Drilling through stainless 3/8" steel bolt
 

I am trying to drill though a stainless 3/8" steel bolt (grade 6) on a pool pump. How long should it take to go 1/2 inch? I think after an hour, I managed to get through 1/8 inch using oil as a lubricant. I am using a 1/4 Dewalt Cobolt bit from Lowls (listed for stainless steel). Is this better than the Irwin titanium bits? I have some diamond bits from Harbor Freight tools, but it seems as if the diamond dust was scraped off very quickly..
Any suggestions on what else to do, i.e. take it to a mechanic who will charge $50 an hour. Are there any suggested drill bits made from industrial diamonds or are they overpriced?

Drilling through stainless 3/8" steel bolt
 

https://www.youtube.com/watch?v=NtqXlOX_kF4
drill a pilot hole.
Black Oxide bits

Drilling through stainless 3/8" steel bolt
 

On Mon, 13 Jul 2015 01:02:49 -0700 (PDT), Deodiaus
wrote:

I am trying to drill though a stainless 3/8" steel bolt (grade 6) on a pool pump. How long should it take to go 1/2 inch? I think after an hour, I managed to get through 1/8 inch using oil as a lubricant. I am using a 1/4 Dewalt Cobolt bit from Lowls (listed for stainless steel). Is this better than the Irwin titanium bits? I have some diamond bits from Harbor Freight tools, but it seems as if the diamond dust was scraped off very quickly.
Any suggestions on what else to do, i.e. take it to a mechanic who will charge $50 an hour. Are there any suggested drill bits made from industrial diamonds or are they overpriced?

With a good bit you should be through it in about 10 minutes. When we
work on molds at work, my maintenance guys do it easily on 10 mm
bolts. Get a good bit at an industrial supply house. Check
www.mcmaster.com for the right type.

Drilling through stainless 3/8" steel bolt
 

On 07/13/2015 03:02 AM, Deodiaus wrote:
I am trying to drill though a stainless 3/8" steel bolt (grade 6) on a pool pump. How long should it take to go 1/2 inch? I think after an hour, I managed to get through 1/8 inch using oil as a lubricant. I am using a 1/4 Dewalt Cobolt bit from Lowls (listed for stainless steel). Is this better than the Irwin titanium bits? I have some diamond bits from Harbor Freight tools, but it seems as if the diamond dust was scraped off very quickly.
Any suggestions on what else to do, i.e. take it to a mechanic who will charge $50 an hour. Are there any suggested drill bits made from industrial diamonds or are they overpriced?




Sheesh


Do not start out at the full size, use a smaller bit first...
maybe 1/8" or even smaller

Drilling through stainless 3/8" steel bolt
 

On Mon, 13 Jul 2015 05:55:31 -0400, Ed Pawlowski wrote:

On Mon, 13 Jul 2015 01:02:49 -0700 (PDT), Deodiaus
wrote:

I am trying to drill though a stainless 3/8" steel bolt (grade 6) on a pool pump. How long should it take to go 1/2 inch? I think after an hour, I managed to get through 1/8 inch using oil as a lubricant. I am using a 1/4 Dewalt Cobolt bit from Lowls (listed for stainless steel). Is this better than the Irwin titanium bits? I have some diamond bits from Harbor Freight tools, but it seems as if the diamond dust was scraped off very quickly.
Any suggestions on what else to do, i.e. take it to a mechanic who will charge $50 an hour. Are there any suggested drill bits made from industrial diamonds or are they overpriced?

With a good bit you should be through it in about 10 minutes. When we
work on molds at work, my maintenance guys do it easily on 10 mm
bolts. Get a good bit at an industrial supply house. Check
www.mcmaster.com for the right type.
The secret when drilling stainless is NEVER let the bit "skate". Keep
a constant pressure on the bit at all times. MAKE the drill cut. If it
skates and heats, the stainless hardens like glass, and NOTHING will
drill it. Start over with a fresh bolt. Clamp it in a drill press
vice. Run as slow as possible (or even slower) and keep pressure on
the drill at all times. A power feed press works best - cuts fresh
stainless like butter.

Drilling through stainless 3/8" steel bolt
 

On 2015-07-13, Ed Pawlowski wrote:

With a good bit you should be through it in about 10 minutes.

!?!?!?!?

