Enlarging an existing hole

[GmB]

How do I keep a mag drill central to enlarge an existing hole?
Is it possible?
Need to go from 30mm to 32mm

 

[JWL]

Set it up with the 30mm bit fitted in the hole and then swop to the 32mm bit?
If you can't swop bits just mark the position or clamp guides to reposition the drill back in the same place

 

[JCB_JCR]

Weld a plate with a pilot hole,to fit the pilot pin in, on the back face?

 

[GmB]

Both good ideas, thank you.
Will depend on what size drill bits the boy next door has, he will be doing the job, just haven’t told him yet...

 

[Chuckie]

Drill a 32 hole in a plate then clamp that over the hole you want to enlarge. It will keep the bit central

 

[Mur Huwcun]

Weld a plate with a pilot hole,to fit the pilot pin in, on the back face?

Either this or make an isert to fit inside the existing hole and inside the cutter just to start the cut. This is how I rebush worn holes etc

 

[Bobthebuilder]

just get a round file and start rubbing

 

[Tim G]

Step drill?

 

[davidroberts30]

Drill a 32 hole in a plate then clamp that over the hole you want to enlarge. It will keep the bit central

This^

 

[TheTallGuy]

Step drill?

Think it's a bit thick for that

 

[TheTallGuy]

Set it up with the 30mm bit fitted in the hole and then swop to the 32mm bit?
If you can't swop bits just mark the position or clamp guides to reposition the drill back in the same place

Yep, done this a few times.

 

[milkloss]

A die grinder would make short work of it but I suspect you want it round!

 

[GmB]

A die grinder would make short work of it but I suspect you want it round!

Yes, a half tidy job is preferred.
Putting a euro headstock onto an MF880 loader and need a hole in the new headstock to match up with holes on a set of 80 brackets

 

[Dman2]

Use a reamer bit

 

[Bury the Trash]

Yes a Reamer would be the safest way,
HMT do a variety, low kick supposed to be , even impact ones not cheap but quality and would be useful to have for another day.

 

[GmB]

Thanks to everyone who made a suggestion, in the end went with @Chuckie, very pleased with the result.

 

[michael N123]

Spit on it an slam it in

 

[ACEngineering]

Drill a 32 hole in a plate then clamp that over the hole you want to enlarge. It will keep the bit central

Exactly this, its the only way it will stop it wandering off, even then it wont be 100% accurate but near enough in most cases.

 

[snipe]

Just line it up and go steady away till it gets started. I do a half hole on top of an existing hole to make a slot sometimes.

 

[wanton dwarf]

just get a round file and start rubbing

Rotary file works.