This is uncharted territory for me. Done similar stuff with wood using Brad
point and Forstner bits but never with metal. Basically, I need a
counterbore (CB) diameter of about 3/4" to a depth of about 3/8" in 1" thick
6061 aluminum. This is to create a recess for cap screw head and washer
along with room to use a hex socket on the cap screw.

Sourcing the correct CB and pilot seems easy enough except that MMC
recommends HSS ($$) for ferrous and carbide tipped ($$$$) CB for non-ferrous
metals. Surely, HSS should work for aluminum or am I missing something?
Also, what would be the best drill speed to use in a case like this? I
normally use wax lubricant for countersinking metal, is this good enough for
counterboring? Finally, is it advisable to buy say a 1/2" aluminum blank and
practice first or am I making a mountain out of a mole hill?

oparr wrote:
This is uncharted territory for me. Done similar stuff with wood using Brad
point and Forstner bits but never with metal. Basically, I need a
counterbore (CB) diameter of about 3/4" to a depth of about 3/8" in 1" thick
6061 aluminum. This is to create a recess for cap screw head and washer
along with room to use a hex socket on the cap screw.

Sourcing the correct CB and pilot seems easy enough except that MMC
recommends HSS ($$) for ferrous and carbide tipped ($$$$) CB for non-ferrous
metals. Surely, HSS should work for aluminum or am I missing something?
Also, what would be the best drill speed to use in a case like this? I
normally use wax lubricant for countersinking metal, is this good enough for
counterboring? Finally, is it advisable to buy say a 1/2" aluminum blank and
practice first or am I making a mountain out of a mole hill?


HSS will work fine, if your drill press will turn slow enough. For a
3/4" counterbore, you could use a 3/4" end mill, but maybe with a drill
press a real counterbore tool is safer. I assume you have a Morse
taper to Jacobs taper arbor attaching the drill chuck to the spindle
of the drill press? These can come off suddenly when there are side
forces or chatter on the tool. You probably want to keep the
counterbore well under 1000 RPM for best results.

Jon

On Thu, 09 Sep 2004 01:20:52 GMT, "oparr" wrote:

This is uncharted territory for me. Done similar stuff with wood using Brad
point and Forstner bits but never with metal. Basically, I need a
counterbore (CB) diameter of about 3/4" to a depth of about 3/8" in 1" thick
6061 aluminum. This is to create a recess for cap screw head and washer
along with room to use a hex socket on the cap screw.

Sourcing the correct CB and pilot seems easy enough except that MMC
recommends HSS ($$) for ferrous and carbide tipped ($$$$) CB for non-ferrous
metals. Surely, HSS should work for aluminum or am I missing something?

HSS works just fine for Aluminum. Thats all my CBs are, and I very
occasionally use them on stainless..but its iffy there.

Also, what would be the best drill speed to use in a case like this? I
normally use wax lubricant for countersinking metal, is this good enough for
counterboring?

at .75, I go about 120 rpm just to keep the chips under control. I
dont worry too much about speeds and feeds with CBs. Too fast is bad.

Finally, is it advisable to buy say a 1/2" aluminum blank and
practice first or am I making a mountain out of a mole hill?

Always drill a practice hole or turn a practice piece the first time
you get a new tool bit, unless you have run them before.

Gunner



"In my humble opinion, the petty carping levied against Bush by
the Democrats proves again, it is better to have your eye plucked
out by an eagle than to be nibbled to death by ducks." - Norman
Liebmann

I have done this using a carbide Forstner bit with WD40 as a lubricant
(slow speed). Not being a metalworker, this is just an every now and
again thing. Otherwise, I'd look for more suitable tooling.
Kingfish

On Thu, 09 Sep 2004 01:20:52 GMT, "oparr" wrote:

This is uncharted territory for me. Done similar stuff with wood using Brad
point and Forstner bits but never with metal. Basically, I need a
counterbore (CB) diameter of about 3/4" to a depth of about 3/8" in 1" thick
6061 aluminum. This is to create a recess for cap screw head and washer
along with room to use a hex socket on the cap screw.

Sourcing the correct CB and pilot seems easy enough except that MMC
recommends HSS ($$) for ferrous and carbide tipped ($$$$) CB for non-ferrous
metals. Surely, HSS should work for aluminum or am I missing something?
Also, what would be the best drill speed to use in a case like this? I
normally use wax lubricant for countersinking metal, is this good enough for
counterboring? Finally, is it advisable to buy say a 1/2" aluminum blank and
practice first or am I making a mountain out of a mole hill?

Most counterbores are piloted, so a drill press does just fine. they are
sized to fit a socket head cap screw with no washer, so the diameter won't
be big enough to fit a socket around a hex cap screw. You may get a deal
where there is a choice of OD and pilot to get to where you need to be.

Brian


"oparr" wrote in message
news:UdO%c.4333$9P4.1707@trndny02...
This is uncharted territory for me. Done similar stuff with wood using
Brad
point and Forstner bits but never with metal. Basically, I need a
counterbore (CB) diameter of about 3/4" to a depth of about 3/8" in 1"
thick
6061 aluminum. This is to create a recess for cap screw head and washer
along with room to use a hex socket on the cap screw.

