Episode 108 DadoStop!

Had a look at the blade(s) after the fact, and found out where the significant cascading sound comes from when the brake activates.  12 separate tungsten carbide teeth ripped loose of the blade.  Most presumably are due to the spacer blades not being in direct contact with the aluminium brake, so were able to move when the blade was (rapidly) decelerating, and knocked the teeth off as they slid past.

It is a good effort, stopping that much spinning steel on a dime!

The Dado Blade of the Router Bit World

The router table has always been particularly good for cutting a groove, particularly in smaller items (such as making boxes).  The orientation of the blade to the timber for one, the diameter of the blade (vs a tablesaw), the speed of the cutter, the accuracy in setup.

The one frustration I have found is having to accept the width of the groove is limited to the width of the cutter of the router bit, or having to take multiple passes.  Unlike a tablesaw, the concept of a dado blade is foreign to the router table.

Well until now that is.

Toolstoday.com have available a really interesting router bit indeed from Amana Tool.  It is an EZ Dial Slot Cutter, and unlike a tablesaw dado blade stack, this router bit does not have shims, or even need to be taken apart and reassembled.

EZ Dial Router Bit

Looking at the anatomy of the router bit, from the top-down.  The top threaded section is the range of adjustment of the router bit, and there are two types available – a 1/8″ – 1/4″, and a 1/4″ – 1/2″.  Next is the locking nut – once the width of the slot is set.  The knurled knob is the adjustment for the router bit, and is then locked in position with the locking nut.

The blade is next – it is a four-flute router bit, but because of the adjustment, each side of the trench is cut with two of the flutes.  As the knurled adjustment knob is turned, two of the flutes move with the knob, and the other two remain fixed.

A bearing then sits under the flutes – useful when following curves, and other times a router fence is not in use.  Just below that is a section with two flats – this is useful if the locking nut is too tight – a spanner can be fit on this section so it can be undone without having to risk damage to the router chuck or shaft lock.

Finally, the shaft is a finely finished, accurate 1/2″ shaft.  (An inaccurate shaft is either difficult to fit the router collet if too large, or at risk of slipping if too small).

Variable slots

I was working with the 1/8-1/4″ router bit, but the concept is the same.  In the above image, the two opposite flutes move, the other two are fixed.  That dial-in adjustment is remarkably liberating.  Being able to set the width of the resulting slot to accurately match the material that will fit in it (whether that be another piece of timber, a sheet of glass etc), and also easy to add an accurate amount of clearance if required.

The quality of the router bit is obvious, as is the finish that is achieved.

Not only can the width of the slot be set, but it can be adjusted with the router bit fixed in the router. (So long as you intend to remove more material – too hard to put material back!) Rather than trying to work out the range to move the router up and down again, a test cut or two, a dial-in of width, and your accuracy and flexibility of the table is increased dramatically.

Once you experience the convenience of a shim-less, dial in width of slot for a router bit, you’ll be wishing a tablesaw dado blade was as easy, as infinitely adjustable, and as accurate.

Available from Toolstoday.com

 

Groove is in the Heart(wood)

The dado blade (or dado set) can be a particularly accurate tool when it is understood correctly.  With a combination of spacers and shims, a dado (or groove) of very precise width and depth can be cut in a single pass.  Unlike a router bit producing a groove, the size of the stock to fit that groove does not have to match the router bit, nor do you have to make multiple passes to get to the required width, or depth.

The tablesaw is also much more suitable for processing large amounts of stock, and long lengths.

Electroblu Dado Blade

The dado set I have been using recently is this one from Amana Tool (through Toolstoday.com)  It is an 8″ dado set, with a 5/8″ bore.  The bore accurately matches the arbor of my tablesaw, so I don’t have to try to juggle washers for each blade and spacer, and means the blade set will produce a more accurate and flat-bottomed groove.  It has most recently also been upgraded to have the environmentally-friendly Electroblu coating, which help mitigate heat buildup during the cut (which has an adverse affect on accuracy – the more heat, the more the blade can warp.  This then results in more runout and therefore a change to the effective width of the cut.)

Click here to see the blade at Toolstoday.com  Don’t worry that the blade is not blue – the photo has not been updated yet to include their latest coating that is now standard on their blades.

Dado Stack Set

It is a particularly nice set, with four 1/8″ spacers and one 1/16″ spacer (or chippers), and a set of shims of various widths.  The outside blades (which must always be used for every cut) are dedicated left and right (as is normal for dado sets).  The blades are not ATB – they are either bevelled left, or right only (depending on which blade it is), with every 6th tooth being flat ground.  They each have two teeth missing – this allows a place for the chipper blade to rest, so that the carbide teeth can overlap without knocking into each other.  The flat ground teeth result in square corners at the bottom of the groove.  Many other dado sets leave a telltale triangle cutout, where the bevel cuts deeper than the chippers.

Inner edge of outside blade

An interesting feature of the outside blades is a raised section on the inside, effectively increasing the thickness of the blade, and when not using any chippers or shims means the two outer blades can rest against each other, again without the carbide teeth impacting.

