# What The Heck is Pattern-Making???



## 33706 (Mar 5, 2008)

I see them occaisionally. Tools of all sorts of interest to the 'Pattern-Maker' Is this trade part of fabricating sand-cast molds for the foundry industry? I just don't get it. And now, here's this vise posted locally, looks like a nifty old bench vise, but my god, it's $1500!!! Holy Moly! It's 18" wide!! But, I've seen even attachments, soles actually for Stanley #55/45 planes for use by Pattern Makers. As a kid, I used to peek in the back door of an old bronze casting factory, (it was always open, and hot as blazes) but I never saw any woodworking going on, so…I dunno! I am aware of the techniques used by Rodin to make elaborate bronze statuary, starting with a sculpted original, which in industrial processes may have been created in wood using pattern-maker equipment?? Anyhoo, here's a pic: 
*If you REALLY know what pattern-making is, in the industrial sense of the word, please explain it to me!!!* Of course all comments are welcome.


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## MoPower (Feb 6, 2009)

You are correct. Pattern makers make wooden replicas of the parts to be cast.


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## 33706 (Mar 5, 2008)

Thanks, Scott! Google mostly had hits on dressmakers supplies, sheesh!


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## BlairH (Jan 19, 2009)

I don't think I can help as much as I should be able to but up until 2002 I was on my way to becoming a third generation pattern maker. My grandfather opened his business in the 60's after moving to Canada from Germany, my Father then took over until the shop had to close it's doors due to lack of business, mostly to CNC technology.

In our shop the work was mostly comprised of machine parts for mining and railroads. You are right about being a "part of fabricating sand-cast molds for the foundry industry", expect that our role was creating the original part out of wood using a blueprint. The patterns needed to be extremely precise, up to 1000th while also allowing for shrinkage depending on the type of metal the final part was to be produced in. This wood pattern was then sent to a foundry to be cast in sand to make a mold.

There's a lot more to it but that's the jist. I was only working for a couple years before my Dad had to close his doors so I don't know a lot about the entire process but if you have any other questions, I'll take a stab at them.


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## 33706 (Mar 5, 2008)

Thanks, Blair!
I'm curious about metal-casting at home, looks like fun! I met an old man in the neighborhood who casts simple objects like coat-hooks and fishing lures out of aluminum coke cans. Then there was that movie about "The World's Fastest Indian" about an old-timer who raced his ancient motorcycle with pistons he casted himself in his garage crucible… It's indeed a shame that one more artisan discipline has faded away. This stuff fascinates me, but I'd bet that few people would have much regard for the old processes that built this country.


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## MoPower (Feb 6, 2009)

Pattern makers really are machinist working with wood instead of metal. The tolerances they sometimes work with are way tighter than what most furniture designs require. Those guys are good !


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## Loren (May 30, 2008)

An Emmert vise in complete condition is worth $500-750, so
I'd say your local seller's price is unrealistic.

Search google for "backyard foundry" and you'll find a lot
of information about how to do simple casting yourself.


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## patron (Apr 2, 2009)

PATTERNMAKER, WOOD (foundry)

Plans, lays out, and constructs wooden unit-or sectional-patterns used in forming sand molds for castings according to blueprint specifications, using handtools and power tools: Lays out pattern on woodstock, dividing pattern into sections according to shape of casting to facilitate removal of pattern from mold, utilizing knowledge of casting techniques, and using marking and measuring devices, such as scriber, shrink rule, and square. Cuts and shapes parts, using bandsaw, lathe, planer, and router. Fits and fastens parts together to form pattern or section, using glue, nails, dowels and screws. Trims, smooths, and shapes surfaces, using handtools, such as plane, drawknife, chisels, and mallets. Assembles sections and verifies dimensions of complete pattern, using templates, straightedges, calipers, and protractors. Glues fillets along interior angles of pattern. Paints pattern in standard code colors to indicate method of assembly. Shellacs, lacquers, or waxes finished pattern. May construct templates for use in shaping irregular curves in pattern [TEMPLATE MAKER (any industry)]. May construct wooden models. May be designated according to type of pattern constructed as Die-Cast Patternmaker (foundry); Die-Lay-Out Worker (foundry). May repair broken or damaged patterns and correct patterns to compensate for defects in castings and be designated Pattern Setter (foundry).


