Surfacing Bits

Had an interesting revelation tonight about surfacing bits.  While Ivan was visiting, having a look over the Torque Workcentre, the discussion turned to surfacing bits.  I was thinking the 3 interchangeable flute Carbitool bit had its carbide tips misaligned from use or something – they didn’t sit flat on the table.  But when I got out my Granite reference block and placed each of the bits on top, they all had the same issue – the bottom of the teeth were not flush with the table as I expected.

Surfacing Bits

Now for one (particularly with interchangeable tips) to be out I could understand, but not all three, both Carbitool and Whiteside, and particularly the (fixed) 6 flute.  That one if no other should be the perfect form for a surface cutter, so if it has the same angle on the bottom of each tooth, then that is the way it should obviously be.

So then I was left with working out why it is that way, now my belief that the bottoms where flat had been squashed!

What I am thinking now is the tip of each tooth is the part that does the cutting, the rest is actually superfluous and is primarily chip clearing, rather than cutting/flattening.  If the bottoms were flat, then the tips would scrape, rather than cut.

It is surprising how long I’ve had surfacing bits that I have never realised that!

Surfacing Bits

4 Responses

  1. What exactly do you use your surfacing bits for? What applications and why do you have 3 bits?

    • Surfacing bits are for producing a smooth surface on a board/plank/burl.

      You’d use a jointer/planer for the same reason, or a thicknesser, but they have obvious limitations on size – if the board is too short it can become dangerous planing it, and definitely can get very nasty trying to pass it through a thicknesser. A wide board presents another challenge.

      If you have a large plank/tabletop/burl that is 2, 3 even 4′ wide (1300mm), how would you surface it? The solution is bringing the tool to the workpiece, rather than the other way around, and that is where a surfacing bit comes into its own.

      Why 3? Because I can 😉 Means I can choose the right bit for the job at hand. A 2 or 3 flute bit is able to cope with large feed rates and/or deeper cuts. The 6 flute bit is like a fine toothed blade – slower cut rate (as it cannot clear chips as fast), but a finer finish.

      The interchangeable bits mean you get 4 times the usage out of the bit before it needs sharpening.

  2. I’m with Dave. I don’t own and ahe never used such a bit.
    Do you have any references on how to set up?

    • Fundamentally, get the base parallel to the plane of travel of the router. Easiest way is to ensure the router is moving along paths that are parallel to the reference plane (such as the table base the workpiece is sitting on), then set the router so it is perfectly perpendicular in both the X and Y directions. That way the bit should be traveling perfectly parallel with the base.

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