How do I cut a perfect circle for my box?

[jeff96]

I have'nt decided if i'm going with a ten or a twelve yet, but how do I make a complete circle for the sub to fit in? I tried a jigsaw but it came out pretty sloppy. I remember in shop class we use to have an attachment to the drillpress that would make perfect circles but i doubt they make them that large. Any ideas thanks.

 

[91Ranger4x4]

I used a rotozip to make mine.

 

[jimbo74]

i was just thinking a rotozip with the circular attachment, my dad used that when he had to make a subfloor around our toilet for new flooring....

 

[B94Sport]

I just used a piece of scrap MDF that had a nail in one end and a pencil in the other to draw the circle (spin the wood around the nail axis), then drilled a small hole for the saw, then used a Black and Decker hand-held jig saw to cut out the large circle. If you go slow, it'll come out perfect.

 

[VairKing]

I always use a compass, draw the circle, then carefully cut it out with a jigsaw...have had nothing but perfect results...

 

[james t]

i made this in HS. its measured out to fit just about every 5.25, 8, 10, 12, and 15 out there. just need a 6.5 and itll be done. you screw the first screw in the center of were you want to make the cut. then screw the selected size screw out just enough to scratch the MDF... and scribe a perfect circle.

 

[jeff96]

Thanks for the answers so far, I used a jig saw last time but it came out more ovalish. Here is another question, I have always had twelve inch subs but I am getting a ten now, what size is the cutout for a 10 inch sub? I should probably wait till I get it but I have the whole side of my car pulled out where I am putting the amp under the stock speaker and the sub box I just made in the cargo holder area. Thanks for the info.

 

[KPT]

I always just use the cardboard piece the sub shipped in to draw the circle on MDF and a jigsaw to cut it out.

 

[AnabolicFrolic]

rotozip with a circle jig for the big jobs like subwoofers.

Or i use a jigsaw if im doing small templates for like 6.5 speakers etc

 

[B94Sport]

Originally posted by jeff96
I have always had twelve inch subs but I am getting a ten now, what size is the cutout for a 10 inch sub?

The size of the cutout you need will vary. You should be able to find the info on the manufacturer's website, or it will definitely be provided with the sub, either in the manual, or as a template.

 

[MONMIX]

A nail and a pencil with string is an old reliable trick.

The opening has to be good but not flawless.

As long as it seals well.

 

[stretch]

You could take James T's idea one step further by attaching a router to the board instead of nails to scratch the MDF. As you turn the board around the nail the router will cut a perfect circle for you.

 

[jeff96]

Thanks for all the answers they've helped i'll let you know how it goes.

 

[V8BoatBuilder]

I used the cardboard insert the sub came packed in, and a jigsaw with a very thin, high TPI blade. The thin blade, and a steady, slow hand are they key.

 

[tac0meat]

i always used a router to cut my holes. most routers have an attatchment for cuttin holes. they vary widely in look but basically it is a piece of wood or plastice about 2 feet lont and 4 inches wide. has multiple holes or is adjustable. place a nail in the center of where you want the hole and place the hole cutting thing over the nail. then just go around the circle with the router. using this method you can make a perfect hole for anywhere form an 8" sub on up with about 10 seconds of cutting.

to measure the subs i take 2 carpenters sqaures and place them on either side of the underneath of the sub, then i can tell how far away the squares were and the size of the sub