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## 33706 (Mar 5, 2008)

Thanks, *patron*! Good stuff there! I'm starting to 'get it' now.
*Loren*, thanks for the guidance on values, I have no idea what I'd expect to pay.
Gotta admit, though, a vise 18 inches wide would be one *bad-ass * addition to anyone's workbench!


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## crank49 (Apr 7, 2010)

Most large foundries used to have pattern shops where the patterns were made. I say WERE, because the entire industry has been gutted by the EPA, unions, and competetion with cheap slave labor in places like China. I worked in a foundry for 31 years. I designed and built two pattern shops. There used to be a couple dozen foundries within an hours drive of my home. Now there is one.

Another aspect of making patterns is the pattern maker has to allow for shrinkage of the material that is being cast when it solidifies. In the case of iron, it's about 6%. So, the pattern has to be about 6% larger than the desired finished product.

The pattern also has to be designed to be split in two parts with draft. That is, at least 2 degrees of taper from the parting line so the mold halves, called the cope and drag, can be separated to get the pattern out of the mold.

Pattern makers still have work, but it is now mostly running CNC mills for plastic injection molds. The wood patterns were unique to the metals industry. I have a baby foundry in my basement because I just love the whole process. I now make tiny castings for jewelry.

By the way, that pattern makers vise was sold by Kindt-Collins, a major supplier of pattern making supplies at one time.


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## patron (Apr 2, 2009)

as i understand it

woodworkers
boat builders
pattern makers
piano makers
all the cast iron and gears of old
were made in wood first

(with a 2 deg. 'mold release' angle)
and allowance for any machining
after casting and settling)

today with cnc machines
and computer plans
most 'plugs' (real part for casting)
can be made by the machine
or the metal directly machined
plugs are for making molds 
for multiple pieces
(plastic fiberglass cast metal)

think auto engines
all the parts were made in wood first


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## Loren (May 30, 2008)

I had an Emmert vise for several years. It lacks a quick-action
feature and so there is a lot of cranking involved in changing
vise set up. They are very robust and the large jaws can clamp
and hold items of substantial weight… as patterns were often
made of solid laminated mahogany this would be a factor in
working on them.

For furniture work the vise certainly has a "biggest, baddest,
and most versatile ever made" type of appeal but it really is
not designed for the type of work most woodworkers do.


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## dbray45 (Oct 19, 2010)

I have seen materials other than wood being used for pattern making - wax, bakelite, plastic/epoxy resin, and in a few cases aluminum.

Historically, wood has been the "go to" material for sand casting. Then you get into the tool and die making.


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## ssnvet (Jan 10, 2012)

Patern making can be done on a large scale. When I was an intern at the GM tech. center back in the stone ages, they made 1:1 scale replicas of the auto bodies. When they had the lines exactly as they wanted them, they disassembled the patterns and used them to draft their documents as well as to produce tooling.

CAD has obsoleted most of that process. And now 3D printing rules the day for making fast and accurate blanks for investment casting.


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## 33706 (Mar 5, 2008)

Thanks for all the terrific replies, everyone!
I find it odd that nobody here in LJ has 'fessed up to being a pattern-making artisan. Step up and be counted! What a noble trade, obsolescent as it is now. Your work helped build a nation.
Let's see some more replies, this is a whole other dimension of woodworking that is seldom heard about!


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## dkirtley (Mar 11, 2010)

That looks like a nice vise but can't say I can see $1500 in it. I picked up my knock off at woodcraft for like $250 including shipping.


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## HamS (Nov 10, 2011)

I work at one of the larger brass foundries in the US. Almost all our patterns today are made of aluminum using CNC machines. A wooden pattern would not hold up to as many impressions as are made from a pattern. The wood patterns are made in the specialty foundries where they cast runs of small numbers. The guy that runs our pattern shop still makes a wooden model of a pattern, just because he likes to do it and our owners think it is worth maintaining those skills. I have seen the casting made from a hand made wooden pattern and the same casting made from the CNC machined aluminum and the only way you can tell the difference is if they use really fine green sand, sometimes yo can see the wood grain in the casting. Most castings are made with the coarser sand, becse it is a lot stronger than the very fine sand. I sed to work at a ceramic inslator manfactrer and they had wooden molds around for some of their castings for the hardware for some of the inslators that went into power stations. some of that hardware was two stories tall, and the moild was in three large pieces.

