How do I accurately transfer CAD drawing to sheet of wood?

[haggis999]

The most useful one will have a bearing top and bottom. If you're routing material with a grain, you will probably want to turn the workpiece (with template still attached) over to ensure you're routing "downhill" to avoid chipout. Wealden do one e.g. https://www.wealdentool.com/acatalog/On ... m_871.html and there's an expensive but well recommended one from the US firm Whiteside.

Cheers, W2S

PS not as expensive as I'd thought, but without the double shear feature: https://www.routercutter.co.uk/combination-trim-bit

I note that both of the bits you recommended have noticeably larger cutter diameters than the 9.5mm (3/8in) bit I used to create my master shelf. I'm limited to a shank of no more than 8mm, so the diameter of the Whiteside would be 12.7mm, while the Wealden is 19mm.

I'm assuming that larger bits will be more efficient at quickly clearing a lot of wood when following the template of my master shelf, but they would obviously not match the tighter radius cuts I made in the interior corners of the rectangular notch on one edge. Do you think the advantages of a large diameter bit outweigh the associated need to adjust those two corner curves afterwards?

 

[Woody2Shoes]

The most useful one will have a bearing top and bottom. If you're routing material with a grain, you will probably want to turn the workpiece (with template still attached) over to ensure you're routing "downhill" to avoid chipout. Wealden do one e.g. https://www.wealdentool.com/acatalog/On ... m_871.html and there's an expensive but well recommended one from the US firm Whiteside.

Cheers, W2S

PS not as expensive as I'd thought, but without the double shear feature: https://www.routercutter.co.uk/combination-trim-bit

I note that both of the bits you recommended have noticeably larger cutter diameters than the 9.5mm (3/8in) bit I used to create my master shelf. I'm limited to a shank of no more than 8mm, so the diameter of the Whiteside would be 12.7mm, while the Wealden is 19mm.

I'm assuming that larger bits will be more efficient at quickly clearing a lot of wood when following the template of my master shelf, but they would obviously not match the tighter radius cuts I made in the interior corners of the rectangular notch on one edge. Do you think the advantages of a large diameter bit outweigh the associated need to adjust those two corner curves afterwards?

I think that, from what I've learned about routing, it's best (for several reasons) to try and avoid ploughing out large volumes of material (definitely in a single pass; and also, frankly, in multiple passes - which are difficult to do with a hand-held router anyway in situations like this). I think that, as one of the YT videos mentions, it's worth leaving yourself with as little to rout as you feel brave enough doing i.e. rough-cut as close to the line as you can first. An excellent tip, extending this idea, that 'Custard' offered some time ago on another thread, is to put some masking tape on the edge of the template and rout to that before a final pass with the tape removed (the final pass therefore only requiring the removal of the merest gnats bodypart, maximising the chance of a smooth surface finish).

I think the Wealden cutter would probably be fine - they wouldn't offer it in an 8mm shank if they didn't think they could make it suitable for (economic manufacture and) safe use (I assume they don't specify table-only use). I think that the difference in the amount of "internal corner-tweaking" required between a 12.5mm dia. cutter and a 19mm one is negligible.

Are you thinking of getting/making a router table? Could be handy in future for this type of project (it would also reduce the risk of "tipping" the router off perpendicular WRT the workpiece, amongst other possible benefits).

Cheers, W2S

 

[haggis999]

Assuming you don't have a need to select a specific bit diameter and are not aiming to remove large amounts of wood, is there any reason for preferring larger diameter bits?

There is nothing obvious on the Wealden website that limits their 'Up-Down Shear Trim' router bit to table use. I last used my router several years ago and may not use it again for a long time after completing my current project, so I'm not sure I can really justify the expense of a router table, despite the obvious benefits. They appear to cost in the range £50 - £430, but I suspect that anything less than £100 might lack sufficient rigidity and be poor value for money.

Thanks for that taping tip for a final rough cut. Masking tape is probably easier to follow than a pencil line. BTW, do you use metric or imperial gnats for measuring purposes?