been wishing Peter had his own show. Unfortunately . . . <sigh>

 

Frosty The Lucky.

[rockstar.esq]

That would be a great show.