# concave jig



## rrwc110 (Jan 31, 2011)

I'm building hardwood skateboards and am trying to build a jig that will let me rout a concave deck and also a convex bottom. I figure the jigs will just have to have opposing arcs. Any thoughts or ideas would be great. thanks!


----------



## jw2170 (Jan 24, 2008)

G'day Ryan

Welcome to the forum


----------



## gav (Oct 12, 2009)

Hi Ryan, first off as you probably know, the curve in a skateboard is usually made by bending it into shape.
If you're determined to rout them, you want a rail and sled type set up.
2 straight rail set parallel to each other and a sled that the router is mounted to that has a concave base and another convex base.
The router and sled travel on the rails.
Hopefully this picture will make it clear for you even though it's being used on a guitar.


----------



## jlord (Nov 16, 2009)

rrwc110 said:


> I'm building hardwood skateboards and am trying to build a jig that will let me rout a concave deck and also a convex bottom. I figure the jigs will just have to have opposing arcs. Any thoughts or ideas would be great. thanks!


Hi Ryan, Welcome.
Look into bent lamination for your decks. I worked with a guy & this is how he made his boards. They came out very nice.


----------



## rrwc110 (Jan 31, 2011)

I really appreciate the tips The picture is cool and helps a lot. About laminations, We're trying to go a different way than other longboard builders. We're using exotic hardwoods and making each board to order for customers. We can guarantee that no two boards will be the same.


----------



## rrwc110 (Jan 31, 2011)

Great picture, one of my friends recently asked me to build him a guitar, so perfect!


----------



## taxque (Jun 30, 2009)

*Why is the profile created with this jig Convex?*



gav said:


> Hi Ryan, first off as you probably know, the curve in a skateboard is usually made by bending it into shape.
> If you're determined to rout them, you want a rail and sled type set up.
> 2 straight rail set parallel to each other and a sled that the router is mounted to that has a concave base and another convex base.
> The router and sled travel on the rails.
> Hopefully this picture will make it clear for you even though it's being used on a guitar.


Hello Gavin,

I see the arc base in the photo - but do not understand why it creates a convex profile on top of he neck. It seems that the top of the bit is the same distance from the top of the guitar neck so it would simply plane/flatten the top of the guitar neck as the router is moved along the rails. 
Is the arc base actually being rotated back and forth on the rails to get the curve?

Greg


----------



## gav (Oct 12, 2009)

Yep, apparently that's how it works. For a guitar neck it's quite a shallow curve.


----------



## Mike (Nov 22, 2004)

Greg, the arc of the jig is what defines the cut. If you think this is way out there check out these jigs and the legs they make. Photo 3 shows using a round over bit on one of the legs. The Router Workshop videos are priceless with all the excellent information offered; I highly recommend them.


----------



## taxque (Jun 30, 2009)

Thanks Mike - those legs are out there. I will have to check the videos out. I used to watch the show regularly and picked up a lot of good tricks.


----------



## rlp_581026 (Aug 19, 2009)

Gav - 

Thanks for the guitar neck post. I'm building one now and have been deciding whether or not to radius the neck. This looks like a good solution for doing that.


----------



## robersonjr (Dec 5, 2009)

Ryan, if you route a board to get the curve you are looking for, it will make the board very weak especially for a skate board which will be subjected to extreem pressures. Thus the reason for bent lamination construction. You can still make each different with the top lamination. Just something to consider. Robbie


----------

