How to Sight a Gutter and Adjust Your Gutter Machine to Run Correctly

Machine service & troubleshooting
Katie Bowles|May 4, 2022

Knowing how to sight a gutter so you can adjust your seamless gutter machine to produce gutters without any defects or curvature is critical for correct installation, customer satisfaction, and keeping the machine in tolerance. It also gives you a deeper look into how your gutter machine is running upon the start of a project, find any adjustments you may need to make, and allows you to effectively work with Service department if you encounter issues.

At New Tech Machinery (NTM), our experienced Service Department helps clients troubleshoot problems with their machines and walks them through making adjustments to their machines. However, it’s critical to know when your machine is out of tolerance and what adjustments to make to produce a straight gutter.

In this article, we’ll discuss:

  • Why knowing how to sight a gutter is important for keeping your seamless gutter machine in proper tolerance and for quality installation
  • What issues to look for when sighting a finished gutter
  • The right way to sight a piece of seamless gutter
  • How to properly adjust your NTM seamless gutter machine if a gutter isn’t coming out straight

Why Is Knowing How to Sight a Gutter Important?

man operating a combo gutter machine in trailer

It’s good practice to learn how to sight a finished seamless gutter to understand what an improperly formed gutter looks like and how to fix it. It’s also important to know this procedure to effectively communicate with the Service department if there’s a problem with your gutter machine.

Practice sighting a gutter on every first run of the day to ensure your gutter machine is in proper adjustment and you’re producing straight gutters. You’ll also need to sight a gutter anytime you change the gutter size (like changing a combo machine from 5″ to 6″), switch to a new type of material, or use a new coil (even if it’s the same type of material). 

If you don’t make sure that your gutter is coming out straight, it can lead to a few issues, including:

  • It affects the pitch of the gutter ⁠— If your gutter is running uphill or downhill, it can cause high or low spots in the gutter and cause the gutter system not to drain correctly. 
  • Improper redirection of water — Gutters going uphill, downhill, away from the house, or into the house aren’t redirecting water properly. They can also cause the water to stagnate and potentially pull the gutter away from the house.
  • Your portable gutter machine could crash — If you don’t regularly sight your gutter, running material through your machine while it’s out of adjustment could crash the machine.
  • Oil canning — Installing a gutter that’s running away or into the house, or that has uphill or downhill, could lead to oil canning.
  • It doesn’t look great on your customer’s home — Aside from the above issues it can cause to your home or gutter machine, gutters that aren’t straight don’t look good.

Download the complete roof panel and gutter machine maintenance schedule

What to Look for When Sighting a Gutter

examples of what uphill gutter, downhill gutter, into the house, and away from the house gutters

Knowing a few industry-used terms when sighting a gutter will help you talk to the New Tech Machinery Service department so they can better direct you on how to correctly and safely adjust your gutter machine over the phone.

Let’s talk about some of the standard terms used when sighting a gutter or describing how your gutter is coming out of your seamless gutter machine when talking to a Service Technician.

The Gutter Is Running Uphill

Imagine that the gutter has a slight bow upward towards the sky when looking at the bottom of your gutter from one end. This means your gutter is “running uphill,” where the ends of the gutter are higher at either end than they are in the center. 

The Gutter Is Running Downhill

When looking at the bottom of your gutter from one end, you can tell it’s “running downhill” when you see the gutter is bowing slightly downward. Downhill is when the ends of the gutter are lower than the center of the gutter.

The Gutter Is Running Away From the House

When looking straight at a gutter, if it seems like the center of the gutter looks touches the fascia but the ends do not, that means it’s “running away from the house.” 

The Gutter Is Running Into the House

Alternatively, if you see the ends of the gutter bowing towards the house and the center is pulled away from the fascia, that means it’s “running into the house.”

You may even experience some of these issues simultaneously with your gutter machine, typically uphill and into the house or downhill and away from the house. 

If you encounter any of these situations when sighting your gutter, it’s crucial to understand how to make the necessary adjustments to your seamless gutter machine. If you’re unsure of the correct adjustments to make on your gutter machine, or if you have any questions as you’re adjusting your machine, contact New Tech Machinery first.

How to Properly Sight a Seamless Gutter

NTM service technician sighting a piece of gutter

To properly sight a seamless gutter on any NTM gutter machine, first, you’ll run material so that it forms a gutter 7′ to 8′ long. Hold the finished gutter in your hands and look down at it. Keep the opposite end on a level surface on the ground with the face of the gutter (the part with the decorative edge) in your right hand and the back of the gutter (the part that goes against the fascia) in your left hand. 

Remember: Small adjustments go a long way! Before adjusting anything on your gutter machine, measure the positions of each component, write them down, and mark all adjusting bolts before moving them. That way, you know where each piece started, so you can go back to that spot if your adjustments make things worse or if you turn something the wrong way.

