The Internet Craftsmanship Museum Presents:

Ingvar Dahlberg

Added to museum: 5/31/07

Model engineering that includes a complete 1910 Mercer T35 Raceabout in miniature

Ingvar Dahlberg (Click on this or any other photo to see a larger image.)

Though Ingvar Dahlberg has created other models, he has become best know in model engineering circles for his 1910 Mercer that is complete in every detail. (Click on photo to view a larger image.) Photo: Stefan Svensson

An Introduction from Ingvar Dahlberg

I have made a model of a car that is one of the most famous U.S. cars from the early twentieth century. I have made a 40 % size (2/5) scale model of a U.S. road racer called the “Mercer T35 Raceabout” from the year 1910.

In order to tell you something about my background I taught mathematics, physics and chemistry for 40 years. I have taken a keen interest in mechanics since I was a boy and I have been making models of internal combustion engines all my life. I started early and made my first engine, a 2-stroke, 14 cc engine 61 years ago when I was just fourteen years old. All my pupils studying physics have seen it run on the teacher's desk.

Ten years ago I happened to set my eyes on a picture of the Mercer Raceabout in one of my son’s motoring books and immediately decided to build a model of it. I have taken more than 500 pictures of the making of the model. On the last page of my website you will also find pictures of my ¼-scale 9-cylinder Wright J-5 Radial Engine and a 50-pound, 200 cc Supercharged V8-Engine.

Mr. Dahlberg with the unpainted Mercer nearly completed. Photo: Rolf Bergbom.

My Mercer model is well known in Europe as I have brought my models to five large exhibitions in England  Donington, London, Harrogate and twice to Bristol and even to Sinsheim in Germany.

A lot of text and pictures have been published in magazines like Model Engineer and Engineering in Miniature (England) and in Maschinen Im Modellbau (Germany). Last year the U.S. magazine Model Engine Builder published a centerfold picture together with the story behind the car.

Ingvar Dahlberg, Mariestad, Sweden

In additon to what he wrote in his introductory e-mail to the museum, it should be noted that Mr. Dahlberg also produced and sold kits and components for teaching elementary electronics in Swedish schools for 30 years and is still in business doing that. This has allowed him to build up the workshop that makes his other wonderful projects possible. In it he has built a Stuart 4B steam engine, a "Sea Lion" IC engine designed by Edgar Westbury (designer of the museum's Seal engine project) and a Wright J-5 9-cylinder radial engine. He and his son also completed a thorough restoration of a classic sports car--a 1949 MG-TC. His work on the full-size MG influenced much of how he took on the task of building the model Mercer as both are based on a fundamentally simple design.

—Craig Libuse

Building the Mercer

After seeing a  photo of the 1910 Mercer in one of his son's books on vintage cars, Ingvar Dahlberg was immediately inspired to make one himself. The 70 kg miniature automobile took five years to make, because other than the tires and spark plugs, he had to make every part himself. As is often the case in such a venture, starting with an initial part of piece of material dictates the scale of the project. In this case, Ingvar was able to locate several bicycle tires at a local shop that closely matched the look of the original tires used by Mercer and were 12.5" in diameter. The size of these tires decided the 40% scale of the model, which turned out to be a 106 cm wheelbase and 56 cm track.

Since no plans of the car could be found, he started with photos in the book and the size of the tires, drew two circles of the proper size and center distance on a piece of paper and proceeded to draw a side view of the car in the size he would build it. He again worked from photos to draw other views of the car, scaling items from the pictures until he had views of all sides drawn.

Since he already had six tires, he decided to start the construction process with the wheels. Patterns were made and the rims were cast in light alloy. The wooden spokes (different front and rear because of the brakes) were then cut from birch using a radius mill and rotary table. He then continued on to weld up the frame and cast the front axel. He then built the springs, radiator, gearbox, rear differential and fenders. The car was now taking shape.

The bodywork and dash came next. The brass running lights, dash instruments (non-functional), brake levers and other detail parts required many different types of machining operations. For example, the headlamp rim required a metal spinning process to produce. The dash is made from mahogany. The brass rear license plate is etched with the words "California Horseless Wagon."

