Port depth measurement location?

In my ongoing attempt to get my forms for Cast-able core just right, I presume the port depth of 2" is fairly critical, but...... From where to where, do  I make this two inches?, please see the two photos, noting that the cast-able mix will fill the void (i.e. the thin cardboard core shown, will be burned out for nearly exact 7" core size,  The port box mold is exactly 2" but when mated up with the riser, I loose some depth in creating a good glue over lap, I can make the port core (mold) longer, but what is considered best? Perhaps best said, If the 1.6" measurement was 2", is that about right? With the casting, I get one chance to get as close as I can to desired measurements.

Everything else is falling into place. Thanks in advance.

Hi Scott;
The port depth is 2.5" on all three of my stoves.
Indeed the specs say 2" but Peter was ok with using the standard thickness brick of 2.5".
With your casting, I would get as close to 2" as you easily can but not worry too much.
This is a spot you can adjust a bit as needed.

Hi Scott, you mention thin cardboard, Is that just for the port and the rest of the mold is more solid.
I an just checking as the refractory mix will need a serious vibrating and that requires  a very sturdy mold.

Fox James wrote:Hi Scott, you mention thin cardboard, Is that just for the port and the rest of the mold is more solid.
I an just checking as the refractory mix will need a serious vibrating and that requires  a very sturdy mold.

Hello James, --Everything is stout, and only the inside mold for the  riser is cardboard but made to withstand the vibrating as it is a concrete core mold (technically, but will have core plugs for extra strength, glued in and will burn out)

thanks for your concern,

thomas rubino wrote:Hi Scott;
The port depth is 2.5" on all three of my stoves.
Indeed the specs say 2" but Peter was ok with using the standard thickness brick of 2.5".
With your casting, I would get as close to 2" as you easily can but not worry too much.
This is a spot you can adjust a bit as needed.

Thanks Thomas,
     Excellent, so with that in mind I added .45" to my present measurement, and should maintain  within the 2-2.5" range.