Thursday, 29 September 2011

How to handle a drawknife and other tanged tools

To follow on from the post on how I sharpen drawknivies. Here is how to put new handles on it. I will assume that either you have handles, or can turn new handles, either on a pole lathe or a modern electric lathe. If turning on a pole lathe either turn green, dry the handles, and then turn again when dry to fit the ferules, or turn from seasoned wood. I often turn dry wood on the pole lathe if I want round turnings. If possible use the original ferules or use new ones or cut some from brass or copper pipe. The ferules will need to be put onto seasoned wood, we do not want the wood to shrink and the ferules to become loose. This is a C Whitehouse drawknife, and I turned the the handles to the same pattern as the originals.
I use long series drill bits and I drill in from each end rather than drilling all the way through. This way you will get the entry and exit holes in the right place. This process is not easy, so practise on odd bits of wood to hone your technique.
If necessary drill a larger hole part way through if the the tang is thick at the blade end. The old handles are split off using an old chisel.
I am lucky that the tangs are in reasonable condition. This one had a bit of rust and is slightly thin in the middle, but will work well enough. Sometimes you will need a new tang welded on. Unless you can do this yourself, find a friendly blacksmith or fabricator to do this for you.
 Make the tang straight by heating it with a blow torch. Make sure that the blade section does not get to hot as making the blade too hot can change the temper or hardness of the steel. Note that I have the blade on my anvil, which acts as a heat sink for the blade.
Make each tang straight and in line with each other.
Heat the tang up again and push the handle onto the red hot tang.

Do not push the handle all the way onto the tang, leave enough so you can hammer the handle firmly onto the tang. Pull the handle off as soon as you have got far enough down the tang. It is best to let the tangs cool down slowly as quenching in water can harden the tang and make it brittle.
When the drawknife is cool to the touch, paint linseed oil onto the tangs and inside the burnt hole. Using a scrap bit of wood with a hole drilled into it, bang the handle fully down into place.
I made a washer from a bit of brass, and if the tang sticks out a bit to far just file or cut the excess off. You only want 2 to 3mm protuding above the washer.
Using a ballpein hammer, mushroom over the tang. Do this hammering the tangs outer edge around in a circle, do not hit the tang square on in the centre.
The finished  handle.
Bevel up
Bevel down
With a wooden mask for the blade.

I use the same general principles for putting handles onto chisels.

Saturday, 24 September 2011

Carved wooden hummingbird.

Sometimes it takes a simple addition to lift an item into being a great artefact. If you read my last post I was happier with the hummingbird drinking nectar from a wooden flower on a thin bent willow stick, which was totally impracticable. The other set up was functional and long lasting, but lacked something. At the workshop I had an idea of putting leaves onto the base of the flower. Needing something that was quick and simple I picked up some ash shavings from the shaving horse and fashioned them into petals.
The whole fanbird and flower is now more balanced.  I have noticed that it so easy to go too far with finishing or embellishment and ruin a piece of work. The" KISS" saying has a lot of truth to it, "keep it simple stupid". I thank my good sense to use waste shavings rather than making or carving wooden petals, which could have made the bird with flower more expensive and time consuming.

Thursday, 22 September 2011

Hummingbird fan bird, with real wooden flower!

Same bird but 2 different flowers and flower stems. I know which I like best, but it is very likely to get broken.
I love the way it moves in a slight breeze. The other issue is that the thin willow stem will droop over time
This one will last and is easier to post and pack.

All fan birds are for sale, I hope to revamp my fan bird page on my web site and also have a few for sale on a sale page on this blog, very soon.

Saturday, 17 September 2011

Drawknives , the blunt, the handleless, and the pitted. Make them cut like new

 I have used draw-knives for over 20 years now and I can still get passionate about them, as a tool for shaping wood. Both with rough and fine work, they are hard to beat. Of course you need another tool, the shaving horse to use them efficiently. Here is a link, to the Bodgers forum with lots of pictures of shaving horses.
I have a collection of draw knives I need to sell. Some of them need a lot of work including new handles, and some of them just need a good sharpening, so I thought I would take a few photos and share with you.