Chipper Blades

This particular dado set has only 2 tooth chipper blades.  This may seem a disadvantage (the general principle is the more teeth a blade has, the finer the cut), but the chipper blades don’t impact the side of the cut, where smoothness really counts.  Chippers only remove the material in the middle of the groove, so they only touch the bottom of the cut, and with a combination of the quality of the carbide, the angle of the grind and these chippers leave a very smooth finish.  The other really important aspect is the chipper blades have to be exactly the same diameter as each other, and the outside blades.  This leaves a flat-bottomed groove.  If one is over (or under) sized, it leaves a step in the groove base.

Dado Stack

As you stack the dado set, you stagger the individual blades so that the carbide teeth have no chance of pressing on each other.  Other than risking damage to the teeth, if they are pressing on each other, they will distort the effective width of the dado stack.  When using shims, you need to space them out between each of the blades used.  It is a good idea to put the thinnest ones nearest the arbor washer & nut.  That way it is easier to change the finest shims to fine tune the effective width of the stack.  When measuring the width of the blade stack, you cannot simply add up all the width of the components.  The amount of runout of the two outside blades (in particular) (and to a lesser degree, the runout of the chippers) needs to be added to the final width, as does the runout of the tablesaw itself.

This can be determined by trial and error.  Set up the stack for a certain width of cut (adding together the kerf of the outside blades, the chippers and spacers used).  Perform a cut, and measure the result.  This will give the actual width of the cut, and the difference between the two is the runout of the stack and tablesaw combined.

Zero Clearance

Despite the fact I have a 10″ tablesaw, an 8″ dado blade set is more than enough.  There are a number of reasons for this: Unlike a normal blade, the dado set is only ever for cutting a groove (and more often than not, no more than 1″ deep).  There is therefore no need to incur the extra expense of a larger blade.  A dado set is already much heavier than a single blade, and can really push the limits of the saw motor just to get it up to speed, let alone maintain that speed during a cut.  A larger blade has significantly more bulk and mass, and can exceed your saw’s capacity to spin it up.  The benefit of this set, is those 2 tooth chippers have a lot less bulk than other chippers, so this also helps deal with the overall bulk of a dado set.  The other thing is that a dado blade really does not need anywhere near the depth of cut of a standard blade.  It is for cutting grooves, not cutting workpieces in twain.

As far as how this blade performs, it is excellent – but you’ll have to see the associated video (which I am working on) to see the result.  Needless to say, I had a precisely cut dado that absolutely matched the board I was inserting, so the friction fit was beautifully tight.

To get that precision, I took the typically supplied notes on the various combinations of blades, chippers and shims to achieve a standard set of widths, and threw them out the window.  Instead, I came up with a comprehensive set of every single combination possible, in order of increasing width, so I can exactly choose what combination to start with to match the board I am inserting into the resulting groove.  Instead of having about 24 combinations that were provided, my list is just over 3000 combinations.  And because I have it in Excel, it is easy for me to add in the runout of the blades and tablesaw to end up with even more precision.

Out of interest, I have attached the full list below (and below the smapshot of part of the table)

Snapshot of a few rows of the table

Dado Set Combination pdf

The Dado set by Amana Tool, from Toolstoday.com is a worthy version, and well worth considering when looking for a dado set for your workshop.  When the video comes out, you will see just how precise a dado set can be!

I box, therefore I am

Ever tried a box joint (also mistakenly called a finger joint by Triton)?  Some regard it as a poor-man’s dovetail, but it is a legitimate joint in its own right, and can be used as a stunning joint, with the added bonus of significant glue area. You can pin the joint for even more strength, and if you take that one step further, the wooden hinge I made recently is another version of a box joint.

There are a number of plans out there to make a jig.  Some of them even offer the ability to have a couple of sizes of fingers.  Generous.

If you are fortunate enough to have an LS positioner on your router table, they are a pretty simple operation, but even that has some limitations.

They can be a stunning joint can’t they!  And those with variable spacing, or a central key pin are even more interesting.  As you become inspired by the joint, don’t you find yourself wishing someone like Incra would come up with a jig, incorporating their typical clever engineering, and insatiable appetite for precision?

Yeah, well, they did.  And it is a stunning looking tool at that.  Works on both the router table and the tablesaw, utilising the mitre slot.

I don’t have too much to add to the topic yet, other than these initial photos which just start to reveal the qualities of the jig.

On the tablesaw, this is one of those occasions where a dado blade really comes into its own.

The jig is currently available on pre-order through Professional Woodworkers Supplies.  The initial shipment is almost completely accounted for already, so if you are keen, be quick.

As I mentioned, I’m not going into a lot of detail as yet, but that is destined to change.  And you can talk to whomever you like on the blogs and forums, but at the moment I have loan of THE first pre-release model (the one that starred in the photos and video) to put through its paces, and there isn’t another one currently in the wild.  Just another Stu’s Shed exclusive!

It certainly has some very cool innovations – look forward to getting to know them better and to bring them to you as well.

