Drilling small rounds on center

[Scotty W]

Forgive me if this has already been answered.  I'm looking for the best way to drill centered holes through the brass rings shaped around some ends of my boom and other masts on my ship.  I'm afraid to try to use a center punch to keep the .6mm bit from walking because it might crush the tiny little piece.  How do you

guys put perfect holes straight through both sides of the brass and wood?  Thanks! Scotty

 

[Snug Harbor Johnny]

  Before using a center punch on any piece of metal, a 'prick punch' is lightly tapped to get a very small dink where layout marks or scratched indicate.  A prick punch looks much like a center punch, except that the angle of the tip is much more 'pointy' than the angle of a center punch - which corresponds to the standard angle for drill flutes.  The end of a piece of drill rod (or a shank broken off a drill) can be ground (dipping the end frequently in water to avoid losing the hardness) to a sharp point, then it would be a miniature prick punch that might be safe to use on the item in the photograph.

 

If the concern is that the  fragility of your work piece won't hold up against any sort of impact, you might slip the brass ring off the yard and support the ring with a brass rod that just fits through the ring.  Then a prick punch would be safer - and a 0.6mm drill will 'bite' without needing further punching.

 

  If ring removal is inconvenient, then a thicker (relatively) metal collar that has already been crossed drilled and just fits over the brass ring you want to drill through will act as a 'drill bushing' to guide the drill - no punching is needed in that case.  For multiple sizes of brass rings, multiple bushings would have to be made.

Edited February 11, 2023 by Snug Harbor Johnny

[Scotty W]

I have already glued the brass ring in place so will look for something to act as drill bushing to put over it or make a center prick from a screw perhaps since they are pretty hard. Thanks for taking the time to help me out.

[BANYAN]

One option that I use is my mill or if you have one a small press-drill.  I put the piece (well protected) in a vice, or lay it in a 'V' block braced/packed to keep it level.  If I lower the drill slowly, I have had success in keeping it centred.  I have since obtained a 'sensitive' drill attachment which allows me much more 'feel' and control.

 

However, if doing it by hand (pin-vice etc), SHJ has given the best advice for using a small awl to prick a light dent.  Alternatively, you might file a very small flat using a small needle file at the point you want to drill - this may help with the bit wandering?

 

cheers

 

Pat

[Roger Pellett]

Doing this is a two stage operation.  Stage 1 is locating the center of the cylinder.  Apparently you have figured out how to do this.  The second stage is to mark out the location and to keep the hole from skidding off of it.

 

I have a small Proxxon rotary engraving tool.  A Dremel rotary tool would work 

too.  My tool is fitted with a tiny burr.  I often use this to grind a tiny dimple in brass before drilling.

 

Roger

[Scotty W]

Got it! I used a combination of the suggestions so thank you all. I had a little pointed diamond grinding bit which I placed in my drill press. I placed the piece into a slot I cut into some wood then aligned and secured it. I then brought the bit down until it just touched the marked spot I wanted and made the prick. Next I put the .6mm bit in my press and very slowly brought it down and it drilled nicely. Thanks for all the great suggestions! 

[allanyed]

I have found that the method Roger describes is pretty much full proof.  I mark the spot with a fine tip marker pen then use a tiny burr which will get the hole started without wandering.  Then all that is needed is to finish the hole with a drill bit.

Allan