Crazy Wooden Workout Machine Inspired by Connect Four

Furniture & Lighting Home Woodworking Workshop
Crazy Wooden Workout Machine Inspired by Connect Four


An interesting tip came floating through the digital ether to land in my inbox a couple weeks ago. I’ve been looking at this wooden contraption full of hinges, pulleys, weights, and grips, trying to figure out how best to describe it. This is a home made workout machine, designed and used by an engineer named Matthew Beresford, and it is really pretty incredible. I’ll let Beresford tell you what it is.

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What did you build?

I developed a concept exerciser made mostly out of wood components. With my system, a person can perform both the butterfly and lat pull down exercises and transition between them with minimal effort.

Why did you build it?

I have always been fascinated with weight training machine design. I had a bench press weight set at home that did not come with a butterfly attachment. I was able to get a steady supply of material (scrap wood) from a local source, so I decided to construct a workout routine by stacking columns of weight (instead of accumulating weight plates) in a moving grid generating even or uneven resistance.

I also consider what I made could be a benefit to the Maker community since it does: (1) represent an extension of DIY culture (i.e. advancing individual knowledge, learning new skills, and the feeling of satisfaction that comes from building from your own ideas), (2) how to apply simple machine principles (i.e. pulleys, leverage, and weight resistance) in making a project and, (3) woodworking (which allows a person to be creative and is a wonderful medium for artistic expression) activities in a positive manner.

My main reasons for assembling the exerciser were: (1) personal need and (2) promoting a positive message within the Maker universe (I hope to inspire others to think up their own homemade exerciser arrangement and use what I made as a primary design reference).

What makes it special?

What makes my work distinctive concerns the butterfly arms and the weight container.

Butterfly Attachment

The detached butterfly arms
The detached butterfly arms

The butterfly attachment arms can be quick disconnected and re-attached as a 1 piece item. The jackknife motion that the butterfly arms travel in as they flex forward and return to their starting position is another possible example of originality as compared with others in the industry.

Weight Grid (my son’s Connect Four game was one design inspiration for this)

The weight grid, inspired by the game Connect Four
The weight grid, inspired by the game Connect Four

Unlike traditional stacked weight plate machines, a person is allowed to make a variety of pattern configurations on the grid (X,□, /,\, —, etc.) by using cup shaped ballast inserts.

An individual can position the weights in organized horizontal/vertical patterns or treat them more as random free weights in the load basket. My exerciser uses a container (it itself weighs about 25 lbs.) that can hold up to 24 cylinder inserts (instead of using weight plates) to change the amount of force a user exerts for each repetition.

In their current form my system’s weight supplements are ½ pound each (about 2 ¾ inches long and 1 14/16 inches in diameter): making them easy to manage. If solid roll stock were used in their construction they would be estimated to each be in the 2 ½ to 2 ¾ pound range.

When not in use, weights can be placed in the grid container for compact storage.

At one point I contemplated that one could focus on certain muscle groups in the upper body by placing inserts on my exerciser’s weight grid, in particular patterns (X,□, /,\, —, etc.). This may have been beneficial for those in need of rehabilitation (through segregation of muscle areas that needed treatment) in such disciplines as Kinesiology or Physical Therapy.

Unfortunately, after consulting with two professionals in Kinesiology (2 individuals with PhD’s who specialize in Biomechanics) they informed me that such results were not a practical outcome of my model. From their perspective, I created more of a novelty than a treatment tool.

After recalling the different gyms I have been in, and conducting an online review, I have not seen others using a grid arrangement as a way for people to move mass around as I had done.

What did you learn building it?

  • I learned that I have a lot of respect for anyone who innovates or invents.
  • I learned how much dedication you have to have in order to innovate while working full time and supporting a family.
  • I learned how much ideas on paper can change drastically when fabricated physically.
  • I learned that making a change to one area of a system can influence results within the same dynamic in ways one may or may not be able to predict.
  • Most butterfly attachment arms generally run on a formal tracking system physically linked to a main unit. I learned how challenging it was to develop removable butterfly arms that hang and pivot in mid air.
  • The exerciser’s weight box glides up and down on a vertical guide pathway. I researched various ways of how to make that container move vertically on the frame while keeping the friction between the connectors on the weight box and the conduit surface it to a minimum. This was in order to make the climb and drop motion as fluid and controlled as possible.

I considered using various sprays, waxes, greases, lacquers, covers, wheels, and ball bearings to accomplish that. I ended up sanding the inside of the track extensively and then mounted furniture mover inserts to the weight box on its four corners for a successful connection. I learned here how important considering a variety of ideas provides solution to a problem.

If I were to start over and do things again?

I probably would have done some more background research in the areas of Fluid Dynamics or Biomechanics and asked for more design help from a Cabinet Maker and a Carpenter I knew as I developed everything.

If I had consulted with people in those areas, the time it took to design and redesign the overall unit as well as the weight box might not have taken so long.

Where can someone find more information?

Here is my YouTube link for more information.

A gallery of pictures illustrating my efforts can also be found at Pinterest.



About Matthew Beresford:

I am married, 43 years old, and I have 1 son (who is 11).

I found the exerciser project challenging. I spent about 3 ½ years working on it part time (nights/weekends) and I have no formal training or education in any crafting or design related disciplines.

Some of my outside interests are fishing, bike riding, weight training, spending time with family, and working on home improvements.

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I get ridiculously excited seeing people make things. I just want to revel in the creativity I see in makers. My favorite thing in the world is sharing a maker's story. find me at

View more articles by Caleb Kraft


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