How to Buy a Good Saw Blade
How to Buy a Good Saw Blade
“How to buy a good saw blade?” is a question that comes up frequently. It is especially difficult because saw blades are pretty much performance only. There’s really very little you can do to a saw blade without affecting its performance.
Following is a comparison I did with three different saw blades. It is in no way a complete comparison but it does give some simple tools to use when examining saw blades.
Analysis of Three Saw Blades
The top blade is a custom-built blade from Carbide Processors sold under the name World’s Best. The metal blade is a Japanese import from a company with an excellent name in tools. The bottom blade is a Chinese import from a company that is eight years old.
Size of saw tips
The first and easiest thing to check is the size of the carbide saw tips. Tungsten carbide is a very expensive material so the use of a larger tip generally means a higher quality saw blade. A bigger saw tip benefits the user two principal ways. A bigger, thicker saw tip means more sharpenings and thus more time between retipping. Even with the most modern carbide grades nothing takes the place of sheer mass for durability. A bigger piece of carbide is much more likely to survive both routine cutting and the occasional unpleasant surprise such as a nail buried in the board.
- Saw tip sizes on comparison blades
As you can see from the chart, the custom saw blade had far and away the largest tips followed by the Chinese saw blade and then the Japanese saw blade.
- Analysis of brazing on three saw blades
The next thing to check is the quality of the brazing. What you look for is regular, consistent brazing. Both the top blade, the custom blade, and the bottom blade, the Chinese blade, have beautifully consistent brazing. The metal blade, the Japanese blade, shows variations in the brazing from tip to tip. You can readily see this by the differences in the yellow globs of braze alloy behind the tips.
If we look closer at the brazing we can see several things. In all three pictures you can see the saw tip on the right and the steel saw shoulder on the left. In between you can see a ridge of the braze alloy. What happens is that the tip is brazed on a little oversize so they can be ground down to sharpen it and make it the exact size. This leaves the flat ridge behind the saw tip because they grind down a little of the braze alloy when they grind the carbide.
If you look at the left-hand in the middle pictures you will see a little bit of color on the steel to the left of the saw tip. This is very good. It means that the steel was very clean and very receptive to the braze alloy. A wee bit of the braze alloy actually wicked its way out onto the steel. This is a very good indicator that the pocket was properly prepared so the braze joint is very, very strong.
By comparison the right picture shows that the braze alloy bulged up behind the tip and did not flow out onto the steel. This may still be a good braze joint but this steel could have been cleaner when the brazing was done.
There is a black circle in the middle of the braze alloy in the right picture. There is Zinc in the braze alloy. Zinc has a low boiling point. If the braze alloy gets too hot the zinc boils out and leaves these holes. A couple of small holes are okay. This is a large hole. Again, this may be a very good braze joint but the quality could be a little tighter.
If you look at the right-hand picture you can see a ready/orange line just to the left of the tip. There are two ways to braze saw tips. One way is to use solid braze alloy and the other is to use a sandwich of braze alloy/copper/braze alloy. Both ways can give excellent brazes.
Traditionally the sandwich was used for very large parts to compensate for the difference in coefficients of expansion between tungsten carbide and steel. Typically the part had to be at least a half inch in at least one dimension and usually larger before the sandwich was used. When silver was around five dollars an ounce this sandwich material was much more expensive than solid braze alloy due to fabrication costs. Now that silver is at $38 an ounce this sandwich is a much less expensive material.
Again, both materials can give excellent braze quality.
The World’s Best, custom-built, saw blade retails for $101.99
The Japanese import with the famous name retails for $91.00
The unknown Chinese import retails for $59.00
There are many, many other factors that go into judging a saw blade. Using just the very basic comparisons above the best saw blade is the World’s Best, custom-built saw blade.
It is also the most expensive and has a lead time of 2 to 4 weeks since each one is built to order.
The best blade overall, again using just a very simple tests above, is the relatively new Chinese import that no one’s ever heard of.
Quite honestly, I was shocked once I start examining the Japanese blade. I’ve been familiar with this brand name for at least a decade and always had a great deal of respect for it. This is not what I expected to see.
If you are inspecting sawblades and see a saw tip with lines in it don’t get too excited. Typically, new saws are oiled prevent them from rusting and the oil does a wonderful job of attracting fibers.
On the left is a picture of a saw tip with cloth or paper fibers on it. This is perfectly acceptable as the fibers just wipe off. On the right is a picture of a badly cracked saw tip. Something went horribly wrong during the grinding; maybe a clogged wheel or too much pressure. In any case the saw tip was hot enough that it cracked in several places. Incidentally, this is a saw tip on a saw blade I bought over the Internet. It is from one of the most famous and most expensive saw blade manufacturers in the country.
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