Abhishal Kochhal

Maker · Engineer · Author

AbhishalKochhal

Applying to study mechanical engineering

I’m a high-school senior in San Jose, and I design and build precision machines. I built my CoreXY 3D printer, Boaz, twice: once the way the hobby builds them, and once the way a machine shop would. Then I wrote the book on the difference.

Explore Boaz Résumé The book on Amazon
boaz_cad_v7 · final assembly
CAD render of the Boaz CoreXY 3D printer: an aluminum extrusion frame with gusset plates, a belted Z axis and an enclosure.
Boaz, the final CAD assembly after the rebuild.

Exhibit · October 3, 2026

Boaz at Maker Faire Rocklin 2026

“Boaz: A DIY 3D Printer, Built Twice” was accepted as an exhibit at Maker Faire Rocklin, held at Sierra College in Rocklin, California on October 3, 2026. I showed the machine running, with a poster on how I built and measured it.

Photos and videos The exhibit page The poster

Boaz in numbers

Measured, including the parts that fell short

Eight criteria were fixed before the build. The rebuilt machine met seven.

16:00
Speed Benchy, first attempt

A standard test boat, printed in 16 minutes against a 20-minute target.

7 of 8
Preset criteria met

Y-axis acceleration fell short of its target.

1,000
Part PETG contract

About 50 boxes a day. A $300 store-bought machine beside it made 60.

< 0.001 in
Pressed-idler runout

Wobble on every pulley kept: about 25 thousandths of a millimeter.

The story

I had a working printer, and rebuilt it anyway

The short version of a project I began in 2023, for readers who do not build machines.

2023 · Start

A machine nobody sold

I wanted a fast printer I could customize, for less than the established kits cost. I designed my own and paid for it at about $100 a month.

2024 · First build

It worked, with flaws

The first machine printed about 200 toys for a charity drive. It also needed a person to adjust every first layer, and it could not print a threaded lid that fit.

Diagnosis

A measurement problem

I traced each flaw to a cause: a pin 0.04 mm too small, a bed warped by 1.6 mm, rails set with printed jigs. Machine shops solved these a century ago.

2026 · Rebuild

Same design, built properly

I rebuilt it with a dial indicator and a granite block, tested it against eight targets set in advance, and published the results, including the two that went against me.

Mechanical engineering

The subject I want to study, met on the shop bench

Boaz and the robotics years touched most of a first mechanical engineering course list. I want the theory behind what I have already had to do by hand.

Design

CAD from a master sketch

I drew Boaz in Onshape and Fusion 360. The rebuilt motion system grows from one 2D master sketch, with its sheet-metal profiles extruded from it.

Fits and tolerances

Hundredths of a millimeter

I traced a first-build flaw to a pin 0.04 mm undersize. The rebuild's 0.05 mm interference on a 5 mm pin is a heavy press that yields the aluminum around the hole.

Metrology

Measured, not assumed

I set the rebuild with a dial indicator and granite, held pulley runout under 0.025 mm, and mapped the bed at ten thousand points.

Dynamics

Mass and vibration

I designed the toolhead around its center of mass and measured resonance to set input shaping, for a toolhead that reverses tens of times a second in infill.

Manufacturing

From one part to a thousand

I laser-cut sheet metal and CNC-milled parts for FRC Team 604, and ran a 1,000-part PETG order on a machine I built.

Testing

Criteria set in advance

I fixed eight pass-or-fail targets before the rebuild, then reported the one it missed and the production race it lost.

Portrait of Abhishal Kochhal

About

I build the machine, then measure it

I’m Abhishal Kochhal, a twelfth-grade student at Leland High School in San Jose, California, and I expect to graduate in 2027. I have designed and sold 3D-printed drone parts and printer components since 2022, trading as MRCAT-51 Drone Parts on eBay and Etsy, and I draw in Onshape and Fusion 360.

I built competition robots with Leland's FRC Team 604 from 2023 to 2025, where I led design of the loading subsystem, and with a FIRST LEGO League team at Bret Harte before that. I am a certified drone pilot, I belong to Leland's RC plane club, and I show my work at local maker faires.

Boaz is my own machine, built twice. Building Boaz is my account of both builds. I am applying to university to study mechanical engineering.