Th


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## Infernal2 (May 20, 2012)

Here's a great picture of a cast…

http://www.backyardmetalcasting.com/lathepics2/lathe6_stockpattern.JPG

The general idea is to make two part casts in green sand (oil impregnated sand) with a sprue (a hole to pour the casting material in). The wooden part is usually covered in a parting material like baby powder so that the the sand doesn't stick to the wooden mold. As Patron noted, most casting these days is done in foam (or wax) so that when the liquid metal is poured in the mold melts and is "lost." As Patron also noted, CNC milling has pushed common casting into something else entirely since there is little need to make wooden patterns.

As to the usefulness of the vice… well, they are pretty nice to have around but most I've seen are VERY expensive. I made do with a swivel axis machinist vice for that kind of work.


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## Dark_Lightning (Nov 20, 2009)

My wife's mother's father was a pattern maker for GM. He made the intake manifold patterns, etc., for early '60s Buicks, iirc. Had some interesting tools in his old garage, anyway. I've been married 31 years, so don't ask me where those tools are, they are long gone. I was a mechanic in those days and wasn't interested in them. My great-grand children will have no clue what some of my tools were used for.

Nowadays, it's CNC and 3D printing (try that with wood, though you could use different color materials to simulate grain, believe it or not). I've used 3D printing (some prefer the terms stereolithography or additive machining) to make first articles out of plastic to verify the design. WAY cheaper than cutting the metal on a first article. Some metal additive machining uses laser sintering to make a usable part, right off the bat. Wild stuff.


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## cjwillie (Sep 6, 2011)

I worked in a pattern shop for about six months before getting into cabinetmaking. Cabinet work is much easier and not held to as tight tolerances as patternmaking. I found patternmaking boring and not something that motivated me. It was working with wood but not woodworking.


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## wapakfred (Jul 29, 2011)

A local foundry had a fire in it's pattern storage building. The FD had a hell of a time putting it out…imagine the Texas A&M bonefire times 3 or 4, and a small town FD trying to fight it. It was quite a loss for the foundry, a lot of those patterns where still in use.


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## MedicKen (Dec 2, 2008)

Here is a video that kind of explains and shows some of the pattern making process towards the end. Patternmakers had to be the most skilled as their "patterns" were used to make parts for various machines.


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## tierraverde (Dec 1, 2009)

poopie,
"Worlds fastest Indian" 
My favorite movie. Everyone should see this classic.


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## CAH (Mar 26, 2012)

This is great, reminscing about foundries and patterns and draft angles. All the skills involved in building these. Of course the high volume production used metal patterns because of wear. The patternmakers also made the coreboxes with different shrink and draft requirements. Some very knowledgeable people have weighed in on this topic.
I would think a home foundry would have to be restricted to non-ferrous metals, copper-based, aluminum, zinc. Don't fool with magnesium, too risky.
CAH


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## 33706 (Mar 5, 2008)

Thanks again to everyone for the great replies! *MedicKen & Infernal2*: Wow, great videos! I wonder how many people were influenced by that movie and made their career choice because of it? * Jim C*: Casting aluminum pistons in your own garage… who'd a thunk it?
I'm glad that this site has now shed some light on a lesser-known aspect of woodworking. I find it odd that such a field that requires such a high degree of skill results in woodenwares never seen by the public to enjoy, or even display or use in their home. Pattern-makers must indeed be a special breed of animal! Hats off to these unsung heroes.


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## bobsmyuncle (Jan 12, 2011)

A good friend of mine is a retired patternmaker. He showed me a few of the things he worked on and they were incredible.

First off, they have to use "shrink rules" so that the model is slightly oversized so when the metal cools, the resulting casting is of the appropriate size. Each metal has its own coefficient of contraction and thus its own shrink rule.

Given the casting, you have to figure out the "part lines" so that your patterns can be withdrawn from the sand and often match a mating pattern on the opposite side of its void.

Because of this, almost all patterns have a slight taper to them, i.e., nothing is square. Convex edges have a leather "fillet" added so there is no sharp corner to create a stress point.

In addition to allowing for shrinkage, you also had to allow thickness for the specified amount of paint to protect the pattern.

Some patterns also have "core boxes" to create internal voids, and all need sprues to allow additional metal reservoirs to draw in the metal as it cooled.