I start off by flattening the back of the knife. The back, in my definition, is the flat side. I always keep this side absolutely flat and never put any sort of bevel on it. I know that some authors and sharpening practitioners advocated a back bevel, but I see this as making the knife less useful. Why? Because if the back is flat then it operates as plane, against which the edge is guided. If you have a bevel on this side then the knife needs to be held at an angle against the wood, and it is then easier to erroneously dig in or pull out, when pulling the knife. A slight change in the angle the knife is held, then the more likely the blade is to produce an uneven surface. Anyway, the knife has a bevel on the other side with which to make concave cuts.

When the back has been flattened and any pits have been ground out, I then joint the edge. Jointing is running a stone at a 90 degree angle to to back of the blade. In other words, I am making the edge blunt. This takes out any chips and hollows and makes the blade straight or of the desired curve or crown.
I only joint when renovating tools, or when the edge has been damaged. If I get an odd imperfection in the edge I often leave it, and it will sharpen out over time.

The next step is to take lots of metal off the bevel. I want about a 20 to 25 degree angle for the primary bevel. The most useful machine for this is a bench grinder. A belt sander works well as well, but I have a dedicated wood one, and do not like using it for metal.
Bench grinders are great, but they do need to be used with an understanding of how they work. It is very easy to overheat the steel blade and make the edge soft. A bench grinder is aggressive, and it is easy to damage a blade very quickly.  This quality of the bench grinder is very useful in regrinding primary bevels, something that would take hours to do with,even, a very coarse bench stone. Start by using one on larger tools such as an axe.
You may well ask why do I not use the belt on this bench grinder. Simple: it is so under powered that it almost useless. This is a bottom of the line cheapest machine out there, and you get what you pay for. Put any sizeable lump of metal on the belt and only a small amount of pressure will stop the belt.

I have recently made a simple jig for the bench grinder to help guide the draw-knife. I used a few offcuts of wood and a few screws.

Note that I made the jig table at an angle, this is so the draw-knife handles do not get in the way of the grinder housing. I also use a screw to set the angle the knife is ground at, this screw can easily be moved to achieve a greater or lesser angle. This set up is pretty primitive and when I have time I may make a better jig. Before making this jig I just run the draw-knife along the metal table, and I do it freehand. Using a jig this way is a bit more accurate.
I have the jig at a slope because on this grinder it helps keeps the handle of the draw-knife away from touching the body of the grinder.

Remember to do a few passes and check to see how warm the metal is. It is best to do say 4 or 5 passes and then just get on with something else while the metal cools down. There is a lot to be said about not dipping in water to cool the metal down. Some people say that this can cause tiny fractures in the edge, invisible to the naked eye, which can lead to tiny chips.
Back to the bench stone: this one is a modern Norton oil stone and one of the coarsest  they do. I now rub the draw-knife over the stone to produce the primary bevel on the knife. I am not one to get into measuring all the time, as I have been sharpening for so many years that body and brain just get to know what is what, a tacit knowledge that only comes from doing. So do as I say and not as I do, and get a protractor that can measure the angles of your blades, make up wooden blocks so you can compare the angle of the knife you are holding. The last thing you want to do is to put a more obtuse bevel on your tool.
The main thing about sharpening is holding the tool at a consistent angle, and patience, and having a loupe or small magnifying device to study the edge with.
Continue with honing on finer stones and  strop if you want to. Yes I said strop, I strop most of my cutting tools, because it is my belief that the finer the edge of the tool has been polished to the longer it will stay sharper for. A quick strop can bring the edge back to life again and saves time using the hones.
On a side note, if you are using a draw-knife for a lot of concave cutting then a more obtuse bevel works better, or is this just an excuse for acquiring more tools?

Monday, 12 September 2011

Rocking Chair

I made this rocking chair for a lady I met on a spoon making workshop that I ran last year. I later met Marilyn again, at Rivenstone Festival, where she commission the chair.

The chair is made from ash split and shaved from the log. The seat is a plank of London plane. All other parts are made from oak. The plan was for me to have it made by this summer when she came back to Devon for a holiday. I had the it dry fitted but not glued up for a test fitting, but seven days later she collected the finished chair.
Chair making is something I rarely do; but this is a copy of a similar chair that Anton Coaker from English Hardwoods commission from me many years ago. Anton gave me a not quite dry slab of burr oak to make the seat from. Since making the chair, the seat has dried and moved, and although smooth to the touch it is bumpy and warped. This has not detracted from its function, feel or appearance. Every time I buy wood from Anton I see it in his kitchen and can see how well it has stood the test of time with 3 children growing up with it, and sometimes using it as a climbing frame.