Occasionally I have to elongate by about 6mm an 8mm diam hole in 2-3mm thick mild steel. A round file would do it but none of my usual sites define the diameter of their round files. A stepped drill bit would just enlarge the hole which is not what I need. A power tool option would be nice. Any suggestions ?

On 20/10/15 11:18, fred wrote:
Occasionally I have to elongate by about 6mm an 8mm diam hole in 2-3mm thick mild steel. A round file would do it but none of my usual sites define the diameter of their round files. A stepped drill bit would just enlarge the hole which is not what I need. A power tool option would be nice. Any suggestions ?

hand tool - a punch?
Or a nibbler?


--
Global warming is the new Margaret Thatcher. There is no ill in the
world it's not directly responsible for.

On Tue, 20 Oct 2015 03:18:06 -0700 (PDT), fred
wrote:

Occasionally I have to elongate by about 6mm an 8mm diam hole in 2-3mm thick mild steel. A round file would do it but none of my usual sites define the diameter of their round files. A stepped drill bit would just enlarge the hole which is not what I need. A power tool option would be nice. Any suggestions ?

I have a small set of what look at a glance like twist drill bits but
whilst they have a conventional hss bit to start with, the rest of the
bit is more a power file / burr / arbour.

http://www.axminster.co.uk/axminster-drill-saw-rasp-set

The best use is for drilling a hole in thinner / softer material and
then being able to open the hole up or take it in a slightly different
direction.

Because it is rotating, if you were trying to extend the hole in just
one direction (to turn it into your slot for example), you have to
make sure you are applying the side load in the right direction (which
may not be the obvious angle).

You might be able to make this work if you had the bit in a pillar
drill and pushed the job between guides?

Cheers, T i m

On Tuesday, October 20, 2015 at 1:39:26 PM UTC+1, T i m wrote:
On Tue, 20 Oct 2015 03:18:06 -0700 (PDT), fred
wrote:

Occasionally I have to elongate by about 6mm an 8mm diam hole in 2-3mm thick mild steel. A round file would do it but none of my usual sites define the diameter of their round files. A stepped drill bit would just enlarge the hole which is not what I need. A power tool option would be nice. Any suggestions ?

I have a small set of what look at a glance like twist drill bits but
whilst they have a conventional hss bit to start with, the rest of the
bit is more a power file / burr / arbour.

http://www.axminster.co.uk/axminster-drill-saw-rasp-set

The best use is for drilling a hole in thinner / softer material and
then being able to open the hole up or take it in a slightly different
direction.

Because it is rotating, if you were trying to extend the hole in just
one direction (to turn it into your slot for example), you have to
make sure you are applying the side load in the right direction (which
may not be the obvious angle).

You might be able to make this work if you had the bit in a pillar
drill and pushed the job between guides?

Cheers, T i m

Yes I wondered about those but the description says " Use in wood, plastics, aluminium etc. No mention of steel. Besides I'm slightly chary of Axminsters tin coated drills as in the past I didn't find them great.

But thanks for the suggestion any way.

Axminster no longer put an email address for technical queries on their site. When I used an old email address for this query I had it was ignored.

On Tuesday, October 20, 2015 at 2:32:54 PM UTC+1, fred wrote:
On Tuesday, October 20, 2015 at 1:39:26 PM UTC+1, T i m wrote:
On Tue, 20 Oct 2015 03:18:06 -0700 (PDT), fred
wrote:

Occasionally I have to elongate by about 6mm an 8mm diam hole in 2-3mm thick mild steel. A round file would do it but none of my usual sites define the diameter of their round files. A stepped drill bit would just enlarge the hole which is not what I need. A power tool option would be nice. Any suggestions ?

I have a small set of what look at a glance like twist drill bits but
whilst they have a conventional hss bit to start with, the rest of the
bit is more a power file / burr / arbour.

http://www.axminster.co.uk/axminster-drill-saw-rasp-set

The best use is for drilling a hole in thinner / softer material and
then being able to open the hole up or take it in a slightly different
direction.

Because it is rotating, if you were trying to extend the hole in just
one direction (to turn it into your slot for example), you have to
make sure you are applying the side load in the right direction (which
may not be the obvious angle).

You might be able to make this work if you had the bit in a pillar
drill and pushed the job between guides?

Cheers, T i m

Yes I wondered about those but the description says " Use in wood, plastics, aluminium etc. No mention of steel. Besides I'm slightly chary of Axminsters tin coated drills as in the past I didn't find them great.

But thanks for the suggestion any way.

Axminster no longer put an email address for technical queries on their site. When I used an old email address for this query I had it was ignored.

WHOOPS Sorry Axminster. The contact details are under Contact Details. Doh !

fred wrote:
Occasionally I have to elongate by about 6mm an 8mm diam hole in
2-3mm thick mild steel. A round file would do it but none of my usual
sites define the diameter of their round files. A stepped drill bit
would just enlarge the hole which is not what I need. A power tool
option would be nice. Any suggestions ?

Easy as peas. You want a standard cut tooth pattern, 6mm shank, 8mm head
carbide
burr. Ideally used in professional cylinder head porting equipment at
up to 15,000 rpm like mine but they'll do quite nicely in an ordinary
drill albeit taking a bit longer.

http://www.master-abrasives.co.uk/pr...ide-burrs.aspx

Part number C081906 in the pdf would suit.
--
Dave Baker

fred wrote:
Occasionally I have to elongate by about 6mm an 8mm diam hole in
2-3mm thick mild steel. A round file would do it but none of my usual
sites define the diameter of their round files. A stepped drill bit
would just enlarge the hole which is not what I need. A power tool
option would be nice. Any suggestions ?