One of the nicest patterns that I saw he made, just before he retired, was for an industrial mixer. It was a helix into the middle, then a cross piece and the other half a helix on the other side. It was made for a pair of stainless steel augers that when run in one direction drew the mixture (food products) to the center, and when reversed, drew it to the ends of the tube. And they had to be machined to tolerances that would mesh perfectly between the pair. And there was a hollow all the way through the tubes to allow for coolant or heating solutions. Oh, and the size of the pattern was about the size of a full-sized van. I think it took of crew about six months to build it.


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## 33706 (Mar 5, 2008)

Thanks, bobsmyuncle! I always wondered how a router bit got the name 'core box' and now I know! I know of 'sprues' only from plastics injection molding, dies with multiple cavities sometimes had hot runners with cooled tooling. Wish I could see that enormous mixer mold!


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## helluvawreck (Jul 21, 2010)

There used to be an old foundry here. It finally closed down about 15 years ago. It was a rough old building and toward the end just a bunch of old timers were there. A lot of old castings were left laying around outside and after it was shut down it was interesting to wander around what was left of it.

helluvawreck aka Charles
http://woodworkingexpo.wordpress.com


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## Sylvain (Jul 23, 2011)

Another trade which has disapeared with the advent of computerisation: 
large wooden printing blocks used mainly in advertising.

http://woodtype.org/about/tour


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## ITnerd (Apr 14, 2011)

Hey PK, I'm a little late to the party, but this is one of my favorite stories about patternmaking.

A nice show of the tools, and a little story about the men themselves. Courtesy of Patrick Leach, and his shamefully addictive stanley website.

Happy Sunday morning to you all,


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## oldnovice (Mar 7, 2009)

Here is a video of the Ferrari factory that shows the foundry, the pattern they use, and the actual casting process, in other words, the making of the engine. They "fine tune" each of the patterns before they use them. There are a lot of Ferrari factory videos available on YouTube if you are interested!

Ferrari foundry

Unfortuntely, it is subtitled!


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## crank49 (Apr 7, 2010)

At my former employer they have high speed high pressure green sand molding that uses aluminum or steel patterns. Green sand is sand mixed with water and bentonite clay. The mold making machine uses a huge hydraulic ram to compress the sand clay maiture into a mold. This machine makes a mold every 6 seconds, 24 hours a day, 5 to 6 days a week.

The wood patterns are used for parts that may only produce a few dozens or hundreds of castings and then wont be used again till maybe 5 to 7 years later when those parts are worn out. The wood patterns are used in what is called a nobake mold. This is a chemically bonded sand. A silica sand, phenolic resin, sulfonic acid mixture that is vibrated into the mold to compact it and then sets up in about 15 minutes. The patterns can only get extracted after this set up time; otherwise the mold would collapse.

The oil sand someone mentioned earlier is sand mixed with an oil like Tung oil. It sets up to a semi solid state on its own and then, after the pattern is drawn, it gets baked in an oven to dry the oil and make a solid mold. This process is normally only used for processes where some flexibility is needed in the mold due to complex shapes and difficult draws; like for pump impellors for instance.


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## 33706 (Mar 5, 2008)

I hope there are others who are enjoying the great replies here as much as I do. These personal stories are GOLD! speaking in behalf of myself and many others, there is no limit to the appreciation we have when others share a little slice of their life, as these stories about life well-lived as a woodworking pattern maker.


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## oldnovice (Mar 7, 2009)

poopiekat*

When I was in school, too many years ago to count on your fingers and toes, I took a course in foundry and made my very first patterns. The professor told us that imperfections in the pattern would show in the casting so we should prepare our patterns with care and attention to detail.

I took his information seriously and when he inspected my pattern we prepared the sand mold. The following day we cast the molds with aluminum and were waiting for the casting to cool when there was an unscheduled fire drill so we had to leave the buildings. Upon returning to class there was not enough time to empty our molds so we left the classroom until the next day.

The following day we came to class and the prof told us that our molds had been emptied but, unfortunately, the castings had all been melted down by the foundry clean up crew that evening as they had no idea our class had been cut short!

That was my first experience with pattern making and casting in a foundry! The remainder of the experience was well worth the time and I still have a deep respect for foundry work whether it be jewelry or engine blocks!


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## shipwright (Sep 27, 2010)

I have made some patterns in by boatbuilding stage. Rather than fill this thread with photos, I posted some here a project.


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