As part of our oscillating multi-tool blade comparison (which is funded by Bosch), the first thing we looked at was cutting speed for each of the three Bosch, Dewalt, and Imperial metal-cutting blades. We discussed those results last week in our oscillating blade best cutting speed post.
Here, we’re going to take a closer look at cutting performance, or ease of use. I will also refer to this as the ease of cut. This is important because it closely relates to the user experience you can expect to have when using each blade.
Testing
The testing fixture, discussed in Part 4, involves a horizontally-mounted oscillating multi-tool that is pulled with constant force towards a vise holding a 16D common nail. How fast each blade cut through these nails was discussed in Part 5, and this post examines how easily each blade cut.
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The original plan was for each blade to cut through (20) nails or nail sections.
Results
Bosch OSC114C Blade (Carbide Teeth)
Bosch’s blade was problem-free and cut each nail effortlessly. Cutting times lengthened slightly every couple of nails, but there were no signs of trouble.
http://youtu.be/Mcww6rBjN2Y
I couldn’t decide which cut to show you, so I went with number 10. This was the fifth cut made in nail #2, making it the tenth cut for this blade.
The smooth performance of the Bosch blade did not prepare me well on what to expect with the other blades and what was to come.
This is the same Bosch blade whose cutting speed was discussed in the last post.
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Imperial MMT340 Blade (Bi-Metal and TiN-Coated Teeth)
The Imperial blade started off cutting nicely, but it seemed to dull really quickly, to where it stopped cutting and started kind of grinding. It’s a sign of diminishing performance when you start seeing fewer chips being produced, and more dust.
http://youtu.be/m7FBTTsamnY
This video shows cut number 4, which took nearly 10 seconds. As you can see, it is heating up, the teeth are dulling, and sparks start flying towards the end of the cut.
This is the fourth cut in nail #1. This is the same blade that had the fastest cutting speed for cuts #1 and #2, as discussed in the last post.
Dewalt DWA4209 (Bi-Metal and TiN-Coated Teeth)
The Dewalt blade that managed to cut through a nail in a little over 12 seconds didn’t do so well on cut number 2. It sparked a bit on the first cut, but on the second it sparked more and seemed to get stuck halfway through the blade. I stopped the blade after 40 seconds. It didn’t do any better on the third attempt.
Thinking there was maybe something wrong with the blade, I took a few minutes and set things up with a new blade.
http://youtu.be/C61WsEyYDZg
Maybe it needed a little push? I gave the sled a few gentle nudges, but nothing changed. I stopped the test after 45 seconds.
For reasons I don’t yet know, the fresh Dewalt blade could not cut a single nail at all. The same unpredictability was mirrored by several more Dewalt blades.
Maybe there was something wrong with the tool or the setup? I swapped in a used Bosch blade that had already made 19 cuts, swapped in a fresh nail, and the Bosch blade made its twentieth cut in about 8 seconds.
Note: The video is not continuous. I cut out a ~1-minute section where nothing is happening. I left the nail in the vise during this time so that you can see nothing has changed with the setup during the time gap.
Conclusion
I was really expecting for a more even comparison, at least at first, but that just wasn’t possible. The Bosch blade was the clear winner.
In testing, I ran a couple of Bosch blades through 19 cuts, and expected to do the same for the two other blades. Then, I would do a final 20th cut for each blade in a single video to show the different cutting times. That was the plan, but none of the other brands’ blades could make that many cuts!
Here, the blades are all being pushed (or rather pulled) into the blades with a constant force of about 8.5 pounds. That the Dewalt and Imperial blades aren’t cutting the nails that well and are heating up and creating sparks means that they’re working a lot harder than the Bosch blade.
In real-world use, you can still cut metal with all of these blades, but after the first few passes cutting tougher metals, the Imperial and Dewalt blades will probably have to be pushed into the work with greater force.
Actually, there will be three options: 1) reach for a fresh blade, 2) push the tool and blade into the work with greater force, 3) deal with progressively longer cutting times. There’s also option #4: swap the Imperial and Dewalt blades for a Bosch blade.
Though the difference isn’t as striking in handheld testing, as with speed of cut, this testing translates to real-world performance as well.
Initially, the Imperial blade doesn’t show any signs of trouble. It cuts through the first few nails with the fastest cutting times. But after those first few nails, the Imperial blade slows down and works a lot harder.
