Good hole saw for 4" cast?

[Stevey]

Any recommends on a decent hole saw bit for cutting in to a 4" cast down pipe?...

No chinese brands...bless em..

 

[solo]

Starret, Bosch, but I think you'll struggle whatever you use. I think some of the guys who visit here recommend chain drilling. Either way cast is a b***h.

 

[fazedup71]

been watching this post myself for some idea's, i have never been able to cut a hole into a cast pipe, i tried once and failed! so now i just replace in plastic

 

[chr15]

Use a starret hole saw and use a drill with a low spin speed. Get some cutting oil and a squirt can and get someone to keep the drill cool by giving it a squirt now and again, take your time and you'll get thru it.

 

[TicklyT]

Many power drills spin much too fast for a hole saw. The speed usually recommended for cutting cast iron is about 70 feet per minute.

A 2" hole saw has a circumference of about 6", so that means running it at about 140 RPM for the best results.

Spinning the saw too fast will quickly overheat and blunt the saw and possibly even work harden the iron you are trying to cut.

So it's a case of make haste slowly.

 

[oilman]

I found absolutely no problem drilling a cast flue pipe using a lennox saw and after grinding away the vitreous enamel. I used a DeWalt on it's lowest speed and just kept the speed down. No lubricant either. No problem.

 

[arfurrrr]

Lenox is the only hole saw to buy

 

[JPH/01]

oilman:What do you use covers after cutting ?. I usually end up robbing chrome covers off of bends !.

 

[oilman]

Mmmm, so do I.

 

[Stevey]

Many thanks for that..

I see what you mean about low speed cutting, keep the heat down etc.
Regarding low speed cutting, I bet it wouldn't take much too crack a bit of the cast off if the drill were to jam on a higher speed..

I'll post a picture when I do it.