A Slab ‘o Granite

Precision requires precision tools, there is no two ways about it.

Whether it is assuring that your square is square, your plane blades are honed to just the right angle, straight edges are straight etc, it is beneficial to have a true surface to reference off.  Taking that one step further, where it comes to sharpening particularly, if you are relying on a flat surface to create a reference plane (either the surface you use to dress your waterstones for example, or a surface to conduct the Scary-Sharp technique), then you need a surface who’s flatness is assured.

And what better way than a solid slab of granite?  You can get it wet without fear of rusting, it is dimensionally stable through a wide temperature range, and is comparatively inexpensive.

I picked up this tool from Carbatec – a Granite Surface Plate.

Granite Surface Plate

Granite Surface Plate

Measuring 300x230x50mm (12″x9″x2″) and weighing in at around 12kg, the real significance comes in when you look how flat it is.

It comes with a certificate of testing, and in this case, the block has a variance of 0.00008″ (2.1 microns, or 0.0021mm) over 7.5″.  So she’s pretty flat.

Certificate of Testing

Certificate of Testing

It will be featuring in some sharpening episodes in the near future

Stu’s Shed goes to Brisbane!

MagSwitch have invited me to the Brisbane Timber and Working with Wood Show, so guess where I’ll be on the 23rd and 24th May! (no, I won’t be there on the Friday)

I’ll be there talking about the MagSwitch range on the Carbatec stand – heh: this is going to be fun!

You know what I think about MagSwitch from the various posts on this site, so come along and see the products in person, and some of the shop-made jigs incorporating the MagJig as well.

Better yet, at this show the whole new range of the MagSwitch family will be available for purchase, so the Universal Featherboard and MagFences will be there and for sale.

Drill Press Laser

This is a short product video I produced for PWS to showcase their Drill Press Laser.

The Drill Press Laser is available from Professional Woodworkers Supplies

Pro Drill Press Table

This is a short product video I produced from PWS to showcase their Pro Drill Press Table.

The Pro Table is available from Professional Woodworkers Supplies

Securing a Shed

I had an interesting question posed via email about how to hold down a shed, particularly in high weather affected areas.

To qualify, I am not a structural, or civil engineer, so these are just my thoughts on the issue, so take them in that regard.

———–

As I see it, there is one primary failure method for a structure subjected to high wind, and that is for the roof to lift (whether or not it also lifts the walls with it!)  A roof, like any flat or convex curved surface causes a pressure differential when air blows over it, creating lift.  When the lift exceeds the strength of the fasteners (either locally or in total), the roof fails, and as does the structure.

The local building codes will hopefully have some guidelines, particularly on wind strengths to consider.

If you can secure the roof down sufficiently (and consider that the heavier the roof, the stronger a wind would be required to lift it), then the whole structure can be considered one element, and the problem becomes a lot easier.  Then you need enough bolts (I typically use dynabolts from Ramset into concrete, which have a high pull-out load (ie how much force needed to rip them out of the slab)).  If you REALLY want to get technical, this pdf product sheet gives you the calculations for working out just what a bolt can take, based on what material it is afixed into.

As a basic rule-of-thumb, I’d place a dynabolt in every 1.5m or so, with a minimum of 3 per wall (one in each corner, one in the centre).  Probably overkill, but the bolts are cheap, and a lot cheaper than watching your shed become the next door neighbour’s shed curtesy of a wind gust!

So the shed is secured down, and anything you add to the weight of the structure will also help – a full woodrack works wonders (yes, speaking from experience here!).

So back to the roof then – the real source of weakness.  A heavily constructed roof will survive a lot better than one that clips (or worse, rests) together.  So if you have one made from sections of tin that simply rest one on the next, and clip in top and bottom, you are destined for some heartache.  If you improve the structure so the roof is one unit (rather than a bunch of panels), things rapidly improve.  It can be as simple as steel rivets, so you end up with one large panel for a roof.  That way, if an individual joint or connection fails (such as round a doorway), the entire roof still has to be lifted, and not the individual panel. (Did I mention I really don’t like clip-together sheds?  At least not without some aftermarket modifications!)  If you want examples of what I mean, just watch any video footage of a hurricane.  What do you see blowing around?  Lengths of corrugated iron.  If you see an entire roof going, then we are dealing with something else (tornado!)  Corrugated iron is normally screwed to the structure individually, so if the few screws holding one panel down fail, that section blows off, exposing the rest of the structure to the full force of the wind, and more panels will often follow.  If the corrugated iron was joined together, separately to being fixed down it would be a lot stronger.

