Mounting a Sight on a Cannon

[CrufflerSteve]

I'd like to have a sight for my cannon. The recoil is fierce so it should
be something that slides on and off easily and is never on when shooting.
I know there were a variety of sights used in the 19th century but I'm not too particular about historical accuracy. I'd just like something fairly cheap that could help me put a projectile in the same county as the target.
I was thinking of something like:

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(The picture will look awful in proportional font.)
This would be a view from the side.

The bottom would attach to the barrel. The top would have a sight on it.
Ideally, one of the sides of it is hinged and other side has a screw or
something so I can vertically adjust the mount.

I'd like to have the bottom fairly thin. I'd have a couple of notches in
one side. Then I'd drill, tap and locktite some screws to the barrel. The
mount would slide on. If the bottom was thin, the screws wouldn't have to
stick out far. The mount could then be slid on and off.

The top would have something that I could attach a weaver base to. It
could then have anything mounted to it.

Any ideas if such a thing exists or could be made fairly cheaply? Anybody out there ever done anything like this or have alternate suggestions?

Steve
http://www.crufflersteve.net/naval.html

[Cannonmaker]

I have been going to design a sight for the guns which I build and sale. The bottom would be V  shaped to cradle over the reinforce of the tube, having a pin in the grove to index into the vent hole. This should have some consistency with each shot.  This would be made of brass so not to risk having a spark. I then would have a set of sights on top. I am thinking about this design and hope to build a prototype soon.

[Cat Whisperer]

Let me toss out a few ideas and observations from experience.

Most of my shooting is with mortars, which are frequently just aligned by sighting the tube in line with the target and a plumb bob.

On the other end of the extreme is the sighting system used on our howitzers (105, 155mm and many others) using an optical sight to align the azimuth setting on the howitzer to a known point (surveyed in) and known angle by shooting (visually) back to a collamiter.

Skipping all those details, because few if any of us will lay an entire battery of cannons shooting black powder, let me point out a few items from machine design, jig & fixture design and some features of cannons.

Many artillary pieces will have a flat surface milled onto the tube so a gunner's quadrant can be placed onto it at that point.  This will give a repeatable measurement of elevation.  (Trajectory changes with elevation changes.)

Locating precisely and with repeatablity two objects can be done using the 3-2-1 principle of location.  3 points of contact define the location of a plane - it is stable (as a 3 legged stool vs a 4 legged stool).  But the plane can slide and rotate.  The next two points of contact locate the object so that it cannot rotate - it can still slide - so the last point of contact prevents that.  Using the minimum points of contact (clamping into them) provides accuracy and repeatability.

Geometries we have in the cannon barrel lend themselves nicely to location of a sight as well.  Your idea of using an inverted vee will align well with a cylinder.  Then one or two locating pins would be needed to locate accurately - one for rotation around the cylinder and one for sliding fore and aft.  The pins could be attached to the tube or to the sight.  The sight doesn't have to be on the cannon at time of firing - just on there when it is being aimed.  My preference would be to have the locating pin independent of the touch hole - to keep away from the crud and because of erosion over time (but that's a minor point).

Optical sights, once zeroed, would certainly be a convenience.

[Will Bison]

Most of my shooting is direct fire so I have direct sights mounted. On one gun I used an old vernier tang from a T/C rifle. The front is a simple pin turned from a 1/4 bolt. I can count the turns on the elevation screw for different ranges and get darn close with the first shot.

I was shooting yesterday with a friend and he came up with the same solution, he ordered a Pedersoli vernier tang sight and installed a simple pin for the front.

These are not inexpensive sights, I think my friend just paid $65 for his rear sight.

[Double D]

Here is a front sight from a bronze gun.



You guys are brillian, so am I!

My idea foa sight was to install a post similiat to the picture above.

The use one of those Vernier Tang sights  with a pin in the vent hole for the rear.

Ah yes great minds think alike

[CrufflerSteve]

This has been very useful. I hope Rick Neff posts some pictures or drawings of his proposed sights.

I had been planning to drill and tap a post for the front muzzle. I have a bunch of brass rods of different sizes. It wouldn't be hard to do up a bunch so I could experiemt with different heights. I'd blacken the backs so I could see them in the Colorado sun.

