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There are a lot of myths around choosing the right abrasive belt joint. Some customers will tell us that ‘the only joint that works is a finger joint’. Whilst another customer might say ‘I make my own belts with a bit of duct-tape’! Normally customers only specify a joint due to historical problems with their abrasive belt supplier.
Thankfully with Cibo we hardly ever need to discuss belt joints. Cibo have spent many years developing the right joints and refining the manufacturing process. Cibo joints work right first time, every time. Consequently we hardly ever need to talk to our customers about belt joints. Even so it is definitely worth understanding the logic behind the decisions made by Cibo.
Belt Joint Option 1: ST over lap joint
The ST belt joint is a traditional overlap joint. The abrasive paper is skived on the top and bottom and then a resin bonded joint is created.
Cibo use the ST joint as the standard for paper backed sanding belts. Cibo guarantee a joint without any additional thickness. Resulting in a perfect finish, even with very fine grit belts.
Belt Joint Option 2: EX over lap and skived joint
Particularly in finer grit paper applications there can be issues with chatter marks on the workpiece. When this happens we recommend moving to the EX belt joint.
The construction of the EX joint is the same as the ST joint. However the additional skiving of the top layer of abrasive is designed to ensure chatter marking is not possible.
Belt Option 3: BB taped butt joint
The ST and EX belt joints are largely used for paper belts. The BB joint is Cibo’s primary option for cloth belts. Unless otherwise specified a BB joint will be used.
Using a tape joint also gives additional options in terms of the type of tape used. Most belt joints are made with Kevlar material. In finer abrasive grit belts a thinner tape is used to ensure the flexibility is maintained.
Belt Joint Option 4: BB-EX taped butt joint with skived top face
Similar to the EX joint for paper belts the BB-EX belt joint ensures no marking or chattering of the workpiece.
The BB-EX joint is ground to an over all width 5mm wider than the Kevlar tape to reduce the risk of marking.
Cibo may recommend the BB-EX joint when working on very hard materials.
Belt Joint Option 5: BB-ZZ taped finger joint
The BB-ZZ joint has several names: The finger joint, the dovetail joint or a sine joint all of which mean the same thing. The interlocking wave edge means that the bonded area on the joint is spread when sanding over the workpiece.
A BB-ZZ abrasive belt joint can be particularly helpful when sanding in very fragile applications such as thin glass.
