Router bits - cutting a circle out of 15mm ply

fwor

I'm trying to make a small circular table top out of 15mm "Vohringer" style plywood (i.e. 15mm ply with a fairly hard-wearing melamine type finish on both sides).

I've had 2 goes already using a jigsaw and the results have been Ok but not quite even enough to look "professional".

I have never used a router before, but I'm borrowing one to cut a slot all round so that I can fit "knock-on" edging" and while I have it I figured I may as well have a try at cutting a circle with it, but... what bit should I use?

Does it seem reasonable to buy a 6.3mm by 25mm dual flute cutter, or is there a better choice for that specific job?

leveller2911

Two ways of cutting a circle with a router but the basic way is:

You can screw the router to a long piece of ply/mdf say 155mm wide. Have a straight cutter in the router and switch on and push down so you router through the ply/mdf. Then from the hole measure back to radius you want for your circle and nail a pin in the ply/mdf. You now have a "router Jig".

Turn the "table" upside down so the underside is face up and then mark the centre point of the circle you want to cut. Pin the router "Jig" onto the "table" (being careful not to hammer the pin all the way through the "table" top and try a dry run of moving the router around the top as a test run before switching on.. Then switch on the router and just go 4-6mm depth at each pass getting deeper each time till you router full through the table top. Remember to pack the "table" up off the bench so you don't router through the benchtop.

Then you need to but a "slotting" cutter the correct width for the tap in edging.

I deal with a couple of companies but Wealden tools are cheaper and their cutters are decent enough. Is the router a 1/2" or 1/4"?. You need to buy the right cutters for the job. 1/2" routers can fit 1/4" cutters but not vice versa. If you have a 1/4" router then take it slowly and not too deep with each cut.Double fluted cutters will give a better finish to the melamine edges than a single flute. The cutters won't be much good for future use as chipboard blunts them quite quickly so no point buy great quality ones such as "Trend Porfessional". Trend also do a "craft" range so also look up their website.

http://www.wealdentool.com/acatalog/Router_Cutters_1.html

http://www.wealdentool.com/acatalog/Two_Flute_71.html


They do slotted cutters etc as well so just have a browse.The slot cutter will depend on what is needed for the knock on edging.

fwor

Thanks for that - it wouldn't have occurred to me to make a jig that way! And for some reason it didn't occur to me to do the cut in several stages, but it all makes sense and I guess puts less strain on the router.

It's a 1/4" router (and a pretty cheap DIY one at that) so I will definitely try to take it slowly!

Norman_Castle

fwor wrote: »

Thanks for that - it wouldn't have occurred to me to make a jig that way! And for some reason it didn't occur to me to do the cut in several stages, but it all makes sense and I guess puts less strain on the router.

It's a 1/4" router (and a pretty cheap DIY one at that) so I will definitely try to take it slowly!

A straight 1/4" cutter taking shallow cuts wont put much strain on the router. The cutter can break from the lateral force.

Simple circle jig

http://www.wwgoa.com/article/shop-made-router-base-plates/