High C

When sawing, a blade can either be designed to cut while in tension, or compression.  If the blade is being pushed into the cut, then it is likely to be a compressive stroke – typical for western handsaws.  Nothing wrong with this, although as a saw blade tends to be pretty thin, it will try to buckle when in a compressive load, and so the saw either needs the blade to be thick and wide enough to cope, or have some inherent features to stabilise the blade.

Hand SawThis is a typical panel saw.  The thickness of the steel, and the overall width of the blade means it can cope with the compressive forces during the cut stroke, where the blade is pushed into and through the material being cut.

211803This is a small crosscut saw (and specifically a dovetail saw, from Veritas), which also cuts on a compressive stroke.  It has thinner steel, and a narrower overall width, so uses a support bar along the length of the blade to keep it stable.

Japanese SawsJapanese blades tend to be used on the pull stroke, a tension stroke so they are significantly thinner than their western counterparts.

Some blades are attached at either end, which presents a different opportunity, namely allowing the blade to be placed into tension increasing the beam strength, and resulting in a push stroke being able to occur without the blade going into compression, despite the direction of the cut.

This is the principle that bandsaws and scroll saws work on, as well as handsaws such as the bowsaw

IMG_5918-bowsaw-turning-sawand the coping saw.

The fact that these blades never go into compression is obvious from their blades.  They can be very thin, and therefore particularly good at cutting curves.

A cheap coping saw has a thin frame, which will bend if the tension in the blade is too high.  The blade needs to stay in tension however, and this is particularly important when cutting curves in the timber.  If the blade is not tight enough, then it will wander in the cut.

To make a frame more capable of dealing with  tension conditions, you need to modify the frame.  There is a common structure in use that greatly improves the structure’s strength.  The box section design of a bridge.

 

1024px-The_Little_Belt_Bridge_(1935) The diagonal bracing transfers load, so no one area has to cope with the entire load, and therefore fail.

Knew Concepts have recognised that fact, and have produced a coping saw with the same engineering principles bought into play.

That saw is the Knew Concepts Coping Saw, sold in Australia by Henry Eckert (.com)

_DSC2465-EditThe saw has significant strength in the frame, allowing the blade to be used a lot tighter than usual.  When plucked, I swear the blade produces a high C!

The crossbracing really strengthens the frame.

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The saw looks bulky, but is really light – beautifully so.

To get a blade that tight needs a special mechanism.  One that can be quickly released so the blade can be repositioned at a different rotation (8 different positions at 45 degree increments), and fed through a hole cut in the object to allow internal cuts (then as quickly retensioned).

_DSC2468-EditIt works on a preset tension using a knurled knob, then a cam lever allowing that tension to be applied and released.

It is beautifully made, simple and light, and based on sound engineering principles.

Knew Concepts Coping Saw

Shed Character

While down purchasing timber from Chris Vesper last weekend, I was also picking up some other items to add to the overall shed ambiance,

I have always found a real appeal in the workshops of old, where there were continuous power shafts, powered by a variety of means (such as waterwheel), and then with a combination of really wide leather belts and pulleys used to transfer the power to the current machine.

Chris had a really old wheel, and in this case a wooden one. Now I do 🙂

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Love the clamping mechanism it uses to grip the shaft, and how it is made up of laminations.

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It is now resting on a bracket off one of the shed beams.

The other I have wanted for a long time for the outside shed wall. Some of the old, really large sawblades, from a saw mill.

I know my old man has some in New Zealand, but there is a slight problem. They are in NZ! It’d cost too much to get them over. Instead, I found out Chris had some for sale, so I got a pair of similar size.

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Cool huh! Well I think so 🙂

Update: Have been thinking about the position of the blades this evening, and think I’ll relocate them, with one on either door. My original plan was for them to flank the doors, but fitting them to the doors themselves is probably even better.

Fly Weight

It has been a couple of years since I started the “Battle of the Blades”, and although there are different divisions in the battle, there is no Fly Weight.

There will be, very shortly, a couple of new contenders, competing for the very top spot of their divisions, and these are both produced by FLAI (pronounced “Fly”), and bought into Australia by Promac, the importers of other top shelf goods including Tormek and BMI.

Flai Mustang

The first blade is the Mustang, competing against other wood-cutting blades, but that hardly represents what the blade is about.  This blade doesn’t care what it comes up against (within reason).  Wood? of course.  Wood derivatives? Well duh. What happens if this blade comes across nails embedded in the wood? Now we are talking, and this blade keeps on cutting.  Try doing that with a standard combo blade and see how the teeth look!  Copper, aluminium, mild steel even.