The clutch and gear case were designed around a radio control servo that actuates the clutch to operate the one forward and one reverse gear. Though not a duplicate of the original internally, this was done to make the car functional in demonstrations. The differential case was based on the case of an electric motor found in a junkyard, and, not trusting his gear cutting skills at the time, the close-fitting internal gears were purchased rather than custom made. The end pieces and bushings were turned and the driveline was complete.

An October, 1994 issue of Srictly IC magazine had plans for a 1/6 scale Simplex engine that closely resembled the original engine used in the Mercer. No detailed original engine plans were found that showed the internal workings, so this was decided to be the best alternative. The original engine had a massive 5 liter displacement, which would have meant a 320 cc scale model. Not looking for any land speed records with the model, Ingvar decided to reduce that to 120 cc. The crankshaft started as a 10 Kg billet of steel that was band-sawed to shape and was eventually whittled down to 800 grams after many operations in the lathe and mill. Patterns were made for the upper and lower crankcase plus side cover, the parts were cast and then machined in the mill.

Casting the engine block presented a problem. The Mercer did not have a separate cylinder head—it was made in one piece. It required the design and building of a special 3-part molding flask, which he did in his own workshop. He then took it to the foundry where the pour was done. The core was made from eleven sand cast pieces glued together. After a few initial problems, block castings number 4 and 5 came out well and the machining was begun. Valves were turned from discarded valves from a tank engine, as they provided a proper mix of materials for the job and were also easy to turn in the lathe.

Steel and iron parts were bead-blasted and then taken to a plant near his home where they were coated with a zinc-iron galvanizing which was so far the best  rust-proofing treatment. This process applied to 85 parts involved in dipping in several baths and electroplating solutions alongside thousands of parts being done for the 1998 Volvo S70 engines. Yet it was not at all the rust proofing treatment that was of interest. When returning after the zinc-iron-bath all parts were dipped for three minutes in a chromium-bath. Coming up from this bath all parts had taken on a deep and very smooth black colour. Afterwards all parts were sprayed with a two-component clear lacquer to a very good finish.

Based again on some help from Robert Washburn and articles from Strictly IC magazine, Ingvar constructed a camshaft grinder and ground his cams from SIS 2940-03 (Swedish Standard) material because it could be heat treated without distortion. The engine is a twin cam design, but Ingvar ground a third cam to be able to show along with the car for people interested in seeing how the engine was made. Construction of the cylinder blocks took one whole year, but then the engine was finally able to be assembled. A dual ignition system was developed when the original Hall type system proved inadequate, and the engine was first successfully run in May, 2001.

Mr. Dahlberg did all the paint spraying himself, starting with an etching primer for the aluminum parts. It took about three weeks to do the preliminary painting tasks, but for the final finish he took the parts to a local professional painting company that had a dust-free booth where the final finish was applied. That took just 25 minutes but resulted in a perfect finish. The finished car is quite large at 5.5 feet long and weighs 150 pounds.

The car was then fully assembled after painting. Mr. Dahlberg had never actually seen a real Mercer in person until relatively recently. An American car collector who purchased a castle in  England had learned of Ingvar's model through a fellow collector in Sweden. He brought a Mercer to England to race in vintage races. In May, 2004 Ingvar was invited down to go for a ride through the English countryside in a real, restored Mercer similar to his, which was quite a thrill. In any case, he now has his own version of the car of his dreams that he can start up and enjoy at any time. At present, plans call for partial disassembly of the model so the engine can go back into the machine shop for some improvements that will make it run better.

Ingvar Dahlberg's Workshop

Ingvar Dahlberg's well-equipped and well-lit shop is seen from several angles. The smaller thumbnails include Ingvar in the photos along with the Mercer. (Click on any photo to view a larger image.) Photos: Stefan Svensson

Other projects by Ingvar Dahlberg

The Mercer is certainly not the only thing Mr. Dahlberg has ever built. Obviously the skills to accomplish the many and varied tasks required to make a complete car were developed over the years on other projects.

