flanging 8

In the previous post I showed videos of modern flanging machines.  These weren’t the kind of flanging machine I was trained on back in 1973.  I first learned to run a Blue Valley flanger similar to this one.


It’s very primitive in comparison.  The table, orange on this machine, moved across the two parallel flat slides, on a large screw (unseen down inside the bottom of the machine).  Absent from this picture is the lower center post, which could be bolted into position at different angles, depending on the shape of the head being formed (it was threaded, and was screwed into the threaded hole in the middle of the orange table).  The center post could be screwed up or down, depending on the depth of the head.  The upper center post (which can be seen in this picture extending straight down) moved on wheels across a pair of flat slides inside the upper part of the machine, and could be bolted into different angles, to match the angle of the lower center post.  When clamped down upon the head resting on the lower center post, the upper center post was pulled along by the movement of the table.  At the end of each center post was a bearing pack, which allowed the head to spin as it was held in place.  The icr roll, bolted to the end of the shaft, turned, spinning the head.  The large flat forming roll shaped the head around the icr roll as the metal spun.  There was a middle roll, along with the two side rolls, which steadied the head as it spun.  The shaft turning the icr roll was powered by electricity, as was the screw the table moved upon.  The upper center post, the side rolls, and the middle roll was powered by air pressure.  The flanging roll was hydrolic, at least as it moved up and forward to form the head.  It fell back into position for another run simply by gravity.  Very annoying.  I was constantly cleaning and oiling the slides it fell back down on to try to speed the process up.  Most of the time it fell back very slowly no matter what I did.  To see most of what I just explained in operation, I’ll repost the video from ‘flanging 2’.

The operator was responsible for setting up his machine.  Besides changing the icr rolls, the angle and height of the lower center post had to be set, and the angle of the upper center post to match, The position of the middle and side rolls had to be adjusted.  And the table had to be placed according to the size of the head being flanged.  You measured to get it close, then bolted it down so it wouldn’t move on the bottom slides.  The table was in two pieces; the back part was bolted down and had a piston mounted on it, and the front part was connected to the end of the rod that came out of the piston (hydrolic, naturally) so you could move this part of the table a short distance forward or back as you formed the tank end.

That’s what got my partner in trouble.  I didn’t tell you I had a partner?  Sorry, it slipped my mind.  My mind is getting slipperier and slipperier .  Another flanger trainee was hired at the same time I was.  We were about the same age.  He said his father owned a construction company, but he didn’t want to work for him.  Never said why.  But at the end of our training he went to first shift and I remained on second.

He didn’t last long.  Apparently he forgot to tighten the bolts (there were eight of them) that fasten the back half of the table in place, and was operating the machine with the table loose.  And Charley F. witnessed it.  That’s the trouble with first shift, much more supervision.  Charley, if you remember, was the maintenance supervisor.  He was the one who tried to break into Roy H.’s locker, and Charley was one of the three involved in the night raid that got three third shift employees and their foreman fired for drinking on the job.  He was an excellent maintenance supervisor, and he did not like seeing his machines being abused.  And he had one hell of a temper.  I heard he chewed my partner out royally.  So he quit.  Screamed right back at Charley and walked out.  He most likely went to work for his father after all.  But I don’t know, I never saw him again.

Poor Charley got in trouble over that guy quitting.  He was told to control his temper by the owners.  And he lost some of his authority.  Until this happened, he pretty much ran the shop.  But Elmer D. was promoted from shipping supervisor to plant supervisor, to handle the men.  While Charley was told to stick to the machines and leave the men alone.


flanging 7

More show and tell.  It’s easier to show a flanging machine in operation than try to describe it to you.  Here is a short minute and a half video.  The head being flanged is so small that the upper center post can’t be used.  Instead, the head is bolted to an adaptor, which is a bearing pack bolted onto the lower center post.  The head itself is bolted to the adaptor.  The icr roll, which is bolted to the end of the shaft (which an electric motor rotates) makes the head spin.  The forming roll, manipulated by the operator, shapes the spinning head around the spinning icr roll.  We have many different size icr rolls, to form whatever size corner the customer requires.  The two side rolls merely stabilize the head as it spins.  You can see the upper center post back out of the way, since it is not being used.