The final thing I’ll touch on is banding.  Guyropes (if you are into camping), which are used to hold a tent down.  Where wind is a real factor, throwing a rope over the top of the structure and securing it down significantly improves its survivability, and the same holds true for a shed.  A metal band or two over the top of the structure will significantly improve the connection between the roof and the walls, and effectively increases the overall weight of the shed.  These can be dynabolted directly to the slab.

So those are my thoughts on the subject.  I’m sure there are plenty of books on the subject somewhere!  Hopefully, they don’t contradict the-above thoughts!

Tricky Grains

One of the things that I always had in the back of my mind when deciding if I really wanted to buy a drum sander, was all the sanding I found myself doing with a belt sander when dealing with small burls (for clocks and the like).

More recently, I had forgotten that justification, so over the weekend I wanted to see just how well it would work.  They come pretty roughly sawn, and because of the grain chaos, as well as the hardness (often) of the timber, a thicknesser is just not an option (and also the size of the small burls are way too short to consider putting through a thicknesser.)

Anyway this is was a real quick attempt with the drum sander to see what would happen.

Took it nice and slow (1/128″ passes once full contact was being made with the workpiece).  I don’t have a “just sanded” picture- once I got a result, I gave it a very quick burst with a ROS, and a wipe with some wood oil – I was too keen to see the grain in all its glory.

Burl Before and After

Burl Before and After

Beauty huh!  These are quite small burls (the 5 was the pricetag when I bought that piece – $A5).  These are destined for some desktop application – such as a pen stand (probably), or a desktop clock.

Scraping with Scrapers

These are not cabinet scrapers (which are a skill all of their own), but instead for scraping when you need to remove a surface – such as paint, varnish, stripper etc.

I have had an opportunity to put the Linbide range through some initial trials, and as much as I normally wait until I’ve had a chance to build up a real opinion on a tool, these had me sold straight out of the box (or packaging to be precise).

Linbide Scrapers

Linbide Scrapers

From right to left, are a straight (or flat) scraper, a corner scraper, a profile scraper, and a cutter.  All are sporting Tungsten Carbide blades which makes a lot of difference to the performance of the blade (and the durability of the sharp edge)

They are very utilitarian in their look, but that does not detract from their performance, and the handles are surprisingly comfortable and provide a good grip.  The blades are replaceable (and with the straight and corner scrapers, the blades are reversable).

I took one to my front windows (external) which are increasingly desparate for a repaint.  I had a mind to a couple of years back, but after trying with some sandpaper, decided that job was too big.  I then tried a heat gun, with no success (it might have worked elsewhere, but not on a paint designed to survive the Australian sun).  So I tried a waterblaster, and that stripped the wood apart faster than it did the paint.

So it was with interest that I gave the scrapers a crack at the task, and we had a winner!  Paint came away with ease, and the wood was undamaged.  I don’t need to remove all the paint, just that which is too loose to paint over.  Damn, now I have even less excuses not to paint the house!

To get into corners, and over the different profiles around the windows, we have the profiled scrapers.

Radiused and Corner Scrapers

Radiused and Corner Scrapers

All Tungsten Carbide blades.

Now speaking of Tungsten Carbide, the final tool is called a laminate score and snap knife.  It sports two carbide tips, and is designed to score laminates, and can be used quite successfully as a glass and tile cutter, and will make short work of drywall.  Given its design, it will be easy for it to follow a straight edge.

Not having had a decent scraper before (the last one I had came from a $2 shop), it is quite enlightening to see what difference a quality blade can make!

These scrapers are imported in Australia by the Woodworking Warehouse: www.wwwh.com.au and cost around $20 each.  You can get them from their store in Braeside, or order over the phone 03 9587 3999, or via email sales@wwwh.com.au

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