Drill leaks electricity to case
 

These old drills with low speeds are really nice for drilling large
holes. I have a slightly newer B&D (60's?)that runs at 200 rpm. Perfect
for 1/2" holes in 3/4" bar stock (or as perfect as ANY hand drill is for
that miserable job!) That one got a new cord strain relief last fall.

You can do a quick check on the GFI issue by run an ohmmeter on the
plug: Either of the two blades to the ground pin should be up in the
100k range or better. If not, chase it down. If it consistently blows a
GFI, it probably reads in the low 000's ohms.

As for repair, this one looks like it needs a full teardown, inspect,
clean, repair as necessary. My guess would be the plug, the switch, or
the brushes. The grease in the gearbox will be grey slime. Check the
brushes to make sure they still have wear length to them. Check the
wiring, looking for thin spots in the insulation.

I bought a similar one a while back for $2. It wound up as scrap metal,
saved the chuck. Some you win, some not.

Ignoramus3408 wrote:
I have this Black and Decker 450 RPM drill:

http://igor.chudov.com/tmp/450-rpm-drill.jpg

When plugged into a GFCI outlet, it leaks electricity to ground and
pops the GFCI breaker. The leak is substantial, I believe, however
when plugged into a regular breaker (and handled with caution
appropriate for leaks to case), it actually works and does not blow
the breaker. So, I think, the leak is limited in extent.

My question is, what is the most likely culprit and how to approach
repair of it.

My another question is, what would be a typical application of this
drill. I am trying to decide if I need it for anything.

i

Drill leaks electricity to case
 

If it only pops the GFI with the switch on, means the plug is good. Zip
tie the switch closed and proceed with trouble shooting. Expect to see
serious dirt and crud in the brushes area and the switch area. Blow
everything out, rinse with electical contact cleaner (flamable!)

Ignoramus3408 wrote:

On Wed, 22 Feb 2006 14:50:11 GMT, RoyJ wrote:

These old drills with low speeds are really nice for drilling large
holes. I have a slightly newer B&D (60's?)that runs at 200 rpm. Perfect
for 1/2" holes in 3/4" bar stock (or as perfect as ANY hand drill is for
that miserable job!) That one got a new cord strain relief last fall.


I see. I do need to drill big holes in steel occasionally.


You can do a quick check on the GFI issue by run an ohmmeter on the
plug: Either of the two blades to the ground pin should be up in the
100k range or better. If not, chase it down. If it consistently blows a
GFI, it probably reads in the low 000's ohms.


Well, note that it only happens when the drill is switched on.


As for repair, this one looks like it needs a full teardown, inspect,
clean, repair as necessary. My guess would be the plug, the switch, or
the brushes. The grease in the gearbox will be grey slime. Check the
brushes to make sure they still have wear length to them. Check the
wiring, looking for thin spots in the insulation.

I bought a similar one a while back for $2. It wound up as scrap metal,
saved the chuck. Some you win, some not.


Thanks Roy. I appreciate the advice. I will take it apart and will
have a good look.

i

Drill leaks electricity to case
 

According to Ignoramus3408 :
On Wed, 22 Feb 2006 14:50:11 GMT, RoyJ wrote:
These old drills with low speeds are really nice for drilling large
holes. I have a slightly newer B&D (60's?)that runs at 200 rpm. Perfect
for 1/2" holes in 3/4" bar stock (or as perfect as ANY hand drill is for
that miserable job!) That one got a new cord strain relief last fall.

I see. I do need to drill big holes in steel occasionally.

Hi Igor,

They're also wonderful for large diameter/long wood bits (eg: drilling
for 3/4" hardware thru fence posts), driving lag screws, large hole saws (esp.
thru steel), and sometimes large carbide bits thru masonry.

I have a similar vintage one. I don't use it often, but there
are things it does that none of my others can. Yours is similar to
more standard 1/4" and 3/8" drills, with a D-shaped push handle. Mine
is somewhat beefier - the D handle is rotated 90 degrees, and there's
yet a third handle that can either be attached opposite the handle
with the trigger (like a jackhammer) or come out the side (like a bolt
action on the side of a rifle).

You can do a quick check on the GFI issue by run an ohmmeter on the
plug: Either of the two blades to the ground pin should be up in the
100k range or better. If not, chase it down. If it consistently blows a
GFI, it probably reads in the low 000's ohms.

Well, note that it only happens when the drill is switched on.

Put the ohmmeter on the plug in various combinations (_not_ plugged
into the wall) and pull the trigger. If you see conductivity, it's
probably a dirt/wiring problem on the motor side of the switch. If you
don't, it's probably something to do with the motor windings - eg: a worn
spot that peridiodically contacts some rust or grit on the armature
or something like that.

A very thorough cleaning will likely solve it. If the windings are shot,
it's not worth repairing. Cannibalize it - looks like a good chuck.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.