Why do Scroll Saw Blades Break: 7 Things to Prevent This

Why do Scroll Saw Blades Break: 7 Things to Prevent This

It can be quite frustrating when you start scroll sawing and find yourself having to replace broken blades frequently.  This, in fact, should not be happening frequently, and if you break a lot of blades you may want to check on a few things to help prevent frequent blade breaks.

Based on my experience and some research online from other scroll saw users experiences, I have come up with 7 things to look at to help prevent scroll saw blades from breaking.

An experienced scroll saw worker will tell you that at times a scroll saw blade breaking is not attributed to just a single cause.  It can be the combination of two or more things at the same time.  I have to keep this in mind when I am switching out different types of wood and different thickness of the wood. 

Additionally, it can be that my scroll saw speed and how tightly I am clamping the blades in that could cause some problems as well.  With the question on why do scroll saw blades break, let me go into a bit more detail with 7 things that you can check to help prevent this.  

 

Is my Scroll Saw Speed too Fast or Slow

When you think about the speed your scroll saw blade is cutting at, one might think the faster the blade is moving the quicker you can cut.  Or even the cut might be smother.  These do sound like they might be true, but there are other factors to consider.

sawspeedWhen things go quicker, they generate more heat.  Heat, and extreme cold for that matter, with most metals is not really a good thing.  There is a lot of effort spent in the world on ways to cool metal, take cars for example.  Metal will expand when heated, and I am no science major but that signifies to me that the integrity of the metal is compromised and will make it easier to break.  If a cars engine block overheats, it can crack.

I think that at first if you have a fresh blade in your scroll saw and turn the speed up fairly quick you might have a good experience.  But as the blade dulls and fast speed heats things up, well, you can guess the blade might break more often.

What about setting your speed to slow?  I personally have not done this as it seems to make more sense to turn up the speed a bit.  If it is too slow I think it would take more time to cut my out project for one, and two I think I might have to be more careful about pushing my wood through the blade.  I might stress the flexibility of the tensed blade and cause it to break as well.

Here are some better rated scroll saws that I was looking at on Amazon that have variable speed capability:

WEN 3920 16-Inch Two-Direction Variable Speed Scroll Saw with Flexible LED Light

DEWALT DW788 1.3 Amp 20-Inch Variable-Speed Scroll Saw

Porter Cable 18″ Variable Speed Scroll Saw with Stand

Delta Power Tools 40-694 20 In. Variable Speed Scroll Saw

I have the Dewalt scroll saw, and as pictured above, I like to set the speed at a 5 or a 6 and that speed seems to work well for the projects I typically do.

What Type of Wood is Being Cut

There are various different types of wood.  I have worked with Birch, Pine, and Oak.  Oak, being a much stronger wood, might give me more issues when it comes to breaking blades.  Birch, on the other hand, is a fairly soft wood and may cut easier and give you less problems when it comes to breaking blades.

I have some ambitions to cut some other various woods I have also found on Amazon that look pretty interesting such as Zebra woodBlack WalnutMaple, Cherry, and what in the world is Purpleheart?  You can’t find these in some of the big name hardware stores and I did not know some of these types of wood even existed.

When it comes to the strength of the wood, I tend to focus more on how quickly I push it through the blade.  If I am using Oak and push the wood through too quickly and forcefully, the blades break quicker on me.

I plan to work on more Intarsia projects in the future.  This means I will likely be using some different types of wood for detail on the project.  When I cut, paying attention to the strength of the wood will definitely be something I need to think more about.

Wood Thickness

Wood Thickness when scroll sawing is a very important factor in keeping your blades from breaking.  The thicker your wood is the stronger the blade you will need for cutting.  You don’t want to use a size #1 blade on a two inch thick piece of wood unless you really like to pay for new blades.

Additionally, the reverse of this, a very large blade, say size #8 on a 1/8″ board combined with too slow of a speed may snag on the wood more easily and cause the blade to break, so I have heard and have yet to try, or maybe not try.  Not to mention that your cut might not look as good had you used a smaller, finer blade.

I will move into scroll saw blade sizes in relation to wood thickness in the next topic.

I have found that most of my projects are typically 3/4″ thick.  So I use a lot of #2’s and other blades close in that range.  I have used some smaller thickness wood like 1/4″ and 1/2″ and I typically just use the same range of blades I do as the 3/4″.  I don’t seem to break blades very much so I think I may have my settings at a good place.

