On Monday, 24 July 2017 11:34:54 UTC+1, John Rumm wrote:
On 24/07/2017 09:59, tabbypurr wrote:
On Monday, 24 July 2017 02:03:48 UTC+1, John Rumm wrote:
On 23/07/2017 20:53, jkn wrote:

Hello all This is an enquiry about how to use a router to cut a
slot in the end of a sheet of wood.

Below is an ASCII-art side view of the sheet. The wood is around
18mm thick.

The slot needs to be say 3mm across, and perhaps 15mm deep.


| | slot approx 3mm from edge

| | 3mm slot, 15mm or so deep

/ / / / / / / / / / / / / / / / |-| |------|
| | | | | | | | | |_| | | | | |
|SIDE VIEW |

| ~18mm | thickness of wood

I have a Router (1/2" chuck) available to me. I originally
presumed that the approach would be to get a suitable 'deep
pocket' router bit and cut the slot in several passes. However I
cannot find such a router bit and am wondering if there are any
other options.

You will have difficulty finding a 3mm straight fluted bit - and if
you do, it will be very weak so you would need many light passes to
get to depth.

A 3mm diameter cutter can not do that, no matter how many shallow
passes you make. I know because I have one.

What you know is that your 3mm cutter can't do it...

The limitation with any straight cutter with flutes narrower than the
shank is that they will only have a limited depth of cut before you hit
the tapered section. On many cutters of that type, the max depth is
usually no more that 1/2", which given the OP suggested "15mm or so" may
or may not be adequate.

You can get 1/8" shank router cutters, which for 3mm fluted cutters will
not have the same limitation on depth of cut. You would need either an
adaptor collet for a larger machine, or a small detail router like the
Dremel style add on:

https://www.amazon.co.uk/Hakkin-Tita.../dp/B0187AYWE4


(However as I highlighted previously, there are other and better options
in this particular case).

Whoosh. The limitation with 1/8" sideways cutting bits is the lack of lateral strength. Try to cut the op's slot and they will just break.


NT