As part of our OMT metal-cutting blade comparison, we tested three like-priced blades by Bosch, Imperial Tool, and Dewalt. All three blades are designed to cut metal, but as we’ve seen in the cutting speed and cutting performance discussions, they’re not all evenly matched up.
Here, we’re looking at blade wear and durability.
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To recap, the Bosch blade exhibited best overall cutting speed and best cutting performance, and the Imperial blade is fastest when making the first few cuts. The Dewalt blade seems to have difficulty cutting nails quickly, if at all.
As a reminder, this testing and comparison study was funded by Bosch.
Testing
Each blade was attached to an oscillating multi-tool and a testing fixture was used to cut common 16D nails with constant pressure.
To evaluate durability, we took the best performing blades from each batch and looked at how many cuts they could make (up to 20) until failure. Then we looked at the condition and wear of each blade’s cutting edge.
Blades Tested
Bosch OSC114C – a carbide-toothed metal-cutting blade.
Imperial MMT340 – a TiN-coated bimetal metal-cutting blade.
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Dewalt DWA4209 – a TiN-coated bimetal metal-cutting blade.
A small section of each blade was in contact with the nails being cut.
Blade Failure
Failure is the point at which a blade can no longer successfully cut through a nail. There are a few indications that blade failure has occurred, such as cutting times longer than 20 seconds and a lack of progress, creation of dust instead of chips, and a change in cutting sounds.
Bosch: N/A. The blade discussed here successfully cut through 20 nails with no signs of failure. None of the tested Bosch blades showed any signs of failure after 20 cuts.
Imperial: The blade shown and discussed here and in prior results failed on the 5th nail. Failure is typically observed between the 4th and 10th cuts.
Dewalt: The blade shown below failed on the 2nd nail. Failure is typically observed in the 1st or 2nd cut.
Just to remind you, these tests were done with a special fixture that kept the same region of a blade in engagement for each cut. When operating an oscillating multi-tool in the field, users will usually move the blade from side to side to more evenly wear a blade. Thus, in real-world usage, users should be able to make a greater number of cuts in nails or metal until failure occurs.
Results
Bosch Blade Wear
After making 20 cuts, the Bosch blade shows minimal wear.
The teeth at the action zone are slightly worn, but in this condition the blade in the testing fixture could still cut through a 16D nail in around 8 seconds.
The tops of the teeth, like the sides, are shiny, with the top coating worn away. The dark line over the points of the top edges are shadows due to the lighting used to illuminate the blade for photography. The top and bottom images are of the same blade, but from slightly different angles.
Imperial Blade Wear
This is the Imperial blade after 4 cuts. At this point it produced a lot of heat, sparks, and dust. The fourth cut was made with a cutting time of 10 seconds, and failure occurred during the fifth cut.
Two of the teeth in the action zone are rounded off a little, but I didn’t see the degree of wear that I would have attributed to the slower cutting speeds, sparks, dust, and smoke that were observed.
The front of the blade shows discoloration, due to frictional heating, and damage to the cutting surfaces of the teeth. I was unsure about how to interpret the damage, which was worsened by my waiting to see if the blade could finish cutting through a nail, so I also examined the appearance of a different Imperial blade that failed when cutting its second nail:
There is obvious wear, or damage to the blade’s teeth. I considered that maybe this damage was due to initial impact between blade and nail, but it doesn’t look to be the case. None of the teeth appear to have broken off. They appear to have been worn down.
Since there is greater wear at the center of engagement and less at the leftmost and rightmost areas where the blade contacted the nails during cutting operations, this looks to be wear damage and not impact damage.
Dewalt Blade Wear
This is one of the Dewalt blades, after one cut. Not all of the blades looked this bad after one cut, but they all looked like this – or worse – after failure.
The teeth in the action zone are so rounded over that they almost appear to be filed down. I treated these blades the same as all the others, and made a conscious effort not to release the tool into the nail too quickly so as to avoid broken teeth.
Conclusion
The Bosch blade is the slowest wearing of all three blades. It’s the only blade that can cut 10 or more nails without signs of failure or excessive wearing. Even after making 20 cuts, the Bosch carbide blade shows little signs of wear and no signs of failure.
The Imperial and Dewalt blades wear down and dull a lot quicker and to a more severe degree than the Bosch blade. This is undoubtedly due to the material the teeth are made from – carbide for the Bosch blade, TiN-coated bimetal for the Imperial and Dewalt blades.
As a reminder, all of these blades are comparably priced.
Given what I have seen, the Bosch blade is the most durable and longest lasting.
Table of Contents
Part 1: Comparison Overview
Part 2: Testing & Measurement Tools
Part 3: Test Setup Optimization
Part 4: Final Test Setup
Part 5: Best Cutting Speed
Part 6: Cutting Performance
Part 7: Blade Wear (Current Page)
Disclosure
Bosch funded this comparison testing project. They did not tell us what to say, and made it clear that it was not their intent to influence the results in any way. We were given full control over how the OMT blades were to be tested, and how the results were to be presented.
