Wish me luck!

I have to drill some 16mm holes through 2 x 6mm 316 stainless steel plates on a boat in situ. In fact the holes in question just need enlarging from 12mm to 16mm. I have a decent Black and Decker drill 500 watt/500 RPM and some stainless steel cutting paste. Would be interested if anyone has any tips/suggestions.

Thanks

Mike

I think you would be better off getting a magnetic base drill (they can be hired). Clamp some steel plate onto the boat and use that. Handheld will work, but you do run the risk of the drill grabbing.
Good luck.

Michael

Use a step drill.

Cobalt drill bit?

This is a situation where I would use the folded piece of rag trick to stop the drill from chattering, keep it on centre and keep the hole round.

Graham.

Hi Mike,
I like the idea of renting/borrowing a magnetic drill press (Mag Drill) mounted to a steel plate that is clamped to the stainless steel. You can use the existing hole size drill bit to center the drill, then switch out to the 16mm bit to enlarge the hole. I have several mag drills that I use for applications like yours. The mag drill in the first 2 photos has power feed, while the smaller one in the last photos has a drill chuck with manual down feed.
David

Attachment 379823 Attachment 379824 Attachment 379825 Attachment 379826

Enlarged some holes in 1/4 and 1/2" 316 about a year ago. not really a fun task by hand, just working the edges of the bit. Cobalt would usually do about 3~4 holes before trouble, masonry drill sharpened appropriately produced best results....avoid cooking the material at all costs, if you don't want to be drilling diamond!

Mark the 16mm circle, take out the 2mm margin with a carbide burr in a die grinder.

Quote:

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Originally Posted by Oldbikerider

This is a situation where I would use the folded piece of rag trick to stop the drill from chattering, keep it on centre and keep the hole round.

Graham.

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Thanks Graham,

Would appreciate it you would elaborate further.

Mike

Quote:

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Originally Posted by adbuch

Hi Mike,
I like the idea of renting/borrowing a magnetic drill press (Mag Drill) mounted to a steel plate that is clamped to the stainless steel. You can use the existing hole size drill bit to center the drill, then switch out to the 16mm bit to enlarge the hole. I have several mag drills that I use for applications like yours. The mag drill in the first 2 photos has power feed, while the smaller one in the last photos has a drill chuck with manual down feed.
David

Attachment 379823 Attachment 379824 Attachment 379825 Attachment 379826

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Thanks but I fear the machines in the photos are too big. The plates are part of a tabernacle on a sailing boat and the mast is adjacent, only enough room to get a small drill or grinder in.

Mike

Hi Mike
High feed and low speed for stainless.

Phil