MiamiCuse wrote:
"Sac Dave" wrote in message
...
"MiamiCuse" wrote in message
...
I need to cut a 3" cast iron vent pipe to tie to a new PVC vent.

I am using a Milwaukee sawzall with a metal blade and it kept skidding
and wouldn't start the cut at the right place. I then used a 4-1/2"
angle grinder with a metal blade and cut a little notch and now I can
engage with the sawzall without skidding.

However after 15 minutes of cut I don't think I am making a significant
dent at all.

I used the same sawzall and cut through copper and EMT electrical
conduits like knife through butter. But this CI pipe I am not making any
progress.

I can't use the angle grinder there is simply not enough room around it.

I went to HD and they recommended a "grit iron" blade. Got that and it
seems to cut a little bit, but again after 15 minutes, I am not even 10%
through the pipe. The way I am going it would take 10 hours.

I remember seeing another blade named "ugly metal blade" I wonder if that
would be better.

Is there a better way to do this?

I know a chain cutter may be used, but I want to avoid it. Part of the
reason I am cutting this is because the lower section was cut by a
plumber who used a chain cutter but created a vertical crack line and now
I am trying to cut away all the damaged section.

Thanks,

MC

Ratchet cutter http://www.plumbingsupply.com/snapcutters.html Ratchet
cutters would be best. If you have access all the way around the pipe a
cut off wheel in a peanut grinder.

Thanks but I cannot use this. I am trying to cut away a section that was
damaged by using a chain cutter. I need to cut it the old fashion way
instead of relying on it to break at the weak spot.

MC

If you are only removing a chunk off the
end, say less than about 4", you can
use the method I used in a toilet pipe
in a concrete floor. I needed to install
an offset flange. I used a 2 1/2" cut
off wheel in a 4" drill bit extender. I
chucked the whole thing into a router.
You can't run the router at full speed
as slight unbalances will destroy the 4"
extender. It could also be quite
dangerous if it flied apart. I used a
adjustable auto-transformer
(Variac) to keep the speed slow. I
worked from the inside of
pipe from the open end and slowly but
surely, cut through. I did have a nice
flat spot to set the router faceplate
while going around (the old flange). As
I recall, it only took about 10 minutes.