Using what? A hand drill?

nb

Drilling through stainless 3/8" steel bolt
 

philo wrote:
On 07/13/2015 03:02 AM, Deodiaus wrote:
I am trying to drill though a stainless 3/8" steel bolt (grade 6)
on a pool pump. How long should it take to go 1/2 inch? I think
after an hour, I managed to get through 1/8 inch using oil as a
lubricant. I am using a 1/4 Dewalt Cobolt bit from Lowls (listed
for stainless steel). Is this better than the Irwin titanium bits? I
have some diamond bits from Harbor Freight tools, but it seems as
if the diamond dust was scraped off very quickly. Any suggestions on
what else to do, i.e. take it to a mechanic who will charge $50 an
hour. Are there any suggested drill bits made from industrial
diamonds or are they overpriced?



Sheesh


Do not start out at the full size, use a smaller bit first...
maybe 1/8" or even smaller

For a quarter inch hole ? I 've never had a problem unless I let the bit
rub and work-harden the SS . Heavy pressure and a low speed are key .

--
Snag

Drilling through stainless 3/8" steel bolt
 

On 2015-07-13, wrote:

The secret when drilling stainless is NEVER let the bit "skate". Keep
a constant pressure on the bit at all times. MAKE the drill cut. If it
skates and heats, the stainless hardens like glass, and NOTHING will
drill it.

True dat!

By "skate", Clare means "not cutting". IOW, if chips are not coming
off the work, it's "not cutting" and will harden the SS. Make sure
"chips" are being created and the drill bit is not merely spinning in
place. If the chips are dark blue/purple, you are feeding the drill
with too much pressure. Back off until the chips are jes bluish.

nb

Drilling through stainless 3/8" steel bolt
 

On 2015-07-13, philo wrote:

Do not start out at the full size, use a smaller bit first...
maybe 1/8" or even smaller

I disagree.

I think the poster claimed he was using a 1/4" drill bit. I'd start the
hole with a no. 2-3 "center drill"[1] and finish with a 1/4" HSS twist drill
turning at about 750 rpm[2].


[1] https://en.wikipedia.org/wiki/Drill_bit#Center_and_spotting_drill_bits
[2] http://www.smithy.com/machining-refe...illing/page/22

Do NOT heed the previous advice to drill "slow". The bit may "catch"
on the material and snap the drill bit. Drill at the recommended
drill/feed speeds (the smaller, the faster). Special purpose drills like
carbide, diamond, etc, are unnecessary, as a properly sharpened std
HSS twist drill will work just fine. If you have or plan to purchase
"center drills", make sure you run them faster or as fast as the
recommended twist drill speeds. ALWAYS use a lubricant. Serously,
dirty oil off yer car's dipstick is better than nothing. ;)

nb

Drilling through stainless 3/8" steel bolt
 

On 07/13/2015 11:36 AM, Terry Coombs wrote:
philo wrote:
On 07/13/2015 03:02 AM, Deodiaus wrote:
I am trying to drill though a stainless 3/8" steel bolt (grade 6)
on a pool pump. How long should it take to go 1/2 inch? I think
after an hour, I managed to get through 1/8 inch using oil as a
lubricant. I am using a 1/4 Dewalt Cobolt bit from Lowls (listed
for stainless steel). Is this better than the Irwin titanium bits? I
have some diamond bits from Harbor Freight tools, but it seems as
if the diamond dust was scraped off very quickly. Any suggestions on
what else to do, i.e. take it to a mechanic who will charge $50 an
hour. Are there any suggested drill bits made from industrial
diamonds or are they overpriced?



Sheesh


Do not start out at the full size, use a smaller bit first...
maybe 1/8" or even smaller

For a quarter inch hole ? I 've never had a problem unless I let the bit
rub and work-harden the SS . Heavy pressure and a low speed are key .




Yes...as he said it was stainless steel...otherwise a pilot hole would
probably not be needed.

Drilling through stainless 3/8" steel bolt
 

On 07/13/2015 12:00 PM, notbob wrote:
On 2015-07-13, philo wrote:

Do not start out at the full size, use a smaller bit first...
maybe 1/8" or even smaller

I disagree.

I think the poster claimed he was using a 1/4" drill bit. I'd start the
hole with a no. 2-3 "center drill"[1] and finish with a 1/4" HSS twist drill
turning at about 750 rpm[2].




A pilot hole is never a bad idea no matter what.



Many years ago I got a good laugh when I saw my boss trying to drill a
1" hole through an i beam with no pilot.


I was not really paying attention to what he was doing until I came back
into the shop an hour later and saw him still trying to drill.

He might have been stupid but at least he was no one to give up.

