Drilling brass

[Roger HulettParticipant @rogerhulett83124]

I need to drill three equidistant holes in a brass tube. I presume that I would centre the tube on my lathe and then scribe a line through which the hole centres would go, but how do I position those holes accurately ?.

Having done that I need to cut a triangular hole in the tube (not on the same scribe line), how do I do that ?.

Thankyou.

[Roger HulettParticipant @rogerhulett83124]

[Speedy Builder5Participant @speedybuilder5]

What do you call accurately? Most of us use a centre punch (without deforming the tube) and pre drill with a centre drill. You don't say how big the holes are, or diameter / thickness of the tube etc. A drawing always helps. Triangular holes start off from a round hole, and made triangular by a triangular file. You don't say what machines you have available, so I don't think we can help too much on the limited information. Perhaps give us a bit more info for a more precise answer.
BobH

[JasonBModerator @jasonb]

If they are equidistance around the tube an easy way to divide it into 3 is to hold in the 3-jaw chuck. Then find a block of metal or wood that will roughly fit between lathe bed and one of the chuck jaws, use that as a stop to hold a jaw against, mark position and then do the same with the other two jaws against the block.

If you blue the tube with a marker pen then lightly dragging a tool in the tool post over the surface will mark the positions.

Depending on the triangle a hole drilled first than a triangular file works well.

[pgk pgkParticipant @pgkpgk17461]

Also if you set a pair of dividers to the width of the radius you can walk it around the circumference to divide into 6. Or wrap a pice of paper round the tube and measure/mark and transfer from that.

pgk

[Roger HulettParticipant @rogerhulett83124]

Excellent, thankyou.. I took the easy route. A piece of paper, worked very well. Now for the triangle which I am not so confident with, however will persevere slowly. Thankyou all.

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