Here is a brief video of a larger head being flanged.  Not much is shown, but you can see how the two center posts line up to hold the head in place as it spins.  Notice the icr roll being used this time is much sharper, making a smaller sharper inside corner.

Another video of a flanging machine.  The quality is much better – it has music!  It was done by Italians, of course the quality is better.  Notice the several icr rolls sitting on the floor by the machine.  We change these out to create whatever inside corner radius is required.  Also, this video must be watched on You Tube (why?  I don’t know).  But by clicking on the link it opens another window, so merely close that window after viewing the video in order to return here.

One last video.  This one is rather long, four minutes, but it shows the pressing operation along with the flanging operation.  So it shows a flat circle of steel being transformed into a tank end.  A couple of things to notice as you watch this video.  Day changes to night while they are pressing this one head.  Their pressing process is much slower than what I am used to.  Also, this head does not have a center hole, it is being flanged no-hole.  The head was centered up by the operator before he began, and it is held in place only by the pressure applied against it by the upper and lower center posts.  But the operator has let it slip off-center; by the end of the flanging process one side of the head is much higher than the other.  He did a terrible job.  Also, running a flanging machine is a one-man job.  Having that many men stand around watching me work would make me nervous.  No wonder he screwed up the head.

I hope this helps you to understand what a flanging machine does.

flanging 6

I’ve been describing tank ends, and what all flanging operators do to them.  Better to show than tell.  I’ll start with an ASME flanged & dished head.

ASME flanged & dished

By being ASME code, certain requirements must be met.  The degree of the drop radius (dr) must be equal to the diameter (od, or outside diameter, in this case, although if the customer requires the diameter can be measured from the inside, which would make it id).  The inside corner radius (icr) must be six percent of the diameter.  The straight flange (sf) and overall height (oah) can be whatever the customer wants.  I don’t even know what idd stands for, we don’t measure it.  And thk, of course, is the thickness of the metal.

This is a standard head.  Same as an ASME, but the requirements aren’t as strict.  TL stands for tangent line, the point where the bottom of the straight flange meets the top of the icr, which is kind of fuzzy.


This is an elliptical.  It is much deeper and rounder than an ASME or standard.  The diameter is twice the drop radius (hence the ‘2:1 ratio’).  Another way of saying this is the drop radius is 50 % of the diameter.


This is an 80-10.  The drop radius is 80 % of the diameter.  This head has a measurable icr, whereas a 2:1 elliptical doesn’t.  The icr is 10% of the diameter, hence the name 80-10.

ASME 80-10

This is a dished only.  It doesn’t get flanged, only pressed.  Although we do trim the edge to a required diameter, with either a radial trim or a vertical trim.  A radial trim is one which maintains the angle the edge of the head was pressed to.  A vertical trim is self-explanatory.

dished only

This is a flanged only.  It doesn’t get pressed.  We turn up the edge of a flat metal circle.

flange only

This is a flared and dished.  Instead of turning up the edge of a dished head to 90 degrees, we flare it out to 45 degrees.

flared & dished

This is a shallow head.  The drop radius is much less than that of an ASME.  Which makes the overall height shallower.


This is a cone.  Pressed, or bent, segments are welded together into the cone shape, then we turn up the edge to give it an icr and a straight flange.


I couldn’t find a drawing of a reverse head.  Instead of turning up the edge in the direction of the radius, to make a bowl shape, the head is flanged upside-down and the edge is wrapped completely around the icr roll to give it this weird shape.


Also couldn’t find a drawing of a hemisphere.  These are pressed segments welded together to a dish only head.  Sometimes we put these in a flanging machine to spin it to a certain circumference (they are pretty close to start with) and to machine the edge.