Drilling through stainless 3/8" steel bolt
 

On 13 Jul 2015 17:00:23 GMT, notbob wrote:

On 2015-07-13, philo wrote:

Do not start out at the full size, use a smaller bit first...
maybe 1/8" or even smaller

I disagree.

I think the poster claimed he was using a 1/4" drill bit. I'd start the
hole with a no. 2-3 "center drill"[1] and finish with a 1/4" HSS twist drill
turning at about 750 rpm[2].


[1] https://en.wikipedia.org/wiki/Drill_bit#Center_and_spotting_drill_bits
[2] http://www.smithy.com/machining-refe...illing/page/22

Do NOT heed the previous advice to drill "slow". The bit may "catch"
on the material and snap the drill bit. Drill at the recommended
drill/feed speeds (the smaller, the faster). Special purpose drills like
carbide, diamond, etc, are unnecessary, as a properly sharpened std
HSS twist drill will work just fine. If you have or plan to purchase
"center drills", make sure you run them faster or as fast as the
recommended twist drill speeds. ALWAYS use a lubricant. Serously,
dirty oil off yer car's dipstick is better than nothing. ;)

nb
Recommended speed (RPM) to get the proper cutting speed for stainless
with a 1/4" drill is 1280 RPM, but I find that still too fast usually
(Speed in sfpmX4/ decimal inch diameter of drill - in this
case80X4=320 devided by 0 .25= 1280 rpm) I like 600- 750 - or closer
to 500 RPM for a .5 inch hole. If I'm drilling on the lathe I'l use
300-ish and use the power feed set to about 20 threads per inch

Back up the exit with hardwood or aluminum, or even mild steel so the
bit doesn't catch coming out the bottom.

Drilling through stainless 3/8" steel bolt
 

On 13 Jul 2015 16:39:03 GMT, notbob wrote:

On 2015-07-13, wrote:

The secret when drilling stainless is NEVER let the bit "skate". Keep
a constant pressure on the bit at all times. MAKE the drill cut. If it
skates and heats, the stainless hardens like glass, and NOTHING will
drill it.

True dat!

By "skate", Clare means "not cutting". IOW, if chips are not coming
off the work, it's "not cutting" and will harden the SS. Make sure
"chips" are being created and the drill bit is not merely spinning in
place. If the chips are dark blue/purple, you are feeding the drill
with too much pressure. Back off until the chips are jes bluish.

nb

.... make sure the drill isn't in reverse :)

Drilling through stainless 3/8" steel bolt
 

My bit must have been too worn. I was giving thought to sharpening it using a grindstone.
Well, it just got worse. I got a new bit and drilled a 1/8 pilot hole. The guy at HD talked me into getting a screw extractor. Well, ****, the screw extractor snapped off the tip and is now lodged in my pilot hole!!
I guess I am going to have to drill 3 holes around the extractor bit in order to pull it out.
One of my friends was doing the same thing, and said that even after he got the flange bolts out, the metals had rusted together. Apparently this is a big problem with pool water pumps.
The back housing that I am trying to salvage sells for about $100. Almost wondering if it is worth trying.
Never thought that this would be as difficult.

Drilling through stainless 3/8" steel bolt
 

Yes, I am using a hand drill. THere isn't enough clearance to get it on a drill press.

Drilling through stainless 3/8" steel bolt
 

On Tuesday, 14 July 2015 06:02:29 UTC+1, Deodiaus wrote:
Yes, I am using a hand drill. THere isn't enough clearance to get it on a drill press.

ive used a hand drill with a good cobalt drill bit and a coolant paste start small and work up use the right drill speed TTP Hard Drills are the brand we use see www.ttp-hard-drills.net

Drilling through stainless 3/8" steel bolt
 

On Monday, July 13, 2015 at 10:00:09 PM UTC-7, Deodiaus wrote:

Well, it just got worse. I got a new bit and drilled a 1/8 pilot hole. The guy at HD talked me into getting a screw extractor. Well, ****, the screw extractor snapped off the tip and is now lodged in my pilot hole!!

Oh yeah.
The old "Easy Out" (talk about false advertising)
They're never easy and usually won't get it out
On steel bolts, I've taken to using reverse cobalt drill buts.
If yur lucky, only takes about one per frozen/broken bolt
& ya gotta drill dead center thru the bolt. (not that easy)

Drilling through stainless 3/8" steel bolt
 

On Monday, November 9, 2015 at 2:58:22 PM UTC-5, Shade Tree Guy wrote:
On Monday, July 13, 2015 at 10:00:09 PM UTC-7, Deodiaus wrote:

Well, it just got worse. I got a new bit and drilled a 1/8 pilot hole. The guy at HD talked me into getting a screw extractor. Well, ****, the screw extractor snapped off the tip and is now lodged in my pilot hole!!

