Drilling cast iron
 

Recently got a pattern makers vise (see
www.woodcraft.com/family.aspx?familyid=3516 for a close cousin) and
want to put wood inside the jaws so it doesn't chew up the finish on the
furniture I'm working on. It's Taiwanese cast iron, quite well finished,
but doesn't have mounting holes through the jaws to attach the wood
liner. I shattered a valve cover many years ago drilling a hole in it so
I know there are some things you shouldn't do drilling cast iron. So how
should I support it, what kind of drills should I use, and what should I
watch out for? I'll be drilling 4 fairly small holes, probably about
3/16" through the thinnest part of the web.

Thanks

Jim

Jim,

Have you considered NOT drilling at all? I have used "soft jaws" on a
blacksmith's post vise which were simple "J" bent pieces of steel plate
that slip over the top of the vice jaws to protect the work piece. You
may be able to create a wooden version of this that can wrap around the
top or sides of the vise and then use a couple of screws to hold the
wood faces in place. It looks like there are plenty of recesses on the
back of the vise jaws for the bolts/screws to lock into.

Hope this helps,
Paul

"Jim McGill" wrote in message
...
Recently got a pattern makers vise (see
www.woodcraft.com/family.aspx?familyid=3516 for a close cousin) and want
to put wood inside the jaws so it doesn't chew up the finish on the
furniture I'm working on. It's Taiwanese cast iron, quite well finished,
but doesn't have mounting holes through the jaws to attach the wood liner.
I shattered a valve cover many years ago drilling a hole in it so I know
there are some things you shouldn't do drilling cast iron. So how should I
support it,

From behind with something like a hard wood if you can...

what kind of drills should I use, and what should I watch out for?

Standard drills at Approximately 10% faster than steel RPMs but much less
thrust... Just pull the handle easy on your drill press and let the bit do
most of the work. Very little downward pressure is needed. You can run at
the same RPM as steel (3/16" around 1500 RPM) and barely pull that handle to
drill a few holes like this.

If you had LOTS to do, there would be a faster way... But that's not
needed.

I'll be drilling 4 fairly small holes, probably about 3/16" through the
thinnest part of the web.

Oh look at that! 3/16" it is... grin
--


Regards,
Joe Agro, Jr.
(800) 871-5022
(908) 542-0244
http://www.AutoDrill.com
http://www.Multi-Drill.com

V8013-R

Counter bore some holes in the wood liner and install a few rare earth
magnets.
This way you can make different jaw liners.
2 or 3 12"dia by 1/8" thick glued just shy of flush with the surface
for each liner.
plenty to be had cheap on e bay or from wonder magnet.

and want
to put wood inside the jaws so it doesn't chew up the finish on the
furniture I'm working on.

Wilton sells fiber and rubber jaw liners that work well. They attach with
magnets and stay put pretty well.



what kind of drills should I use, and what should I watch out for?

I have drilled CI castings and I have always used normal drill bits.
Well, maybe not normal, there are Chicago Latrobe with split points.

I doubt you need anythings special for a small shallow hole.

My Darex manual mentions using 90 degree points and double angle drills
which I have not heard of before. Should I consider making a set
for CI use?

chuck

Chuck Sherwood wrote:

and want
to put wood inside the jaws so it doesn't chew up the finish on the
furniture I'm working on.


Wilton sells fiber and rubber jaw liners that work well. They attach with
magnets and stay put pretty well.




what kind of drills should I use, and what should I watch out for?


I have drilled CI castings and I have always used normal drill bits.
Well, maybe not normal, there are Chicago Latrobe with split points.

I doubt you need anythings special for a small shallow hole.

My Darex manual mentions using 90 degree points and double angle drills
which I have not heard of before. Should I consider making a set
for CI use?

chuck
If grabbing at breakout is your problem you drill from both sides.
Set your stop for .050 breakthru and flip the part.
See: http://www.mmsonline.com/articles/099805.html for more.

wws

hone drill edge just enough to take the sharp edge off, a slight flat,
could be a little negative.

use no oil, a little kerosene would be okay.

sjm1.pitt

Recently got a pattern makers vise (see
www.woodcraft.com/family.aspx?familyid=3516 for a close cousin) and
want to put wood inside the jaws so it doesn't chew up the finish on the
furniture I'm working on. It's Taiwanese cast iron, quite well finished,
but doesn't have mounting holes through the jaws to attach the wood
liner. I shattered a valve cover many years ago drilling a hole in it so
I know there are some things you shouldn't do drilling cast iron. So how
should I support it, what kind of drills should I use, and what should I
watch out for? I'll be drilling 4 fairly small holes, probably about
3/16" through the thinnest part of the web.

Thanks

Jim
Glue your wood to some soft copper sheeting which has been cut to
"hang over" the jaws on the vise....
Ken.

"Jim McGill" wrote in message
...
Recently got a pattern makers vise (see
www.woodcraft.com/family.aspx?familyid=3516 for a close cousin) and
want to put wood inside the jaws so it doesn't chew up the finish on the
furniture I'm working on. It's Taiwanese cast iron, quite well finished,
but doesn't have mounting holes through the jaws to attach the wood
liner. I shattered a valve cover many years ago drilling a hole in it so
I know there are some things you shouldn't do drilling cast iron. So how
should I support it, what kind of drills should I use, and what should I
watch out for? I'll be drilling 4 fairly small holes, probably about
3/16" through the thinnest part of the web.

Thanks

Jim

The biggest concern is if the iron is chilled. If it is, it will be very
difficult to drill. Free machining cast iron is gray in color, although it
could have a tough "skin", which is a shallow layer of chilled iron and sand
on the surface. If it's white in color (inside), the chance of drilling
it is very small due to hardness.

For the small amount of work you're facing, a standard HSS twist drill
should work fine. Gray cast iron can be drilled dry, thanks to the free
graphite in its makeup.

Harold

Grind the drill's cutting edge a bit negative on its front face
so that it drags and scrapes the iron off rather than digging in and
lifting it. This also applies to turning cast iron; the tool should
have a downslope on its top surface. Cutting dry is best.

Dan

Rare earth magnets - very clever, I hadn't thought of that.

Thanks

Jim

If you can avoid drilling, do so, the magnet idea is good. Otherwise,
I've just used good, brand-name split-point bits with no problems. If
you get a chilled spot, you're going to have troubles and Asian
castings seem to have those. One hole will be like drilling pine, the
next will shuck the flutes off the drill. The only way to avoid
chilled spots to to anneal the casting and that's not going to be easy
to do without damage on a completed part. It should be done during
manufacture, but it costs money, so it's not one of those things that
gets done on import items that sell to a price.

Stan

"Jim McGill" wrote in message
...
| Recently got a pattern makers vise (see
| www.woodcraft.com/family.aspx?familyid=3516 for a close cousin) and
| want to put wood inside the jaws so it doesn't chew up the finish on the
| furniture I'm working on. It's Taiwanese cast iron, quite well finished,
| but doesn't have mounting holes through the jaws to attach the wood
| liner. I shattered a valve cover many years ago drilling a hole in it so
| I know there are some things you shouldn't do drilling cast iron. So how
| should I support it, what kind of drills should I use, and what should I
| watch out for? I'll be drilling 4 fairly small holes, probably about
| 3/16" through the thinnest part of the web.
|
| Thanks
|
| Jim

Double backed foam tape available all over the place.