Daniel
WOW!!! What a huge difference! Bosch definitely has the top spot with blade construction & long life. Thanks for posting the findings/pictures!
Erik Potter
Stuart, your testing and updates continue to impress.
On a minor note, there is a small error to address in:
“The teeth in the action zone are so rounded over that they almost appear to be filed down. I treated these blades the same as all the others, and made a conscious effort to to release the tool into the nail too quickly so as to avoid broken teeth.”
…I’m assuming the intent was “a conscious effort not to release”.
Stuart
Thanks for the correction!
The effort not to impact the blades with nails about to be cut was more a precaution for the Bosch blades, since carbide teeth are so hard they can be brittle.
I have not seen tooth breakage or impact deformation of any of the blades’ teeth, but the bi-metal blades do seem to wear down rapidly compared to the Bosch.
Tyler
I would love to see testing like this for recip saw blades.
Stuart
Unfortunately, I cannot budget the time, effort, or resources to do thorough comparison testing like this without external funding. Maybe this will eventually be possible without external support, but not in the near future.
Bill K
Pretty radical difference in wear/performance. The pictures are worth 1000 words!
Any thoughts or comments on the somewhat unorhtodox tooth shape of the Bosch cutter?
Stuart
I don’t see why the teeth wouldn’t or shouldn’t be symmetrically triangular. This shape makes the teeth stouter, which could help improve breakage resistance, and the symmetry means they cut in both directions. The thinner and angled geometry of the Imperial blades means it’s faster when fresh out of packaging, but the Imperial blades’ teeth dull a lot sooner than Bosch’s.
Lyman Green
I believe the symmetrical geometry of the Bosch teeth is on of the major factors in the longevity of the Bosch blades. Regular saw teeth and file teeth are forward facing and designed to cut in the forward direction only. Pressure on the return stroke results in broken teeth. Jigsaws have an orbital action to prevent this. With this type of saw, pressure is exerted in both directions. The symmetrical teeth cause equal pressure in both directions, necessary to prevent the brittle carbide from breaking. If the other blades used a symmetrical tooth, I’m sure their performance would be much better. How do design engineers miss this sort of thing?
Stuart
Some of Bosch’s blades, such as the OSC118F bi-metal wood and metal-cutting blade feature angled teeth. I think that the tooth shape is tied into the OSC114C blade’s carbide composition. The angled teeth might work a lot better on certain materials and when the teeth aren’t carbide. I’m sure that brands put a lot of testing and A vs. B prototyping into this.
Bill K
After looking to see if the Bosch cutter was carbide or carbide coated I found the teeth are carbide which explains in large part the cutter’s great performance. Just wonder how much of the cutter’s tooth is carbide.
“The Bosch carbide tip multi-tool blade offers the unbeatable combination of speed, precision and long life. And that’s really long life – 30 times longer use for the carbide blade versus a conventional bi-metal option in metal; it’s the longest-lasting blade for metal cutting available.
For Both Wood and Metal
The OSC114C blade’s carbide tip can cut both metal and wood, including harsh applications like fiber board, cement board, plaster and lathe, ceramic tile, nails, bolts, screws, sheet metal, copper pipe, cast iron and hardwoods. The carbide tip is welded to a high-carbon steel body through a proprietary process; Bosch is the world leader in carbide welding technology.”
Stuart
I would think that the entire cutting edge above the weld line is carbide.
Greg Cross
Please include some Husky products from Lowe’s in your future tests. For years I purchased the major brand of concrete anchors and their associated drill bits for making started holes in concrete blocks. I could only drill and insert about 5 to 10 anchors before this brand’s masonry bit wore out and was useless. Then, I tried the Husky brand from Lowe’s. To my surprise, I finished my project and used one Husky masonry bit to drill about 40 holes for the major brand anchors. Further, the Husky package of five masonry bits cost less than a package of one or two of the major brand bits.
Stuart
First, Husky is Home Depot’s private label brand. Lowes’ brand is Kobalt. Second, neither of these brands produce oscillating multi-tools or OMT blades or other accessories.
Additionally, there is no guarantee that Husky drill bits today will be made by the same company tomorrow. This is especially true around holiday times, when you might see value bit and accessory sets made by completely different OEMs.
Greg Cross
Ok I didn’t mean Husky. I can’t remember the correct name right now.
RyanF
You might be thinking of Blue Hawk.
John
Try comparing apples to apples…The bosch blade is at least $5 more per blade and a completely different blade and purpose than the other two. Go grab a bosch OSC118F blade and compare. Or, compare the bosch carbide blade and the Imperial blade in a wood cutting test. I guarantee the carbide blade will cut slower and burn out in that scenario. This is rigged and paid for by bosch.
I agree the carbide blades are better for metal, but again, apples and oranges here.
Stuart
When the tests were done, quantity pack pricing for the blades were comparable.