It seems very much to be a universal blade – the blade you can leave in the saw and not be concerned what it is going to run into.  That must be such a relief, particularly if you are often using reclaimed/recycled timber.

Flai Ultimate

The other blade is simply called “The Ultimate”, and simply looking at this blade out of the box, I can see a serious challenge to the Freud Industrial for ultimate quality cutting.  The tungsten carbide tips on this one have to be seen to be believed.  A serious 30 degree alternating top bevel slices like twin knives.  This is not even touching on all the other features of this blade (or  the Mustang for that matter) – how the TCT are fixed to the base, the steel used for the body of the blade, and a number of other subtle (and not so subtle) developments in these blades.

These are going to be fascinating to put through their paces.

Saw Blade Quiz

I knew there was going to be a real benefit when I conducted my “Battle of the Blades” sawblade review.

That benefit has just been realised when I conducted the Saw Blade Quiz on Tools Today.com

Cutting Saw Blade
Cutting Saw Blade quiz
by ToolsToday

Heh heh – ok, so I’m skiting (wonder if that is a term particular to NZ/Oz?) I managed 15/10 – there are bonuses to answering quickly! I don’t mind the occasional online quiz (so long as I do well!)

Router Bits
Router Bits quiz
by ToolsToday

Just had a look at their site, and saw they sell tambour door router bits. Just caught my eye, as I’ve had a few people ask about them over the years, and I haven’t found anyone selling them in Oz.  Might have to see if they will export! (Hmm Stu’s Shed Router Bit of the Month review?) 😉

Tambour Door Router Bits

Tambour Door Router Bits

Freud Pro LP20M 25 Blade Review

Freud Rip

The next review from the “Battle of the Blades”. The Freud Pro LP20M 25, 24 tooth ripping blade with Perma-Shield.

Linbide 320 Rip Blade Review

Here is the first review from the “Battle of the Blades”. The Linbide 320 – 24 tooth ripping blade

I am particularly interested to know if this review (which is the first of many!) actually provides the sort of detail and data that you require to make a judgment about whether this blade would be of use to you.

If not – what is missing?

As the reviews are done, they will all be indexed from a common page, and there will be a separate page for each of the cuts with the photos side-by-side so you can compare the results from each blade.

The Battle of the Blades has begun

Had an opportunity over the weekend to start running the sawblades though their paces.  There were some unexpected, and rather surprising results from the tests.  I certainly haven’t gotten through all the blades yet, but already there were some definite stand-out blades, and some that fell rather short of expectation.

Had a couple of other woodworkers around to help (and I think they were interested in seeing what the various blades could do as well), so it was a good shed day.  (It was also the fomal commissioning of the saw 🙂 )

To start off, we replaced the standard insert with a zero clearance one.  There are two reasons for this.  Firstly, it minimises tearout, and secondly (and more importantly for this session), we wanted easy access to the riving knife quick release. It’s how the original insert should have been designed.  No so much the zero clearance (because the blade cannot be tilted with one – you need a different insert for each blade angle), but the opening at the back to allow the riving knife and guard to be added and removed without having to lift the insert and reach underneath each time.

Zero Clearance Insert

Riving Quick Release

Closeup view showing the riving knife quick release

Creating the hole was made significantly easier with the addition of the Pro Drill Table on the drill press.  Might sound like a bit of a sell, but I found that it really did make the drill press more functional, and particularly for this job, having the fence to keep the individual holes lined up, and of course the superior holddowns.  Ok, enough of that, I just wanted to say that it really is a good upgrade!

DrillPress Table

Of the blades themselves, I won’t do a blow-by-blow (as yet), but one surprising result was the Linbide 24 tooth ripping blade.  We were all standing back when it came to cutting the melamine sheet.  The teeth, we thought, was going to literally eat and spit out this sheet, but instead it was “I can’t believe it’s not butter” (or in this case “I can’t believe it isn’t a dedicated melamine cutting blade”) as it was the cleanest of all the blades so far (and that includes the 100 tooth ones), on both the top and bottom surfaces.  Where it came to its actual forte, ripping, it was butter (and what it was cutting went as easy as if it was butter too!)  Quite outstanding.

***Update*** btw, I also discovered why pine isn’t typically used for zero clearance inserts when there are anti-kickback pawls.  Trying to lower the sawblade (which carries the riving knife and attached anti-kickback pawls) causes the pawls to dig into the surface of the zero-clearance plate, and stops the blade from being able to be lowered.  This isn’t true for all saws obviously, as many don’t have an attached riving knife, or anti-kickback pawls either.  In my case, I will look at getting some appropriately thicknessed UHMD plastic, or in the interum some MDF cored melamine.***

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