How To Series ... Bending Brass
Bending brass is actually quite easy once you learn a few things. So let's get in to it!
To control where a fold will be, manufacturers will put a Fold or Bend line into the design. This line is a small slot that has been etched half-way through the brass sheet at the point of the bend.

Normally, you fold into a bend line when the bend is less than 135 degrees. Notice how bend into the line creates a nice corner and the metal pinches together at the bend line.

For bends of 135 to 180 degrees, you must bend against the bend line otherwise the two pieces of metal can not lay flat at the bend due to pinching each other. Other times, you bend outward for better positioning of the piece or better display. The ladder on the Caboose Build is bent outward to expose and "pop out" the rungs.

Image by David K. Smith

Bending Tool #1
Using a sheet metal brake to bend brass will ensure that long straight pieces are bent to the same angle along the entire length of the bend. The brake shown was purchased at a train show for $30. The drawback of a brake is that you must bend the whole piece to the same angle at the same time.

Bending Tool #2
Create a home-made inexpensive brake using a ruler from a combination square. The ruler will hold the brass piece in place while the brass is bent to the desired angle. Again, this will ensure that long straight pieces are bent to the same angle along the entire length of the bend. The drawback of this method is still is that you must bend the whole piece to the same angle at the same time.

A plus is when using the thin edge ( standing up) to hold the sheet. This will allow a thin "U" channel bend not possible using other methods.

Bending Tool #3
My personal favorite method and how I bend 85% of medium & large pieces. This is a hand seamer available from Home Depot & Lowes for $20-$25 US and is used by metal roofsmiths and A/C duct workers to bend metal. This seamer has been slightly modified by a machinist using an end mill to ensure the ends are totally flat. I was able to get the first one machined for $7. Now the the jaw ends meet precisely.

The bass item can now be held and the jaws adjusted so they are right at the bend line. Use you hand or a metal ruler to bend the metal. Metal widths larger than the seamer can still be bent by bending section in small angles until the entire width is at the desired angle.

How to Bend A Car Side

To bend a car side, the best tool is the seamer. The wide flat jaw allows for quick and accurate work.

Place the part into the seamer up to the bend lines

In this case, I need to bed the sides 180 degrees so I will be bending AWAY from the bend line. I start by making a 90 degree bend.

Remove from the seamer

Once the bend has been started, it is easy to complete the bend by hand. Use the seamer to squash the bent joint so the sides will be in direct contact.

How to Bend A Square / Rectangle

This is one of the hardest things for people to do, yet it is actually one of the easiest. The trick, don't try to bend every corner to 90 degrees!!

I am going to use a square bridge column as an example. In this case, the column is made of five sides. The extra side is actually a tab to provide a surface to secure another side to it. The principle is the same. Since the tab is the smallest and hardest to control, it will be first and it will be bent to the full 90 degrees.

Four sides, three bends and the first and second bend will be bent only 45 degrees. Not 90 degrees!!

Once a bend has been started, it will follow where it started. If you bent all the sides to 90 degrees, you would not be able to get to the last bend. So 45 degrees is the magic number for bends 1 and 2.

The third bend for the last side IS bent to 90 degrees. The first two at 45 allow plenty of room to make the final bend.

This is how our column should look. As said before, once bent, the brass will follow that bend.

So now we are going to complete the column by finishing the bends by hand. Do Not Rush This! Take your time and coax the sides into place. Going easy, I have never had a column fail (once I learned the secret).


Have other bending problems, drop me a line and we will help.

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Note: This document is preliminary. Items contained within may change without notice.
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