  • BasedSan Jose, California
  • SchoolLeland High School, class of 2027
  • Applying forMechanical engineering
  • Focus3D printing, motion systems, precision assembly, metrology
  • ToolsOnshape, Fusion 360, Klipper, dial indicator and granite
  • InterestsMechanical design, precision manufacturing, robotics
bed_mesh · 100 × 100 · 70 °C
A 100 by 100 point eddy-probe mesh of the rebuilt bed, almost uniformly flat.
The rebuilt bed: 0 to 0.2 mm across ten thousand points. The first build's bed spanned 1.6 mm.

Featured project

Boaz: one machine, built twice

Hobby printers inherit their construction habits from RepRap, which set out to build a machine that could copy itself, not one that could hold a tolerance. Boaz tests whether five practices from machine-tool building carry over. Both builds share one design and most of their parts, so the first build is the control.

  • Design began in October 2023; the first print came off the machine in 2024.
  • The first build failed at least four of its eight criteria. The failures were specific enough to diagnose.
  • The rebuild met seven, and lost a production race to a $300 machine. Both results are reported.
Read the project Papers, poster and slides

Library

Five ways into the same project

From a 29-chapter book down to a nine-slide deck. Every number in the shorter pieces comes from the book.

01 · Book

Building Boaz

An engineering guide to the effective DIY 3D printer: theory, failures, and the fixes that worked.

On Amazon → 02 · Research paper

Machine-tool practice on a DIY printer

A 13-page preprint, submitted for review to IEEE ISEC ’27: design, failure analysis and rebuild, measured against eight preset criteria.

Read the preprint → 03 · Article

A DIY printer built like a machine tool

A magazine-style feature for makers, in four-page and two-page cuts.

Open the PDFs → 04 · Poster

Conference poster

Motivation, method, results and the eleven rules on one A0 sheet.

View the poster → 05 · Slides

Nine-slide deck

The short version: why, what broke, what changed, and the numbers.

View the deck → 06 · Résumé

Experience and skills

Education, activities, robotics and technical skills on one printable page.

Open the résumé →

Achievements

What I have made, led and earned

Author

Published a book

I wrote Building Boaz: An Engineering Guide to the Effective DIY 3D Printer, 29 chapters, available on Amazon.

Engineering

Designed and rebuilt Boaz

A CoreXY printer of my own design. The rebuild met seven of the eight criteria set before construction.

Production

Printed for real customers

I printed about 1,000 PETG pet-medicine boxes for a medical organization in Iraq, and roughly 200 toys for a charity drive.

Robotics

Design lead, FRC Team 604

I led the loading subsystem at Leland from 2023 to 2025. The team won multiple awards at regional and national competitions and had a competitive run leading up to the world championships (5th place).

Sponsorship

Backed by Duet3D

I received $150 of electronics from Duet3D in sponsorship of the Boaz project.

Business

MRCAT-51 Drone Parts

I have designed and sold custom 3D-printed drone parts and printer components on eBay and Etsy since February 2022.

Certification

Certified drone pilot

I am certified through Pilot Institute, and a member of Leland's RC Plane Club and Habitable World Club.

Academics

3.8 GPA

I earned an Honorable Mention on the National Spanish Exam, and my CAASPP and NWEA scores are above grade level.

Exhibitor

Maker Faire Rocklin 2026

I exhibited “Boaz: A DIY 3D Printer, Built Twice”, with a poster and a live demonstration, at Maker Faire Rocklin, October 2026. Photos and videos.

Path so far

Six years of building things

  1. FIRST LEGO League, Bret Harte

    I designed and built competition robots with a middle-school team.

  2. MRCAT-51 Drone Parts

    I started selling my own 3D-printed parts online.

  3. FRC Team 604, Leland High School

    Design lead for the loading subsystem; laser-cut sheet metal and CNC-milled parts.

  4. Boaz design begins

    The first print came off the machine in 2024.

  5. Computer technology intern

    St. Basil the Great Greek Orthodox Church, San Jose: digitized and organized records, and worked on the website.

  6. Rebuild, measurement and the book

    Boaz rebuilt and measured against its criteria; Building Boaz published.

  7. Maker Faire Rocklin

    Boaz accepted as an exhibit, with a poster and a live demonstration, at Sierra College.

“Precision is not a part you buy. It is a procedure you follow.” From the Boaz slide deck
runout_check · granite
A dial indicator reading the face of a pressed idler, with the assembly squared between granite blocks.
Checking a pressed idler for runout against granite.

Contact

Questions about the work?

About Boaz, the book, the paper, or anything else on this site, write to amkochhal@gmail.com.

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