UKC

I have a length of 41mm (2") square pine screwed flush along the base of a sheet of 15mm ply (1220mm total width). I want to round the base of this off to a semi-circle. The thickness of the pine / ply is 56mm, so my semi-circle will have a 28mm radius.
I could plane it by eye, but what could be done with a handheld router? I'm looking at "round off" router bits, but they don't have a large enough radius from what I can see. Is there another method I could use, or another router bit I should look at?
Cheers!

In reply to JohnV:
you will need a half inch shank router for this to work-
https://www.trenddirectuk.com/trend-router-cutters/trend-tct-router-cutters...

In reply to JohnV:

if these radii are not large enough then the only way (without shelling out for a pro workshop to mould it for you on a spindle moulder-expensive) is to plane it by hand with a block plane, and sand it after to remove any flat/high spots.

In reply to Removed Userena sharples:
Thanks for the reply- those bits aren't big enough either, so planing and sanding it is!

In reply to JohnV:

Depending on the actual application, maybe buy a length of mopstick handrail (circular with a flat on one side). Then cut it in half on a table saw and glue/pin to th base. Or router a groove in the flat and put the ply in that.

Also, look at the size of the 2x2. If you do make a true semi-circle, the won't be much left of the ply. Go 3x2 or 3x3 and put the ply in a rebate. Someone will probably make this profile for you for about £30.

In reply to JohnV:

If I read what you're trying to attempt correctly then the solution is straight forward. However you won't be able use the piece you already have. I made a circle cutting jig for my router out of scrap ply and cost nothing other than time. Glue two pieces of pine together sandwiched between brown paper. Mount your router on the jig and set the radius cut. Remember to leave 'tags' so that when you break through your work piece won't be rotating at the same speed as the router. Break the tags and split the join and hey presto.

In reply to JohnV:

If you have a router or table saw then mark it up, make sure you won't hit screws and it'll still be strong enough then knock as much off the corners as you can with a chamfer bit or 45deg cuts before finishing with a plane. Planing ply is a pain.

Alternatively round over both edges with the biggest radius router bit you have and live with the imperfection, I think my cheepo 1/2" set has a 3/4" radius round cutter. My big router would swing a bigger cutter but I wouldn't much fancy being near it!

One final option if you have the router in a big table (as I do with mine) and a willing helper is pivot a couple of wooden blocks on screws driven into the main axis of your desired round. Add a fence to the table to aid positioning then stand the whole thing up on edge with your helper so the pivot blocks rest on the table surface against the fence. Set a big end cutting bit up to the right height then rock the board back and forth through 180deg over the bit sliding it slowly along the fence to perfectly nibble away the desired radius. Not worth the effort!
jk