[HorridHenry]

I needed to drill and tap a 25mm ground steel rod and came up with this idea to keep it centralised whilst drilling.

I took a square block of 40mm x 3" long Aluminium (brass is better but I don't have any)scribe crossed it at the corners to give me the center of the block length wise and end wise.

I then drilled out a hole the size of the steel rod througth the length of the block(fig.A).

I drilled a hole in the center the size of the drill I needed to tap the steel rod(fig.C)

I then drilled two smaller holes for tapping in M8 thread(fig.B) these two tapped holes secure the steel rod in place whilst drilling to stop it moving.

Any Good?

[txcncman]

Yes. You have built what is called a drill jig. If you need a drill jig to last the maximum amount of time, you will need to make it out of hardened steel, not aluminum or brass.

[holbieone]

you could make it out of aluminum or brass and use drill bushings

[louieatienza]

you could make it out of aluminum or brass and use drill bushings

+1. You can get drill bushings at most online woodworker's supply places. Ground drill rod does drill rather easily.

[RIN]

I use jig I call drilling prism. It is a block of steel (or wood in pinch) with V shape groove cut in it. Before I put the bar I want drill on it I press the drill bit down to center it against it and clamp it to the drill press. Then the round bar sits centered in it.

[txcncman]

I use jig I call drilling prism. It is a block of steel (or wood in pinch) with V shape groove cut in it. Before I put the bar I want drill on it I press the drill bit down to center it against it and clamp it to the drill press. Then the round bar sits centered in it.

V-blocks can work to, even 1 year late.

[handlewanker]

Hi, the mind boggles at the lengths the unskilled will go to, to do a simple job.

Having marked a spot on the bar where you want the hole, and centralised it in the vise.....(an essay is not forthcoming on centralising the job in the vise).....you then pick up the centre with your centre finder or a sticky pin, drill with a centre drill to start and use an undersize drill to drill the hole through, opening up with the drill size you want to end up with.

BTW, anyone who drills a round bar with a vee block in a drill press and doesn't clamp the bar and Vee block to the drill press table is asking for a few cut fingers when the job gets grabbed by the drill.....seen that happen more times than I've had hot breakfasts.
Ian.