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The Dreaded Jigsaw

Handheld jigsaws are cutting tools consisting of an electrical motor and reciprocating saw blade. The blade can be exchanged for various types and gauges for cutting other materials such as plastic or metal in addition to wood. In the context of woodwork, jigsaws are used to cut through sheet materials, kitchen worktops or lumber depending on the machine/blade capacity.

When I first decided how to learn to make my own guitar, the general consensus was "oh, you should never use one of those". For the most part this was correct, however a decade later there are justifiable reasons why this might no longer be the case.

Why have luthiers always been so dead set against jigsaws? Simply, a lack of accuracy and poor capability. Jigsaws have an enduring reputation based off poor results from inappropriate design characteristics for an incorrect end use; the reciprocating blade is supported at one end only, leaving only the stiffness of the blade and retaining mechanism to keep it running true or going where it is intended to go.

Improvements in blade quality, retention/guiding mechanisms and electronics make this far less true of modern jigsaws. Like virtually all common DIY tools an intensely competitive marketplace has forced evolution in quality and capability. Comparing what you'd find off the shelf ten years ago demonstrates a night and day difference; your money gets you a lot more tool, plus the selection is far wider. Even the best jigsaw tool 10-20 years back would have a hard time competing with the average tool on offer now.

Blades are made from more durable and stiffer metals, so flex less. Tooth geometry has been designed to be sharper, cutting and ejecting waste efficiently. Guiding mechanisms keep the blade running where it is supposed to. Control electronics prevent the tool bogging down in the middle of tough cuts. Gearboxes have added pendulum motion (also known as orbital or elliptical cutting action) to help cut through thicker, harder workpieces faster with less hanging up.

So does this change the status of the jigsaw? Does the increase in capability and reliability bring the lowly jigsaw back into the fold of the luthier's daily tooling? Not quite. The workshop of luthiers that use power tools will likely be equipped with a bandsaw which will supplant 99% of the work a jigsaw might be expected to manage.

For those starting their first projects, those on a budget or simply those that won't see realisable returns by investing in larger equipment, choice is often limited to general DIY tools already on hand. Bandsaws are few and far between at this level, especially when the scope of works is limited to working in an apartment, on the dining table, on a small collapsible bench outside the garage door. Jigsaws are an adequate alternative in the absence of a bandsaw.

The huge inertia of opinion in traditional luthiery circles simply hasn't woken up to the fact that we're not working with grandpa's rusty old tool which last saw action back in the 60s. If however you are, then pop that junk back into the dusty crevice whence it came. They didn't do the job properly back then and certainly haven't aged gracefully.

 


 

To demonstrate an average modern jigsaw, I'm going to perform two simple tests on some 40mm thick Birch and Alder. The methodology is simple and practical; how accurately does a jigsaw follow a straight line and how closely can it cut up to a marked line in thick wood?

The hope is that a jigsaw can remove enough wood that a workpiece can be taken straight to the router. In an ideal situation, a router should be used as a shaping tool and only be expected to remove as little wood as possible. The more wood the bandsaw or jigsaw can remove, the easier and safer the subsequent routing will be. Esually a 1/4" (just over 6mm) is good.

For examining how the jigsaw tracks a straight line, a piece of Birch was jointed and thicknessed, then marked up on both sides with lines parallel to the edge. Cutting along a line marked on the top will show any deflection or wandering in the blade by seeing how it deviates from the markings on the underside. The jigsaw was set up to use the pendulum motion (to eject waste) and run at full speed.

 

The first test piece:

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Okay, we can see here that the blade went in at an angle. You can improve the tool but you can't improve the operator....what have we learnt from this? That I didn't check the jigsaw sole setup before using it, that's what....

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Going with that anyway shows that the blade wandered maybe less than its own width out of the other side....that's not bad despite my error....

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Well there you go. Operator error. (I didn't have a proper engineer's square to hand)

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Adjusting the sole of this jigsaw doesn't seem to be a precision affair unfortunately. I'm sure that with a bit more patience it could be teased into perfect alignment, however that curve in the blade isn't going away anytime soon.

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Let's try this again and just bear those factors in mind....

Okay, a far better entry; the blade went in pretty much straight. That's a good start....

