Thread: Routing a small Ellipse

Warmtone,

MDF templates seem to be the way to go if you're going to repeat the process several times. IMHO you need to spend a reasonable amount of time hand finishing the MDF templates with rasp, scraper and sand paper to ensure the collar on the router has something smooth to follow which seems a lot of work for a one off. Obviously at the end of the day your router cut will only be as good as the template you create.

I guess your issue is the 40mm depth otherwise you'd simply hand finish the elipse rather than spending the time hand finishing the MDF template?

What are the dimensions of the cut-out?

HH.

Hi warmtone

I can offer an option that reflects my knowledge of geometry relative to my limited knowledge of routing.

Is it possible to guide a router using a taught piece of string? If so, the attached picture may be a simple option.

Originally Posted by HappyHammer

Warmtone,

MDF templates seem to be the way to go if you're going to repeat the process several times. IMHO you need to spend a reasonable amount of time hand finishing the MDF templates with rasp, scraper and sand paper to ensure the collar on the router has something smooth to follow which seems a lot of work for a one off. Obviously at the end of the day your router cut will only be as good as the template you create.

I guess your issue is the 40mm depth otherwise you'd simply hand finish the elipse rather than spending the time hand finishing the MDF template?

What are the dimensions of the cut-out?

HH.

The dimensions are:
approximately 3' major axis, 2.5 inches minor axis

You're right it's pretty small, maybe the handtools are the way to go. You might be able to get a small circumference sanding attachment for your drill press? Not sure a scroll saw would be able to handle the thickness?

Apologies, I seem to have more questions than answers....

As the ellipse is very small I would also suggest a template, but if it was to be larger I would get one of Patrick Spielman's books on routing and make the combined circle / ellipse jig.

Peter.

If you've still got the old gate you might be able to use it as a template for the new one.

Do you have to slice the rail in half and then join it together again to get the ornamental insert inserted?

Whenever I'm out and about I'm always on the lookout for shapes cut in wood
that I can use for templates.
The craft section of Bunnies is good for this as they have a lot of cheap craftwood projects.
You could use the top of a tissue box cover for example. Then give it to the kids to paint up for Mum for Mothers day.
Also I think Carbatec sell a template kit with various circles, arcs etc made out of perspex.


Darren

Make a template. You can make one in 20 minutes, and even if you never use it again so what. Templates might seem a bit complicated if you haven't made one before but they are quite straight forward once you get into them.

When you make your template, make it on a large piece of mdf or ply so you can clamp it with the clamps well clear of the router.

40 mm is fairly thick so you may need to index the template in some way so you cut the ellipse from both sides and then clean it up with a fine file.

Originally Posted by Wood Borer

40 mm is fairly thick so you may need to index the template in some way so you cut the ellipse from both sides and then clean it up with a fine file.

Or .... just cut the workpiece to whatever depth your router bit can cut to in the first pass ... lets say this is just 15mm deep. Remove the template. Trim out the remaining 25mm with a jigsaw, as rough as you like, cutting to within 1 or 2 mm of the final outline. Then trim off this remaining 1-2mm on a table router and flush trim bit - where the bearing is running on the original 15mm of previously routed surface outline. Works for me!

Qw

Just to clarify warmtone, the ellipse is to be 3 foot by 2.5 inches?

Templates are the go as mentioned. You could either make 1 template for the whole ellipse, or 1 for half the ellipse then flip it over for the other half; or 1 for a quarter of the ellipse and position it four times for the four quarters.

I'd probably go with the quarter idea (less time needed to prepare template), use whatever method to create image on paper (copy existing, string method, CAD program, photocopier to alter size, etc, etc...) , attach paper to template stock (MDF, masonite), cut out with a scrollsaw/bandsaw/jigsaw/coping saw and sand back smooth to the line. Attach template to gate with hotmelt glue/carpet tape/brads and mark out, cut out bulk of the waste with a saw then trim smooth with the router, or rout out the lot in several depth passes.

Reposition accurately then continue. Accurate set out and postioning will give accurate result. Sand smooth any irregularities.

Good luck..........cheers.........Sean, pardon my ellipsis...

Originally Posted by scooter

Just to clarify warmtone, the ellipse is to be 3 foot by 2.5 inches?

Templates are the go as mentioned. You could either make 1 template for the whole ellipse, or 1 for half the ellipse then flip it over for the other half; or 1 for a quarter of the ellipse and position it four times for the four quarters.

I'd probably go with the quarter idea (less time needed to prepare template), use whatever method to create image on paper (copy existing, string method, CAD program, photocopier to alter size, etc, etc...) , attach paper to template stock (MDF, masonite), cut out with a scrollsaw/bandsaw/jigsaw/coping saw and sand back smooth to the line. Attach template to gate with hotmelt glue/carpet tape/brads and mark out, cut out bulk of the waste with a saw then trim smooth with the router, or rout out the lot in several depth passes.


Reposition accurately then continue. Accurate set out and postioning will give accurate result. Sand smooth any irregularities.

Good luck..........cheers.........Sean, pardon my ellipsis...

Just to clarify dimensions of the ellipse - I checked accurately last night

4inches X 3.5inches - apologies for the earlier typo (!!!)

Thanks to everyone for your ideas and feedback - I did actually use the original gate to make a fairly accurate tracing. I used this to dimension the cut I made using a jigsaw.

The upper part of the new gate stile is actually two pieces or Oregon biscuit joined together to get the necessary width. The finished result with the jigsaw is a little on the rough side.

One possibility is the re-use the old gate top as a template - with a flush trim bit as suggested. But can I get a flush trim bit that will handle 30mm??

If it all gets too hard I will make a MDF template from scratch and learn from the process!!

Trouble is it all takes time ..... my wife expected the whole house to be painted in less time than I have taken to make the gate.......

Originally Posted by warmtone

One possibility is the re-use the old gate top as a template - with a flush trim bit as suggested. But can I get a flush trim bit that will handle 30mm??

Yes

Flush Trim Bits