Oh yeah.
The old "Easy Out" (talk about false advertising)
They're never easy and usually won't get it out
On steel bolts, I've taken to using reverse cobalt drill buts.
If yur lucky, only takes about one per frozen/broken bolt
& ya gotta drill dead center thru the bolt. (not that easy)

Maybe even harder now that there's part of screw extractor stuck in the bolt.

Drilling through stainless 3/8" steel bolt
 

On Monday, November 9, 2015 at 3:09:47 PM UTC-5, DerbyDad03 wrote:
On Monday, November 9, 2015 at 2:58:22 PM UTC-5, Shade Tree Guy wrote:
On Monday, July 13, 2015 at 10:00:09 PM UTC-7, Deodiaus wrote:

Well, it just got worse. I got a new bit and drilled a 1/8 pilot hole. The guy at HD talked me into getting a screw extractor. Well, ****, the screw extractor snapped off the tip and is now lodged in my pilot hole!!

Oh yeah.
The old "Easy Out" (talk about false advertising)
They're never easy and usually won't get it out
On steel bolts, I've taken to using reverse cobalt drill buts.
If yur lucky, only takes about one per frozen/broken bolt
& ya gotta drill dead center thru the bolt. (not that easy)

Maybe even harder now that there's part of screw extractor stuck in the bolt.

Time to give up on the drill and use a popper.

Drilling through stainless 3/8" steel bolt
 

On Mon, 9 Nov 2015 10:36:30 -0800 (PST),
wrote:

On Tuesday, 14 July 2015 06:02:29 UTC+1, Deodiaus wrote:
Yes, I am using a hand drill. THere isn't enough clearance to get it on a drill press.

ive used a hand drill with a good cobalt drill bit and a coolant paste start small and work up use the right drill speed TTP Hard Drills are the brand we use see www.ttp-hard-drills.net

When I see hand drill, I think that it's one you crank.

Is that it, or is it a hand-held electric drill that is meant?

Drilling through stainless 3/8" steel bolt
 

On Monday, November 9, 2015 at 5:23:46 PM UTC-8, Micky wrote:

When I see hand drill, I think that it's one you crank.

Is that it, or is it a hand-held electric drill that is meant?

Haven't seen a "hand powered" drill since cleaning out my deceased parents garage years ago.

Drilling through stainless 3/8" steel bolt
 

On 11/09/2015 06:39 PM, Shade Tree Guy wrote:
Haven't seen a "hand powered" drill since cleaning out my deceased parents garage years ago.

I've got one of the egg beater types. A decent one with two pinion gears
is the ultimate cordless drill.

Drilling through stainless 3/8" steel bolt
 

On Mon, 09 Nov 2015 20:35:40 -0700, rbowman
wrote:

On 11/09/2015 06:39 PM, Shade Tree Guy wrote:
Haven't seen a "hand powered" drill since cleaning out my deceased parents garage years ago.

I've got one of the egg beater types. A decent one with two pinion gears
is the ultimate cordless drill.

I had one, and it must have been stolen**. I don't know when though.
The tools in my car were stolen once, but I wouldn't have carried it
in the car.

I once saw a car tool set, labeled as such with a form-fitting plastic
box and some car-typle tools, but one of the tools included was claw
hammer.


**I do have a brace and some bits.

Drilling through stainless 3/8" steel bolt
 

On 2015-11-10, Micky wrote:

Is that it, or is it a hand-held electric drill that is meant?

When I worked as a machinist, to avoid confusion, we used the
descriptive term of the machine. For example, an electric hand drill
was a "drill motor". The singular term "drill" was reserved for
various size/type "drill bits", which could be used in any number of
machines with drill bit chucks, including drill motors, drill presses,
milling machines, lathes, etc. ;)

nb

Drilling through stainless 3/8" steel bolt
 

On Tuesday, November 10, 2015 at 10:57:54 AM UTC-8, notbob wrote:

When I worked as a machinist, to avoid confusion, we used the
descriptive term of the machine. For example, an electric hand drill
was a "drill motor". The singular term "drill" was reserved for
various size/type "drill bits", which could be used in any number of
machines with drill bit chucks, including drill motors, drill presses,
milling machines, lathes, etc. ;)

nb

If in the Service, a drill might really get confused

Drilling through stainless 3/8" steel bolt
 

wear saftey glasses

Mark