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....about 2,5mm of deviation on a straight cut. It's workable. For a luthier, the next job that workpieces see after this is usually routing. As long as the tool can remove enough material so that the router doesn't have to, we're good. It looks like the curve in the blade (no spares on hand) is causing a progressive wander as the cut goes on....Maple and Birch are pretty punishing woods at these thicknesses of course....

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Time to do some al fresco luthiery on an actual workpiece. This is my Lancaster design (CAD plan available here!) in black Alder. As with the previous test, the design has been drawn on both sides to better examine blade deviation in both straight and tighter curves.

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The first cut went halfway before the jigsaw started to cough; likely the motor brushes need reseating. I expected problems like this, since the jigsaw hasn't entirely been taken care of. Thankfully it's not mine....

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Well that's interesting....a little close to the mark! The first cut was offset by around 1,5mm to 3,0mm (1/16" - 1/8") from the corresponding markings on the underside. Clearly I was working too close to the bone here. I kept this in mind for the rest of the cutting and gave it breathing room....

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Aside from the insides of the cutaways and the spluttering motor brushes, the rest went without drama. Of note is a bit of splintering on the exit of cuts like on the lower bout. The upper cutaway was dramatic; the tight curve caused the blade to bind up in the cut and vibrate the jigsaw. For areas like this, it's wise to pre-drill an entry/exit hole (a 1" Forstner bit would work fine) rather than expect a jigsaw to manage its way around tight turns. Having this happen made me a lot more circumspect about the lower cutaway.

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The proof of the pudding. Rough and still problematic. Nonetheless, the line hasn't been crossed at any point but did get very close to it at a couple of points. Aside from the excess at the upper horn and in the lower cutaway, this is good enough to go to routing.

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The jigsaw used was a Würth SPT 135-S, which happens to be a rebranded Bosch GST 135-CE. Specifications may be slightly different under the hood, but fundamentally they are the same. As of writing, the Bosch costs approximately €150. The alternatives I had to hand for the test was a cheapy-cheap-cheap saw at half the price which I am sure would have destroyed the workpiece as much as look at it, and an expensive Festool which simply doesn't represent the average user. This model sits adequately in the accessible "modern" DIY jigsaw bracket; a quick release blade with a guide bearing, pendulum motion, blade stabiliser and motor control electronics. I'm sure the problem with the brushes could easily be remedied if they were easier to access.

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Conclusions

In spite of the enormous improvements made on jigsaws since I first started building, they are not challenging bandsaws as a one-on-one alternative. Guitars have far more complicated shapes in thicker materials than jigsaws are completely appropriate for. Additionally, there always felt like there was a degree of fighting for control in tight corners and balancing issues around areas like the horns. Bandsaws offer a higher level of control.

This is what it comes down to: choice. If that bandsaw is not available, a jigsaw will suffice given adequate understanding and reasonable expectations. You can make one work as long as you know why its not the best tool for the job and make allowances.

In spite of the problematic blade, flaky brushes and faulty operator the result was surprisingly good. This definitely is a world of improvement since the nightmarish old Black and Deckers of the 90s. A bit of patience, adequate work on test pieces, familiarity with the tool's quirks and an allowance for error would pay off. It's not impossible to produce acceptable results with a jigsaw that can be taken straight to the router with little to no additional cleanup.

Does a jigsaw have a place in the workshop? Maybe so. This example produced better results than my first cheap bandsaw ever did. There is however still plenty of room for errors creeping in that could write off the workpiece. Trusting this particular jigsaw any closer than 1/4" of a finished line was clearly still a bit risky. Luck seemed to be a factor. If that's good enough for your purposes then the answer is yes; a good jigsaw in good working condition is an acceptable tool.


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I use only a jig saw, and hand saws, because its really all I have. I have cut many bodies with my jig saw, and if it becomes angled, or off in some way, that becomes part of my body. I enjoy that they all all turn out differently, and welcome those small "flaws" as part of my being an artist, and a woodworker. 

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Thanks for commenting! Well, that was the reasoning for the article really; I think jigsaws get a bad rap, especially from luthiers who have a better-equipped workshops with bandsaws, etc. There are an equal number of people who don't, so jigsaws have their practicalities once you understand their limitations and work within them. I think that the unit I borrowed had just been abused, so the sole locking mechanism had far too much play in it.

