I am a tooling engineer for Edelbrock. Im young and still pretty new to the trade. I design and build some odd ball shit on a daily basis to keep production running, but compound curves for stamping dies back in the haydays with a manual mill ??? This has been a question that I have been pondering the answer for a long time. How on earth without the benefit of Solid Modeling programs and CNC mills did they make stamping dies back in the old days??? If you think about it...Fenders, doors, quarter panels, hoods and roofs????.....Compound curves??? Shit people take for granted. The sheet metal on our cars is much thicker than the sheet metal of cars today. It took some seriously good tool and die engineering, and even better machinists to make the cars that we know love so much, even possible. I am just curious, as a machinist and engineer, how on earth did they machine stamping dies with thier compound curves and such, back in the days with nothing more than a Bridgeport manual mill, some measuring instruments, and a damn good eye? I know there are alot of trick vises, rotary tables, and tools to do jobs like that......but gaddamn!!!... I have to hand it to the machinists who make what we do and love possible, because I have never used or ever seen anyone use tooling that could come close to being able to manualy machine a stamping die for the fender of a '51 shoebox or a 31 model A, repeatably.
They did it with the tools you described, and files, and patience, and care, and pride. There are still a lot of old fashioned machine shops in your area. Take a field trip. Talk to a few "old-timers". GAIN that knowledge. Even if all you do is push buttons to cycle the programs, you'll be a better machinist.
Most modern body panels are stamped in dies that are lost foam cast from cnc cut foam cores. The cast dies are cnc roughed, cnc detailed and hand finished. most old body dies where patterned with wood, cast, manually roughed out(prior to pantogragh mills) and true craftsmen smoothed and detailed the surfaces in the dies with die grinders and emory cloth(read sweat and elbow grease). Either way when the process is screwed up it takes a skilled die maker to detail and blend in the welded up repaired surface of the die. In most cases even today with all the high tech gadgets, the die maker will make changes to the die so it actually works, engineers and designers know what they want the panel made of and how they want it to look, the diemaker finesses the die so the part can actually be stamped.
I often ask myself the same question, and I'm in the CNC biz. With car dies, I think they made patterns out of wood, a full size model, and then ran over it on a tracer mill. It has a stylus on one side and a spindle with a ball mill on the other. And thru hydraulics, the ball mill would be cutting on one side while the stylus was tracing on the other side. the hydraulics allowed the machine to run itself automatically. It's kind of like making coin dies back in the 1800's. they did it with tiny ball mills and pantograph milling machine that traced over a model while the other side was cutting the die. The pantograph allowed scaling, so you could trace a large model and concurrently make a smaller die. No expert on die making here, I just find the subject interesting. The most profound example of "old technology" is the P-51 Mustang, that went from paper to first prototype in 90 days! You'd have a hard time equalling that feat today with modern tools. How they all did it back then "the old fashioned way" is truly remarkable. -85% Jimmy
you don't have to be old to have had experience with manually machining compound curves and 3d shapes...I've done it a few times building 3D contours for plastic injection molds from scratch with only a hand-made part as a reference...it takes lots of time and patience, but the end result is amazing...it's kinda sad that everything is so much simpler these days, I've only been a machinist professionally since '97, but grew up around my dad working in a machine shop...I paid my dues the hard way for years and I learned more from that than I ever could have learned in any machine tool and die or engineering school...and I've very grateful to the guys who've shown me how to do things the "proper" way all those years, it makes me appreciate how simple it is for me to use computer software to program and cut those shapes without having to worry about hand shaping or checking your progress every 5 minutes with a buck or pattern...
I have the UPMOST RESPECT for "old school" craftsman (and woman) whether they were machinsts, welders, mechanics. I love to sit and watch them work their art whenever possible
Along the same lines...kinda...old guy in town, older family friend, I stopped by his house last year...he was out in the garage, making his own telescope..lenses and all. I mean a HUGE telescope, sanding, and shaping the lenses which were about 14" in diameter, by hand...he has 4 years in it so far, he said he's hoping to get it done before he dies (and before we loose more planets, ha) It was a different time back then, and a different mind set. A 25 year old kid would not think of taking on a 4 or 5 year project to make something himself, when he could just go spend $1000 and get it tomarrow. Thats half the problem with alot of the industry.
