ElectroBlu is the new Blue

The double-sided melamine blade from Amana Tool, and sold through Toolstoday.com

It is seriously…..blue

Amana Tool Melamine Blade

Quite a stunning looking blade, but we will get to its looks later.  Function is much more important than looks!  Good thing this blade has both 🙂

The blade is an 80 tooth, 10″ (250mm), with a 5/8″ bore.  That is what suits my saw, they also have 30mm bore, and sizes from 200 – 400mm diameter.

It has 4 straight expansion slots to minimise heat distortion, with copper plugs.  The copper plugs are used as a vibration absorption, and to block up the holes at the end of the expansion slots – both of which in turn decreases operational noise.  The holes themselves are used as a crack-arrestor as they reduce the stress at the end of each slot.

The straighter the blade, (in how it is manufactured, in how accurate the teeth are ground, and the less warping/distortion caused by heat), the better the cut.  This combined with a tooth profile especially designed for melamine results is a remarkable cut.

Clean cut

The edge, on both sides of the melamine, is as clean in closeup as it appears in the above-photo.  It is a beautiful cut, and that aptly demonstrates the quality of the blade.  Getting this sort of result on both the top and underside of the cut is remarkable, and takes a special blade to achieve this.

Crosscut Pine

The blade is also very good for crosscutting, whether that be soft or hardwood.  The finish is near shiny, and showed negligible to no breakout of fibres at the back of the cut.

Crosscut Hardwood

Ripping was harder – being an 80 tooth blade there is only a small gullet between teeth, and where that is fine for crosscutting, is insufficient for clearing waste and the long fibres created during a rip cut.  It is still achievable, but you have to cut slow (risking burning the timber, overheating and distortion in the blade).  Even so, a shiny cut was the result!  Good enough to go straight to a finish, or one final light sand.

Hardwood Rip

But why is it blue?
The blade is finished with a new process, called electro-bluing. It is a smooth coating for the blade, replacing the teflon-like finishes of other blades.  It has only been available since September 2012!  This micron-thin coating is claimed to reduce heat buildup, and the accumulation of resin.  The coating includes the teeth of the blade.  It will be very interesting to see how durable the coating is!

It is also promoted as being an environmentally friendly coating.  If that is a feature you need, this blade (and this coating) offers that, which differs from many other, more traditional coatings.
So this is the MB10800.  A double-sided melamine blade which really cuts the mustard! From Toolstoday.com

The Secret Language of Saw Blades

Ever gone to purchase a sawblade and wondered just what all the codes are engraved on the side (or printed on the packaging)?

There are a surprising number of variables that are possible with saw blades, so many versions that can be considered.  Some are irrelevant when choosing between one blade and another – they distinguish between a blade suitable for wood vs plastic (for example).  Some blades do cross over – the Flai Mustang for example, which will have variables that suit both materials.

For example: ATB D250, K3.0 B30, Z40, H10

ATB

ATB = alternating top bevel – this blade has its teeth set so it is like a chisel, with one tooth cutting to the left, and the next to the right of the kerf.

You could have 4+1 (4 ATB teeth, plus one FT (flat tooth) as a raker tooth, flattening the bottom of the cut).  An ATB blade leaves a V groove in the bottom of a partial-depth cut, and the 4+1 is a way to resolve this, leaving a flat-bottomed kerf.

Other options include HATB (or HiATB), where the teeth are even more angled which is good for melamine, and timbers prone to tearout, TCG (triple chip grind, also known as triple cut, FT (Flat Top), HG (hollow ground)

D250

D stands for diameter – size of the blade in mm.  A 250 blade (or to be exact, a D254) blade is 10″

K3.0

This is the kerf of the blade, measuring across the teeth.  This does not mean the blade will actually cut a 3.0mm wide kerf however. Blades have runout (just how flat is the blade, and during use just how flat it remains as the temperature of the blade changes).  Saws (tablesaws or circular saws) also have runout, and it is a combination of both that will dictate exactly how wide a kerf you will get.  If you want to know it exactly each time, you have to measure it whenever you change blades.  The next time you mount the same blade, it could be different depending on at what point of rotation that the saw is vs the blade.  It is much easier just to do a test cut and remeasure if it is that important.  This concept is greatly (and deliberately exasperated) for a wobble dado blade, which is designed with a large amount of runout which can be dialed in, creating a dado (or wide trench).

