The pan head screw or pan screw is often used for tightening and fixing engine parts of old motorcycles, such as crankcase covers, clutch covers, and generator covers. This is one of the most common bolts that don't loosen up as expected, and the Phillips groove on the screw head is often stripped. In such a case, instead of using a common Phillips screwdriver, use an impact screwdriver or shock screwdriver to avoid stripping the screw head plus the groove, which may not lead to a serious problem.
Special tools that every professional mechanic must have.
The feature of an impact driver is that a blow to the grip end with a hammer applies rotational force to the driver bit at the tip. There are two types of screwdriver bits, short and long, so it's best to choose the right one for the part you need. When the bit holder is removed, many types have a 1/2SQ square head, which can be used with a socket wrench.
Do not rotate in the wrong direction!
The impact driver has a rotation direction, so be sure to check it before use. If the direction of rotation is wrongly set, the head of the bolt may be torn off by the strong torque. It is best to press the bit holder of the impact driver against the floor and check if it moves in the direction of loosening (semi-clockwise). It is best to check the direction of loosening.
Use different bit lengths.
Generally, the short bit is the standard specification and the long bit is optional in many cases, but impact drivers with both long and short bits as standard equipment are also available. However, there are impact drivers with both long and short bits as standard equipment on the market. By using the right bit for the right part shape, you can avoid mistakes.
Hexagon head, common on modern motorcycles
The engine cover tightening bolts have shifted from + groove pan screws to hexagon 8mm flanged bolts and hexagon head bolts. Use the right bit for each bolt head shape. If you use a short bit, the driver body may interfere with the engine cover, but if you use a long bit, you can hit the bolt straight and powerfully without any slanting.
What is the process before loosening the bolts?
When loosening screws that are hard to loosen, or when using an impact driver, be sure to check first that the Phillips groove is not damaged. Also, tap the head of the screw with the end of the T-wrench handle or a flat punch, etc., to return the open + groove. Next, push the grip of the screwdriver grip in the loosening direction (semi-clockwise) and give a blow with the hammer to transmit the impact to the screws and bolts, making it easier to loosen them. If you still can't loosen the bolt, don't force it, use an impact driver.
MEGADORA IMPACTA needs to be in the toolbox!
The MEGADORA IMPACTA developed and marketed by Vessel, a well-known screwdriver manufacturer, can be used as a screwdriver in normal use, but can be transformed into an impact driver with a single blow from a hammer. The secret function of the Mega Dry Impactor is the "cam rotation structure" built into the shaft of the grip. When the end of the grip is struck with a hammer, the driver shaft instantly rotates 12 degrees in the opposite direction. When the force escapes, the built-in spring reaction force quickly returns the shaft to its original position. Vessel's MEGADORA IMPACTA is available in sizes 1/2/3. It should be a must-have for users of old motorcycles from the 80's and earlier, and Honda 4 Mini!
- Point 1・Let's loosen the bolt with an impact driver before the head of the bolt is nipped. If you remove the bit holder, you can install the socket wrench.
- Point 2・Just by setting the screwdriver bit on the screw head and hitting the end of the bit with a hammer to impact the bolt before work, hard bolts become easier to loosen.
Many bolts called pan head screws or pan head screws are used to tighten motorcycle parts, especially bolts of M6 size or smaller. These bolts tend to be over-torqued, which means that they are tightened too forcefully. Even if you try to loosen them, they don't loosen easily (partly due to rust), and the "+ groove of the screw head" is easily damaged! Have you ever had such an experience? Examples of screws that can be easily knocked out include the pan head screws that tighten the engine cover and the pan head screws that tighten the brake master reserve tank cover.
When loosening bolts in areas that are prone to knurling, it is a good idea to give the head of the bolt a jolt beforehand. For example, if the screwdriver groove of the "+ groove pan screw" described here is damaged or widened, you can tap the head of the bolt to push in the open + groove. There are two meanings to this "tapping operation. The first is to correct the shape of the groove for tool access, which has become open or slanted. By tapping the head of the bolt, for example, the + groove is collapsed and the open + groove is restored. In addition, striking the head of the bolt transfers the impact to the threaded part, making it easier to loosen the threads that had been biting.
After striking the head, press the tip of a screwdriver of the same size to the + groove and hit it again with a hammer. By doing so, the tip of the screwdriver will match the shape of the + groove on the bolt head, making it easier to transmit the rotational torque to loosen the bolt. However, it is important to know that by hitting the head of the bolt with a hammer (i.e., crushing the open Phillips groove) before proceeding with the work, the rotational torque can be transmitted to the bolt, making it easier to loosen.
"I'm sure there are many Sunday mechanics who have thought to themselves, "If only an ordinary screwdriver could be an impact driver. The "Mega Dry Impactor" developed and marketed by Vessel, a well-known screwdriver manufacturer, has made such a dream a reality. This product is an evolution of the through-blade screwdriver, but it can also be used as a regular screwdriver.
However, when you hit the grip end with a hammer while inserting the screwdriver into the Phillips slot, the screwdriver shaft rotates in the semi-clockwise direction to "loosen the bolt". Such a great idea for a tool that should definitely be in your toolbox!