To be frank, I haven’t a clue what’s going on with the Dewalt blade. One blade will cut through one or two nails, another can’t make a single cut. Cutting nails with each blade in a handheld oscillating tool is a little different, as you can expose the nail to a greater number of fresh teeth, but it requires more effort to move the tool back and forth horizontally. Eventually, the Dewalt blade will probably still be the first to dull and fail, as we repeatedly experienced during our tests.
Summary
Which blade provides the best and most consistent cutting performance? Out of the three blades tested, the Bosch OSC114C was the only one to be able to cut 20 nails, the only one that didn’t spark, and the only one that didn’t fail unexpectedly.
Buy Now: Bosch OSC114C, Imperial MMT340, Dewalt DWA4209 via Amazon
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 (current page)
Part 7: Durability
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.
Bill K
Great research and report! It will be interesting to hear where this takes you next and how you might leverage your testing equipment and protocols.
Bill K
Stuart,
After looking at the pictures of the cutter blades it appears they are not the same length. If that is true, then the radial speed of the cutting edge will be different (while cutting). Was just wondering, as an additional variable, how much if any difference this would make in heat generation and in the test results.
Stuart
Good point!
The Bosch blade is ~3″, the Dewalt blade a little longer, and Imperial blade is ~3.5″.
This could help contribute to the Imperial blade’s faster initial cutting time. In regard to heat generation, the Imperial blade will have a faster linear cutting speed than the Bosch blade, but it’s also thinner. The Imperial and Dewalt blades also have titanium nitride coatings which should help reduce frictional forces, energy losses, and heating.
To be honest, it would take a lot more equipment (or modeling software) for me to determine why the blades perform so differently, at least with confidence and certainty. There are a lot of coupled and independent factors at play.
The most significant factor is probably going to be the carbide teeth on the Bosch blade vs. the TiN-coated bi-metal teeth on the Imperial and Dewalt blades. The differences between Imperial and Dewalt blades probably has to do with heat treatment and tooth geometry.
Eric
Interesting test. As always, your transparency and honesty is admirable.
I had a thought – I wonder if off the shelf Bosch blades would perform as well as those sent directly to you from Bosch?
I mean that as an honest question and not to accuse Bosch or certainly you of any bias.
I buy cheap blades, but this series shows there can be measurable differences.
Stuart
The Bosch blades (in retail packaging) were sent via Bosch distribution warehouse and not Bosch HQ. There’s no reasonable way they could have been hand-picked. I also have a few other off-the-shelf blades, and cannot see any differences.
Bill K
With more thinking…….
The nail size used in your testing protocol would seem to be an extreme duty cut. I was just wondering how the tests might change if the nail size was much smaller, thus reducing the opportunity for high heat generation and related damage to the cutter.
Based on your results to date, I suspect the Bosch cutter will still prove to be superior, but could the others produce a more competitive performance?
Stuart
A smaller nail size could cause more issues. The smaller the nail, the fewer the teeth that would engage it. Potentially, this could also mean bouncing of the nail from gullet to gullet between the teeth.
On larger materials, such as pipe sections, the Bosch blade is still superior, but the other blades’ aren’t as quick to dull or fail.
Rebar might be a nice test material, but the performance differences might be even more dramatic as with nails.
MT_Noob
Stuart, thanks for the great test and posts.
For clarification, the Bosch blade being tested is their “carbide” version and not simply a bi-metal one correct? Is that what the C refers to in the part number? If I bought just a regular Bosch bi-metal blade it would not perform as well ad the “c” one correct? For example a OSC118F. I know it is mentioned in part one of this series that this is a test of their carbide model. But if someone is not reading the articles closely it is possible they might assume this is the performance of all Bosch wood/metal blades. Do any other manufacturers have a carbide tipped blade on the market yet?
Stuart
Yes, the Bosch blade has carbide teeth, the Dewalt and Imperial blades have bi-metal teeth with TiN coatings. All three blades are priced at ~$15-20 each.
The OSC118F is indeed a bi-metal blade and won’t perform as well as the OSC114C tested here. However, this is understandable as the OSC118F is also quite a bit cheaper.
Thanks, I have added clarification into the post to make this clearer! You’re right, I shouldn’t assume that readers will have read other parts of the series first.
As far as I am aware, Bosch is the only brand that has brought to market carbide-toothed metal-cutting oscillating tool blades.
