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Belt joint

The manufacture of an endless abrasive belt from a roll of abrasive paper or abrasive cloth requires that both ends of the previously cut-to-length section of the roll be joint permanently. The so-called belt joint usually runs at a 45° - 80° angle to the running direction of the belt in order to prevent an abrupt transition at the junction.

The abrasive backing (paper, cloth, plastic) used and the application (machine, contact element, work piece) determine the type of the belt joint.

Belt joint types generally fall into two different categories:

a) the lap joint which is formed by alternately tapered ends that are laid and fused on top of each other and

b) the butt joint which is formed by two ends that abut each other and are joined by means of a narrow strip of (mostly fibre-reinforced) tape either on the front or the reverse side of the belt.

Since there are additional variations within these two types of joint categories, the belt can be perfectly adjusted to the grinding task at hand.
Klingspor uses the following types of belt joints for their abrasive belts:

Overlap joint

F1 standard overlap joint
F1A special overlap joint for wide paper belts
F2 lap joint with sharpened grain points
F5 lap joint without resin and abrasive grain in the overlap

butt joint

F3, F3G zig-zag joint with tape on the reverse
F4, F4G straight cut at an angle to the running direction of the belt with tape on the reverse
F6G butt joint with tape inserted on the grain side; grain and resin in the joint area are removed beforehand
F7G wave joint with tape on the reverse

Selecting the right type of belt joint plays a key role in the area of abrasives. Klingspor ships all belts of standard dimensions and belts available for order from stock with the type of belt joint that experience has proven to be the best choice for this particular belt type. If required by the customer, Klingspor can also manufacture and deliver other types of belt joints that will be better suited for the customer's specific application.

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