# Routing a large cavity



## atticus (Dec 7, 2011)

Hello,

I've been "shopless" for a number of years, so I am in the process of getting the woodworking skills and my projects up to a decent standard again. The current project has me a bit stymied since it requires that I rout a large shallow cavity in a rectangular piece of poplar--imagine an 11x14 inch piece in which I am trying to rout a 10 by 13 inch cavity. I need to define the border using a 90 degree v-groove bit plunged to 1/8 inch. That I've been able to do using a guide jig for each side. My difficulty is accurately cutting out the enclosed 10x13 area to that 1/8 inch depth. Would I do best to use a large router plate to span the entire piece so that I get a consistent depth? I'd appreciate any suggestions. Attached is a photo of what I am trying to achieve.

Thanks,
Atticus


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## AxlMyk (Jun 13, 2006)

A router sled will do it just fine.
Do a search for one, and many threads will come up. I'm sure someone will respond with specific posts and pics.


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## bobj3 (Jan 17, 2006)

Hi

Once you have a frame/template and a ski jig you can do it all in a snap.
With or without the brass guides..
===


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## jw2170 (Jan 24, 2008)

atticus said:


> Hello,
> 
> I've been "shopless" for a number of years, so I am in the process of getting the woodworking skills and my projects up to a decent standard again. The current project has me a bit stymied since it requires that I rout a large shallow cavity in a rectangular piece of poplar--imagine an 11x14 inch piece in which I am trying to rout a 10 by 13 inch cavity. I need to define the border using a 90 degree v-groove bit plunged to 1/8 inch. That I've been able to do using a guide jig for each side. My difficulty is accurately cutting out the enclosed 10x13 area to that 1/8 inch depth. Would I do best to use a large router plate to span the entire piece so that I get a consistent depth? I'd appreciate any suggestions. Attached is a photo of what I am trying to achieve.
> 
> ...


Welcome to the router forum, Atticus

Thank you for joining us.

I would second Bobj3's solution. Then you can run off as many as you wish.


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## atticus (Dec 7, 2011)

Yes, a router sled seems to be the answer. Thank you for your suggestions. 

Regards,

Atticus


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## bobj3 (Jan 17, 2006)

Hi Atticus

You're Welcome 

You may say but how do I make the frame /template very easy job on the router table with some scrap sticks just tack them in place and let the router bit do the work,see below, you can also just rip up some stock and glue them up and wait for the glue to dry all the way, it's a slow way of doing it but it will work also..

The ski jig can be some boards you have in the shop just need two hole in both to support the router on and hold the rods....no big deal..

Also a great way to make a template for the router table mounting plate ,many just buy one but it's so easy to make your own, just place the router plate on the MDF tack the wood strips in place and cut it out,it will always be dead on with your plate..at about 1/10th the price.


====


atticus said:


> Yes, a router sled seems to be the answer. Thank you for your suggestions.
> 
> Regards,
> 
> Atticus


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## atticus (Dec 7, 2011)

*Ski jig*

Thanks to Mike, Bobj3 and James for suggestions. I finally opted for the ski jig which did the job quite well. The only "problem" I encountered was a bit of sag in using "hardware store" threaded rods to support the router, (I used my 1/2" plunge router, which is quite heavy). As it turns out, the minor variation in depth of cut had little effect on the final panels. In the future--and I will be making more panels--I will try to find a less flexible grade of steel than the low carbon mild steel of the inexpensive threaded rods. 

Atticus



bobj3 said:


> Hi Atticus
> 
> You're Welcome
> 
> ...


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## harrysin (Jan 15, 2007)

What diameter and length were the rods? My skis are 12mm and 27.5" long made from bright mild steel and there is no sag, bearing in mind that the skis are operated by using the end cheeks. Driving the router by it's own handles WILL cause variations in depth of cut.


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## atticus (Dec 7, 2011)

*My Router Ski Jig*



harrysin said:


> What diameter and length were the rods? My skis are 12mm and 27.5" long made from bright mild steel and there is no sag, bearing in mind that the skis are operated by using the end cheeks. Driving the router by it's own handles WILL cause variations in depth of cut.


Hello Harry,
Thanks for your reply. Sorry to take so long to respond. 
The threaded rods I used were 3/8", which makes them about 9.5 mm in diameter, and I had them at 24" long between the skis. I did steer the router by the end cheeks and not the router handles. My half-inch plunge router is a 30-year-old Elu which came with 3/8" rods for the edge guide. Those rods were unthreaded, only about 15 inches long and very rigid. It seems that for my next similar project I need to look for similar characteristics in long rods and use a die to cut threads. 

Atticus


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