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I see router bits marketed as flush trim bits, pattern bits, template bits, but they all seem to be similar in design. The cutting edges are exactly lined up with a bearing, so that an exact copy of a piece can be cut.

For example, Rockler sells a flush trim bit:

flush trim bit

and a pattern bit:

pattern bit

and Amazon sells a template bit:

template bit

They all seem to be identical in function (although the linked pattern bit is shorter, so it can't cut as deep of a copy as the others can), so is this just a marketing thing? Rockler's flush trim bit I linked is even listed as a "Pattern flush trim bit".

  • The top link I would read as a Pattern, flush trim, bit. So it's a pattern bit as already mentioned, just specifically a flush-trim type (which may or may not imply there are other types that don't trim flush). – Graphus supports Monica Aug 25 '17 at 6:27
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A flush trim bit has the bearing at the bottom of the bit. This is so that it can trim a layer of laminate (i.e. Formica) that has been attached to the top of a smaller substrate (i.e. MDF or particle board) flush to the substrate.

A pattern or template bit has the bearing at the top of the bit (between the shank and the cutting blades.) This is so that it can follow a template attached to the top of a larger workpiece, cutting the workpiece to match the template. I believe that the terms "pattern bit" and "template bit" are interchangeable.

Your first picture is incorrectly labeled. That is a pattern/template bit, NOT a flush trim bit.

Also worth mentioning, some flush trim bits have cutting surfaces on the tip of the bit to allow plunging it through a laminate. (These typically have a flat reference surface instead of a bearing.) This is useful if you've laminated over a hole in the substrate that you want to remain open.

  • 1
    My understanding mirrors yours, with the caveat that I don't think the terms are interchangeable. On the other hand, language evolves, so there's always the possibility/likelihood that meanings have shifted. At any rate, the difference is where the template goes. Note, too, that their functions swap when you put them in a router table. – Charlie Kilian Aug 24 '17 at 18:38
  • noob here, what is a "top laminated surface flush"? I imagine top means that the piece to be cut is top. But the other words, what do they mean? I can't google them specifically, I just need to know what are they, then I can find the rest for myself. – Santropedro Feb 2 at 22:05
  • @Santropedro A clearer way of saying that is that it can trim a layer of laminate (i.e. Formica) that has been attached to the top of a smaller substrate (i.e. MDF or particle board) flush to the substrate. This is a fairly common operation in the world of laminate counter tops. I've edited my answer to be more clear. – SaSSafraS1232 Feb 4 at 17:15

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