How to make hole in stainless bigger

[Tim M]

I need to make this hole bigger by about 3mm to allow me to fit a new radar reflector. Any suggestions on how to do this?

[martini]

A step drill is about the only option that I can come up with off the top of my head.

http://www.lawson-his.co.uk/scripts/...20Drill%20Bits

[Tim M]

Arh. Wow. I've never seen one of those before. The only slightly issue is a: this is going to be one expensive hole and b: there is another stainless plate just under the one I want to drill (you can see in the photo) - I'm guessing if I use a step drill the bottom plate will get in the way.

Another option: some sort of grinding Dremel attachment

[martini]

You should get away with using a cheap/cheerful bit if it's just one hole. If you've got a grinder just lob the end off the bit.

Or as you say, dremel it, but you'll probably be there for a while and it'll have little resemblance to a round hole by the time you're done

[nugent]

clamp a piece of wood or bit of steell over it and follow through with std starret cutter, wood assists in the centering of arbor if that makes sence

http://uk.shopping.com/starrett-cutter/products

[C2 RIBS]

Tim, you could have a S/S unit made to fit the existing holes and then the top section with the correct holes for new unit. I have some images of how I achieved this, saves all the drilling and it just adds a small box frame above the holes in pic

[Mollers]

A cone cutter.

[Tim M]

Originally Posted by C2 RIBS

Tim, you could have a S/S unit made to fit the existing holes and then the top section with the correct holes for new unit. I have some images of how I achieved this, saves all the drilling and it just adds a small box frame above the holes in pic

Hi Ian. That sounds even more expensive than the hole cutter!

I'm not bothered if the hole isn't very round - it will be totally covered by two nice big washers

[Tim M]

Originally Posted by nugent

clamp a piece of wood or bit of steell over it and follow through with std starret cutter, wood assists in the centering of arbor if that makes sence

http://uk.shopping.com/starrett-cutter/products

I can't see that cutting through this

[JABS]

Tim,

What is the thickness of the material? In total.

What size is the hole at present?

Up 3mm on the diameter?