Bandsawing a Two-Profile Form:
Andrew Thomas demonstrates the most effective way to cut a two-profile form on this machine.
The bandsaw is arguably the most important machine the wood carver will ever invest in. It saves them much time and effort by allowing the speedy removal of all the waste wood around the profiles of the form they want to carve. It is therefore vital to learn the basics of how to use the machine safely, effectively and accurately, so the actual carving of the subject can begin as quickly as possible.
The skill of bandsawing requires many years of experience to perfect by experimenting with a multitude of different forms, each creating various complications to consider and overcome. Learning to set up the bandsaw correctly and safely is a fundamental necessity. But then one must look closely at each design which is to be cut, and initially work through the process intellectually to consider and understand in what direction the cuts should be made and in what order before the cutting procedure begins.
Safety when using machinery is of vital importance, so please ensure that you carefully study and follow your machine manufacturer’s guidelines to set-up and use. Always wear a dust mask, wear eye protection, attach a dust extractor to the machine, use a sharp blade, and never – but never – try to ‘force’ a cut. And always keep fingers out of the line of cut and away from the blade. Use push sticks whenever appropriate to do so. For the purpose of this exercise I am showing how to cut a cat used for a previous project. It shows all of the fundamental cuts I use when bandsawing any profile ready for carving.
Timber, templates and holding
The first job is to select an appropriate piece of timber that has the correct dimensions for the scale of your project, but also allows 6-8mm outside of the design lines. The timber then has to be planed perfectly flat and square on all sides, so that when the front and side profiles of the design are cut, they are in precise alignment with each other.
Scan or photocopy the drawings you are using – in this case it is a cat – enlarging or reducing them to the correct size for your wood or size of project you wish to make, and print them out on to card to be used as templates. Measure the length of the design and mark this on your wood. Then use a try-square to draw a straight line from this position across the front and side edges where the designs will be placed.
Use the templates to transfer the side view centrally on to the widest side of your block, and the front view centrally on to the narrower edge. Make sure that they are both the correct way around, otherwise the form will be back to front, and also ensure that the grain direction is running vertically through the block.
Some thought must be given as to how the block is going to attach to your carving vice. In this example, a 30mm block will be left directly underneath the cat’s form, which will attach directly to the faceplate. Measure and mark this in position.
On some occasions, depending on the subject matter, it can be very useful to make a horizontal cut on all sides, underneath the lower edge of the design, which facilitates this lower edge being more easily carved. Simply mark the central position of each profile view, then measure out 15mm either side and mark this on the wood. When this is cut, the cat form will essentially be attached to the base by a 3cm square block underneath, which is more than strong enough.
Setting up a bandsaw
Before we start the cutting, a brief word on setting up the bandsaw correctly. First, the blade should be correctly tensioned according to its size and the machine manufacturer’s guidelines. Then the two blade guide bearings, one either side of the blade, need to be adjusted to within a fraction of a millimetre from the blade. The rule of thumb dictates the width of a piece of paper.
The recommended blade for nearly all carving projects is a 6mm, skip-toothed 4tpi (teeth per inch), high carbon steel one. This blade can cut a very tight curve of about 16mm diameter into very thick timber. This should be positioned with the teeth just proud of the blade guide bearing either side, and with the rear thrust bearing a fraction of a millimetre behind it.
The height of the blade guides should be set approximately 1mm above the height of the timber on the side view, which will be cut first. This will be adjusted again later when the front-view profile is cut.
The first cut is directly along the outside of the lower line on the side view, up to the 3cm mark. When making ‘stopped’ cuts such as this, the blade needs to be ‘backed out’ every 10mm or so. If this is not done, the fine dust builds up behind the blade, causing it to become stuck in its own channel. If this does happen, switch the machine off and then use a very thin metal shim or 150mm steel rule to clear it out.
Now do the same on the opposite side, remembering to back the blade out of the cut every 10mm, and stop at the 30mm mark. The height of the blade guides will now need to be adjusted to the correct size of the front-view profile. Do this and then check that the blade guides are still in their correct positions in relation to the distance from the blade. Adjust if necessary.
Repeat steps of the earlier cuts and along the front-view profile to produce the 30mm square, solid section at the very base underneath the form.
Denser timber, such as walnut and oak, produce a far coarser dust than lime or basswood when bandsawn, which creates less of a problem with the build-up of dust behind the blade. Therefore, the blade can be backed out every inch or even more. Do a test each time you start cutting out a project to see how the species of timber behaves.
When cutting into an angled corner, it is sometimes wise to not cut the actual angle unless you are absolutely sure that its position will not be adjusted when the subject is carved – which is more often than not the case. If you wish to leave yourself some leeway in these areas, cut in as close as you can with a curved cut, and simply carve the corner details later.
Cutting the curved body
The height of the blade guides will now need to be adjusted again to the correct size of the side-view profile. This area between the cat’s ears is definitely a position that should not be cut angled. Work directly along the outside of the line in a sweeping curve to remove this small section at the top of the head.
The first profile to be cut is always the simplest side of the design, which ideally should be made in just one continuous cut on each side. This is very important because the block has to be reformed squarely again for the second profile to be cut. The lower edge on the right-hand side here has a tight curve which is too sharp for the blade to follow. The dashed line shows the approximate angle of cut.
Cutting and manoeuvring the block accurately is not a simple task and takes a lot of practice to become accomplished at, especially around tight curves. It is a tricky combination of moving it both forwards into the blade and turning it around, slowly and delicately, at the same time.
Start at the top position of the ears on both sides and work down towards the base, slowly along the outside edge of each line. The side-view profile has now been cut on both sides and needs to have all of the dust carefully brushed off the surface. The two offcuts also need to be dust-free so that the masking tape sticks effectively to them.
Never, ever, attempt to bandsaw a form that does not have a flat, square edge in contact with the bandsaw table. If this is attempted, the blade will force it out of your hands in a blink, and no doubt thrust it back up towards your head. The consequences could also cause awful injury to your hands if they were to touch the blade.
Reform the solid block
The block must now be reformed to its original shape so that the front-view profile can be cut safely and accurately. Use a good quality 50mm masking tape to cover the cut lines around the complete block. Ensure that the tape does not cover the front view drawing, nor the opposite edge that will be in contact with the table, otherwise this will mean your block, and consequently your cut, will not be level. The height of the blade guides will now need to be adjusted to the correct size of the front-view profile. Cut the simple line on the right side first, then tape it back together in position again.
This final side is the most difficult area to tackle, due to the tight curve from the chin around the line of the neck to the side. This will be accomplished with four different cuts. First, cut from the top position of the ear, down along the dashed line side, and terminating at the base. Remove this section of wood, brush off all of the dust and run some masking tape over this edge to hold the block tightly together again. Note the dashed line, and the start (S) and end (E) positions which signify the direction of cut.
Make the first cut along the dashed line, up to the line of the neck. Don’t forget to back your blade in and out of the cut every 10mm or so. Now, cut down from the tip of the nose around the mouth and chin area, terminating and joining the cut at the end of the dashed line. If you find the angle a little tricky to follow around and under the chin, then simply cut into the dashed line and go back to it once or twice again from a slightly easier angle.
This line of cut up the side is much easier to accomplish. Start this as shallow as possible so as not to cause an uneven join on the side. Then simply work up to the dashed line cut and the waste wood will drop off, leaving this side completed. You can now peel off all of the masking tape and offcuts of wood from your bandsawn form, leaving you with both profiles cut and ready to be carved.