Despite the widespread use of circular saws, reciprocating saws and jigsaws, the traditional hacksaw for wood is preserved in the workshop of each household. With a small amount of work or in hard-to-reach places where you can’t crawl with a power tool, a hand hacksaw helps out as before. For the tool to work with sufficient performance, accuracy and quality, it must be sharpened on time.
How to determine the moment when it’s time to sharpen a hacksaw
An experienced carpenter is able to determine that it is time to grind the saw, according to the following signs:
- the sound of cutting a tree changes;
- the teeth change color.
Less experienced are also available a number of signs:
- increased material resistance;
- it is difficult to maintain the perpendicularity of the cut;
- the blade does not hold well on the cutting line, the fishing line deviates or bends;
- the blade is jammed in the wood.
Before sharpening the saw, it is necessary to part the teeth, that is, to ensure that they are deflected from the plane of the blade by a certain angle. Correctly divorced teeth guarantee a cut width sufficient so that the blade does not get stuck in the material. With excessively diluted teeth, the cut width will be too large, this will increase the loss of material, pulling force, and also reduce accuracy.
If you sharpen a saw on a tree correctly, it restores its working qualities.
During sharpening, the following geometrical characteristics of the teeth are restored:
- profile angle;
- bevel angle of cutting edges.
Important: blades with hardened teeth cannot be sharpened. They are easy to distinguish. they are black with a blue tint. Conventional blades can (and must) be ground in a timely manner.
Hacksaw wiring requirements
The width of the dilution of the tips of the teeth corresponds to the width of the cut. It was established experimentally that the best wiring width exceeds the blade thickness by one and a half to two times for hard varieties of wood and two to three for softer ones. Given the most popular saw thickness for wood, one millimeter, we get a divorce value of up to half a millimeter for hard varieties and up to a millimeter for soft ones.
Saw teeth of various shapes
When wiring, it is also very important that all the teeth bend at equal angles. The teeth divorced wider than the rest will increase the pulling resistance and wear out quickly. The teeth already divorced by the rest will not participate in the sawing process, and their tops will slow down the broach and reduce its uniformity, making work difficult.
Attention: the bending of the teeth is carried out starting from the middle part. An attempt to bend the tooth at the base leads to a decrease in the strength of the blade and to its destruction.
The teeth deviate from the plane of the blade in a checkerboard pattern, for example, all even to the left, all odd to the right.
Only very experienced carpenters are able to breed saws in wood “by eye”. This skill comes after several hundred divorced saws. Less experienced craftsmen should use a special tool. wiring.
The simplest version of the tool is a flat plate made of durable metal with a slot, into which the blade comes in a preload, with a minimum clearance.
The saw blade should be clamped in a bench vise. The teeth should protrude slightly from behind the sponges. The teeth are clamped one after the other in the groove of the tool plate and bent in the middle part. The wiring angle must be constantly monitored. First, all the even teeth are bent in one direction, then all the odd ones in the other. At the end of the wiring, you can spread the jaws to the width of the wiring and stretch the canvas between them. If any of the teeth are bent more than necessary, they will touch the vise. They need to be fixed.
Video: How to Sharpen a Hacksaw Wood
Cloths with red-hot teeth are not subject to routing.
At different heights of cutting teeth, woodworking efficiency is greatly reduced. Higher ones take up a greater load and are subject to accelerated wear, while lower ones do not participate in cutting. The broach becomes uneven, twitching. Both the accuracy of cut and the quality of the cut surface are reduced.
Alignment of the height of the teeth should be carried out before sharpening the blade. Check the height as follows: the canvas is pressed against a sheet of paper lying on the table. The profile is printed on the sheet, and the print height can be used to determine the height of a tooth. For alignment of teeth of different heights, the blade must be clamped in a bench vise. Prongs above other teeth are subject to file grinding.
Tooth height adjustment
General sharpening requirements
On the basis of wood with a size of 2 × 5 cm from a bar with a thickness of 2 cm, two rectangular isosceles triangles and a steel plate of 20 × 3 mm are fixed. A support plate made of plywood or OSB with a thickness of one and a half centimeters with dimensions of 15 × 40 cm is mounted on triangles and the same clamp plate is fixed to it from below on hinges. The plates are tightened with screws or studs with nuts. wing. If installation is required at an angle of 45 °, the plates are fixed to the hypotenuses of the supporting triangles, and if 90 °. then to the legs.
Hacksaw sharpening rules
To sharpen the saw, you will also need several files that differ in cross-section and pitch of the notch. All of them should be in good condition, without cut or clogged with dust lines of a notch. To sharpen a saw on a tree, the file must be moved smoothly, with constant pressure and at a constant angle. The file’s working movement is “on its own”. On itself, it should be easily stretched, practically not touching the surface of the metal.
How to sharpen a hacksaw on a tree with a file
For sharpening, the blade of a hand saw needs to be clamped between the tool plates so that the teeth rise above them by one and a half to two centimeters. For various types of paintings, sharpening a hacksaw on a tree is done in its own way.
Locking the file for sharpening the saw
To sharpen the transverse hacksaw correctly, the blade should be set at 45 °. The file should be selected with a triangular cross-sectional profile.
To ensure proper sharpening quality, the following sequence of actions must be observed:
- sharpen the left edges of the even (farthest from the master) teeth;
- turn the canvas over;
- sharpen the left edges of the even teeth;
- to form sharp cutting edges and pointed tooth tops
Correct sharpening a hacksaw
To sharpen a longitudinal or universal hacksaw, it should be fixed at an angle of 90 °. Here you need a file with a diamond-shaped cross section. The file moves in the plane of the desktop. The sequence of sharpening the teeth is the same as for transverse hacksaws.
During operation, burrs usually appear on non-sharpened edges, larger or smaller depending on the thickness of the hacksaw blade. They should be smoothed out with a “velvet” file or with an abrasive bar of minimal grain size. The quality of sharpening can be checked in two ways:
- To the touch. Sharpness should be felt, no burrs should be felt.
- By color. On correctly sharpened edges, x glare does not occur under lighting.
Quality is also verified by trial cut. The hacksaw should not be diverted to the side, the surface of the cut should be smooth, without macerated wood fibers.
In order to quickly and efficiently sharpen a hacksaw on a tree, you should prepare a set of equipment for setting teeth and sharpening. Required:
- bench vise;
- measuring tool: protractor and vernier caliper;
- bench hammer;
- equipment that allows you to fix the canvas at angles of 90 ° and 45 °.
You will also need files:
- section in the form of a triangle;
- section in the form of a rhombus;
- Needle files.
A notch is needed whole and not clogged with metal dust.
If the hacksaw is sharpened on time and correctly, it will be easy and convenient to work with it. This tool will last much longer, delighting its owner with an even and precise cut and high quality saw cut wood.