Curving corners on small pieces

[Banga]

Hi,

Any tips on the best way to round off corners on small pieces of wood? Size is approx 75X40X3mm. Need a 3mm radius.

 

[custard]

Disc sander

 

[custard]

Actually at 3mm thick you could just chop them out with a suitably tight radiused gouge.

 

[Banga]

I'm making several lids for boxes so really need some sort of jig. Needs to be exactly the same everytime.

 

[custard]

Okay, then I'd do it on the router table. I'd make a jig with a curved corner, and frames to locate the workpiece, plus a toggle cramp to hold the workpiece with a bit of sandpaper glued underneath to stop any slippage. Then you can route off as many perfect copies as you like with a copy router bit. With a bit of care you could stack a few one top of each other and bang them out three or four at a time. It's not best practise but that's what everyone does in commercial workshops.

 

[Phil Pascoe]

A 3mm radius gives you less than 0.75mm to take off. One wipe of a decent abrasive would do that.

1 1/4mm - sorry.

 

[sunnybob]

I do that on the belt sander.
hold it flat and rotate by hand.
Light pressure gives a very nice roundover.

 

[Banga]

I have router but not a router table. Ideally I'd like to make a router jig out of perspex. I have access to a decent laser so can cut with great accuracy. I could cut the whole piece at once. The problem I have is the size of the radius on the jig to get 3mm radius on the piece.Using a 20mm bush. Maybe there's a formula for it? I really need each corner to be exactly the same.

 

[Garno]

. Then you can route off as many perfect copies as you like with a copy router bit.

I've never heard of one those.

 

[custard]

I have router but not a router table. Ideally I'd like to make a router jig out of perspex. I have access to a decent laser so can cut with great accuracy. I could cut the whole piece at once. The problem I have is the size of the radius on the jig to get 3mm radius on the piece.Using a 20mm bush. Maybe there's a formula for it? I really need each corner to be exactly the same.

It's not really a job for bushing (the diameter's too small), you'd be better off with the simpler solution of a bearing mounted copy bit. Even without a router table you could easily make a false sub base for your router with a small diameter hole so the workpiece/jig are supported right up to the cut, secure the router upside down in a vice and that would be all the router table you need for this job. The critical thing is making the jig large enough to keep your fingers well away from the bit.

 

[sunnybob]

Will the laser not cut 3mm wood?

 

[custard]

. Then you can route off as many perfect copies as you like with a copy router bit.

I've never heard of one those.

https://www.wealdentool.com/acatalog/On ... m_279.html

 

[Banga]

@custard sounds like a good plan. Looks like I'll have to buy a bearing bit then Thanks!

@sunnybob the laser will leave burn marks on the wood.

 

[Garno]

. Then you can route off as many perfect copies as you like with a copy router bit.

I've never heard of one those.

https://www.wealdentool.com/acatalog/On ... m_279.html

Thank you.

 

[sunnybob]

I often burn hardwood with my aggressive sanding, but its quite easy to remove it with fine grit or even wire wool.

 

[novocaine]

the burns from a laser are a bit deeper than those caused by sanding Bob, it's a lot move effort to remove them.

you could make a fairly simple jig for a disc sander, fixed pivot point on a sheet with few locator pins to hold the work piece, put the top in the frame, turn it through 90 against the sander then swap it to the next corner.

 

[sunnybob]

oops, showing my stone age upbringing again.

 

[novocaine]

ug, ug ug ug.
magic shiny light from mystic beast make burn burn.

hope that helps.

 

[Jacob]

3mm radius on a piece 3mm thick?
If it's just a few then just nip off the corner with a sharp chisel and sand it round with fine paper on a block. Couldn't be easier. Practice on a few pieces first. This is very, very, basic. If you really can't do it then woodwork is perhaps not for you!

If you are doing a lot there are dozens of alternative ways depending on what kit and what material you are using.

PS if fine paper on a block is a problem - sand paper nail files

 

[Beau]

Hi,

Any tips on the best way to round off corners on small pieces of wood? Size is approx 75X40X3mm. Need a 3mm radius.

If you are doing lots of these would it not be easier to make a wide as possible section 75x40, radius with a router and then cut all your 3mm slices off? Then a quick pass with a plane on the face of each and your done.