When I used to make drop hammer dies, a set of metal sectional templates was fabricated, both male and female. From those templates a wooden form was fabricated, either male or female. From those wooden forms, casting forms were made. From the casting dies, metal dies were cast (usually a zink alloy). Once the the die was cast it was ground and polished to fit the sectional templates. Usually only one half of the die set was done this way and was referred to as the bottm die. The top die was made of lead and was poured into or over the bottom die. The top die was bolted to the business or upper part of the drop hammer where it was used to form the metal sheet into the lower die with a number of hammer strokes.
A few years ago I got to see some European craftsmen scrape the ways on a huge lathe to true it up. They spent several weeks with it and it was unbelievable. They would work six or seven hours and remove a tiny bit of metal ,but it was as nice as if it had been surface ground when they were done. The reason they couldn't take it out of the building was it's size, it had been in there since WW2 and buildings and walls had been built around it. They all smoked pipes also ,hummm !
Lots of good answers here so far, and some good guesses - but the truth is there are more machines (and brands) than just Bridgeports and tracer mills. One I used to love to run was a die mill. Cincinnatti used to make a heckuva good die mill, it was kind of like having a mill with a built in rotary table. Imagine the J-head of a 3 axis Bridgeport mounted in a big motorized gear and ring above the 2 axis table. That gives you 4 axis, OK? X (back & forth, Y (in & out), Z (up & down), and now W (round & round). Cool, huh? You can crank the cutter from the center and then drive it in a radius clockwise or anti-clockwise, OK? Now - by stopping the cutter, raising it, cranking the table to a new position, dropping the cutter, and starting the ring gear again (in either direction) in the new radius you can make CNC-like intersecting radii. Is my description enough for you? Of course, there are other machines and tools we use - but the real "trick" is using your gray matter. Good math skills are an absolute neccessity, and the ability to communicate with other tooling & engineering personnel. Facility with hand tools of all kinds is good, and you can never have enough reference material. Big tooling shops employ machinists, form & pattern makers, jig & fixture builders, CNC programmers and CATIA jockeys, and more skills and abilities that I'm forgetting. But it all starts with someone who can think in multiple dimensions and has the patience to bring the vision to fruition.
Before 3D cad, I used to create blueprints that had cross sectional views of a part. On a 3 foot long part we would slice it every 6 inches and put those shapes on paper. Here's an ironic and amusing experience I had on a project last year. I had created a 3d file for a part. We expected to turn over this file to a vendor to make the pattern. Expecting the pattern was going to be CNC'd out of foam or metal. Well guess what, none of these hi tech shops could turn it around in our short time frame. Who could do it in time was an 80 year old retired pattern maker. I went back and added dimensions and section views to the 3d file. I printed everyting out on paper and delivered them to the pattern maker. Yes, the pattern came out beautiful all hand carved in wood.
At the university I attend we have a machine room with a very experienced machinist. He makes the compound curves and items of that sort using a knee mill a shaper and a horizontal mill. These machines, his experience and correct tooling allow him to make everything all the professors and students dream up. Everyone is always amazed at what hes able to make with the limited and aged tools he has available. I learn as much as I can from the man and am lucky enough for him to like me (meaning he will answer my questions due to the fact he has no patience anymore). Josh
My grandfather was a paternmaker by trade. Started at 14 on a 5 year apprentiship, that would have been about 1913 or 14. He helped work on some of the earliest ever airplanes back then - interesting guy. Anyway, he used to make ship propellers for the foundry, all sorts of cycloid and epicycloid (sp?) gears big and small, all sorts of tricky 3D stuff - all in wood, by hand. Something like a QC would have been a walk in the park. Oh and they used to make those old perfectly balanced plane props by hand too in '14. Imagine that - big chunk of wood, spinning so fast it would shatter to bits if it wasn't perfect. Best thing is, he left me the bulk of his wierd, wonderful and often hand made tools and the tool chest he made as an apprentice (which makes it nearly 100 years old). And I still use it. That's my little story anyway.
45 years ago we didn't have anything that could print out a paper pattern. I was given a set of x/y co-ordinates and laid them out on sheetmetal. Then it was connect-a-dot to lay out final shape. This was then cut to shape and used as a template for both wood and final die.
