Tapping is making threads inside a drilled hole to enable it to hold a machine screw or a bolt. The tapped hole differentiates itself from a pilot hole by its size and the presence of threads. Screw threads cannot tap a hole by themselves due to metal's hardness. Tapping is straightforward, but you need the correct setup. It is possible to carry out the process by hand but using powered tools is easier and more convenient and yields perfect straight taps each time. An automatic drill press or AutoDrill is consequently the most popular tool.
Before drilling, decide the hole size you need to correspond to the bolts you will use. The hole should have a smaller diameter than your bolts, as the threads will increase it. You need to mark out the location and predetermine the depth.
The tools you will need include an integrated auto driller, a press clamp, tapping fluid, centering points, and tapping bits. If you are not using a regular drilling bit for the pilot hole, you can use two others - a tapered one and a bottoming one. The tapered tap is designed to make gradual cuts, removing little material with each rotation. It ensures little stress and a lower probability of breakage. When you need to cut through, a bottoming tap will ensure the bottom of the hole is full of threads.
It is crucial to keep the tap straight to prevent loss of functionality. Self-centering automated drilling bits are available, but learning how to straighten your taps manually is an invaluable skill to learn. The spindle on the drill lies perpendicular and provides a reliable guide.
Fasten your metal using a vise or a c-clamp to prevent any movement when force is applied. Tighten the metal in its place as it will ease penetration.
Use a center punch to make a divot that defines the drilling path. A good state-of-the-art driller will work with an automatic center punch to let you create a deep enough divot.
Insert your chosen drill bit into your chuck and secure it.
Apply tapping fluid or any drilling oil for lubrication. It reduces friction, prevents overheating, and eases the cut. Automatic systems to include drilling oil are available.
Place your drilling bit into a centered divot and initiate drilling. Use a low-speed setting to allow the bit to grip and puncture the metal. As the depth of the cut increases, adjust your speed to medium and continue applying gentle, consistent pressure. Remove flakes and chips the deeper you go so it does not bind up.
Place your tapping bit into your automatic drilling machine, relocate the part if necessary and repeat the process to thread the hole. Taps are brittle, so ensure you remove chips as they could add unnecessary stress. If you experience any unusual resistance, back up, remove flakes, lubricate and try again. Always make sure your drilling bit is of proper size!
Use a bottom tap to complete the thread at the bottom of the hole.
Remove the tap, clean out the chips from the metal, and the tap and clean the remnant lubricant. Test the threads using a bolt or machine screw. If there is too much resistance, rerun the tap or replace the tap as it may be worn.
AutoDrill provides quality tapping and drilling solutions for manufacturers. Please call us at 1-800-871-5022 or email [email protected] to order.
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