How to cut an 80mm circle in a piece of wood/MDF

[straygoat]

Hello

I'm trying to make some shelves for an alcove at home. To accomodate stereo wires, lamp cables etc., I need to put holes in each of the shelves and attach some of those plastic cable tidy things you get on computer desks (to let the plugs and cables go down the back of the shelves safely). I need an 80mm circle cut in each of the shelves.

What is the best way to do this? I haven't got a jigsaw yet, so I'll need to buy one. Someone mentioned that you can get a compass like attachment that makes it easy to cut circles - is that the case?

If anyone can offer any advice re: cutting the holes and buying a suitable jig, I'd appreciate it. Oh, I've never used a jig in my life, so please bear that in mind!

Cheers

Craig

 

[Golfer1]

Forget buying a jigsaw – you need to buy an arbor and a holesaw.

Holesaws are very cheap - I'd go for a set like this which contains all you need:

http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=100220&ts=56910&id=11002

80mm not in there, but I'm sure you'll find one by searching around a bit.

I last used one when fitting some halogen spot lights into the top of a cupboard. Very easy to use.

I’m sure you can buy them in DIY stores (I think I inherited mine from my Dad!).

Hope that helps,

Or try this kit - this is identical to the one I use:

http://www.gwsupplies.co.uk/tools/product.info.php?item=2874

 

[straygoat]

Thanks, I'll look into it...how do these holesaw things work though?

 

[Golfer1]

They fit into your drill just like a standard drill bit.

You then fit the holesaw onto the ‘drill bit’ and hey presto, you have a rotating hole cutter. The drill bit protrudes beyond the depth of the hole cutter so that you can position your drill bit in the centre of the hole you want to cut.

Drill down nice and straight and the holecutter then makes contact with the board. Carry applying light downward pressure and the hole cutter cuts a nice clean hole for you. Go for the Draper kit in my previous post (I added a link in at the end of the message) and it’ll make perfect sense. As long as you have a drill, that is!

You don’t need a powerful drill for this – I have used both a cordless drill driver and a standard corded drill – both work OK unless you are drilling a hole through something really tough!
Draper Link: http://www.gwsupplies.co.uk/tools/product.info.php?item=2874

 

[straygoat]

Ah...got ya! You drill in the middle and the cutter goes round the outside edge. That sounds easy enough. I'll make an investment in the Draper cutters and see how I get on.

Now all I need to do is figure out the best way of supporting the shelves! Do I go for ugly but stirdy brackets or take the risk of pretty but weaker 'floating' shelves with batons? Hmmm....

Cheers

 

[sidecar_jon]

small tip when using hole cutters, I just drilled a door into a swiss cheese so i know!.... Drill down and let it cut but stop before you go all the way thro, then use the center hole to line up and drill the rest of the hole from the other side. Hole cutters if you drill right thro in one, seem to cause a ragged edge or split the wood as it emerges. If you cant get to the other side you can clamp a bit of scrap wood to it to stop it splitting.

 

[gord55]

Craig - if you manage to find an 80mm hole cutter, please let me know... I've been looking off & on for the past year!

 

[richtom80]

Ok it's not exactly 80mm, but 1mm out should be fixable with file/glasspaper

http://www.gwsupplies.co.uk/p/2863/starrett+holesaw+79mm.htm

Don't forget you will need an arbour to use the hole saw