Hern's 24 pdr mortar

[powder2burn]

Does anyone know for sure if the Hern's 24 pdr. coehorn mortar is actually a full scale?  I was given a coehorn mortar that looks like it is made out of cast iron, the bore sleeved with a pipe(I believe). The fuse hole was not drilled all the way through. Where the fuse hole located is an indented triangle, with the hole started. How the vent was finally made is a story in of its self.

To those of you who have a full size Hern coehorn mortar, I would to know the dia. of the muzzle, the length of the bore, total length from the muzzle to the bottom of the trunnion, width and dia. of the trunnion.

Thanks

[Cat Whisperer]

Powder2burn -

WELCOME to the forum!  I've seen one, but that was a LONG time ago.

Sounds like you're interested in competition requiring something exact?

[Rickk]

I would go outside and measure mine for you but it is dark and really cold out there right now.

I believe it is about 95% outside scale.... really close - maybe not perfect.

Hern barrels (like several other manufacturers) are shipped with un-drilled vents. There is a cast depression (indented triangle) where the vent goes, but no dill hole as shipped from the factory.

There is a 1/2 inch bore liner, with a breech plug way down there at the bottom.

It should weight something like 90#

Bore is 2.250 diameter, 10.0" deep. That I am 100% positive of.

Trunion I believe is 2-1/8"diameter (or was it 2"?... I think it was 2-1/8).

Sound about right? If still not sure, I can venture out there on Saturday

Rick

[Rickk]

lemme ask some more stuff... did you aquire just a barrel, or an entire mortar?

Hern's plans, if the optional hardware kit was purchased with the barrel, call for a base that is 31" x 15 " x 9 ". That doesn't mean that the person who made the mortar bought tha optional hardware kit or followed the plans, but if he did, that would be the size.

If you have a base, and the hardware doesn't look like hardware store improvisation, describe the hardware.

Hern hardware has 4 cast handles. The bolts all have round heads with no slots or flats - I believe that is how the originals were made as well.

There would be two thru-bolts on each handle, as well as two more bigger diameter thru bolts... one abouve each handle.

The trunnion caps are flat steel, each being held in place with a pair of thru-bolts coming up thru the base.

[powder2burn]

Cat-Rickk

I just want to know what Hern's measurements are to see if that is what I have.  I do not need one for competition. On page 13 Of AOP's  Coehorn 24 Pdr. Motar Book #22  gives the length of the mortal bed As 31" but I cannot tell if the height is an ( or a (9) inches for height. The width is 15"

What I have is a tube, 13.5" from the top of the muzzle to the bottom of the trunnion.
The face of the muzzle (dia) is 6.5"
The bore is 2.25"
The depth of bore 10"
No powder chamber.
Dia. of the trunnions is 2"
Length of the trunnions is 1 3/8"
Length of the trunnions from one end to the other end is 9"

My incomplete bed is 10.5"a wide, 7 3/8" high, 26" long.  I used an untreated oak landscape timber, cut to 26" and bolted together. The 26" length looked better portioned than the 31" length.

[GGaskill]

Dimensions from AOP #22:

Max OD--8.65"
Muzzle face dia--7.65"
OAL--16.32"
Depth of bore (muzzle to bottom of chamber)--13.07"
Trunnion length--12.5"
Trunnion Dia--2.75"
Mortar bed--31"x15"x9"

[Rickk]

O ya, I forgot to mention that Herns do not have a powder chamber either.

I am pretty sure that's what you have.

I would be interested in your fuse hole drilling story.