How to Fold Engineering Drawings: A Step-by-Step Guide

What You’ll Need

Engineering drawing(s) – clean and dry
A flat, clean work surface (table or desk)
Optional: a bone folder or ruler to crease sharp folds
Optional: paper clips or binder clips to hold folded sets together

Step-by-Step

Identify the target size. Determine the final folded size you need – typically A4 (210×297 mm) or US Letter (8.5×11 in). Check if your office or client has a specific standard (e.g., ANSI or ISO).
Lay the drawing face down. Place the print on the table with the printed side down so that the title block (usually in the bottom right corner) ends up on top when folded. This ensures the title block is visible without unfolding.
Fold the right edge inward. Take the right edge of the drawing and fold it toward the left, aligning it with the left edge of the final size. For an A4 fold, this means bringing the right edge to about 210 mm from the left. Crease firmly.
Fold the left edge inward. Now fold the left edge (which is now the original left plus the folded flap) toward the right, so that the width matches the final size. You should now have a long strip that is the correct width but still the original height.
Fold the bottom edge upward. With the strip lying vertically, fold the bottom edge up to the top, aligning it with the top edge of the final size. For A4, that means folding up to 297 mm from the top. Crease.
Continue folding the remaining length. If the drawing is longer than the final height, fold the bottom edge up again, accordion-style, until the entire strip is folded to the final height. Keep the folds parallel and crisp.
Fold the top edge down. Finally, fold the top edge down over the last fold, so that the title block (which was originally at the bottom right) is now on top and visible. This is the standard “fan” fold.
Press and flatten. Use a bone folder or your hand to press all creases flat. If you have multiple drawings, stack them and clip them together.

Common Mistakes

Folding with the print side up – This hides the title block and can cause the printed side to crack at the creases.
Incorrect first fold – If the first fold is not aligned to the final width, all subsequent folds will be off, and the drawing won’t fit in a file.
Uneven accordion folds – When the drawing is very long, the folds may drift, making the final stack lopsided.
Skipping the crease – Not pressing firmly results in a bulky, messy fold that doesn’t lay flat.

Tips

Always fold on a hard, flat surface – a soft table can make creases less sharp.
Use a ruler as a straightedge to guide the first fold for perfect alignment.
If you fold many drawings, make a cardboard template of the final size to check each fold.
Store folded drawings vertically in a filing cabinet to save space and keep them flat.
For large sets, fold each drawing the same way so the title blocks align when stacked.

Troubleshooting

The drawing doesn’t fit the file after folding. Unfold and measure the final size. Adjust the first fold to be slightly smaller (e.g., 1-2 mm) to allow for paper thickness.
The title block ends up on the bottom. You started with the print side up. Unfold and start over with the print side down.
The folds are crooked. Unfold and refold using a ruler to align edges exactly. Take your time on the first fold – it sets the pattern.
The paper tears at the crease. This happens if the paper is old or brittle. Use a bone folder to gently crease, and avoid pressing too hard. If the tear is severe, you may need a new print.
The drawing is too thick to fold neatly. For blueprints on heavy paper, consider rolling instead of folding, or use a larger final size.

Frequently Asked Questions

What is the standard size for folded engineering drawings?

The most common is A4 (210×297 mm) in metric countries, and US Letter (8.5×11 in) in North America. Some companies use A3 or Legal size for larger prints.

Why is the title block always on top?

So you can identify the drawing without unfolding it. The title block contains the drawing number, revision, and other key info – it’s meant to be visible at a glance.

Can I fold a drawing that is already laminated?

Yes, but laminated paper is thicker and may not fold as flat. Use a bone folder to crease firmly, and be aware that the laminate may crack at the folds over time.

How do I fold a drawing that is wider than it is tall?

Follow the same steps, but start by folding the long sides inward to reduce the width, then fold the height. The principle is always to reduce both dimensions to the target size.

Is there a difference between folding for filing and folding for mailing?

Filing typically uses a fan fold with the title block on top. For mailing, you might use a simpler C-fold (fold in thirds) to fit a standard envelope, but the title block may not be visible.

What do I do if my drawing is too large to fold on a standard desk?

Work on the floor or a large table. You can also fold in sections, but ensure the first fold is accurate. For very large prints, consider rolling them and storing in a tube instead.

Sources: ISO 216. Menus and buttons can differ slightly by version. Spotted something out of date? Tell us.