He has built a 1/4 scale Wright J-5 9-cylinder radial aircraft engine, a Westbury "Sea Lion" 4-cylinder and is nearing completion on a 200 cc supercharged V8 engine. He is a member of a club called "The Engine Builders" who have their annual informal meeting at the Swedish Gliding School at Ålleberg near the city of Falköping. Less of a club and more of a collection of people interested in building engines, they get together when they can for the fun of running and talking about engines.

More information and photos of the Mercer project as it was being built can be found on Mr. Dahlberg's personal web site at He has kindly given us permission to reproduce many of those photos on this site.

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Here are some photos of Mr. Dahlberg's Mercer and other projects:

(Click on any photo to view a larger image.)

Since he started by purchasing the six tires, Ingvar decided to build the wheels first. he made a pattern and cast the six rims in light-alloy. The wooden spokes seen here were made from birch wood. Because the Mercer has no front brakes, the spokes are different on front and rear wheels. The spokes were made using a radius mill on a rotary table. The final photo shows the wheel rims being drilled to accept the spokes.
Milling the front axle, which has been cast from light alloy. Note the completed front spring sitting on the right side of the table.
Milling the frame. The frame is made from 20 mm x 40 mm steel tubing. The forward part was hammered over a 20 mm piece of profiled steel and then welded to the front part of the frame. (Front springs have been assembled in this photo.)
The completed front axel with spring, steering arm and spindle.
Front and rear axels are in place and for the first time the frame sits on its wheels and tires.
The frame starts to receive other components, such as the radiator, rear axel banjo (differential), running boards and rear fenders.
The left photo shows some of the spun brass components and an assembled side lamp. The second photo shows the rear lamp and number plate holder are made from brass.
A heavy form was turned from metal and then the headlamps were formed over it by the process of spinning. Turning the form generated about a wheelbarrow full of chips. Spinning the 1.5 mm thick brass plate would work harden it, and it had to be heated several times to anneal it during the process. Other photos show the headlamp rings and reflectors being spun and then the final headlight assemblies.
The radiator frame and tanks are made from brass.
The brass headlamps and radiator have been attached to the front of the Mercer.
The mahogany plywood dash is fitted with the (non-functional) instruments. The instrument faces were drawn full size and then reduced in a photo copier.
A detail photo shows the handbrake and gear lever mechanism.
The gearbox was designed to use a radio control servo to operate the mechanism to change from forward to reverse. Only one ratio was used, as the car was only to be operated at slow speed.
The finished gearbox with cover in place.
The clutch utilizes a strip of phosphor-bronze wrapped around a wheel. This is operated by a landing gear servo. When stretched, the strip softly stops the wheel, and power from the engine is transferred to the forward/reverse part of the gearbox. The gear lever is operated by an ordinary servo motor mechanism.
The differential housing was made from part of an electric motor case found in a junk yard. The ends were turned from aluminum and the axel bushings from bronze. The beveled gears were purchased rather than being hand made, as Ingvar did not yet trust his machining abilities in the area of cutting gears for such a critical task.
Construction of the crankshaft was started by cutting a 10 kg (22 lb) piece of steel bar with the band saw. It was then surfaced with a fly cutter. The next step was to use a surface grinder from two 90° angles, and then, after marking it was returned to the bandsaw.
The journals of the crankshaft are turned in the lathe.
The finished crankshaft. What started as a 10 kg billet now weighs only 800 grams.
Teeth for the starter gear are cut on the flywheel. The next photo shows the massive flywheel installed on the end of the crankshaft.
Making the pattern for the crankcase was an interesting job. Once cast, Ingvar could begin the process of milling them. The upper and lower crankcase halves and the gear cover were then assembled and attached to the ground baseplate on top of two parallel blocks and fixed in the lathe. After arboring for the crankshaft, he then fixed the gearcover and arbored the front bearing seat. The upper two parallel blocks were then removed so he could bore the holes for the camshafts. The photo shows the process for boring the holes for the distributor.
Articles from Strictly IC magazine led to the construction of a camshaft grinder. Ingvar attached it to his tool grinder and made the camshafts from SIS 2940-03 steel—a Swedish standard material made for nitro-carbonization that allows hardening of the camshafts without distortion.
Here a grinding operation is being performed one of the camshafts. The engine requires two camshafts, but Ingvar made a third so that he could show it along with the car.
  This section includes a number of photos of the process to cast the cylinders. Ingvar notes that it took one full year to get from the first patterns you see to the finished, machined cylinders. Once the cylinders were cast in metal the sprues were trimmed off and the part was ready for machining.
Here the holes in the cylinder casting are bored on the mill (left) and lathe (right).
When you machine your valves from a larger valve, engineering decisions about the proper alloy of metal have already been made for you--you know you are working with the right stuff. On the right are the original valves from a tank engine Ingvar started with, and on the left is a Mercer valve being turned from one of the larger valves.
The engine block (with early distributor) prior to and during assembly.
The cylinders are ready to be bolted to the block.
The intake manifold, carburetor and air cleaner.
The finished engine is seen from several angles. The engine was first successfully test run in May, 2001. In the photo of the right side of the engine you can see the original distributor before it was modified for better performance.
Here, the rear axel assembly is attached to the car and wheels are in place.
Final assembly of the car is begun.
Here, holes for the engine mounting bracket are being drilled.
The assembled car prior to painting. The raw metal body parts were taken to a plating facility and given an electroplated finish to protect them. The parts were processed alongside production Volvo parts for a modern car, which made for an interesting contrast.
The engine compartment before and after the bodywork was painted. Those with sharp eyes will note the difference between the early distributor design on the left and the more sophisticated double magnet version that ended up being the final mechanism shown in the right-hand photo.
Each part was disassembled again and painted using automotive quality paint in a professional, dust-free spray booth.
More details of the final assembly.
The completed car looks ready to drive.

