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.
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.
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.
Bosch OSC114C – a carbide-toothed metal-cutting blade.
Imperial MMT340 – a TiN-coated bimetal metal-cutting blade.
Dewalt DWA4209 – a TiN-coated bimetal metal-cutting blade.
A small section of each blade was in contact with the nails being cut.
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.
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.
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)
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.