These are the different kinds of tank ends I’ve worked on at Brighton.

flanging 5

Brighton Corporation abides by the standards of the ASME (American Society of Mechanical Engineers) Boiler and Pressure Vessel Code.  This document sets the specifications for the metal fabrication we engage in.  As this applies to flanging, we often go beyond what the code calls for.  Such as circumference.  I don’t even know what the code requires, but our standard is plus or minus an eighth of an inch.  No matter how large or small of a tank end.  Our straight flange (the straight edge of the tank end that extends above the curved corner) is plus or minus a quarter inch in length and two and a half degree of toe in or toe out from perfectly straight.  The inside corner radius we form can be slightly larger than called for, but not smaller.  The overall height can be one and a quarter per cent of the diameter of the head deep to five-eighths of a per cent of the diameter of the head shallow than what is called for.  Thin out allowed is fifteen per cent of the original thickness.  Out of round can be one per cent of the diameter.  Bevels (the edge cut to a certain angle, inside or outside) can be plus or minus two and a half degrees of what is called for.  Tapers (the edge cut to a certain thickness at a certain angle, inside or out, which can be longer than called for, but not shorter) can be plus one sixteenth of an inch and minus nothing.  Bore-ups (the edge cut perfectly straight to a certain thickness and a certain length, blended in with a taper at the bottom) need to be pretty much dead on, and like tapers can be longer but not shorter.  The radius, which is the depth the flat plate is pressed to by the press operators (which we have to maintain, even if it is a crappy press job to begin with) can be plus or minus a quarter inch of the template used to form it with.  These are most of the specs we must meet, although I’m sure I’ve missed some.

Except customers can request (and pay dearly for, I hope) specs more restrictive than code.  Such as ridiculously small thin out.  Or overall heights.  Or out of rounds.  Or perfectly straight flanges.  Or circumferences even closer than an eighth inch.  Or tapers to a thirty-second of an inch, or less.  Even weights have to be held to certain limits for some customers, which is illogical since the mills producing the plate cannot guarantee the metal won’t be a little heavy or light.  Some customers require a perfect radius.  Some customers request tighter tolerances on any combination of these things, or on everything.  Which gets ludicrous.  We are a metal fabrication shop, not a machine shop.  Machine shops can do extremely fine work on small pieces.  The tank ends we work on range from five inches to over three-hundred inches in diameter.  Huge pieces of metal to try to form to such exacting specs.

Normally, we are the last machine the tank ends pass through (unless they get polished, in which case they go to the polisher).  After us comes inspection.  Lately, we flanger operators have inspected our own work ourselves.  Things go much more smoothly this way.  But most of the time I’ve been at Brighton we’ve had an inspection department.  We’ve always had a quality control department, with or without inspectors.  Ray M. was the QC manager when I was hired.  He had the final say on whether a piece got sent back for rework or not.  No one overruled him.  No QC managers we’ve had since he retired have had such authority.  The inspector we had when I first started was another old guy, Don M.  When he found something he didn’t like he would call you over and show it to you.  You were expected to fix your own mistakes (unless you messed something up so badly you didn’t know how to fix it).

There are a lot of things that can go wrong.  The worst is if you squeeze a tank end below the minimum thickness.  There is no way to make a head thicker.  If a head is thinned out then it is scrap.  Most everything else can be fixed.  Just not necessarily by you.  If metal shavings get crushed into the piece by the icr roll while you are machining the edge, the shallow pits can be belted out on a polisher while the deep pits need to be welded up.  Or if you hump up the radius while forming the head, it would have to go back to the press to be smoothed out.  There are so many things that can go wrong.

When I first went to work on my own I was supposed to go to my foreman with any problems.  Only Jim D. knew nothing about flanging.  When a head I had done turned up being three-sixteenths inch deeper than acceptable, he signed for it, saying, “Who can see three-sixteenths of an inch?”  That was the last time he ever said that.  He got chewed out for that, once Ray saw the inspection sheet.  All inspection reports cross the QC manager’s desk.  Inspection was a humorless job.

But I still had some fun with them.  Bill R. was an inspector who’d lost most of a finger while operating a metal shear.  When he’d take his gloves off and lay them down, I’d sneak up and slip a piece of chalk into the finger of the glove that his bit of a finger went into.  Then I’d watch to see how long it took for the chalk to work its way down and reach his stub.  When he finally felt it he’d yank the glove off and pull the chalk out and glare all around to see who was messing with him.  Sometimes it would take an hour before he realized the chalk was in there.  Most of the inspectors were totally without humor.  I’m glad they’re gone.

