Oscillating tools cutting screw - tools vs blades?

[JHZR2]

I was helping someone with a project, and they had a dewalt cordless oscillating multi-tool. Pretty neat little gadget, and it had a unique blade change device... Unique enough that apparently you have to use dewalt or a few other brands' blades, not the universal ones....

I have a corded fein multi master.... A few years old, which I love. I've cut all sorts of stuff with it. But I didn't have it with me, so I was using this dewalt brushless tool with dewalt branded wood/metal blades.

I was trying to cut the ends off a few spax screws that were protruding out of the wood on the backside of something that was fastened. It wasn't visible, and didn't need a good finish, but we didn't want screw end points sticking out either.

Well, I couldn't cut the screws! I got one or two, and then the blade's teeth were more or less gone. Eventually I resorted to a cutoff wheel in a dremel, which made short work...

But it made me wonder... As I've never had issues cutting nails with my fein and with fein blades...

Does the actual OMT make much of a difference? I mean, it oscillates... But I'd suspect that speed and arc length differences could create variability.

What about blades? I've primarily used Bosch and fein blades, though I've used some third world blades on wood...I've found the fein blades to last really well.. Was the dewalt blade a dud?

Trying to understand what the issue was since I don't think cutting the ends off screws with an OMT and a new blade should be that tough...

Thanks!

 

[expat]

I have used Dewalt jig saw blades in my Bosch jig saw and have found them to be inferior to genuine Bosch and even some other less expensive brands.

I have never found any oscillating tool blade to last very long at all, but I have never tried Fein.
My last batch of blades were Kent cheapies, they don't last long either, but they are not too bad for the money.

I tend to reserve the tool for impossible cuts where no other tool will do.

 

[mk378]

Some wood screws, especially drywall screws are made of very hard steel. A grinding rather than sawing tool is appropriate.

 

[Astro14]

Originally Posted By: mk378
Some wood screws, especially drywall screws are made of very hard steel. A grinding rather than sawing tool is appropriate.


This.

Nails are soft. But screws are hardened and rolling the threads hardens them.

 

[pandus13]

Originally Posted By: Astro14
Originally Posted By: mk378
Some wood screws, especially drywall screws are made of very hard steel. A grinding rather than sawing tool is appropriate.


This.

Nails are soft. But screws are hardened and rolling the threads hardens them.

it happen to me with Rockwell wood blades: they got hung into drywall nails (about 3 nails); they used roof nails for drywall....
but clearly not the right tool/blade for the job (too soft?)

 

[JHZR2]

Originally Posted By: mk378
Some wood screws, especially drywall screws are made of very hard steel. A grinding rather than sawing tool is appropriate.


Concur. I was sort of curious, if not well defined in my OP, if there are some blade variants better suited.

I found a test on toolguyd that shows a bosch, dewalt, and one other blade type on nails. The Bosch could do 20, the fancy dewalt metal coated blade could do one or none depending upon the test. And I think that was on non-hardened 16D nails.

So the dewalt blades seem universally bad on top of the screw hardness. I have some spax screws. I might try a fein blade just for kicks.

 

[2cool]

To cut hardened metal, you could try the carbide coated blades vs. the Dremel. Either way, the metal removing method is grinding.

 

[EA82]

I bought the dewalt corded multitool Last black friday on amazon, got it for $89. The blade that came with it wasn't much better than the value pack i bought on amazon, integra brand i think. I normally don't use the multitool for any kind of metal, I use the sawzall with a metal blade.

 

[sleddriver]

Originally Posted By: Astro14
Originally Posted By: mk378
Some wood screws, especially drywall screws are made of very hard steel. A grinding rather than sawing tool is appropriate.
This.
Nails are soft. But screws are hardened and rolling the threads hardens them.
This X2. I'll bet those Spax screws were quite hard. Just like a file that skips over hardened steel.