Using an Adze to Finish a Timber Beam
I've never used an adze before but always fancied having a go. Its quite a skill to master but repetition and practice soon develops the motor memory required.
The adze was the only tool I didn't have so I plunged in to ebay to find one. For £30 I secured an I. Sorby 2lb 12oz Adze head, made in Sheffield (just down the road from here). The condition was OK but the blade needed some serious re grinding and it needed a handle, more information about the Adze grinding and Adze handle here, later.
Different cuts with an Adze
I found the adze can be used in many different ways all depending on the ark and power of swing, the angle of contact and how the strike is followed through. It'll be different again to use on hardwoods and seasoned timber, on this job its very green softwood.
The primary cut is a scallop due to the curved blade. Working diagonally to the grain its possible to get a scalloped out shaving in a single stroke.
Working along the grain a deep cut will rip / split out. Good for taking off high spots. If the blade doesn't follow through to remove timber, pushing the handle lifts the split. The timber can then be worked from the other direction to clean off whatever is left.
Going along the grain, with the blade attacking almost parallel to the surface angle it's possible to take off long shavings.
Delicate "nibbles" can be taken, working around a knot form all sides to get a reasonable finish without ripping at one side.
And I'm sure there's many more in between.
Working to tolerance with an Adze
With a bit a practice, flattening the critical side of the beam to a tolerance around 1/8th of an inch per foot wasn't a problem.
Working with a taught string line it's easy to identify the high spots and swipe them off. Gradually working down to accuracy level you need. For this particular job only one side needed to be flat to any degree of accuracy, this is the side the floorboard will be on.
For all the other sides any degree of accuracy is purely for aesthetic reasons. With this mind the string line was only used as a rough guide. The rest done by eye, after all that is how it will be judged.
Final finish with an Adze
Working the softwood in it's green state makes it virtually impossible to finish all areas without some tearing. The fibres of green timber part more easily. Also I'm working on on sections of the timber where the grain dips and rises so sometimes it cuts and sometimes it rips, similar to using a plane the wrong way for the grain.
I soon came to the conclusion that it wasn't worth the effort trying for an absolutely perfect surface. However I did manage to clean up the surfaces to a reasonable degree using more delicate strokes with the blade at an angle to the grain and often working from the centre outwards. And adjusting the direction of working to suit the grain. A draw knife could be a better option working the wet timber. When the timber has seasoned it'll be much easier to get a good finish using the adze.