Great to hear from a luthier that "work within the wood"; often I have to keep reminding myself that not every luthier pre-ordains the end result using templates and precision working where it is truly not always needed. The wood has a lot to say, and sometimes it needs to be listened to. :peace

Post a build or two over on the forums!

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I'd always thought jigsaws were more likely to cause chipping and tear out - your cut looks rough but no big pieces are missing. Think that's a concern? 

It would be interesting to see how cheap bandsaws stack up. Is a ~$200 band saw workable or junk?

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Jigsaws do have that problem, and there was a bit of splintering and chipout here. Nothing massively destructive, but pendulum motion does help allay the issue somewhat by moving the blade out of the face of the cut on the downstroke. That would otherwise "push" wood out of the underside of the workpiece. The top is a different matter. Some jigsaws have zero-clearance inserts which help prevent blowout on the top (I think the Festool has that) but generally it's not too bad unless you really hack at the workpiece. Once you know the "fractious personality" of whichever tool you're using you can compensate for excessive splintering by making more allowances at the margins. This is another one of those balances between coarse stock removal with a jigsaw in advance of finishing cuts with a router. You either risk the jigsaw chowdering your workpiece or you risk offering too much material for the router to safely remove.

Good question about cheap bandsaws. I think once we have enough money coming in the Patreon hat each month, we can look at buying a crap bandsaw in simply for illustrating why they are problematic. Around the couple of hundred mark (where the crossover between expensive jigsaw and cheap bandsaw exists) things get a bit more complicated. Small benchtop bandsaws have pathetic throat capacity where you might struggle to evacuate material from cutaways, and have excessive blade wandering  at body blank thicknesses. This is entirely where the pros of a good jigsaw overlap with the cons of a bad bandsaw.

Overall I prefer the "workpiece over the tool bed" approach of a bandsaw over the "tool on the workpiece" both for large cutting and routing operations. There's a much larger bearing surface, and you can easily chicken out of an operation if things look like they're getting out of hand. You can't always do that with a bucking jigsaw or a runaway hand router!

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16 hours ago, Prostheta said:

Good question about cheap bandsaws. I think once we have enough money coming in the Patreon hat each month, we can look at buying a crap bandsaw in simply for illustrating why they are problematic.

I was really hoping you'd say something along the lines "Cheap bandsaws are amazing - there's no point in dropping big bucks on a high-end band saw!"... 

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That would be a perfect world, wouldn't it? There's a lot more you can do with any bandsaw than a jigsaw of course. However, at the cheapy low-end they present their own problems, so it's not entirely a graceful transition from one to the next. They'll do the job given a lot of patience, false starts and fiddling around. I'll do a jigsaw vs. cheap bandsaw video at some point in the future. Excellent topic!

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I have a jigsaw that I use only to crosscut long boards, since I have yet to build a proper table saw crosscut sled (which is a bit challenging on a jobsite saw). I just clamp a straight edge perpendicular to the board as a guide for the jigsaw sole. It isn't entirely accurate, but it does fine for making a safe cut in a pinch. Using high-quality blades is a must, as with most tools. Stock blades are garbage in most cases (I use a Ryobi).

Then, there are also those who have relied on jigsaws so are able to compensate for the tool's foibles with skill and superior handling. My brother is a wizard with one! Me, not so much.

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That's the thing, Rich. Once you start considering buying a decent jigsaw, you start approaching the territory occupied by small bandsaws. There's still a great deal of consideration to be done with jigsaws as to whether they're appropriate to a task on thicker materials. Fundamentally, the way they work undermines how useful they can be. The risk is always there.

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On clamped down boards and riding a straight edge guide, I am OK with them. They can get squirrely quick though! I liken it to a jumpy upside down scroll saw with only one stable point that can do a bit more flesh damage.

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Pretty much! In the context of guitar maker use, they are the cheapy alternative to a bandsaw and beyond that, the result goes to the router. If a jigsaw can't produce a rough product that can safely be take to the router, it is not an appropriate tool. Even scroll saws and their lack of power cut straighter than a jigsaw since the blade is supported at both ends.

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Exactly. A decent scroll saw certainly is not as inexpensive as a jig saw, but I'd much rather go that route. Then again, it is asking quite a bit to task either saw with cutting through ~1.5-1.78" of 1500+ Janka Scale hardwood!

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