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This is the flow of work through the shop.  Metal comes in through shipping mostly by truck, although the largest pieces come by rail.  Most metal is shipped to us in one of three ways:  in pre-cut circles, in sheets (that we cut circles out of), or in segments (that we weld together to form a circle, on an automatic welder called a seamer).  Most of the flat circles of metal are then sent to the presses, where they are pounded into dish, or bowl, shapes.  Most of these pressed heads then have a center hole drilled, or burned if they are too large for the drill.  Most of the bowl-shaped heads (drilled and undrilled) go to the flangers, where they are spun to form an inside corner and a straight flange, and the edge is machined.  Stainless steel heads are then pickled (acid-cleaned); the rest are washed.  They are then marked-up and/or stamped with relevant information.  Then shipped out.

All of this metal is moved through the shop with forklifts.  From electric walk-behind pallet stackers

walk behind stacker to 50-ton diesels.

50-ton forklift

Although most of our forklifts are much smaller, and run on propane.


When I first started I wasn’t qualified to operate one.  A license is required.  Then one day help was needed in shipping.  My foreman at the time, Tom H., brought me into the break room and gave me a written test, and a booklet where I could find all the answers.  I quickly became qualified.

Driving a fork lift in our shop is tricky.  The aisles are narrow and sometimes, when we are crazy busy, crammed with material.  The machines are tightly situated, so you are loading a very large head into a small machine in a tight area.  You pick up this piece of metal that can weighs tons, maneuver it around stacks of metal scattered everywhere, while people dart in front of you, behind you, wait impatiently for you to finish so they can use the fork lift.  You load a flanging machine by lining up an inch and a half center hole (in a head with a diameter of 100 to 125 to 150 inches, or even bigger) onto a pin you cannot see.  Without wrecking the machine or the piece you are loading, or the fork lift for that matter.  Fun.

Actually, it is.  It’s a break from the routine.  Designated fork lift drivers have come and gone.  At times we’ve had them, other times we are expected to go get a fork lift and take care of things ourselves.  Felan R. was the best.  That old man  could drop a huge dished head onto a inch-and-a-half pin first try.  When he’d see me having trouble lining a center hole up with the pin, he’d joke, “Put a little hair around the hole, you’ll find it.”  Recently, laser pointers have been installed on the larger flanging machines.  It is directed onto the top of the center pin, so that when you load the head you merely line up the laser beam with the center hole.  But the machine I usually run never got one of those.

I’ve never done any damage with a fork lift.  Never wrecked any material, never crashed into a machine, never run anyone over.  Which has happened.  Stan C. was carrying a large head on his forks and didn’t see the golf cart in the aisle in front of him.  The golf cart was totaled (but the driver escaped injury).  Another time an operator left a fork lift running as he got off.  Which people do all the time.  Only this time he also left it in gear and the emergency brake off.  The forklift continued on driver-less down into a loading pit, about a 6-foot drop. And garage doors are a favorite target of people driving a fork lift, every single one has been damaged or crashed through, some numerous times.  Which will endear you to your co-workers if it’s the middle of winter and it’s your fault that a damaged garage door is hanging open while gale-force winds at sub-zero temperatures whip snow into the shop.

I have done things like spill a load, where a head or a stack of heads will slide off the forks.  Or lose control of a head as I’m loading my flanging machine, where a head will slide out of the machine onto the floor.  Usually hitting the floor with a bang, kind of startling to the guy working with his back to you at the next machine.  And I’ve gotten a fork lift stuck in the mud.  You can’t get off the pavement in the kind we have, they are too heavy.  Mike H., another very good forklift driver, laughed at me trying to get unstuck, unsuccessfully, for quite a while.  Then he showed me.  If you ever get a forklift stuck, merely run the forks down into the ground.  This forces the front wheels up enough that you can back out.  Some practical information for the next time you are driving a forklift.