Advice required

[UKRob]

I'm after some tips from any of you craftsmen regarding recessing around a drilled hole. My problem is this - I've made a few pairs of scales for Feather and now Kai folding razors and use a Chicago type screw at the pivot end. The screw itself is 4mm with one end cap of 9mm and the other at 8mm so I like to recess the domes of the end caps which is easy enough using a recessing bit. The problem I have is in ensuring that the recess is central over the 4mm drilled hole - up to now I've positioned the screw and drawn round the cap then recessed the piece by eye - can anyone suggest a more accurate method?

 

[antdad]

I don't know what it's called but you can buy what is essentially a small end mill with locating mandrel on the tip for precisely that sort of operation. I have some somewhere if I can find 'em.

 

[pugh-the-special-one]

I use these types on my cordless drill when I counter sinking screws Rob I don't know if this would be of any use to you.
http://www.axminster.co.uk/axminster-axminster-combined-drill-and-countersink-with-depth-stop-prod819624/

 

[antdad]

I think he wants a flat bottomed hole Jamie.

 

[Gairdner]

In knife making, the use of a 'step drill bit' is the method often used when fitting loveless bolts. I think the bolts have a threaded screw section lower down which goes throught to the other side where it is gripped by a bolt topped with an end the same as the other side.

Shite explantion from me so a pic might help:

Step drill bit:

So you've got the thin bit at the very end to drill/ mark the through hole and the thicker part to recess the head and still have a flat bottom - ooer.

Probably about as much help as fly in the air but I tried....:blush:

 

[UKRob]

Yes Tony is right. However, I think I might have come up with a way round the problem -if I clamp the piece in position on my pillar drill, then change from the drill to the router without moving the piece, I should be about right. Then when I turn the piece over, I put the drill bit in again, clamp into the new position and change over to the router again.

I'm sure I only came up with this because I asked the question so thanks.

Tony, I'd be interested in your solution anyway.

Graeme, thanks for your suggestion - I didn't,t know such things existed. I suppose they come in various size combinations so I'll search for them.

 

[pugh-the-special-one]

Just found the perfect tool for the job Rob.

http://www.tool-net.co.uk/p-387109/trend-snappy-snap-cb-1tc-4mm-x-9-5mm.html?gclid=CLaQ_IHnlroCFUXKtAodYCcA8w

 

[BraveBlades]

Just found the perfect tool for the job Rob.

http://www.tool-net.co.uk/p-387109/trend-snappy-snap-cb-1tc-4mm-x-9-5mm.html?gclid=CLaQ_IHnlroCFUXKtAodYCcA8w

ahhh you beat me to it Jamie - i knew what i was looking for but couldn't find it lol

 

[antdad]

Good idea that would certainly do, sorry I can't find them atm but Graeme's step drill bit is essentially the same thing.

Edit...well done chaps that's it.

 

[daz]

You are looking for a "counter bore"
Now that you have the correct name your search should hopefully be easy
I use them all the time at work, but not in the sizes you require. But they will be out there somewhere!