7 1/4 Inch Blade With a 7 Inch Saw

I was given this 7 inch Sears Craftsman saw. Can I use it with a 7 1/4 inch blade?

This project required only a 7 1/4 inch circular saw blade and a heavy duty work glove.

This is the data plate on the saw. As you can see, it is Model Number 315.27802. I purchased one of these saws late in 1968, but my wife made me sell it when I bought a 10 inch radial arm saw she also encouraged me to buy. In time I did not feel too badly because circular saws came to be standardized with blades 7 1/4 inches in diameter, but this saw was made for a 7 inch blade. Those have not been easy to find. But, you may see one of these saws on sites like eBay. This is the second one I have seen in recent years. An older friend is downsizing and asked me to take some things he will never use. This saw probably belonged to his father.

I still have a 7 inch blade from about 50 years ago. For the sake of comparison I laid it over the 7 1/4 inch blade my friend’s father had on the saw. The arbor holes align. Not much is needed to make the larger blade fit.

The photo shows the places where the saw teeth on a 7 1/4 inch blade come into contact with the retractable blade guard. There are only two, and they are not deep. (The last person to use this saw had put the 7 1/4 inch blade on incorrectly. A thick retaining washer was on the inner side of the blade, but belongs on the outer side of the blade. That caused the blade to be farther out from the saw motor than it should be. The blade was also more likely to slip while spinning.)

The blade guard may not be completely concentric with the saw arbor. When the blade guard is fully released the 7 1/4 inch blade did not scrape on the blade guard. But, as I manually retracted the blade guard, it began to bind more and more with teeth on the blade. I wore a heavy glove on my other hand and moved the blade back and forth to remove soft aluminum from the inside of the blade guard. Then I retracted the blade guard a bit more and repeated the process. Eventually, I had the blade guard fully retracted and the teeth no longer scraped on the inner surface of the blade guard.

I want to put a carbide tipped blade on this saw. I will test its clearance by hand to see if teeth from it bind and repeat this process as necessary.

I already have a couple of uses for this saw. I liked the original one I bought in 1968 very much and look forward to getting some good use from this new-to-me saw. Anyone who has one of these saws need not fear that they cannot get a blade suitable for it.

The process I used works in part because the blade guard is soft aluminum. If you found a 7 inch saw with a steel blade guard, it may not be as adaptable.