Sourcing the correct CB and pilot seems easy enough except that MMC
recommends HSS ($$) for ferrous and carbide tipped ($$$$) CB for
non-ferrous
metals. Surely, HSS should work for aluminum or am I missing something?
Also, what would be the best drill speed to use in a case like this? I
normally use wax lubricant for countersinking metal, is this good enough
for
counterboring? Finally, is it advisable to buy say a 1/2" aluminum blank
and
practice first or am I making a mountain out of a mole hill?

Jon Elson wrote:

oparr wrote:
This is uncharted territory for me. Done similar stuff with wood using Brad
point and Forstner bits but never with metal. Basically, I need a
counterbore (CB) diameter of about 3/4" to a depth of about 3/8" in 1" thick
6061 aluminum. This is to create a recess for cap screw head and washer
along with room to use a hex socket on the cap screw.

Sourcing the correct CB and pilot seems easy enough except that MMC
recommends HSS ($$) for ferrous and carbide tipped ($$$$) CB for non-ferrous
metals. Surely, HSS should work for aluminum or am I missing something?
Also, what would be the best drill speed to use in a case like this? I
normally use wax lubricant for countersinking metal, is this good enough for
counterboring? Finally, is it advisable to buy say a 1/2" aluminum blank and
practice first or am I making a mountain out of a mole hill?


HSS will work fine, if your drill press will turn slow enough. For a
3/4" counterbore, you could use a 3/4" end mill, but maybe with a drill
press a real counterbore tool is safer. I assume you have a Morse
taper to Jacobs taper arbor attaching the drill chuck to the spindle
of the drill press? These can come off suddenly when there are side
forces or chatter on the tool. You probably want to keep the
counterbore well under 1000 RPM for best results.



If you are going to go with the end mill one way to make things a little
safer is to:

1. Drill the hole for the "bolt".

2. Drill to almost 3/8 inch with a 3/4 drill.

3. Finish up with a 3/4 end mill to make the bottom flat.
Lower the end mill into the hole made by the drill before
starting the drill press. A foot switch on the drill press is a
great help and lets you have one hand for the quill feed and
on hand for the work.

Ray Spinhirne




Jon

Thanks all for the advice.

Jon,

I'll use lubrication and clamp the workpiece well to minimize chatter and
spin at my lowest available speed (around 600 RPM).

Ray,

I'm a foot switch nut, use it with all rotary tools, can't see how anyone
could use a drill press without one. I even use it with a miter saw in case
my finger "freezes" on the button in time of danger.

Gunner,

Yeah, I'll buy a 1/2" bar to practice on. Good advice.

On Thu, 09 Sep 2004 17:28:01 GMT, "oparr" wrote:

||Thanks all for the advice.
||
||Jon,
||
||I'll use lubrication and clamp the workpiece well to minimize chatter and
||spin at my lowest available speed (around 600 RPM).
||
||Ray,
||
||I'm a foot switch nut, use it with all rotary tools, can't see how anyone
||could use a drill press without one. I even use it with a miter saw in case
||my finger "freezes" on the button in time of danger.

So how does one find a foot switch, and wire it?
Are there OTS switches?

Texas Parts Guy

In article , Rex B says...

So how does one find a foot switch, and wire it?

Clipper makes them, I bought mine from McMaster Carr.
Get the larger one, it scoots around on teh floor less.

For a single phase motor I just wire it in series
with the column mounted switch - so I need to have
the pedal down and the switch up to get it to run.

My former boss used to call the switch on the
column the "anti-suprise-mode switch!"

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

So how does one find a foot switch

Got mine at Sears. It has an electrical cord with three prong plug and
socket for the drill (or whatever) on the switch body, plug and play,
nothing to wire. Note that you basically want an on/off switch, not to be
confused with some variable speed foot pedals for sewing machines etc. MMC
et al should also carry them.

"Rex B" wrote in message
...
On Thu, 09 Sep 2004 17:28:01 GMT, "oparr" wrote:

||Thanks all for the advice.
||
||Jon,
||
||I'll use lubrication and clamp the workpiece well to minimize chatter
and
||spin at my lowest available speed (around 600 RPM).
||
||Ray,
||
||I'm a foot switch nut, use it with all rotary tools, can't see how
anyone
||could use a drill press without one. I even use it with a miter saw in
case
||my finger "freezes" on the button in time of danger.

So how does one find a foot switch, and wire it?
Are there OTS switches?

Texas Parts Guy

What about using a flat bottomed drill - one at 90 deg? I only did it once
and that was in a 1/4 in. hole with a pilot hole already in place. It was
OK for a brass ball valve seat.