In the meantime, have a gander at the following Incra video – it explains a lot.

 

A Night at the Opera

Or more like, a night in the shed 🙂  Got a number of things done out there which was very refreshing, and actually felt like real woodworking for once. I even got to make some sawdust!

As I’ve mentioned before, I’ve had some trouble with my current inadequate power supply to allow me to use dado blades on my tablesaw. As a bit of a test, I purchased a tradesman’s extension cord yesterday which has a 1.5 mm core rather than the standard 1.0 mm (or even smaller) in typical household extension cords.  I plugged this feed directly into the tablesaw, and gave that a try and the difference was quite remarkable. Even running a standard blade, the saw sounded somehow different.

I then fitted a dado blade, and this time I was successful. The saw easily managed to bring the dado set up to speed. I must admit, that it has been a while since I’ve been that nervous around woodworking equipment- the first time you use a dado set is scary!  When a typical blade has lots of whirling teeth looking for something to eat, like a circling shark, a dado set looks like a whole school of sharks, and they know what they want.

On the other hand, it sure makes cutting a trench or a dado easy! (Funny that).  This dado test is going to be very interesting, and I’m now in a position to start testing the various blade sets that I have.  There have already been some irregularities come to light, so that is what this battle of the dado blades is all about.  One set appears to have the wrong outside blades, as the tooth count is incorrect to match with the chipper blades so that they cannot stack correctly (and I’m getting some feedback from the relevant company about that), and the set I used last night (CMT) had a very poor trench, because one of the chipper blades is over 1mm oversized which I was very surprised about with a set costing over $400.  Anyway, all this will be revealed in full Cinecolor in the reviews in the near future.

Next, a very rusty demonstrator got to shoot the raw footage for Episode 41 of Stu’s Shed TV which briefly covers some of the jigs that can be used on a wetstone sharpener.  I did get a very respectable edge on my carving knife, so the next tomato will pay the price in the kitchen!  I’ve said it before – the Triton sharpener should come with a knife jig – it is the best excuse to justify buying a tool ever!

Then finally, and inspired by my article about the Chris Vesper Joinery Knife, I had a further play with that laying out some rudimentary dovetails, and that inspired me to (finally) assemble the Dovetail Master I got from the Australian Wood Review over a year ago.  I had put it into the “too hard to think about now” basket, but last night everything just clicked.

Dovetail Master

It comes disassembled, but it isn’t actually that hard to put together.  Of course the proof will be if I actually can use it to produce a handcut dovetail, but it looks like I managed to assemble it without too much drama.

Disassembled Dovetail Master

It is currently on special for all of $35 from Australian Wood Review (direct link to the product) fwiw.

So it was a good night – some sawdust made, some video shot, some old jobs completed.  Good times 🙂

The MagJig and the Incra Fence

I had an idea a while ago as soon as I saw the MagJig by MagSwitch – this has the potential to a problem that has perplexed me for ages. How do I get in incredible accuracy of the Incra LS Positioner fence on the Triton?

The problem was always fixing the fence down well enough to use the fence accurately, yet able to be removed easily, and without damaging the Triton top (ie drilling holes etc). Now that I also have a cast-iron cabinet saw, it also provided the perfect solution for using the Incra fence on that as well (and there is NO way I’m drilling holes into that top!!)

So off to the drill press, and a couple of 40mm diameter holes later, and the MagJigs inserted, we have a perfect solution.

The MagJig inserted through the mount that I use for the LS Positioner on the router table

The LS Positioner secured firmly to the tabletop. Now, to qualify the photo, I have removed the vertical panel support from the LS Positioner, but I have not removed the Wonderfence, which you certainly would before using the LS Positioner on the tablesaw.

Secondly, I would definitely use the Deluxe Aligner to ensure the fence was perfectly parallel with the blade (or more precisely with the mitre slot in the table.

The Deluxe Aligner is perfect for the task. (Obviously this is a photo from my file, and is not aligning the fence!!)

Finally, and one of the great things about the Incra LS Positioner is once it is set up and parallel to the blade, it is an absolute cinch to zero the fence to the blade, allowing extremely accurate cuts to be made. You’d definitely want to ensure an absolute minimum of blade runout, because the LS Positioner will give 1/1000th of an inch accuracy to your cuts!

And just to prove a point, here it is on the Triton, turning it into a precision machine!

There will definitely be more posts / video on this in the future – the possibilities are too good not to explore this further. (Again, if this was actually about to be used, the Wonderfence would be removed leaving the straight fence only). Attaching a false (MDF) fence to that would then allow the blade to be partially buried in the fence for shaving cuts, or the use of a dado blade (but not on the Triton obviously!)

Contractor Saw version of SawStop

A first look (video) at the Contractor SawStop can be seen here on Fine Woodworking

It also shows just what happens when the SawStop is fitted with a dado blade, then made to cut something fleshy.  Stopping that blade sounds violent!  Still does though, with the resulting minimal amount of damage to the ‘subject’.

They are not yet on the market, but could be in Australia later this year. No indication at this stage of the price point.