Chamfering a hole

[Lykle]

It seems that the more I make, the less I know.
Things that seem to be quite straight forward turn out to be not so easy in real life. Live and learn.

So, I made the body of the Trebuchet and it looks a bit messy. To clean up the look, I think I want to put a chamfer on the edge of the hole. I would like it to be an even 2mm all around.

Looking at it, I think I have concluded there is no way I can do this with clever tooling or such. The only way I think I can do it now is with the little deburring tool like this one:



Or use a Dremel but then getting it an even 2 mm all around is going to be tricky.

Any better ideas?
This is a picture of the part as it is now. I know the surface is not what it needs to be yet, that will come.

[vtsteam]

Maybe something like this, since you have a small bearing-pilot hole inside....


EDIT: lower stop collar sets angle of cut, not depth.

[Jonny]

Decent knife will do a better job than a deburer, quicker and more controllable too. I have to debur irregular shapes, tried many a thing two decades ago then found a knife some one made me and still used daily.
Nice sweeping flow or it will dig in.

[Lykle]

Ha! Nice sketch!
That would vary the angle of the cut along the hole, but it would work. I will think about it.
Another tool to build, mama!

Using a knife? Never thought of that, I will have to try that on a scrap piece first.

Not sure what I am going to do yet. Wanted to leave it unchamfered, but I am afraid the edge will look a bit messy.

[vtsteam]

You need to vary the angle of the cut along the hole if you are to meet your original spec of an even 2 mm land all around. Hence the design.

I would change two things on further consideration.

1.) The fixed arm shouldn't be tapped for the screw, but just make it a sliding fit, and fit a plunger (instead of a screw) to pass through the top of the arm and topped with a small knob.  That way you can apply hand pressure instead of depending on the spring.


2.) Put a knob on top of the pilot shaft, as well. Could be just a second stop collar.

[Meldonmech]

Hi,
     I normally use a small half round or triangular scraper, made by Moore & Wright.

                                                          Cheers David