Bob Swinney
"Gunner" wrote in message
news
On Thu, 09 Sep 2004 01:20:52 GMT, "oparr" wrote:

This is uncharted territory for me. Done similar stuff with wood using
Brad
point and Forstner bits but never with metal. Basically, I need a
counterbore (CB) diameter of about 3/4" to a depth of about 3/8" in 1"
thick
6061 aluminum. This is to create a recess for cap screw head and washer
along with room to use a hex socket on the cap screw.

Sourcing the correct CB and pilot seems easy enough except that MMC
recommends HSS ($$) for ferrous and carbide tipped ($$$$) CB for
non-ferrous
metals. Surely, HSS should work for aluminum or am I missing something?

HSS works just fine for Aluminum. Thats all my CBs are, and I very
occasionally use them on stainless..but its iffy there.

Also, what would be the best drill speed to use in a case like this? I
normally use wax lubricant for countersinking metal, is this good enough
for
counterboring?

at .75, I go about 120 rpm just to keep the chips under control. I
dont worry too much about speeds and feeds with CBs. Too fast is bad.

Finally, is it advisable to buy say a 1/2" aluminum blank and
practice first or am I making a mountain out of a mole hill?

Always drill a practice hole or turn a practice piece the first time
you get a new tool bit, unless you have run them before.

Gunner



"In my humble opinion, the petty carping levied against Bush by
the Democrats proves again, it is better to have your eye plucked
out by an eagle than to be nibbled to death by ducks." - Norman
Liebmann

On Thu, 09 Sep 2004 17:28:01 GMT, "oparr" wrote:

Thanks all for the advice.

Jon,

I'll use lubrication and clamp the workpiece well to minimize chatter and
spin at my lowest available speed (around 600 RPM).

Ray,

I'm a foot switch nut, use it with all rotary tools, can't see how anyone
could use a drill press without one. I even use it with a miter saw in case
my finger "freezes" on the button in time of danger.

Gunner,

Yeah, I'll buy a 1/2" bar to practice on. Good advice.

If you scrounge around a bit..you generally dont have to "buy" scrap
stock.

Guner

"At the core of liberalism is the spoiled child -
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosphy of sniveling brats." -- P.J. O'Rourke

On 9 Sep 2004 13:25:34 -0700, jim rozen
wrote:

In article , Rex B says...

So how does one find a foot switch, and wire it?

Clipper makes them, I bought mine from McMaster Carr.
Get the larger one, it scoots around on teh floor less.

For a single phase motor I just wire it in series
with the column mounted switch - so I need to have
the pedal down and the switch up to get it to run.

My former boss used to call the switch on the
column the "anti-suprise-mode switch!"

Jim

I have one on one of my drill presses and enclosed it in a plywood box
made of 3/4" ply. Helps protect the switch from accidental activation
and makes it very hard to move by accident

Gunner

"At the core of liberalism is the spoiled child -
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosphy of sniveling brats." -- P.J. O'Rourke

On Fri, 10 Sep 2004 11:26:45 -0500, "Robert Swinney"
wrote:

What about using a flat bottomed drill - one at 90 deg? I only did it once
and that was in a 1/4 in. hole with a pilot hole already in place. It was
OK for a brass ball valve seat.

Like an endmill? Thats tough because most drill bits have a
relatively thin web, which makes them very springy and they tend to
walk around. Compare an endmill and a drill bit and you will see the
endmill is far far stiffer. Without stiffness, you need a pilot to
keep it lined up. Ive cut with some sucess (generally poor) using the
spade type wood working bits, but Ive always had to make a small pilot
hole to keep it from wandering.

This bit is NOT recommended for any metals.

Gunner


Bob Swinney
"Gunner" wrote in message
news
On Thu, 09 Sep 2004 01:20:52 GMT, "oparr" wrote:

This is uncharted territory for me. Done similar stuff with wood using
Brad
point and Forstner bits but never with metal. Basically, I need a
counterbore (CB) diameter of about 3/4" to a depth of about 3/8" in 1"
thick
6061 aluminum. This is to create a recess for cap screw head and washer
along with room to use a hex socket on the cap screw.

Sourcing the correct CB and pilot seems easy enough except that MMC
recommends HSS ($$) for ferrous and carbide tipped ($$$$) CB for
non-ferrous
metals. Surely, HSS should work for aluminum or am I missing something?

HSS works just fine for Aluminum. Thats all my CBs are, and I very
occasionally use them on stainless..but its iffy there.

Also, what would be the best drill speed to use in a case like this? I
normally use wax lubricant for countersinking metal, is this good enough
for
counterboring?

at .75, I go about 120 rpm just to keep the chips under control. I
dont worry too much about speeds and feeds with CBs. Too fast is bad.

Finally, is it advisable to buy say a 1/2" aluminum blank and
practice first or am I making a mountain out of a mole hill?

Always drill a practice hole or turn a practice piece the first time
you get a new tool bit, unless you have run them before.

Gunner



"In my humble opinion, the petty carping levied against Bush by
the Democrats proves again, it is better to have your eye plucked
out by an eagle than to be nibbled to death by ducks." - Norman
Liebmann


"At the core of liberalism is the spoiled child -
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosphy of sniveling brats." -- P.J. O'Rourke