B30

This is the size of the bore – the hole through the middle of the blade.  Depending on your saw you can either get a blade that specifically matches your saw, or one that is larger and get some saw blade bushes (or reducers) to match both the blade and you particular saw.  They are not as convenient (but are still easy to use), and they allow you to purchase blades that are suited to your needs without necessarily being made for the size bore you require.  Of course, if the hole is smaller than your arbor, you have a problem! Getting back to dado blades for a sec, when using stacked dados, I would strongly recommend getting one where the bore is correct for your saw – there are enough things to juggle without also having to try and manage a bunch of bushes as well.

Z40

Z stands for the number of teeth.  A ripping blade can have around at little as 24 teeth, a crosscut blade as many as 100.

H10

H is the hook angle (or rake angle). Large hook angles are an aggressive blade, particularly for ripping soft timbers.  Small, zero or even slightly negative for crosscutting hard timbers.

 

These are just some of the variables and codes that can be written (engraved) onto the blade.  They may not all be listed, and some blades may list a whole bunch more.  If you know these at least, you are well on your way of being able to distinguish between one blade and the next.

 

Some other variables include top clearance angle, top bevel angle, gullet size, gullet plug, expansion joints, noise reduction slots, max operation RPM, carbide type, base blade material, blade coating, body thickness and so on.  We’ll stick with the most common concerns at this stage!

 

New Trays for the Pandora

As mentioned yesterday, the trays I made felt rushed, and subsequently I wasn’t happy with the results, and so a remake was in order. One of those things – less haste, more speed.

I decided that I really did want it to have dovetailed sides – the wall height was around 20mm, so it would involve a single pin and two half-tails, with a wall thickness just sufficient for the Gifkins Dovetail Jig. Once the Silky Oak was machined square and to size, the dovetails were cut and the sides dry-fitted together.

Tray sides dovetailed, ready for slots to be cut for the base

It was only a dry fit at this stage, as I wanted to have a captive base, as I had done for the main box. With a clamp holding the box together, a groove was cut all round the inside of each tray, about 5mm from the bottom and 5mm deep.

The inside dimensions of each tray were again measured, and 10mm added to give the size for the base. In reality, I tend to cut it about 0.5mm-1mm undersized, so there is no chance the base will stop the sides coming together completely during the glue-up.

How I measure this is with a rule, and in this case I regularly turn to the Woodpeckers Rules, which are particularly easy to read. By setting the reading under one of the teeth (and ensuring the desired dimension is on the correct side of the tooth), I set the fence position (or the stop on the mitre gauge, depending on the cut – rip or crosscut).

Setting up the Incra Miter Gauge

Setting the rule to measure to the side of the blade tooth

The photo doesn’t show an actual measurement, but in any case accuracy is always something both difficult to achieve, and worth pursuing. Even measuring to the edge of the tooth is not an assured result. All blades (and all tablesaws for that matter) have a degree of runout. The only real way of determining a measurement is with a test cut. You can take some steps to actually get accurate measurements, but it still involves a test cut, and measuring to the side of a specific tooth, and measuring to this tooth each time. So long as the blade does not slip on the arbor, and you do not change blades then this will then remain reasonably accurate.

In practice, this degree of accuracy is rarely needed – wood is reasonably tolerant in any case, and there are other ways of ensuring accuracy. One is gang-cutting. If I want two sides to be cut to exactly the same length, you can either use a fixed stop that each side butts up against (such as the Incra Shop Stop), or cut both sides at the same time.

Back to the bases, once they were cut to size, it was over to the router table to cut the rebate around the edge. To set it accurately so the base sits flush with the bottom of the sides, I use the same router bit as used to cut the trench. It needs to be dropped an accurate amount, and I have a reasonable way to achieve that, and it doesn’t involve a rule.

Setting accurate router bit height

A router bit is a power chisel, so I use it as such. Without turning the router on, I lightly scrape the endgrain just enough to reveal the exact height of the router bit. This leaves a mark to line the router bit up with when dropped to the lower position.

Scoring the exact chisel height

Tray base and sides, ready for glueup

Each tray got glued and clamped. One interesting aspect of dovetails, is you primary clamp the tail sides, which pulls the pin sides in. I still use a clamp to ensure the actual joint is not loaded up until the glue sets – you don’t want the wood fibres getting compressed unnecessarily. You may note that I used pine for the base – given I planned to cover the working surface with felt, I didn’t see the point wasting top quality timber in that situation. It doesn’t look bad from underneath, and will rarely get turned over in any case.

