Thread: Router bits and templets

Hi Hareward,

You haven't provided a lot of info about what you are trying to do, but I will weigh in to try and help sort some of it out for you.

The items that you call Templets are template guides, and they appear to be generic ones rather than specific inlay ones. The template is the pattern that you are going to use to define the inlay.

Bit size is an open question, but ideally it wants to be small relative to the size of the inlay pattern. The smaller it is, the tighter the minimum internal radius it can cut. For example a 6.5mm diameter bit physically cannot leave an internal radius smaller than 3.25mm, so a fair degree of rework is required to obtain a tight corner for the tip of a leaf for example. On the other hand, if the bit is too small, there is a lot of routing to clear the inlay reccess if you are using a 3mm diameter bit for an inlay in the 100mm + size range.

Inlay kits are available which comprise a router bit (typically 1/8inch), a template guide, and a sleeve that fits over the guide portion of the template guide. The diameter of the template guide is not critical, but should not be significantly larger than the bit, as once it gets too large this starts to interfere with access to tight portions of the pattern. The sleeve is sized to be a tight fit on the guide, and have a wall thickness exacly equal to the difference between the radius of the guide and the bit (the offset of the setup). The intention here is that with the sleeve installed, the offset is doubled.

I have seen systems where the sleeve has an internal O ring to lock it to the guide and others where they use a recessed set screw.

For the guides that you have the difference in diameter between the two is 12.7 - 11 = 1.7mm. So the difference in radius would be half that (0.85mm). The required bit would 11 - 1.7 = 9.3mm diameter which would not fit through the opening in the smaller guide, so the guide combination would not be suitable.

Thanks Malb, now I know how to calculate what I need.

Many thanks.

Regards


Hereward