Professional photographer Stefan Svensson composed this photo from a photo of the model and a photo of Ingvar dressed in vintage driving gear with his son holding the scarf out as if it were flying in the wind. The images were blended in PhotoShop with Ingvar's foot on the throttle and hand on the steering wheel. Now we all know what it would look like to see Ingvar actually behind the wheel and driving his Mercer at speed—the perfect conclusion to his 5-year dream.

The second photo is no trick. Ingvar finally got to take a ride in a real Mercer several years after building the model.

Other projects by Ingvar Dahlberg

Ingvar Dahlberg was off to a good start building this engine at age 14. It made the cover of the Aug/Sept 1992 issue of Strictly IC magazine in the . About the engine he says: "

“I was just 14 years old when I built this 14.3 cc two-stroke engine. It was made with simple methods. The crank-case was cast in a flowerpot with sand. The pattern was as simple as possible. Light-metal from discarded pistons were melted with the aid of a gas-burner and poured into the mould. The petrol tank was made of a nickel-plated baking powder pot.

The engine used to be equipped with a standard contact breaker, a   3/8" spark-plug and a  standard coil for full-size cars.  Nowadays the engine is run with a glow-plug. All my pupils during 40 years of teaching Physics have seen it run on the teacher's desk when studying IC-engines.”

This Sea Lion engine was designed by Edward T. Westbury and built by Ingvar Dahlberg. it is somewhat similar to the Seal engine the Foundation is working on. Ingvar's model made the cover of Engineering in Miniature magazine in May, 1992.
This 1949 MG TC was restored by Ingvar and his son. The design of the post-war MG follows very basic automotive principles and is not all that different from the 1910 Mercer in many respects. Working on this car gave Ingvar the confidence to try building an entire car (in miniature) from scratch.
  This 200 cc supercharged V8 was very close to being completed when photographed in January, 2005. It weighs 25 kg (55 lb).
  This 1/4 scale model of a Wright J5 9-cylinder aircraft engine displaces 130 cc. The model was designed by the late Karl-Erik Olsryd, and complete drawings have been published in the Swedish magazine Allt om Hobby and the US magazine Strictly IC. The cylinder heads were supplied by Karl-Erik. Casting sets and bearings are now also available for others wishing to build this engine.


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