Usual disclaimer about being a crappy draftsman.
The dimensions on this drawing will produce a bed for a 24 pdr CS mortar. If you wish a smaller bore size, take your desired bore diameter and divide it by 5.82. The answer should be multiplied by the dimensions on the drawings, the answer to that will be the new dimension that you would use.
Example: 1" (new desired bore dia) / 5.82 (original 24pdr bore size) = .1718 (you can use more decimal places but it won't get you much)
Next: .1718 (your multiplier that you will use on every dim change) X 44" (dim of sides for 24 pdr from drawings) = 7.5592 (the new length of your 1" dia bore bed sides).
Sheet-1 is the pic that Lance posted of a real one.
Sheet-2 is how I determined the dimensions by removing the perspective and interpolating the dimensions from a known sized object, in this case the trunnion. The drawings for the actual barrel were supplied by DoubleD. The accuracy of all the dimensions shown on the drawings depends on how well I could define the edges of the photo and the accuracy of the mortar barrel drawings. I will admit there was a lot of guessing involved and I have no way of knowing the accuracy of the 24pdr drawings. If you should build one of these in the 24pdr size and take it to a shoot and someone shows up with an original and points out that yours is a bit off, please refer him to me and I will take all the blame
The remainder of the sheets are dimensioned drawings in .jpg format
I would recommend obtaining the nuts bolts and washers before you start construction and make alterations to your parts to fit the hardware. The smaller the object in the photo the harder it is to measure accurately, so I went out in the shop and measured nuts and washers off an engine originally made in 1916, they are old pattern and are different than what you would buy in the hardware store. In the picture of the original mortar it looks like they used bolts instead of a rod threaded on both ends. It also looks like the bolts were put in oppositely, for example it appears, and I stress appears, that in each cap square there is one bolt with the head up and the other has the nut up. The pairs of handle bolts appear to be done the same way.
The top edges appear to be slightly beveled, you can see this in the picture. This bevel is not shown on the drawings.
If you find I have left out a dimension please let me know and I will repost whichever sheet.
Lance and DoubleD,
Thank you very much for the information you sent me to put it together.
MikeR C
