How to Magnetize a Screwdriver Bit at Home
Most parts for a sharpening machine can be made literally from anything, following the general principle of the device. As an example, take laminated or polished box plywood with a thickness of 8–12 mm, which was universally used in the manufacture of cases for Soviet radio equipment.
The base must be heavy. About 3.5–5 kg. Otherwise the machine will be unstable and unsuitable for sharpening a heavy chopping tool. Therefore, the inclusion of steel elements in the design is welcomed, for example, the base of the body can be “shoe” with an angle of 20×20 mm.
From plywood, you need to saw two parts in the shape of a rectangular trapezoid with a base of 170 and 60 mm and a height of 230 mm with a jigsaw. When cutting, leave an allowance of 0.5-0.7 mm for processing the ends: they must be straight and exactly match the marking.
The third part is an inclined plane from a plywood board measuring 230×150 mm. It is installed between the inclined sides of the side walls, while the trapezoid of the sidewalls rest on the rectangular side.
In other words, the base of the machine is a kind of wedge, but the inclined plane should protrude in front of 40 mm. At the ends of the side walls, lay with a thickness gauge two lines indented half the thickness of the plywood. Drill three holes in each plank to fasten the parts with screws. Transfer the drill to the ends of the inclined part, temporarily connect the base parts.
In the rear part, the side walls are connected by a bar 60×60 mm, which is fastened to the end by two screws on each side. In the bar, you need to make a 10 mm vertical hole with an indent of 50 mm from the center, that is, 25 mm from the edge. To be sure of verticality, it is better to drill with a thin drill on both sides, and then expand. At the top and bottom, screw in two holes with an internal M10 thread, and a 10 mm long 250 mm hairpin in them into the hole. Here it may be necessary to slightly adjust the lower foot if its thread does not coincide with the stud.
Remove the flat inclined part from the base. It needs to be finalized by equipping with a fixation and clamping device for the tool being machined.
First, set aside 40 mm from the front edge and cut a groove about 2 mm deep along the line with a hacksaw. Use a sectional or shoe knife to chop the top two layers of veneer from the end of the plank to form a sample into which you can insert a 2 mm steel plate flush with the common plane.
The handrail consists of two steel strips 170×60 mm and 150×40 mm. They need to be folded together along a long end with uniform indentation along the edges and to make three through holes of 6 mm. The slats on these holes need to be pulled together, placing the hats on the side of the upper, larger plate. Bake each cap by welding it, welding it with the plate, then remove the influx of metal and grind the plate until a perfectly flat plane is obtained.
Attach a narrower reciprocal level to the selection at the edge and transfer the holes with a drill, then fasten the handrail with bolts. Before installation, it can also be magnetized with direct current, this will help in sharpening small blades.
The second part of the handicraft is the clamping bar. It is also made of two parts:
- The upper L-shaped strip is 150×180 mm with a shelf width of about 45-50 mm.
- The lower reciprocal level is rectangular 50×100 mm.
How to Magnetize a Screwdriver Bit at Home
The details need to be folded in a manner similar to how the parts of the handicraft were folded, placing the reciprocal bar at the far edge of the upper clamp. In the center we make two holes with an indent of 25 mm from the edges of the small part, through them we tighten the parts with two 8 mm bolts. You need to start them in opposite directions, while the head of the upper (near) bolt is located on the side of the clamping plate. The bolt caps are also welded to the plates and pre-sanded until a smooth fillet is obtained.
On an inclined board with an indent of 40 mm from the edge, draw a line with a thickness gauge, and make one 8 mm hole 25 mm from the upper and lower edges. Connect the marking of the edges of the holes and use a jigsaw to cut with an allowance. Bring the groove with a file to a width of 8.2–8.5 mm.
Fasten the clamping and reciprocal level through the groove in the plank. Tighten the bolt protruding from the top with a nut so that the bar retains minimal mobility, then lock the connection with a second nut. To clamp or release the strap from below (in the base niche), screw the wing nut onto the second bolt.
Sharpening angle adjustment.
Put a wide washer on the stud screwed into the base block and tighten the nut so that the shaft does not rotate in the footings.
The adjustment block must be made of a small bar of solid material with dimensions of approximately 20x40x80 mm. Take carbolite, textolite or hardwood.
15 mm from the edge of the block, a 20 mm end is drilled on both sides, the hole expands to 9 mm, then we cut the thread inside. With a distance of 50 mm from the axis of the hole made, a second one is drilled, but in the flat part of the part, that is, perpendicular to the previous one. This hole should have a diameter of about 14 mm, in addition, it must be greatly flared with a round rasp.
The shoe is screwed onto a hairpin, so it is possible to relatively accurately adjust the height of the eye without a complicated screw lock system as in the original machine, which is a little more difficult to implement in practice. In order for the block to be stationary during operation, it must be counter-bolted on both sides with M10 nuts.
Carriage and interchangeable bars.
For the sharpening carriage, you will need to coaxially weld 30 cm of the M10 pin and a smooth, even bar 10 mm thick. Two solid whetstones with dimensions of approximately 50×80 mm and a thickness of up to 20 mm are also required. In each bar in the center and indented 20 mm from the top edge, a 10 mm hole should be made.
First, the wing nut is screwed onto the bar, then the wide washer and two bars, again the washer and nut. Between the whetstones, rectangular grindstones can be clamped, but it is better to make several interchangeable whetstones.
As a basis for them, take a lightweight aluminum profile with a flat part 40–50 mm wide. It can be a profile rectangular pipe or pieces of an old cornice profile.
We skim the flat part and degrease it, “Moment” paste on it strips of sandpaper of different grain sizes from 400 to 1200 grit. Choose a fabric-based sandpaper, and glue a strip of suede leather on one of the bars to straighten the blades with abrasive paste.
How to sharpen.
For proper sharpening, make several patterns with angles of 14–20 from plywood? For cutting and 30–37? For cutting edges, the exact angle depends on the grade of steel. Lock the blade parallel to the edge of the handrail and press it with the bar. According to the template, adjust the angle between the planes of the grinding pad and the inclined table plate.
Begin sharpening with a large (P400) bar if the edge does not have the correct angle. Get the descent strip to take the form of a straight strip without meanders or waves. Reduce the grain size and pass on both sides of the blade first with a bar P800, and then P1000 or P1200. When sharpening the blade, carry out the bar with a little effort in both directions.
After sharpening, the blade needs to be fixed with a “leather” bar, on which a small amount of GOI paste is applied. When editing the blades, the working movement is directed only towards the edge (towards itself), but not against it. And finally, a little advice: if you sharpen knives with polished blades and engraving, paste over them with masking tape so that the crumbling abrasive does not leave scratches. It also does not hurt to glue the surface of the handicraft with vinyl self-adhesive.