Marking Out
Marking out is the process of transferring your designs onto your work piece. This can be done using a Scriber which scratches into the surface of the metal, as well as other methods. Once you know where you need to drill, a Center Punch is used to create a small locator hole for the point of the drill to bite into. If you don't use a Center Punch, the tip of the drill can move around on the surface of the work piece and you may end up with your hole in the place.
Pilot Holes
For larger holes over 12mm in diameter it is useful to first drill a smaller pilot hole. This reduces the friction on the drill bit and helps stop the drill bit over heating and becoming blunt.
Backing Off
As the drill progresses through the work piece, the fluting on the drill feeds the swarf away from the two cutting edges. If you are drilling a deep hole the swarf can block the hole. To avoid this happening we do something called "backing off". This is when we intermittently remove pressure from the drilling head to allow the drill bit to clear away any swarf before beginning to drill again.
Chain Drilling
If you need to cut a slop into a piece of sheet metal you can do this by chain drilling. This is when you drill a series of adjacent holes, the required diameter of your slot. A metal file is then used to remove the remaining unwanted material.
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| Scribe |
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| Center Punch |
Marking out is the process of transferring your designs onto your work piece. This can be done using a Scriber which scratches into the surface of the metal, as well as other methods. Once you know where you need to drill, a Center Punch is used to create a small locator hole for the point of the drill to bite into. If you don't use a Center Punch, the tip of the drill can move around on the surface of the work piece and you may end up with your hole in the place.
For larger holes over 12mm in diameter it is useful to first drill a smaller pilot hole. This reduces the friction on the drill bit and helps stop the drill bit over heating and becoming blunt.
As the drill progresses through the work piece, the fluting on the drill feeds the swarf away from the two cutting edges. If you are drilling a deep hole the swarf can block the hole. To avoid this happening we do something called "backing off". This is when we intermittently remove pressure from the drilling head to allow the drill bit to clear away any swarf before beginning to drill again.
Do not be tempted to try and clear the swarf with your hands. It is incredibly sharp and can cause serious injury!
Chain Drilling
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