Once the trays were glued, and sanded, I tried the fit to the main box.

Testing for fit of the tray inside the box

You know you have the fit pretty right when the tray struggles to sink into the box – not because of friction between the sides but because of air pressure in the box! With a little more sanding, it slips down nicely, still with a little resistance, and a very satisfying “shhhh” as the air escapes. Love it!

I had another detour at this point. After the trial a week or so earlier of the dividers, it was time to make them for real.

Jarrah interlocking dividers

The dividers were cut with the thin-kerf CMT blade, and again the Incra Miter Express proved invaluable.

FWIW, Incra and Woodpeckers gear all comes from Professional Woodworker Supplies, and the CMT blade from Carbatec. Thought I’d mention it if you were looking at what I use.

Main tray with dry fit of Jarrah dividers

I was happy with the main tray with the dividers made, but when I fitted them into the smaller tray, it looked too hard to get the individual charms out, and too much like a iceblock tray.

The “ice bock tray”

Again, when not being prepared to accepting something not quite right, I decided there was no option but to remake the dividers for the upper tray. This time, I chose a wall height of 6mm. When working with power tools, that is small, and risks putting fingers too close to blades.

So it was time for handtools. Yeah, I know – shock, horror.

The sides were cut close to the height required, and then it was time for the handplanes.

There was no point trying to bring a handplane to the individual piece – too hard to see what is going on, let alone controlling it, so I reversed the situation, and used the plane in the same way as it’s power equivalent: inverted!

Inverted HNT Gordon Trying Plane

So I took my HNT Gordon Trying Plane, and mounted it in my Veritas twin-screw vice. The individual sides (the dividers) were then run over the top of the blade. The blade was set for a very light cut – there is no rush! If you haven’t set a traditional wood plane blade before, there are no adjustment screws, it is all done with a careful tap tap of the wooden mallet you can see in the top right of the photo.

The new, 6mm high dividers

So the new dividers in comparison with the original ones – chalk and cheese, and right.

I haven’t mentioned how I cut the slots, other than the Incra Miter Express. The short lengths were done very easily in two passes, and all gang-cut at once. With the Shop Stop set, the first slot was cut, and then the whole bunch rotated and the second cut. Took no time at all. I had made some trial cuts to ensure the blade height was just right.

The two long lengths obviously took a little longer, and the V groove track on the Incra fence was invaluable, allowing me to move the stop exactly 22mm between cuts (20mm for the gap, and 2mm for the kerf)

These V groove racks that ensure accurate positioning of the Shop Stop are invaluable.

So the whole jewellery box was coming together. Next, we will look at the lid, and then final assembly.

Hope you are enjoying the process!

Real Smooth Shave

Gave the first new bandsaw blade a quick workout today – the 1/2″ 3TPI bimetal blade.

It has a regular tooth set, and slices beautifully.  When resawing, it vastly out-performed my current 1″ carbon resaw blade – it is obviously significantly sharper – not surprising given how easily carbon blades dull off.

So not only it is superbly sharp, because it is bimetal it will hold that edge for longer.  I guess I have found my new “standard” blade – the one that will stay on the bandsaw by default, so whenever I want to do a quick cut without going to the trouble of changing blades, this is the one that is a jack of all trades. So yes, very happy with this first blade, and looking forward to testing the others.

The general rule is to have as few teeth in the cut as possible.  Too many, and the gullets fill and clog and the blade cannot cut well.  Too few teeth, and the cut is rougher than is necessary.  Having a range of blades, sizes, tooth configurations, tooth numbers will mean you will have the best blade for the job.

Straight-faced tooth with deep gullet to remove shavings.

Deep gullet and 10o undercut face which digs in more, and tends to curl the shavings.  Good for harder woods.  I would imagine though, that it is likely to dull off quicker, given there is less material backing the tooth edge up.

Similar to Hook Tooth, but has the teeth at 90o . Chips rather than shaves – good for materials that would otherwise clog up the blade.  Effectively increases the gullet (which clears the formed chips out of the cut), without having to increase the overall tooth size.

Has a combination of teeth closer together for a finer finish, with some teeth having large gullets for chip clearance.

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