Introduction: Plasma Cutter Circle Guide

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I have recently bought a cut 40 plasma cutter, not an expensive A brand, but a cheap made in China plasma cutter.

So no readable instruction manual, no free accessories, no extras basically. But that's OK by me, I'll just make my own free accessories.

Step 1: Tools and Materials

Tools needed:

  • a drill and drill bits
  • a saw
  • glue
  • fine grit sandpaper
  • a measuring device, I used callipers, but a ruler will do
  • a pencil or other means of making markings

Materials needed:

  • a nut and bolt
  • flat wooden board
  • a ball bearing
  • a small neodymium magnet
  • optional, washers or extra nuts (stand-off distance)

The size drill bit you'll need to use is determined by the diameter of the nozzle of your plasma cutter, and for the central hole it's determined by the bolt head.

The thickness of the piece of wood you use is determined by the length of the nozzle of your plasma cutter, and if you're not using a drag tip, the stand-off distance has to be added to the length of the nozzle. The width of the piece of wood should be wide enough to accommodate the ball bearing, and the holes for the nozzle. The length of your piece of wood determines the maximum radius you will be able to cut.

If you, because of the stand-off distance, use a piece of wood thicker than the bolt head, use washers or nuts to get the bolt head flush with the bottom of your piece of wood.

The width of the bolt is determined by the ball bearing you have available, and the length by the total thickness of the piece of wood, the ball bearing and nut together.

I used a 2 component epoxy glue, but if you have an other reasonably heat resistant glue able to bond metal and wood, by all means use that glue.

I salvaged the ball bearings and their inserts from old inline skate wheels, and the neodynium magnets from an old mobile phone's speaker and broken on-ear headphones.

Step 2: Drilling the Holes

Drilling the holes is well easy.

  1. Find the centre of your piece of wood and mark it.
  2. Mark two lines along the full length of the piece of wood, at the same distance from the edge
  3. Measure out the distances you want to use as radii for your circles alternating between the two lines, and mark those
  4. Drill out the holes
  5. Finnish the holes by sanding them

The centre hole should be a fair bit larger than your bolt head, allowing for uninhibited rotation

The holes at the sides should be the a good fit for your plasma cutter nozzle, allowing it to rotate but not have to much play inside the hole.

I made two circle guides, one with whole centimetres (2,3,...)on one side and half centimetres (2.5,3.5,....)on the other side, and a second one with quarters (2.25,3.25,...) and 3 quarters (2.75,3.75,...).

Step 3: Gluing

This is easiest step, but also the easiest step to ruining the project if you get it wrong.

    1. Line up the ball bearing above the centre hole and mark its position, see the image for the view from the bottom if properly aligned, and glue the ball bearing into place
    2. Glue the magnet to the bottom of the bolt head

    Make sure no glue gets in contact with the centre of the ball bearing, and don't use too thin a glue, as it might find its way into the ball bearing.

    Step 4: Finnished

    That's all folks, that's all it takes to make a simple circle guide.

    Ones the glue has set, your circle guide is ready to be assembled and used.

    It took me about 15 minutes (+24h glue setting time) to make, how long did you need to make this?

    Let me know how you feel about this plasma cutting accessory. And if you come up with improvements, do share them, there's always room for improvement!

    Step 5: ​Warning

    Warning, Warning !

    The wood will char a bit on the bottom, and won't last forever. If this is a major issue for you, replace the wood with a non-combustible material