Will's idea of vernier tang sight is great. I have a spare one from my Bodine rolling block. I took the stock one off and put a better one on. The original is pretty nice. I have to admit that I was thinking about permanently mounting it and wondering how it would hold up.

Double D brought me back to reality. Why make it permanent? Have a pin for the vent hole in the rear of the sight and a put a small, discreet post for the front hole. That would work well.

Steve

[guardsgunner]

It would be easy to turn the vernier tang sight into a PENDULUM-HAUSSE SIGHT by adding 2 small pins and a soldering a bulb to the bottom. I would think a pair of freeze plugs fron the auto parts store would work for that. In fact , if you solder that to a cut out brass side and have something close to the real thing. It hangs on a small bracket on breech.
It would be easu to remove, height and windage adjustable; and  it would look fairy historical accurate. Might have to try this for myself.

[Cat Whisperer]

This wesite has pictures of  several types of sights:

http://www.cwartillery.org/chapman.html

[Double D]

For the Pendulum hausse you are going to need a base.  How about following Jeff's  idea with a v block and pin in th vent with the hooks for the sight pivots for the sight on the back of the bracket.

One sight solution that I saw some years ago at the cannon shoot in Grants Pass, Oregon was a Leupold 3x9 varible rifle scope mounted on a bar.  The bar had a hollow pin in front that slipped over a pin front sight and solid pin in the rear that dropped in the vent hole.

[Max Caliber]

Here is a picture of a tang sight that I have had on my three quarter scale 6-pdr for many years. The sights pivot hole is threaded .250X20tpi and the bracket hole is smooth. When the knurled screw is tightened it pulls the sight against the bracket holding it securely. Up the barrel is my lock for using .22 blanks for ignition.

[Cat Whisperer]

... The sights pivot hole is threaded .250X20tpi and the bracket hole is smooth. When the knurled screw is tightened it pulls the sight against the bracket holding it securely....

Like the two parts of a hinge!  Good idea - disassembleability and secure mount when needed.

Good idea on using the blanks as a primer as well.  Available and most likely powerfully reliable.

[Evil Dog]

This is a rear sight from a 1903 Springfield Rifle.... purchased on eBay for about 10 bucks.  It is just epoxy glued (Micro-Bed) to my half scale Napoleon about 1" in front of the fuse hole.  So far it has worked really well with a vertical pin near the muzzle for a front sight.  Just fold the ladder down prior to firing.

[Double D]

Lot's of good ideas coming out here.

Looks like the consensus is a simple post for the front.

I have another idea for the rear, at least for the mount.   Get  piece of pipe ID near  breech diameter at the vent.  Open the ID to breech diameter at the vent and cut off a band.  Section the band in  1/4 or  1/2 diameter. In the middle of the section mount a pin to fit the vent and mount he actual sight center over the pin.  Drop the pin into the ven hole the arms of the band would help keep the sight upright and square.

MaxCaliber what is thew source of your sight?

[Max Caliber]

DD, Thats a Thompson Center sight. The front is a 1/4 inch brass post screwed into the barrel like your picture of the Napoleon sight. It's thinned at the top down to around 1/16 inch thick, The rear is easily removable and works well.

[Calamity Jane]

On my 1/3 scale 6-pounder, I used a front post. Fer the rear sight, I bent a piece of 1/8" brass rod into a U shape and made a little slider what moves up and down on the U. The U fits, upside down into blind holes in a piece of square brass attached to the back of the breech. Material cost was nuthin and it works.

Ya kin sort'a see it in this picture http://www.geocities.com/diannebest/Cannon/Cannon.html

[Cpt Ed]

Here is a picture, before painting and reducing the height by 1.5",  of the front sight I placed on my SBR half scale Parrott Barrel. I did not want to drill and tap into this fine barrel.

We are still working on the rear sight. I have a brass scale breech sight made my Chapman & Son, but want a more permanent mounting. So off of my Shiloh Sharps comes its Soule Mid-Range Tang Sight and on to the cannon it will go.



Also here is the front sight mounted on the barrel, before reducing its height.



Always think safety...be a Complete Cannoneer.