Thread: Routing a circular table edge ogee profile

I would use a trammel, set at the exact distance to rout the edge. No doubt same as you set up to cut out the circular table.
Hope that's clear enuf fer ya...

Bearing-guided bits are mainly produced for following templates and for putting a profile on your table edge will not work unless used in a table. The problem is that - if the bearing rides on the existing edge, then the cut will reduce the overall diameter - as del as leaving a thin residual layer of ply. Once you complete the circle, the bearing will then take a dive inwards to the new edge - not good!

In a table, if the bearing is set in line with the fence, the profile will be cut consistently. All of that said, please remember that ply is composed of several layers with the grain direction constantly changing between layers. For this reason, some tearout/raggedness can be expected. Beware plywood splinters too, they're vicious!

wolften's suggestion of a trammel is the way to go if no table is available.

Ray

Thanks kindly for your comments above. The only problem using a trammel is with having a pivot screw in the centre of the table.

Looks like I might just use the trammel to make a 600mm round template out of 12mm MDF, clamp it to the table, and run the router base around it, in stages, careful not to shift the template once the cut has started

No need to clamp it, Jill. Screw the template to the underside!

Ray

Thanks Ray, but I am cutting an ogee profile that requires it to be cut from the top.

Mmmmm....... Unless I use the bearing on the ogee bit against the 12mm thick MDF circular template screwed to the underside

Originally Posted by JillB

Mmmmm....... Unless I use the bearing on the ogee bit against the 12mm thick MDF circular template screwed to the underside

Precisely so! The bearing will ride around the MDF, giving you the edge profile required. That's the entire purpose of the bearing.



The drawing above shows a straight cutter in use with a template to reduce the size of a workpiece to that of the template. Your job involves the same principle, except that the template starts off at the same size as your workpiece.

Ray

If your router has appropriate holes for guide bars: https://www.woodworkforums.com/f88/router-compass-50372/

Cheers,
Joe

Originally Posted by JillB

Thanks kindly for your comments above. The only problem using a trammel is with having a pivot screw in the centre of the table.

Looks like I might just use the trammel to make a 600mm round template out of 12mm MDF, clamp it to the table, and run the router base around it, in stages, careful not to shift the template once the cut has started

Use trammel but you don't have to drill a hole. I would simply piece of 3 or 6mm MDF with a hole matching the pin drilled .. Use double sided tape to fasten it (make sure it is heavy duty one) Stick that in the center and you can use tremmel without the need to drill a hole

Originally Posted by JillB

Thanks kindly for your comments above. The only problem using a trammel is with having a pivot screw in the centre of the table.

Looks like I might just use the trammel to make a 600mm round template out of 12mm MDF, clamp it to the table, and run the router base around it, in stages, careful not to shift the template once the cut has started

place the pivot hole in a board stuck to teh table with double sidded tape.

less chance of a stuff up compared to clamping a full sized template

thanks for the comment, ian. Only problem is my steel trammel, which slides into the fence holes on the router, pivots at the same level as the base of the router

Originally Posted by JillB

thanks for the comment, ian. Only problem is my steel trammel, which slides into the fence holes on the router, pivots at the same level as the base of the router

Then stick a packing piece to the base of the router...

Jill
Just to understand the problem can a template the same diameter be added to the material?

If so I think I may have the solution to your problem. But before I send it to you I will first see if it will work on another similar cutter as I do not have the one in question, but the method I have in mind is the same irrespective of the shape. Obviously it is not a 'One-Cut' process.

Thursday is my woodworking day solving all sorts of problems with the router so I could be lucky.
Will get back to you as soon as possible
Tom
P.S. How are the trinket boxes going?

The solution is already shown in post 6, as realised by the OP. Her existing trammel will cut the template from 12mm MDF, which can then be fixed to the underside of the workpiece. The bearing-guided cutter will then ride around it, cutting the edge profile in one operation. Clamps are not necessary, as the template can either be screwed, hot-glues or taped to the underside. Job done.

Ray

Sorry if I mislead you Jill as today is Friday and I had changed the woodworking day due to other commitments yesterday. So today I had a go at solving your problem of routing the edge of the material which was only 20mm thick jarrah and as I said it should not be done in one cut but in a number of cuts.
Tom