MT_Noob
I am certainly going to get some of these Bosch carbide tipped blades and try them out. I had tried some of the imperial blades to cut nails previously, and after the first nail they were unusable. So I thought I could only really use my oscillating tool for wood/plastic. But these blades look like a game changer. Thanks again for the empirical testing. It confirms my personal experience with the imperial blades in my use case.
Larry
Your test is not a comparison by any means. You are using a Bosch “Carbide” blade. The Imperial Blade as well as the DeWalt are “not” Carbide blades. That is like comparing an American made car to a high end super car.
I have been using the Imperial Blade for several years. I have yet to have any of the problems that you and your users are experiencing. I would make sure that the blade you test is indeed the right blade for the project.
Chris Pyfer
Dremel makes a carbide metal cutting blade. Would like to see a comparison test. I have both and like the Bosch better.
Stuart
I might have used the Dremel before, but am not quite certain. In general, I find that Bosch OMT blades and accessories are a little stronger/tougher/longer-lasting that Dremel ones. The Dremel accessories are aimed more towards DIYers, and the Bosch ones are more aimed towards professional users, so a difference in quality is not unexpected.
Bill K
One last inquiry…. I promise!
In your tests the blade is driven with a constant 8.5# load. Are the test results the same if a lower load is used (like 4#)? One hypothesis might say a lower load would allow the cutter teeth to take a smaller bite, thus reducing the heat generation and related cutter degradation.
Stuart
I couldn’t lessen the load, at least not easily. Based on how the platform was designed, the load is around 8.5 pounds with the weight basket unloaded. Heavier loading results in quicker cutting speeds, while lighter loads in theory should result in longer cutting speeds.
The problem with too light of a load is that the tool bounces back a lot more easily and noticeably, resulting in impact damage to teeth. Friction-accelerated blade wear is a possibility, but it’s a factor more users might experience in the field, at least compared to impact damage.
None of the blades take huge bites out of the nails that they’re cutting. Chips are all very small, indicating that the blades still nibble at the blade, even with the 8.5 pounds of cutting force.
Bill K
How about testing with a cutting fluid? It’s a simple test that would effectively remove heat generation as a variable.
Stuart
When I started off, I used made multiple cuts in each nail. A cut was made, the nail was raised and retightened in the vise, and cut again. Then I started swapping out nails after each cut.
Users are not going to use cutting fluids in the field. They’re going to make the cuts as needed, often as quick as they can. Cutting nails sticking out of or into wood is not a task that is shown finesse.
Heat generation is not going to be the biggest issue here. With the Dewalt blade, I don’t think friction is dulling the blade, but that the dull blade is increasing the friction. Some fresh blades cannot cut even just one nail. Cooling the blade won’t undo the damage to the teeth.
Josh
Is it possible that the test rig is somehow contributing to lesser blade efficacy/shorter tool life? It may be worth making a few test cuts by hand to see if there’s any change in blade wear.
Eliminating the human factor is a great way to get reliable results, but the human serves as a useful backup to confirm the validity of the results.
That said, Bosch is known for making great blades, carbide blades are well know as better for metal cutting, I’d be reasonably confident in these results as-is.
Stuart
I considered that, but saw similar results when testing the blades with a handheld multi-tool. Moving a handheld tool back and forth horizontally helps to stretch performance, as more teeth are used to make each cut.
From what I have seen, the performance difference is still there, whether with cut number 4 in the testing fixture, or cut number 10 handheld.
The test fixture wasn’t optimized to exploit the advantages or faults of any of the blades.
Larry
One more thing to add. How does that Bosch carbide cut through wood?
Robb
I’m curious why no fein blades were used in the comparison? Perhaps I missed it?
Stuart
The scope of the testing was to look at Bosch, Dewalt, and Imperial blades. While I was interested in testing Fein blades as well, I could not find any Fein metal-cutting blades. Their universal cutting blades seem to be designed for wood, plastic, and non-ferrous metal-cutting applications. They are rated for “cutting Metal up to 1/32-inch” and so it wouldn’t be fair to compare them to Bosch and Dewalt’s metal-cutting blades, or Imperial’s blade that is advertised as being capable of cutting nails. For what it’s worth, Fein blades are pretty darned good, but they’re not ideal for cutting tougher metal.
Monte
How many cuts in total you could make with the Bosch blade ?
Stuart
I gave up at 30. The Bosch blade was still going strong, and I decided that it probably wouldn’t be too helpful to test the blade until it failed.