Industry
Fact-checked

At AboutMechanics, we're committed to delivering accurate, trustworthy information. Our expert-authored content is rigorously fact-checked and sourced from credible authorities. Discover how we uphold the highest standards in providing you with reliable knowledge.

Learn more...

What is a Keyhole Saw?

C. Ausbrooks
C. Ausbrooks

A keyhole saw is a precision cutting tool with a long, thin blade used primarily for cutting tight curves and small holes in soft wood, plastic or drywall. Other names for the tool include alligator saw, drywall saw and compass saw. Keyhole saws are often used to create openings for pipes and electrical wiring, and for making small incisions that cannot be made with drills, electric saws or auger bits due to size constraints.

The blade of the keyhole saw is attached to a wooden, iron or plastic handle, and blades vary widely in length, width and number of teeth. Most keyhole saw blades are 5 to 15 inches (12.7 to 38.1 centimeters) in length, with 5 to 20 teeth per inch. Keyhole saws may be fixed or retractable, depending on how the blade attaches to the handle.

A keyhole saw is often used to cut drywall for construction projects.
A keyhole saw is often used to cut drywall for construction projects.

A retractable keyhole saw commonly features an iron handle, and various blades are attached to the handle with screws. The blade can also be retracted into the handle to protect it from flexing or damage if it is obstructed during use. Fixed keyhole saws are less expensive and perform the same task, but they lack the ability to retract.

In the construction trade, the keyhole saw has experienced modification to make it easier and more efficient to use for various tasks. Keyhole saw blades with a sharpened tip are available, and these blades are gently pushed through drywall or soft wood. This process negates the need for using an electric drill to create the initial hole, saving both time and power.

Using a keyhole saw requires first drilling a starter hole into the wall and then inserting the blade. The saw is moved forward and back slowly by hand, and the blade cuts on the back stroke. If a sharpened-tip blade is being used, a starter hole is unnecessary and the blade is simply inserted into the wall and used to cut away the desired portion. Applying excess pressure on the blade while cutting should be avoided, as this can cause the blade to become stuck or jammed in the wall.

Older keyhole saws require more maintenance than newer models, as the older versions typically have crosscut teeth that need to be manually sharpened by a craftsman. More contemporary models of the saw feature replaceable blades that can be removed when they become dull or damaged. Newer fixed blade keyhole saws are often replaced completely when necessary, as this usually costs less than having the blade repaired.

Discussion Comments

JimmyT

Can you use a keyhole saw to cut PVC pipe? I know the real purpose of a keyhole saw is to fit into small areas and cut out holes, but I have a piece of pipe that I need cut, but don't have anything else to cut it with.

I have a hacksaw, but the blade on it is too dull to really do anything. I don't think the keyhole saw has a plastic cutting blade on it, but it seems like it might work. I just want to make sure I'm not going to ruin the blade by using it.

cardsfan27

If you are a someone who likes to do home improvement projects, a drywall saw is a must in the toolbox. At the time I bought mine, it was more of an impulse buy, but I've used it several times since.

My family used to own some rental houses, and I ended up being the person who had to do repairs when someone moved out. If I ever had to replace sections of drywall, the keyhole saw could cut out holes for light switches and outlets in a flash.

kentuckycat

@titans62 - I'm pretty sure you can get a metal saw blade for a keyhole saw. I'm not positive how much one would cost, but I can't see them being extremely expensive. If you got one, I'm sure the edge wouldn't be all that smooth. Keyhole saws tend to be pretty rough cutting saws.

If you have or can get a reciprocating saw, that might be a better option. I know they make reciprocating saw blades for metal, and it would give a fairly smooth cut. I don't know how much cutting you're needing to do, but metal shears would be another option. They wouldn't have any problem cutting aluminum. You can buy special shears for cutting rounded edges, too.

titans62

Do they make keyhole saws for cutting metal? I am working on a project, and I need some sort of saw that I can use to cut some holes in a piece of sheet metal. The metal is aluminum if that matters. I have looked at the hardware store in town, but it is small, and they didn't have one. I don't want to spend a trip to a bigger store if these don't exist.

I have a drywall keyhole saw, but the teeth on it aren't the right size or type to be cutting through metal. If they do make them, how much do they usually cost? Also, how smooth is the edge they leave? Obviously, I'd rather not have sharp jagged edges left over.

Post your comments
Login:
Forgot password?
Register:
    • A keyhole saw is often used to cut drywall for construction projects.
      By: Greg Pickens
      A keyhole saw is often used to cut drywall for construction projects.