What type and size router bit do i need

[samsung laptop]

I've ordered a katsu 101748 wood trimmer so I would like to get some router bits before it arrives so could someone tell me what type and size I will need to fit door hinges and to round the edge over on stair treads. I need a router bit that's 1/4" or 3/8" shaft so I've looked on toolstation but they have so many sizes from metric to imperial I just don't know what to buy.

[Thewindowguy]

Don't buy router bits from tool station there usually silver line and there rubbish , trend bits are good and the erbaurer bits from screwfix are ok , I have a Makita trimmer and wouldn't use much over a 12mm straight bits , regards to door hinge cutting free hand or template ?. If it's a 1/4 collet you will need 1/4 shank bits my router takes 1/4 and 8mm bits using a collet cone. Also pay attention to the max speed of the bits and make sure there is enough shank in the collet , also have a practice if u have never used one before. Regards to metric or imperial if your using templates and a guide bush don't mix the 2 measurements .

[samsung laptop]

I've never used a router before but I will be using it free hand.

[Job and Knock]

I actually have the 110 volt version of that trimmer and I'd recommend for the (freehand) hinge recessing job that you go for a hinge mortising bit, such as the T310 (1/2in or 12.7mm diameter) from Wealden Tool:

Wealden Hinge Mortising Bit 001 01.gif (6.41 KiB) Viewed 3633 times

The open centre of this type of cutter means that it cuts more cleanly and is less likely to clog than a conventional straight 2-flute cutter whilst the smaller diameter (1/2in) means that there will be less waste to chop-out in the corners with your chisel than if you opt for a larger diameter bit

For rounding-over you are restricted by the size of the opening in the base of the Katsu (31.75mm or 1-1/4in) to smaller diameter (and therefore smaller radii) ovolo/round-over cutters which will give you more of a "square with a rounded edge" look than a full bull-nose. I use Trend and Wealden cutters and the sort of cutter you should be looking at is the Wealden T1329 6.35mm (1/4in) radius ovolo with the optional TB452 bearing to produce a round-over

Wealden Small Ovolo Bit 001 01.gif (7.92 KiB) Viewed 3633 times

Wealden Small Ovolo Bit 001 02.gif (4.09 KiB) Viewed 3633 times

As ever there are lots of cheap cutters on the market, some good, some bad, but the ones I've suggested are good enough for trade use and should last a hobbyist for years. Good quality medium price brands include Wealden, Trend Trade and CraftPro ranges, Whiteside. etc

As mentioned above speed is important - so always check and set the speed so that you do not exceed the maximum revs allowed for the cutter. If nothing else the higher the speed the more vibration you'll feel. Personally I'd recommend turning the speed control down to "4" (22,000 rpm) but certainly less than "5" (27,000 rpm) for both these cutters

All the cutters I've mentioned above have 1/4in shanks - and your Katsu will come with 1/4in and 3/8in collets (at least mine did). 1/4in is a common shank size but 3/8in is disappearing fast and almost extinct

Finally, should you want to use the Katsu fixed base trimmer (or for that matter its' "progenitor", the Makita RT0700C) for template routing I cand confirm that the plastic sub-bases in both fixed base tools are designed to accommodate Porter-Cable type screw-thread pattern guide bushes - and versions of these in metric sizes are available from both Trend (16 and 30mm only) and Axminster Power tool (UJK sets: 10/12/14/16/18/20/24/30mm)