Next, follow these steps to check the straightness of your gutter:

  • Look down towards the top of the gutter to check the finished gutter for straightness.
  • Look down all the faces of the finished gutter for any curvature. If you notice the gutter sides bowing left or right, it could mean running into or away from the house. If you look straight down the gutter and see that the bottom is curving up or down, that may mean that the gutter has uphill or downhill.
  • If you notice any curvature in your gutter, adjust the blue or green station on the swing shaft of your gutter machine as needed until the gutter comes out straight. Adjusting the green station helps fix gutters running into or away from the building edge. Adjusting the blue station helps fix uphill or downhill gutters.
  • Measure across the top of the gutter to ensure that it’s the correct width that you want to produce. Doing so ensures that your hangers will fit properly and won’t pull the gutter away from the house or deflect the gutter when installed.
  • Double-check that the gutter’s face, bottom, and back are smooth and free from any waviness or oil canning. Also, ensure that the inside bottom of the gutter doesn’t have any dimpling.

How to Adjust a Seamless Gutter Machine to Produce Straight Gutters

diagram of the gutter box assembly

As it applies to any NTM seamless gutter machine, adjusting the swing shaft on your machine can help solve any above issues. The gutter box near the exit end of your gutter machine completes the main shape of the gutter profile and allows for easy adjustments. Ensuring it is in proper tolerance enables the machine to form a straight and level gutter. 

On the gutter box assembly, there are three primary adjustment areas:

  • Entry mount adjustment – This adjustment is factory set and should not be changed.
  • Exit mount adjustment – This adjustment assembly controls the uphill and downhill effect and the gutter’s width.
  • Swing shaft adjustment – This assembly applies pressure to the head of the gutter, causing the forming head of the gutter to go into the house or away from the house. Adjusting this will help straighten your gutter.

How to Adjust a Seamless Gutter Machine: Uphill or Downhill Gutters

To fix uphill or downhill of your gutter, you’ll adjust the vertical axis, which is color-coded blue, on the exit mount adjustment assembly. By raising or lowering the box and rollers inside appropriately, you’ll control the uphill or downhill effect of the gutter. 

  1. Loosen the “F” bolt on top of the box assembly.
  2. Turn the “E” bolt CLOCKWISE to raise the box to adjust for an uphill gutter.
  3. Turn the “E” bolt COUNTERCLOCKWISE to lower it to adjust for a downhill gutter. 
  4. Retighten the “F” bolts.

Watch this tutorial video on adjusting the blue station to fix uphill or downhill gutters on your MACH II™ 5″/6″ Combo Machine, or refer to your machine manual in the Gutter Box Adjustments section.

How to Adjust a Seamless Gutter Machine: Gutters Going Into the House or Away From the House 

To fix gutters going into or away from the house, you’ll need to adjust the swing shaft assembly, color-coded green. This assembly applies pressure to the head of the gutter and is the most common adjustment used to straighten the gutter. To straighten your gutter:

  1. Loosen the two “J” bolts on top of the gutter box assembly enough so that the swing shaft assembly can slide.
  2. Turn the adjustment bolt “K” to move the swing shaft assembly.
  3. To fix gutters going away from the house, turn bolt “K” CLOCKWISE a quarter of a turn at a time.
  4. To fix gutters going into the house, turn bolt “K” COUNTERCLOCKWISE a quarter of a turn at a time.
  5. After making an adjustment, run an 8′ long piece of gutter to check its straightness.
  6. If needed, adjust further by repeating the steps above, and be sure to check the gutter lip before completing any adjustments.
  7. While holding the swing shaft adjustment assembly so bolt “K” is against the box assembly, retighten bolts “J.” 

Check out this video on adjusting the green station to fix gutters going away or into the house. You can also check the Gutter Box Adjustments section of your machine manual for written instructions.

Final Thoughts

gutter coming out of end of gutter machine

Making it a part of your routine to check the straightness of your gutters can ensure that you’re installing quality products, that your machine remains in alignment, and that you avoid any more significant potential issues in the future.


  • Always sight a gutter at the start of every run, and also when performing a changeover to a new gutter size, switching types of material, or when you run a new coil.
  • Understand the terms used when sighting a gutter, like “downhill/uphill” or “into/away from the house” so that you can effectively talk to an NTM Service Technician.
  • Small adjustments go a long way when adjusting your machine based on how the gutter came out of your machine. Make a note of your starting point and your progress so you are able to set your machine back to the way it was before.
  • Double-check all sides of the gutter for straightness, dimpling, or other imperfections before running another piece.

New Tech Machinery’s Service Department is available over the phone for troubleshooting assistance or to talk you through how to make the correct adjustments to your gutter machine. Contact a Service Technician, Monday through Friday, 7:00 AM to 3:30 PM MST, with any questions.

Need help with your machine? Visit the NTM Service & Support Center