The Joist Attachment is to be used with pre-grooved decking. The Attachment can adjust to work with almost any pre-grooved board. The Attachment can adjust in very fine increments.
The attachment mounts to the back of the HIDfast tool and registers the level of the fastener precisely off the joist surface rather than the top of the decking. By adjusting the attachment up or down, you can fire fasteners with the spur at the precise height off the joists to match the groove height on the deck boards. This saves time when installing dense composite decking and hardwoods.
Using the two supplied screws, fasten the J Attachment to the two lobs on the lower housing of the tool. Use the 5mm Allen wrench that is supplied with the HIDfast Tool.
Be certain that the Attachment is secured snugly. Now loosen the side lock screw on the Attachment, a quarter or half turn should be adequate, use the 6mm wrench from the HIDfast Tool. With the lock screw loose, the adjusting screw at the back of the Attachment can now be adjusted up or down, 6mm wrench. The standard foot plate can be taken off of the tool when using the J Attachment, or it can be set to its highest setting and lock it there, (recommended).
The Joist Attachment is designed to be placed on the joist ahead of the decking, and then slide the tool to the lead edge of decking until the face of the tool contacts the decking edge. Use a scrap piece of the grooved decking to set your fastener height correctly. Drive a fastener through the lead edge of the decking.
Now the vertical spacer bar and short point of the fastener is showing. The fastener must be set so the back edge of the next deck board is slid under the short point of the fastener.
The lower portion of the groove must be pushed slightly down to the joist by the short point of the fastener. The pressure downward on the groove should be light to moderate. The decking should not be loose or floating under the short point of the fastener, readjust until the back edge of decking is snug. PDF Instructions