Easy as peas. You want a standard cut tooth pattern, 6mm shank, 8mm head
carbide
burr. Ideally used in professional cylinder head porting equipment at
up to 15,000 rpm like mine but they'll do quite nicely in an ordinary
drill albeit taking a bit longer.

http://www.master-abrasives.co.uk/pr...ide-burrs.aspx

Part number C081906 in the pdf would suit.

I was thinking of suggesting similar. I have a set of straight versions that
are very good at creating odd shaped holes in steel.

This is one of them

https://dl.dropboxusercontent.com/u/49024805/Burr.jpg

Mike

Dave Baker wrote:

fred wrote:
Occasionally I have to elongate by about 6mm an 8mm diam hole in
2-3mm thick mild steel. A round file would do it but none of my usual
sites define the diameter of their round files. A stepped drill bit
would just enlarge the hole which is not what I need. A power tool
option would be nice. Any suggestions ?

Easy as peas. You want a standard cut tooth pattern, 6mm shank, 8mm head
carbide
burr. Ideally used in professional cylinder head porting equipment at
up to 15,000 rpm like mine but they'll do quite nicely in an ordinary
drill albeit taking a bit longer.

http://www.master-abrasives.co.uk/pr...ide-burrs.aspx

Part number C081906 in the pdf would suit.

Isn't there some risk that the bearings in an ordinary drill
might not be up to taking the side loading if this was done too
often?

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.

Chris J Dixon wrote:
Isn't there some risk that the bearings in an ordinary drill
might not be up to taking the side loading if this was done too
often?


OTOH an angle grinder with an 8mm tungsten carbide mortar rake....

--
Robin
reply to address is (meant to be) valid

On 20/10/2015 15:02, Dave Baker wrote:
fred wrote:
Occasionally I have to elongate by about 6mm an 8mm diam hole in
2-3mm thick mild steel. A round file would do it but none of my usual
sites define the diameter of their round files. A stepped drill bit
would just enlarge the hole which is not what I need. A power tool
option would be nice. Any suggestions ?

Easy as peas. You want a standard cut tooth pattern, 6mm shank, 8mm head
carbide
burr. Ideally used in professional cylinder head porting equipment at
up to 15,000 rpm like mine but they'll do quite nicely in an ordinary
drill albeit taking a bit longer.

http://www.master-abrasives.co.uk/pr...ide-burrs.aspx


Part number C081906 in the pdf would suit.

I'd think manual filing with a coarse round file might be faster, if you
only have normal drill speeds.

In my experience, one problem with trying to make slots using "drills
with side-cutting teeth" is cutting in the direction you want to go,
because the rotating tool deflects you sideways. Not an issue with
Dave's high speed cutters for two reasons, first the power tool is
designed to be easy to hold and stabilise, second at very high speed you
need little applied force, so the sideways force is small compared to
the mass of the tool and they are therefore easier to keep "on track".

fred wrote:
Occasionally I have to elongate by about 6mm an 8mm diam hole in 2-3mm thick mild steel. A round file would do it but none of my usual sites define the diameter of their round files. A stepped drill bit would just enlarge the hole which is not what I need. A power tool option would be nice. Any suggestions ?

Die grinder,(like a potent dremmel)with a carbide cutter (burr)

http://www.ebay.com.au/bhp/carbide-burr

In article . com,
F Murtz wrote:
fred wrote:
Occasionally I have to elongate by about 6mm an 8mm diam hole in 2-3mm thick mild steel. A round file would do it but none of my usual sites define the diameter of their round files. A stepped drill bit would just enlarge the hole which is not what I need. A power tool option would be nice. Any suggestions ?

Die grinder,(like a potent dremmel)with a carbide cutter (burr)

http://www.ebay.com.au/bhp/carbide-burr

My feeling is that with relatively thin steel I'd file it out by hand
before you've found the chuck key for a power tool. And hand held cutters
in thin steel have a habit of wandering all over the place.

But I am assuming you have a decent vice that it can be clamped in.

--
*Why do overlook and oversee mean opposite things? *

Dave Plowman London SW
To e-mail, change noise into sound.

On Tuesday, October 20, 2015 at 4:59:17 PM UTC+1, Dave Plowman (News) wrote:
In article . com,
F Murtz wrote:
fred wrote:
Occasionally I have to elongate by about 6mm an 8mm diam hole in 2-3mm thick mild steel. A round file would do it but none of my usual sites define the diameter of their round files. A stepped drill bit would just enlarge the hole which is not what I need. A power tool option would be nice. Any suggestions ?

Die grinder,(like a potent dremmel)with a carbide cutter (burr)

http://www.ebay.com.au/bhp/carbide-burr

My feeling is that with relatively thin steel I'd file it out by hand
before you've found the chuck key for a power tool. And hand held cutters
in thin steel have a habit of wandering all over the place.

But I am assuming you have a decent vice that it can be clamped in.

--
*Why do overlook and oversee mean opposite things? *

Dave Plowman London SW
To e-mail, change noise into sound.

Axminster finally came back and recommended a particular round file which I will have a go with.
No vice. This is to resolve a problem with two components not aligning correctly when being assembled at the customers premises. Normally its only 2-3mm, or less, astray, but recently it was more like 8mm. Hard to force that much into alignment with a big boot.