Route large radius arches

[Domenicxx]

I have this problem...

I always need to create large radius arches..... they can range from say 900mm to 5000mm and anything inbetween.

I am new to doing this sort of work.... so any help would be graetly apppecaited.

if say you had some templates make up say at 500mm up to 4000mm @ 1000mm intervals how can you use these templates to create the radius you require. what would a jog look like?

e.g. if you had a a 2000mm radius template what would a jig look like that by using the 2000mm template with a jig to create say a 2300mm radius arch.

i hope this makes sense. it seem a waste of time always starting from stratch when i want to create a new arch say @ 4000mm when if i a template already at 3000mm why not use that...with some sort of jig..

[damienhazo]

what would a jog look like?
it seem a waste of time always starting from stratch when i want to create a new arch say @ 4000mm when if i a template already at 3000mm why not use that...with some sort of jig..

Sydney? You sure about that? Seems strange to me that someone has been given the responsibility for such large arches but has no idea how to implement a large beam trammel...

[bookend]

I can't think of any way to attach a jig onto an existing semicircular template to alter the radius to make it do the work of a larger one.

I'd just create a new template with a trammel.

Maybe Damien could explain what he has in mind?

[gobfish]

make one out of wood 1200 long , then just ad a stick to it and you can go as big as you like.


have fun steve

[munruben]

:whs:Yep, sometimes the simple way is the best way.:)

[joe greiner]

Some variations of this notion have been posted. For the present question, consider:

Most plunge routers have transverse holes in the base to accept an edge guide. For fixed base routers, an edge guide can be made with an auxiliary base plate. Either way, Google [router "edge guide"] for possibilities. Attach the edge guide with the fence upward instead of downward; if some of the guide still protrudes downward, you'll probably need to use the auxiliary base plate version. Clamp a stick of appropriate length to the fence. The stick doesn't have to be in line with the radius. Measure the radius along the hypotenuse "in air" as shown in pic 3 at
http://www.woodworkforums.ubeaut.com.au/showthread.php?t=50372

The stick can extend beyond the router, above the workpiece, as long as it doesn't hit anything.

Joe

[Rookie]

Maybe Damien could explain what he has in mind?

Perhaps Damien was thinking that if he just put a slice of lemon into a gin and tonic, he may come up with a great idea. :U

Sorry Damien. Got where you're coming from but you won't have seen the Schweppes advertisement (http://www.bandt.com.au/news/5c/0c02865c.asp) over there.

[damienhazo]

My thread says to use a beam trammel. All of the threads thereafter do the same. What more is there to explain? Other than perhaps the fact that it is used to replace the existing jig, not suppliment it...

[johnbro]

There's another way. See this thread http://www.forums.woodnet.net/ubbthreads/showflat.php?Cat=&Board=UBB8&Number=3431293&Forum=f8,f2&Words=arc&Searchpage=0&Limit=25&Main=3429807&Search=true&where=sub&Name=&daterange=1&newerval=4&newertype=w&olderval=&oldertype=&bodyprev=#Post3431293

It references another link which describes a method using a couple of boards at an angle to each other and a template with pins to follow the boards. Anyway, you could create a arc of 10m radius without having a 10m trammel.

HTH

Johnbro

[johnbro]

Different approach:

http://www.forums.woodnet.net/ubbthreads/showflat.php?Cat=&Board=UBB8&Number=3431293&Forum=f8,f2&Words=arc&Searchpage=0&Limit=25&Main=3429807&Search=true&where=sub&Name=&daterange=1&newerval=4&newertype=w&olderval=&oldertype=&bodyprev=#Post3431293