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SUPPORT FORUMS FOR DECWARE SPEAKER PLANS >> Deathbox Support Forum >> DB 10 Port issue
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Message started by Matt on 09/08/08 at 12:43:00

Title: DB 10 Port issue
Post by Matt on 09/08/08 at 12:43:00

Don't know if anyone else has cone accross this problem, but I'm builing a couple of DB10s and I'm at the port cutting stage, and I noticed that the port is 2 5/8" in height, but is 7 1/2" wide. So it isn't a half circle, it is a section of a circle, so how do you draw this accurately with out knowing the radius of the circle?

Maybe I'm missing something really simple here so fill me in here if I'm just dumb.

Also I'm wondering if it is possible to use the port design from the DB12 because that looks much nicer, or would that cause issues because the DB10 port is designed exactly for that box?

Any help would be just super.

Title: Re: DB 10 Port issue
Post by ZYGI on 09/08/08 at 22:45:53

Matt,

You are correct, its not a 1/2 circle, its an arc the 2 5/8 would be the cord height. There is a formula for this, but I can't find it right now, I've gotten lazy over the years and let my CAD program figure it out. It came up with a 3.99107" radius, a 4" radius will work just fine. Just remember to round the inside of the port prior to assembling the box, round the outside of the port over after the box is assembled.

BobZ

Title: Re: DB 10 Port issue
Post by 2kdime on 09/09/08 at 01:12:24

I too was having issues with this today. So in a sense, you can make an 8 inch circle out of paper. And then lay it on the board so the edge rests at the 3 inch mark. And the top of it rests at 2 5/8. And then trace around it?

Title: Re: DB 10 Port issue
Post by Matt on 09/09/08 at 09:24:31

Yeah, I think that is what I'm going to do. Or else I was going to get a piece of mdf and put a screw at 1 3/8" from the edge then attach a pencil to a 4" bit of string then lining that up with the centre (where the port should be) and drawing the arc that way, but I think your way with a 8" circle sounds easier.

I'm surprised that more people have not mentioned this as a problem, because it is rather difficult to figure just how to draw this arc. My wife and I were trying to figure out the area of the port and with the dimentions given it is rather difficult.

I guess most people are just guessing or free hand drawing the port?

Seems like a strange size and shape due to it's difficulty to draw, but I assume there is a good reason for it so I'll make it how it says.

How are other people out there doing this??

Title: Re: DB 10 Port issue
Post by ZYGI on 09/09/08 at 22:43:37

Another way of drawing an arc, is to take a flexible wood strip, very thin, and drive a nail at the 2 5/8" center mark, and clamp two pieces of wood where the bottom of the arc meets the bottom of the edge and bend the wood around the the tree points.

Another way would be to purchase a cheap compass, works great for this kind of application.

BobZ

Title: Re: DB 10 Port issue
Post by IndySphile on 09/15/08 at 06:40:03

I used a thin strip of wood to draw the arc. Mark 3 points with a pencil 2 5/8" down and 2 points at 7 1/2 width apart and bend the strip till you have an arc that touches each point. have a buddy trace the line for you (unless your lucky enough to have that third hand). Dont forget when laying out your points that center of the board isnt center of the arc, its offset 3/4" , its easy to overlook that one :-/