“Henry’s D.5” – Dad Builds Elaborate Mini Cat D5 Dozer Replica (Video)

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mini replica Cat D5 dozer with boy in seat beside large Cat wheel loader
Randy Chrisman went all out on Henry's "D.5" mini dozer, which he built to scale using designs of Cat's Next Gen D5 dozer.
Randy Chrisman

When Randy Chrisman decided to build a mini dozer for his 3-year-old son Henry, he admits he got a little obsessed with what eventually became a scaled, working replica of a full-sized Cat D5.

“I don't know what prompted it,” he says. “It got out of control though.”

In building what Chrisman dubbed the “Cat D.5,” he spent about a year off and on studying the designs and specs on Caterpillar’s website of its Next Gen Cat D5 with straight blade. Using 3D modeling software, he designed all the components to scale as similar as possible to the 170-horsepower medium-sized dozer.

“Everything's purpose-built for the dozer,” he says. “I spent many hours just staring at Caterpillar’s website just following the lines.”

(Check out the video at the end of this story of Henry running his D.5.)

Amazing Mini Features

henry and father randy chrisman in unfinished D.5 mini dozer in shopHenry enjoyed visiting the shop while his father built his D.5 mini dozer.Randy ChrismanThe D.5 runs on a 24-horsepower Cat 1.1-liter diesel engine obtained from the local Holt Cat dealership close to Chrisman’s home near Sacramento, California.

The mini dozer has Parker hydraulics. The straight blade is about 50 inches wide, 18 inches tall and 240 pounds. The blade goes up and down and tilts with proportional-controlled hydraulics.

“It’s fully functional,” Chrisman says. “We had to tone the hydrostats down a little bit because it has more pump and weight than it has horsepower, but it will get a full blade of dirt.”

The mini dozer even has a full LCD touchscreen display, where Henry has a tachometer, parking brake control and throttle.  

It has seat and seatbelt switches and indicator lights. “Both the seatbelt and the seat switch both have to be activated before it'll move,” Chrisman says.

The little D.5 has three operation modes to be selected:

  • Remote Only enables the dozer to be operated solely by its belly pack remote control.
  • Local Only enables it to be operated solely by the joysticks and requires the seatbelt and seat switches to first be activated.
  • Blended mode enables Dad to override the joysticks when Henry is in the seat. “When he gets too close to Mom's car, or whatever may happen, we can redirect him.”

It Took Much Longer Than He Expected

3 year old boy on mini dozer frame in shopMore fun than monkey bars! Henry plays on the D.5's frame.Randy ChrismanChrisman and his family run a rice farm, and he has extensive engineering knowledge and experience with computer-aided design, or CAD, as well as building farm equipment.

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He first intended to convert a stand-on mini track loader into a mini dozer, but the price for even a used, beat-up model was way too high. He had already begun crunching numbers and learned that the small Cat engine wasn’t out of budget. So he decided to build it himself with some help from friends.

It took much longer than he expected.

“I was supposed to have it done in November for his 3rd birthday,” he says. “And I missed that window. So then it was Christmas. And then I missed that.

“But we got it pulled off for the end of January.”

He posted his progress and Henry’s excitement about the project on Instagram beginning in January. By then, he had the Cat engine. The CAD drawings were sent off to a local steel supplier for fabrication, and all the parts arrived a couple weeks later.

“It basically showed up in a kit at that point,” he says, “just pallets of processed material.”

The parts were tabbed and notched to be locked into place and welded. With help from friends, it was assembled in three to four days and then sent off for powder-coating.

“When it came back, we bolted it all together, wired it up and plumbed it up,” he says. “That was another five days or so, two to three of us working on it.”

He says it was a comical sight, seeing full-sized guys standing shoulder-to-shoulder with their arms buried in the tiny machine.

Henry was thrilled.

Videos Go Viral

D.5 mini dozer on display at showOn display at an ACMOC showRandy Chrisman“It was fun watching Henry’s face and his eyes light up when he sees it,” his dad says. “He’d crawl on it and look inside it, sitting on it, and we're still building it and putting wires together.”

“He couldn't be patient,” Chrisman adds. “So he had to drive it out of the shop before it was done.”

Videos of Henry operating his new D.5 delighted Chrisman’s Instagram following for the “Henry’s D.5” channel.

One video of him operating in the snow drew close to 3 million views. Two others neared the 2 million mark.

Word spread to the local chapter of the Antique Caterpillar Machinery Owners Club, and father, son and D.5 were invited to show the mini dozer at some events starting in February.

“We just showed up to put it on sight display,” Chrisman says. “People just started flocking around it with cameras.”

They heard lots of positive feedback about the mini dozer – and from plenty of envious adults. Comments such as “the luckiest kid” and “I wished I had this when I was a kid” were often heard.

Henry takes it all in stride. His dad acknowledges that it might be a little soon for him to grasp the full coolness of the dozer. But he definitely knows how to operate it, though he also likes to let Dad run the remote control for him.

“He drives it really well,” Chrisman says. “He can navigate around the yard, around the vehicles. He turns it through the doors in the shop.”

His father hopes the D.5 will be a learning tool for Henry as he grows up.

“We built Henry a dozer,” Chrisman says, “for the hobbies, for life lessons, learning how to fix it when it breaks as he gets older, and learning how to run a blade – just life skills.”

Watch Henry below in his D.5: