Specialized Drill Bit
 

Or at least one that is semi-specialized.

I need to drill holes in 1/4" thick metal rails, top and bottom to put new
pickets in. The design the owners like best involves a countersunk screw
on the top rail.

What's the best way?

1. Is there likely to be a bit for metal that will combine drilling the
through hole and the countersink part, the same way there is for wood?

2. If not, I can do the operation in two steps-the through hole first,
then the countersink portion.

3. In either case, how do I control for depth for the countersink part,
so the top of the screw ends up being flush, or nearly so, within paint
thickness?

4. Also, the countersink should have the same angle as the screw itself.
How difficult will it be to match?

5. Any suggestions for suppliers? HD and similar stores probably won't
have the bits I need.

Thanks,


charles

Specialized Drill Bit
 

Outlets that sell metal working supplies have them.

"Charles Bishop" wrote in message
...
Or at least one that is semi-specialized.

I need to drill holes in 1/4" thick metal rails, top and bottom to put new
pickets in. The design the owners like best involves a countersunk screw
on the top rail.

What's the best way?

1. Is there likely to be a bit for metal that will combine drilling the
through hole and the countersink part, the same way there is for wood?

2. If not, I can do the operation in two steps-the through hole first,
then the countersink portion.

3. In either case, how do I control for depth for the countersink part,
so the top of the screw ends up being flush, or nearly so, within paint
thickness?

4. Also, the countersink should have the same angle as the screw itself.
How difficult will it be to match?

5. Any suggestions for suppliers? HD and similar stores probably won't
have the bits I need.

Thanks,


charles

Specialized Drill Bit
 

Maybe a center drill would work for you? Google "center drill" for
examples.
They are for metalworking. You are correct, you will not find them at HD.


"Charles Bishop" wrote in message
...
Or at least one that is semi-specialized.

I need to drill holes in 1/4" thick metal rails, top and bottom to put new
pickets in. The design the owners like best involves a countersunk screw
on the top rail.

What's the best way?

1. Is there likely to be a bit for metal that will combine drilling the
through hole and the countersink part, the same way there is for wood?

2. If not, I can do the operation in two steps-the through hole first,
then the countersink portion.

3. In either case, how do I control for depth for the countersink part,
so the top of the screw ends up being flush, or nearly so, within paint
thickness?

4. Also, the countersink should have the same angle as the screw itself.
How difficult will it be to match?

5. Any suggestions for suppliers? HD and similar stores probably won't
have the bits I need.

Thanks,


charles

Specialized Drill Bit
 

check out one of those step drills. the angle might not be perfect but it
might just work. they cut very fast and easy to control the depth
Mike
"Charles Bishop" wrote in message
...
Or at least one that is semi-specialized.

I need to drill holes in 1/4" thick metal rails, top and bottom to put new
pickets in. The design the owners like best involves a countersunk screw
on the top rail.

What's the best way?

1. Is there likely to be a bit for metal that will combine drilling the
through hole and the countersink part, the same way there is for wood?

2. If not, I can do the operation in two steps-the through hole first,
then the countersink portion.

3. In either case, how do I control for depth for the countersink part,
so the top of the screw ends up being flush, or nearly so, within paint
thickness?

4. Also, the countersink should have the same angle as the screw itself.
How difficult will it be to match?

5. Any suggestions for suppliers? HD and similar stores probably won't
have the bits I need.

Thanks,


charles

Specialized Drill Bit
 

Charles Bishop writes:

What's the best way?

What species of metal?

Wide selection of bits he

http://www.use-enco.com/CGI/INSRAR?PMSECT=0000000606

Use a center punch to start the hole.

Use cutting oil and the right bit rotational speed.

Use a drill press if you have one. A good drill press will have a stop
setting to get the countersink depth just right.

Your screws probably use a 60 degree included angle.

Specialized Drill Bit
 

you'll need to determine the angle of the countersink. the most common are
90° and 82°.
you can get chamfer tools accordingly. an easy place to find them is at
www.mcmaster.com

To control depth, if not in a drill press situation, you'll need to cut and
try.
bill

"Charles Bishop" wrote in message
...
Or at least one that is semi-specialized.

I need to drill holes in 1/4" thick metal rails, top and bottom to put new
pickets in. The design the owners like best involves a countersunk screw
on the top rail.

What's the best way?

1. Is there likely to be a bit for metal that will combine drilling the
through hole and the countersink part, the same way there is for wood?

2. If not, I can do the operation in two steps-the through hole first,
then the countersink portion.

3. In either case, how do I control for depth for the countersink part,
so the top of the screw ends up being flush, or nearly so, within paint
thickness?

4. Also, the countersink should have the same angle as the screw itself.
How difficult will it be to match?

5. Any suggestions for suppliers? HD and similar stores probably won't
have the bits I need.

Thanks,


charles

Specialized Drill Bit
 

In article ,
tt (Charles Bishop) wrote:

Or at least one that is semi-specialized.

I need to drill holes in 1/4" thick metal rails, top and bottom to put new
pickets in. The design the owners like best involves a countersunk screw
on the top rail.

What's the best way?

1. Is there likely to be a bit for metal that will combine drilling the
through hole and the countersink part, the same way there is for wood?

2. If not, I can do the operation in two steps-the through hole first,
then the countersink portion.

3. In either case, how do I control for depth for the countersink part,
so the top of the screw ends up being flush, or nearly so, within paint
thickness?

4. Also, the countersink should have the same angle as the screw itself.
How difficult will it be to match?

5. Any suggestions for suppliers? HD and similar stores probably won't
have the bits I need.

Following up my own post with additional information and thanks for the
input so far.

This work will be in the field, on (E) steel railings. The steel is flat
stock and is 1/2" thick. I'll need to drill a through hole with a
chamfer(?) to include the screw head so it is flat to the top of the bar
stock. Bad ASCII art follows:

_______ _ _ ______________
\ /
\ /
|| 1/2"
|| Steel Flat
|| Stock
_________||_______________

In woodworking they have bits that will drill and countersink in one
effort, and I'd like the same for the steel. The wood bits can have a
"stop" added to the bit so it isn't countersunk too much, and again this
would be more efficient than doing it by eye.

The center drill mentioned might work for a two pass attempt but the shaft
isn't long enough to go through the 1/2" steel. Same for the step drill.

Again, this is in the field, so a drill press won't be available.

Thanks for the help.