Hydraulic Pump Mount

Design problem: Create a mount for a hydraulic pump to actuate a dump trailer

I had been wanting to learn to use our CNC plasma cutter for a while and I had never really welded anything. Then, a friend requested my help for this project... This gave me the perfect opportunity to learn a bit more about both of these skills. He asked if I could create a mounting system to attach a hydraulic pump and accompanying gas-powered engine to the tongue of his dump trailer. He needed it to be strong enough to hold these two moderately heavy mechanisms on to the trailer tongue and for it to be able to withstand being driven around very bumpy terrain.

Dump trailer tongue. Mounting location is the large rectangle with bolts sticking up.

Prototyping at a distance

This project had a very different feel than most things I set out to work on because the goal involved building something mechanical for a friend that lived beyond my normal driving distance. This meant the concept and all accompanying measurements and decisions had to be made remotely. I have to admit, it was quite a challenge to fully understand what I was being asked to build and how it would all come together. But after many text messages with photos and a video call over Zoom, I had enough infomation to mock up a design in CAD.

Pump tank width

Pump top face plate

Pump tank height

Engine on pump coupler 1

Engine on pump coupler 2

Bottom of engine

Overhead view of the top mounting surface for the engine above the pump mounting surface.

Finalizing the plan

After much back and forth / clarifying the concept of what I was trying to build and how the various parts needed to be oriented, we had a Zoom call where we looked at the initial 3D model in Fusion 360 and discussed changes. There were a variety of changes that were suggested to make the welded mount stronger and easier to build.

First CAD Prototype

This first prototype was overly complicated and had multiple sections of angle iron between the base plate, the pump shoulder plate, and the top engine plate. We decided to simplify the design and ended up with a much stronger and a mount that was easier to build.

After we settled on those structural changes, the next thing to confirm was the spacing between the pump mounting shoulder plate and the engine mounting plate, so they would be spaced properly. That led to many conversations about the best way to measure and design the mounting holes for both mechanical components.

Showing the mounting holes on the bottom of the engine

These images represent some of the back and forth conversations we had about how to get the components to fit in the right places.

Corresponding sketch of mounting holes

Not physically being able to see any of these parts or how they were supposed to be oriented to one another was a big challenge.

CAD Sketch for engine mounting holes

When I first created this sketch, the geometry led the bottom left mounting hole to be improperly placed too close to the large center circle. After much back and forth, I deleted the 2.5" spacing from right edge and made the 3 mounting holes equally offset from the 6.5” large hole.

Finalizing the CAD

Once we got the spacing for the engine mounting holes set, we moved on to create the location for the actuating level to run the hydraulic pump. I wanted to save room on the top mounting surface to try to plasma cut some kind of text / logo. We settled on TEMPEST CASTLE as the text that should go on top. The text is a stencil style text that was created in Adobe Illustrator and then exported as a DXF to use on the plasma cutter.

Plasma Cutting

This project was a great opportunity for me to refresh my skills and understanding around using the CNC plasma cutter. For this project, I exported each element that was intended to be plasma cut as a DXF and brought all of those outlines into Adobe Illustrator to layout the design to prepare for plasma cutting. Then I brought the assembled layout into VCarve which is a tool I am used to using for creating wood inlay designs for use on our CNC routers.

For plasma cutting, we basically tell Vcarve the thickness of the steel we are planning use and create toolpaths for both the outside and inside contours we want to cut. For some of the finer details, like the TEMPEST CASTLE lettering, we add to adjust the entry and exit points for each cut to lead in or out of the design to avoid making unwanted marks in the metal. VCarve has a node editing mode were you can select the desired entry/exit point and this makes it fairly easy to control where each cut starts/finishes.

Check out this short video of the plasma cutter working on cutting some of the parts for this project.

Learning to Weld

Welding is something I had basically no experience with prior to this project. This project was exciting to take on because I knew I would get a chance to get some practice welding something substantial. Getting all of the steel pieces aligned and in position to be welded was a fun challenge to add to the learning of process of welding. The 3D model was great for visualizing the overall design of the final product and it had an additional benefit of making it fairly easy to create alignment jigs out of plywood to help get each piece of angle iron placed where it needed to go. I design the jigs in the model and exported them to be milled on the CNC router. They worked really well and helped keep pieces where the needed to be when I was focusing on my welding.

Overall, the welding went fairly smoothly and it was really fun to get to work on welding something of this size. The metal pieces were thick and it gave me some great practice.

3D Model with welding-alignment jigs

CNC milled welding-alignment jigs in action!

Main pump and engine mount structure welding.

Finish mount before powder coating

Powder Coating

The final step for this project was putting a powder coating finish on the entire welded structure. The challenge for this part of the project was the size and weight of the mount. Our powder coating oven is only about the size of a convection toaster oven, so this wasn't even close to fitting. Since the temperature that powder coating ovens need to reach is only around 275 F degrees, I thought it might work to use a pottery kiln. I wanted to try to get powder coating material on as much of the part as possible, so I came up with a system to hand the part upside down by the mounting holes in the bottom angle iron.

Powder coat application

Powder coat is applied by using a charged sprayer connected to compressed air. Opposing charges are applied to the sprayer and the metal which causes the powder coat material to be attracted to the metal.

Preparing to powder coat

The entire hanging system was moved into the kiln and suspended upside down during heating

Result (Round 1)

Unfortunately the powder coating looked best on the bottom side, because it was applied while the mount was hanging upside down. Fortunately, powder coating can be applied multiple times...

Result (Round 2)

We were disappointed with the powder coating on the top surface of the mount. Since that was the most visible area, we decided to experiment with adding a second coat of powder coating material. This time we coated the mount in the normal orientation which made it much easier to apply the powder to the top surface. The powder seemed to have no trouble adhering to the surface for this second coat! In the future, we plan to experiment with thicker applications of the powder coat material by adding more powder for each application...

After second coat was added

Ready to deliver

Final Assembly

I drove the finished mount to our friend and over the next few weeks, he began to test fit, adjust, and mount the components onto the mount. There were several places were holes needed to be re-drilled to get a more precise fit, but overall the spacing was spot on and the coupler between the the engine and pump lined up nicely!

Coupler between engine and pump

Front view of pump and engine installed on mount

Side view of actuating lever for hydraulic pump with engine mounted above the pump. Ready to install on trailer

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