Scroll Saw Blade Size

As I have mentioned there are various different blade sizes.  I believe the range goes from #3/0, #2/0, #0, #1… all the way to #12.  Wood thickness recommendation is given for each size of blade; Blade sizes #2/0, #0, and #1 are good for 1/8″ wood, #2, #3, and #4 are good for 3/8″ wood, #5, and #6 are good for 1/2″ wood, #7, #8, and #9 are good for 3/4″ wood, #10, #11, and #12 are good for 1 1/2″ wood.

I like to use some good Olson blades as well as my Flying Dutchman352cd-20180921_102554 spiral blades you can find on Amazon.  I get a good smaller size range with the Flying Dutchman spiral blades.  The Olson’s are nice as they are double reverse tooth for smoother cuts.

I admittedly, as I mentioned above, have used #2 blades on 1/2″ to 3/4″ wood as I like the finer cut.  But I think I may break a blade or two more than if I had used a larger blade, it can be hard to tell though.  These sizes in relation to wood thickness may be a recommendation as well, but when they make recommendations, they do it for a reason.  And that reasoning is likely due to less blade breaking.

Blade Clamping May be Wrong

This one is interesting in the topic of breaking scroll saw blades.  When you clamp your blades down, you might clamp them incorrectly to the point where it can create uneven stress on the blade.

clampI know that when I clamp a blade in, I see it sometimes bend out, top clamp, or bend in, bottom clamp.  To help avoid this bending, I will clamp and re-clamp several times until I note that the blade is not bending.  My clamping and re-clamping is lightly done, meaning I don’t clamp down hard when I see it bending.  I ease off and re-clamp until I don’t see the bend, then I clamp down a little harder as a final clamp to secure the blade.

It takes me a little patience, but when the blade is in there fairly strait, I think it helps keep the distribution of tension on the blade more even.

Am I Feeding the Wood too Quickly

As simply said, forcing the wood through your scroll saw can be a big issue in breaking scroll saw blades.  We do need to feed the wood through, but force it to quickly and you can cause issues such as creating more tension on the blade, more heat, and more work the blade has to do on each repetition of the blade.

I have noted in my past that when I push the scroll saw project too quickly, I do tend to break more blades.  Better to have patience.  Scroll sawing projects to me is all about having patience anyway.

Scroll Saw Tension to Tight

Tension by far would be the factor in most blades breaking.  Most research I have done on this would point to this being the #1 reason scroll saw blades break.  I have done quite a few scroll saw projects and cut outs and found that I break a blade every one or two projects on average.

sawtensionWith my Dewalt scroll saw I have a variable tension on there I can adjust after I attach the blade to it.  I typically work with 3/4″ pine and found that a tension of 2 or 2 1/2 on the Dewalt seems to work fairly well.  I  have since put my tension down to 2, as it seemed I was breaking blades just a bit more then desired, and I am doing fairly well not breaking blades too often.

There are people that mention that you should tighten up the tension and pick at the blade to make a sound.  This sound is supposed to be some kind of middle ‘C’ note.  I am no musician, so this advice I have found does not do much for me.  I do pick the blade to make sure it is tight, then I start cutting.  When I start cutting, I try to visually note if there is a slight bit of play in the blade when I push the wood through it.  Does the wood give a little bit as I cut.  If blades keep breaking, slightly reduce the tension like in my example of going from a 2 1/2 to a 2.

Another tip I have read is to push on the blade, not while running obviously, and see if a not too hard push but a firm one, will give you an 1/8″ play in the blade.  I will go out to my scroll saw this moment and see if this the case…  Turns out this is fairly good advice.  I gave a firm push in the middle of the blade while I had my tension on my Dewalt at setting 2.  I got a little under 1/8″.  So I think I might be on the right track here with my settings.

Conclusion

If you feel that this is a lot to think about to keep your scroll saw blades from breaking, I am with you on that.  I try to keep it simple and keep my tension and speed at a good spot, I use a blade that can handle the thickness of wood I am using, I get my blades clamped correctly, and I take it at a good pace in my cutting.  As time goes on I have got used to the process and I seem to keep from breaking too many blades.