Episode 74 Flai U Blade

Episode 74 Flai U Blade

Belleville Spring

I was flicking through my new copy of “Standard Handbook of Engineering Calculations”, and saw something that looked surprisingly familar, but somewhat out-of-context.

What looked just like an arbor washer (used on a tablesaw in between the arbor nut and the blade), was a Belleville Spring, and it is the sort of application that a Belleville Spring is used for – preloading bolted assemblies, and in the case of a tablesaw, it is used to transfer the tension in the bolt to the side of the blade so it doesn’t slip under load.

The original arbor washer on my tablesaw was either underrated (or I was too aggressive in tightening) because it collapsed early on, and I have since replaced it with a rigid arbor washer.

Interestingly, Belleville springs (also known as coned disk springs, or cupped spring washers) are stackable, and can be used in parallel (producing a stiffer spring with the same deflection), or opposite resulting in a lower spring constant with greater deflection.  The ability to finetune stacks of Belleville springs is a big reason why they are used on Formula 1 cars.

Belleville Stack

There is probably no benefit in knowing this from a woodworking application, but I do like understanding why things are designed as they are.

Only your imagination

I was having a chat with Dennis today in Carbatec, (who also has a Torque Workcentre), and once we started talking about different ways to make use of the machine, the ideas just kept coming.

From a different method for supporting the support arm (allowing a longer outfeed arm to be used without support at the very end of the arm), through to different tools that can be mounted to it.

His latest trick has been to mount a biscuit cutter to the Torque Workcentre and apparently it is a very effective.

Dennis' Biscuit Jointer

Especially using the built-in stops of the TWC for repeatable positioning of the biscuit slots.

So my thought was – if it is good enough for a biscuit, why not a Domino? Think there is definite merit in being able to do so, particularly for large production runs, for example dominoing shelves for a bookcase (for example).  The side panels could have loose tenon slots (mortises) cut use the stops to produce the left and right slots very simply.

Mock-up of Domino on the TWC

A couple of tapped holes in the base of the Domino used to mount accessories look also quite suitable for mounting to the TWC. They are not subjected to any more loading than normal Domino operation, with the plunge on the TWC used to bring the Domino in contact with the workpiece before the original plunge method of the Domino used to cut the mortise.

Mounting holes

Yet another accessory for the TWC that may become available in the very near future!

Thanks for the idea Dennis!

Episode 73 Crosscutting on the TWC

Episode 73 Crosscutting on the TWC

Metric Wooden Hinges

Heard a rumour recently (actually more than a rumour – if it happens to be dropped into conversation by Professional Woodworkers Supplies, then it is a fait accompli), that along with the recent release by Incra of their top-line products with a metric version, the HingeCrafter is also going to have a metric version.

The only holdup now for it to make the market, is waiting for the metric Whiteside router bits to be developed.  So good news for those who want, or have a metric Incra LS Positioner, and want to be be able to use it in conjunction with the HingeCrafter to make a stylish wooden hinges for their project.

Class

The hinges can then be made in the same timber as the project (or contrasting as a feature), and really look to lift a project to another level.  Imagine getting a stylish dovetailed box with a hinged lid, and how it would look if the hinges were brass compared with wood.  The whole project goes from “wow”, to “WOW”.

Contrary to what you might expect, the HingeCrafter is not actually used to form the hinge knuckles.  That is achieved on the router table, with the Whiteside router bits and the LS Positioner.  The HingeCrafter is used to bore the hole for the hinge pin.  It is both important that the hinge pin is perfectly straight (so the hinge operates smoothly without binding), and that no breakout occurs as the hole is being drilled (let alone having too much side pressure causing weaker timbers to have knuckles break off altogether).

HingeCrafter

With the included drill bit (and assuming the metric will be the same as the imperial), hinges over 10″ long are possible (254mm in metric).

Manufacturing Steps

Hinges

Any sizes you want (length of bit depending – the hinge can be up to twice as long as the available bit), and 4 different diameter hinges.  Made in your timber of choice, either matching the project, contrasting with it, or both!  And no more of those brass screws who’s heads seen designed to shear and pop off at a moment’s notice.

Prototyping

I’ve started prototyping the switch mechanism to complete my electro-mechanical starter for the dust extractor.  The first rocker was very basic, getting some of the initial ideas out of the head and into a product.  From that, this second, still crude prototype is being developed, including additional ideas such as adjustable ends for the rocker, multi-hole positioning for the electric central lock, more scalloping both front and back of the rocker.  I’m using another offcut from the thin cutting board to reduce friction between the rocker and mounting board.

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I’ve mounted the servo onto a board that will initially be duct taped to the starter box.  The 12V transformer will be mounted to the other side of this board.  It will certainly be interesting to see if this actually works!

The Engineer’s Bible

This isn’t the first time I’ve mentioned the Engineering Bible on Stu’s Shed – back mid ’09 it made an appearance – a book that I have wanted to own since first discovering it in 1997/8, but refused to justify the $A200 price tag.  For some reason I jumped on Amazon recently, and found it on there for $US107 (and at current exchange rates, that is $A112).

And that went straight into the shopping cart. (Along with the latest Stephen Hawking,

and perhaps as an unusual juxtaposition, the Lincoln-Obama Inaugural Bible.  Seemed fitting buying a real bible with the Engineer’s one!

But more than that, there is history there, and it is beautifully presented, and has a picture of the Seal of the President of the United States on the cover, and is $US100 (except on the day I was looking).  I got it for $US4.75. Brand new. No idea why it was that price. Wasn’t going to ask.)

So back to the “Standard Handbook of Engineering Calculations”.  Not much more to say, but I am now holding my own copy. Finally. 🙂

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