The first time I considered the use of a flat stone in my workshop was while reading Somogyi books, and I was very quick to get one. It is not as big as the one he mentioned but it is a fundamental tool in my everyday working, so much so that I’m considering getting one or two extra ones to speed things up.
But first let's look at the tool I have, it's a flat slab of granite to within 0.001mm across its surface. It measures 457x152x51mm and weighs approx. 11kg. It costed me 50 euros plus more or less 20 euros in shipping has I don’t recall the exact value. So this gives a total 70 euros investment. Not the most expensive tool, but also not cheap if you are starting in lutherie. The good news is that you can recover some of that money pretty fast!
Here are five cases of use that can either help in your building or help save money in tools allowing you to tool up faster!
1 – Make straight edges! One of the most immediate things you can make with your stone plus a sheet of sandpaper are straight edges. With a 450mm long stone you can easily make a 500/550mm long straight edge in aluminum, but even better is that you can make shorter ones if you might need them. One piece of aluminum of 50x3x1000mm cost approx. 10 euros and is good for at least two straight edges!
2- Restore old tools. This one was quite predictable but a flat stone like this is a must have to restore old planes and chisels. I only really use two hand planes while making electric guitars ( a block plane and a stanley 5 ½) and the flat stone was an essential part in restoring the old Stanley nº 5 ½ that I bought. Not only is it a must to restore old tools but it is also essential to check new tools like those affordable chisels one might just buy.
3- Sharpening blades and chisels. Using the scary sharpening method, gluing several grits of sandpaper to the flat stone you can have an affordable sharpening system ready to go for a few bucks. Now over time the price of the used sandpaper will be higher than the cost of a good sharpening stone, but the initial investment barrier is definitely lower with scary sharpening. And one method does not have to replace the other, you can use water stones to keep your tools sharp every day and quickly set up some sandpaper on the granite stone to bring some misused tools to life.
4-Sand wood to be flat. This is the most common use I give to my stone. I use it to flat the neck and fretboard before I glue them up, to get the scarf joints good to glue, to get perfect flat edges on the fretboard before cutting the binding stripes...last but not least it is on the flat stone that I work the edges of the body blanks to do perfect book-matching joints.Yes I know that all of the handplanes lovers might not be fans of these approach, but it actually is fast and much easier to learn than doing such a large joint with a handplane, specially for beginners.
5- All other uses!!
Tool making: fret rockers, notched straight edges and leveling beans.
Flattening sharpening stones
Making flat sanding blocks
Use in combination with a square to check for perfect 90º
And last but not least, use as a paper weight to keep those sandpaper sheets flat!
Now it's not just how much money you can save when you are just starting, but most importantly,it’s about what it can help you do better. Sanding the body blanks perfectly flat before bookmatching and getting your necks and fretboards perfectly flat too are just a few examples of how precious a really flat surface can be in your workshop.
That's it for this week, happy playing and building!