When I started gunsmithing school one of the first skills they taught was how to use a file. You got a 2x2x3 piece of cold roll steel and had to make three sides to perfect light tight 90 degree angles. top and two sides. Basicly a maddening experience that took up many hours. What I learned is with enough patience and time you can make anything with the simplest of tools.
I love using files! I have so many different sets, sizes, shapes, and patterns it boggles most folks' minds. A very versatile tool, IMO. Whenever one of the bosses use to complain about how long a difficult job would take, I'd just open my tool drawer full of files & rifflers and say "Well, I can always use these - it'll take awhile but the part will be right!"
I'm 52 and retired now, but I'm a Journeyman Tool and Diemaker who learned in the old days. I served my apprenticeship in small "job shops". We had models that were made by a model shop and the models were "traced" by a duplicator and cut into steel. Then the dies were hand finished by "Die Barbers" who used grinders and stones, and then spotted the two ahlfs of the die together. Pride, Craftsmanshipa nd a lot of time....now it's a computer generated model and math data to accomplish the same tasks. Quicker, faster,a nd more accurate. I've built both molds, stamping dies, and special machines in my day. Seen a lot of stuff come down the pike, and there's always a different way to skin a cat. 30 years in the trade. ....and a lot of it behind a flat bastard or a die riffler.
My grandfather told me about one like that 'cept they had to make a cube, with the least amount of material taken away. Whoever had the perfect cube that was also the biggest got top marks.
I've heard that one too. I believe that the Purdy apprenteces are the ones that did that. Love of hand fitting on those old double express rifles to make sure both barrels shoot to point of aim.
I remember watching this as a kid in the late 60's. Iirc it was called Kellering or maybe Kettering but it was duplicating a prototype that set next to the mill. This was in a small shop in Ohio but the times I remamber they were doing hoods that were fairly flat at that time. Thanks for jogging my mind.
I agree that the file is often a forgotten work horse. I don't know how I would rework some production tools if I didn't have something as simple as a file or even some sand paper. I wasn't aware that the old body stamping dies were cast. My mind was thinking in terms of Machining male and female dies out of a solid chunk of tool steel. I know my way around a manual mill, lathe, and an NC, but my few years of limited experience look more like a pair of "training pants" compared to the skilled guy's who toil day and night in machine shops doing highly complicated tool and die work. I think that shit is so awesome. Although much easier than machining tool steel, I had the pleasure of watching an old timer,who worked doing aircraft restoration for a museum, mill a prop for a plane from the late 40's, the way they used to. It was interesting to me how "period correct" the guys who worked in that restoration shop were. They didn't use any sort of new technology to restore those planes or make replacement parts. It was all done in house the way they used to make things. NC's do some amazing shit these days, but everytime I look at something that was made pre-NC, I just think Damn!, there was a lot of highly skilled craftsmenship that went into that, as well as the thought "how the hell are we gonna make this one?" I've seen machined forms for making one-off hand made body panels and even that shit just amazes me. Im glad my post sparked so much feedback.
It's called Kellering - and no tool'n'die machinist I've ever met seems to know where the name for the process comes from. I've done it lots of times on CNC machines with ballnose endmills, and never tire of watching the metal smooth out into the programmed shape.
Cool. I remember being fascinated by it as a 8or9 year old.They always had to drag me out cause I just wanted to watch "one more lap".Sounds like the only thing thats really changed then is your either digitizing a prototype or its entirely computer generated. Would be interesting if someone knew where the name came from.
I designed a injection-molded piece for the craft company I was working for (WAY out of my expertise then and now, but I'm working on it), but they had confidence in me to design it because they knew even less than I did. The mold maker used a probe EDM to make the mold, they used CNC to make the sinkers, but my dad (retired tool and die maker) said he has made sinkers by hand on a manual mill. Is there a EDM big enough to cut a fender die?
Oh Ya!! I've seen edm tanks that you walk around in. I am also a Tool and Die maker and now a tooling designer. I have designed and built Molds, Dies and fixtures for about 15 years or so. I am still amazed at what they could do back in the early 1900's. I just back from IMTS in Chicago, now a days you don't even need to be a tool maker to build stuff. Design-Program and cut! There is some amazing equipment available today that wasn't around even when I started a short 15 years ago. 3d Solid modeling is one. I couldn't imagine designing a mold or die in 2d let alone with a pencil and paper. I also have great respect for the craftsmen from the early days.
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