The 433A millwright exam, explained

• Four options (A to D) on every question, exactly one right. No trick questions, but the wrong options are written to look right to someone who half-knows the answer.
• Written in English or French.

How the 135 questions are split

The questions follow the trade’s six blocks (the Red Seal “major work activities”). The bigger the block, the more of your score it decides.

Three kinds of questions

• Knowledge and recall (30 to 40%): definitions, facts and principles.
• Procedure and application (40 to 50%): what you do, in what order, in a given situation.
• Critical thinking (20 to 30%): reading a problem, working out the cause or the number.

Most of the exam asks you to apply what you know, not just remember it.

What you’re given on the day

A formula sheet and a list of acronyms come with the exam. The formulas cover the trade’s usual calculations: area of a circle, force from pressure and area, sling stress (up to three legs), shims at a foot (G × A ÷ B), drill rpm from cutting speed, surface speed, thermal expansion, wire rope clips and their spacing, and the working load limit of 6 × 19 wire rope. You still need to know when to use each one.

How to get your 433A in Ontario

433A is Ontario’s code for the Industrial Mechanic (Millwright) trade. Your 433A ticket, or licence, is the Certificate of Qualification Skilled Trades Ontario issues when you pass this exam, and as it’s the Red Seal exam, it comes with a Red Seal endorsement, recognized across Canada. The trade is voluntary in Ontario, so you can work without it, but it’s the proof you’re fully qualified.

1. Finish your apprenticeship: 8,000 hours, 7,280 on the job and 720 in school over three levels. Then send in your completion form to get your Certificate of Apprenticeship. If you learned the trade elsewhere, a Trade Equivalency Assessment can approve you to write instead.
2. Pay the exam fee in your Skilled Trades Ontario Portal account.
3. You’ll get an Authorization to Test letter by email.
4. Book a date, time and place in the Portal’s Examination section. Exams run at Skilled Trades Ontario sites and at colleges across the province.
5. Pass with 70% or better: that’s your 433A.

If you don’t pass

You can rewrite after 30 days, paying the fee again. Your results show a percentage for each block: put them into the free retake plan to see which blocks have the most marks to win back, and spend those 30 days on them.

How to get ready in 30 days

Give each block time in line with its share of the exam, and keep the last week for what you’re weakest at.

Read the explanation for every question, the ones you got right too: why the wrong options are wrong is where the exam’s traps are. Work the calculations on paper with only the formula sheet. The pass mark is 70%, but aim for 80% in practice so a bad day still passes.