Tapping a Radiator

bob young

start with a 1/8 " pilot hole . then the exact correct drill that matches tap size. very slowly.

USA498

tapping a radiator

I would like to know if there are any tricks to tapping a new hole for a additional vent in a very large and mostly cold radiator. I already have a Gorton 'D' on it but only 4 out of the 20 or so fins gets warm after a 1 to 1.5 hr run.

Many Thanks !

Mike T., Swampeast MO

I've tapped a number of rads from steam systems for water use. Seems to be very easy as the cast iron drills and taps very well. I drilled slowly and used plain cutting oil when tapping.

USA498

Did you have to start with a small bit and work your way up ?

Mike T., Swampeast MO

Believe that's exactly what I did. No joke about the exactly correct drill size.

Bob W._3

My 1/8 - 27 NPT tap specifies a 21/64 drill bit, which seems to just fit in a 1/8 female fitting. Not sure what the outer diameter of 1/8 pipe is; depends on the type of pipe.

USA498

Thanks for the info.

Tom R.

Pipe size

1/8" pipe is all the same O.D. - wall is thicker on sched. 80

Boilerpro_3

Are your main vents big enough?

A gorton D is equal to the largest main vent avialable except the Gorton #2. Also, does your boiler have a nice long on cycle?

Boilerpro

USA498

Tapping radiator

Thanks for the reply.

The Main vents are gorton #2's located at the end of the return ( about 16" back from the end ). The Gorton D is on the ratiator that is slow to heat. I can only get about 4-5 fins out of 22 to heat on a pretty cold day. The firing time is approx 1 to 1.5 hrs. I thought a second vent might do the trick.

Thanks again

Bob W._3

Probably will, but if you can vent the riser to that rad it would be even better.