# Jig for curving MDF



## Voncarlos (Oct 15, 2008)

I've started a speaker building project and wanted to make the sides a gentle curve. To accomplish this I built a router rail jig to make a 9' radius. I first drew a plan using AutoCad 2004.



















The first task was to accurately cut the bottom rail and top carriage runners at 
a 9'1.77" radius. This required a lot of preparation.



















The cutting bit is a BOSCH micro solid carbide, upcut, end mill. ¼" cut ¼" shank, 2½" OAL. 
The cut had to be perfect at 90 degrees. Each pass would cut about ⅛" (2mm) off.

Here is the 9' extension to hold the router.










Here is one side of the guide rails cut. I've embedded two ½" rectangular steel tubes into the bottom of the rails 
to help support the weight of the router.The top parts of this will be the carriage for the router and the bottom are the rails.










With router attached and all mating surfaces sprayed with lacquer and waxed. It slides very well back and forth.










The router is the venerable Hitachi M12V at 15A, 3¼HP. It will accept a ¼" or ½" shaft bit and weighs in at 12.4lbs. 
The bit is a Grizzly double fluted straight bit, ½" shank, 1¼" cutter diameter and 2⅝" OAL.










As the router is slid back and forth, the side being cut will be pushed under the router. 
I used the top half of some cam clamps to act as hold-downs to the side piece.










It produced a beautiful 9 ft. radius curve. The material is 1⅛" MDF. I removed about 1mm from the apex and that left a ¾" edge.










If you'd like to see the rest of the progress on this project, take a look at the *AudioCircle* forum I'm posting updates on. 

http://www.audiocircle.com/circles/index.php?topic=59326.0

Thanks, VonCarlos


----------



## bobj3 (Jan 17, 2006)

Bump

Mark had to fix the post, Thanks Mark now it works 

Just a note ,,,it's best to resize the snapshots, they will load quicker and upload quicker 
Looks like you up loaded just over 5mb. of pictures,, for the dialup user it's a real night mare 

Here's a free program that will let you resize them b/4 you upload them 

http://www.irfanview.com/
========
picture below
Was 634kb now 32kb
======


----------



## Voncarlos (Oct 15, 2008)

I'm sorry for that, thanks for your help. I've been in the DSL world for so long now that I forget that some areas are still having to use dialup. As a former Graphics Designer, I should have known better. I'll definitely watch those Mbs in the future. Thanks Again, VonCarlos


----------



## AxlMyk (Jun 13, 2006)

640x480 works good.


----------



## jjciesla (Oct 20, 2007)

Voncarlos, WHAT A JIG!! 9 FOOT radius! My shop is only 9' wide X 13" long. Very nice job.
EDITED
Had the wrong dimensions. Jim


----------



## Ghidrah (Oct 21, 2008)

Clever jig!!!

P.S.
I thought I had a small shop 22'LX13'W with a lally at the 6'6" mark on the W.


----------



## AxlMyk (Jun 13, 2006)

Ok. I'll bite. What is a lally?

I used a similar method to make the curves for an Atlas stand legs, although it was only 63 inches.


----------



## Voncarlos (Oct 15, 2008)

AxlMyk said:


> Ok. I'll bite. What is a lally?
> 
> I used a similar method to make the curves for an Atlas stand legs, although it was only 63 inches.


My guess would be lally column? Haven't heard that term in ages.


----------



## BobSch (Sep 11, 2004)

Voncarlos said:


> My guess would be lally column? Haven't heard that term in ages.


Yep. Here's what Wikipedia has to say: en.wikipedia.org/wiki/Lally_column

(Darn 10 post minimum...)


----------



## Ghidrah (Oct 21, 2008)

If you were a framer you'd hear it on a regular basis, sumthins gotta hold yer girt up!


----------



## Cassandra (Mar 15, 2006)

BobSch said:


> Yep. Here's what Wikipedia has to say: en.wikipedia.org/wiki/Lally_column
> 
> (Darn 10 post minimum...)


 
lally: support column consisting of a steel cylinder filled with concrete

lally column: http://www.google.com/search?hl=en&rls=com.microsoft:en-us&oi=definer&q=define:lally+column&defl=en

Cassandra


----------



## Voncarlos (Oct 15, 2008)

Here's the current state of the project.


----------



## dovetail_65 (Jan 22, 2008)

Hey that's a nice set of pictures at the link!


----------



## Robert7 (Dec 23, 2008)

That speaker cabinet is a monster. Good job.


----------

