Hi all. Some quesitons about an 1862 Type I Gatling

Hi all,

I am creating a 3D CAD model of an 1862 Type I Gatling, with an eye towards making one one day.

I am working from the original patent drawing.

I have a lot of questions, but here are a few to start with:

1) Is the brass cylindrical casing around the lock, etc., one piece that slides over from the rear?  Or is it two pieces that bolt to the rails top and bottom?

2) There is a round cylindrical piece that the barrels screw into, just in front of the grooved cylinder carrier, which is just in front of the lock carrier.

Are these separate pieces?  It seems they all rotate together, so it would be nice to machine them out of a single piece, but it would seem difficult to me to machine the chamber carrier from \"above\" rather than from the end, which would not be possible if they were all one piece.

Perhaps this is why there is a groove at the front and rear of the chamber carrier, to get rid of the ball radius that would result at the ends of the carrier channel if machine from \"above\"?

3) What sort of ratio do I want for the bevel gears?

Here is what I have so far:

This might help some.
viewtopic.php?f=7&t=67

bruski

Thanks Bruski.

His non-firing replica looks to be a pretty close copy in concept.

It does look like he has made his so that the brass shroud completely encircles the mechanism.

I\'m still wondering whether the lock carrier, cartridge carrier, and the rear barrel disk are machined from the same piece or not.

From the patent drawing, it appears that they were intended to be so.

Here is what I have so far.  I have modeled the rear barrel plate, cartridge carrier, and lock carrier as separate items.

I would machine the pieces individually and then use dowel pins to assemble them. The pieces should be machined with a boss protruding out some to fit into a reccess in the other mating part. The shaft with a long spacer where the barrels are should be threaded on both ends to tighten everything together.
 Do you have a copy of the RG-G plans?
bruski

Hi Bruski,

No, I do not have any plans.  I am creating the CAD model using the 1862 Gatling patent drawing.

I had considered making the parts individually and using dowels to lock them together, so I am glad to hear you suggest it also.

I believe the part can be made in one piece also.  I believe that is why there is a groove fore and aft of the carrier fingers - the channels for the cartridge carrier are made with a ball-nose end mill which would naturally result in a radius at the ends of the carrier trough.  To eliminate this, they used a lathe to machine a groove that eliminated the radius in the trough.  The cartridges are supported by the remaining middle material.

I have some more questions.  Refer to the drawing below.

1) The the primary longitudinal section, component I is the recoil plate that the locks bear against.

Is this a separate piece from the main shroud A?  Or is it made with A?  In the section view, at the top there is a line across the cross section, while at the bottom there is no line.  It is hard to decide if this is all one piece or not.

Of course, in manufacture, it could easily be a separate piece secured inside the brass shroud with screws that penetrate from the outside.  But I am wondering what you all think the original intent was.

2) It appears to me that the barrels screw into the rear barrel disk, which is part of the carrier and lock assembly.  All of this slides onto the main shaft from the year, and bottoms out on a step in the shaft.

What keeps this assembly from backing off the shaft?  

In the 1865 patent drawing there appears to be a nut on the main shaft that is threaded on after the lock assembly to secure it in place.  This is absent on the 1862 drawing.

If the muzzles were press-fit into the front barrel disk, then the barrel disk would prevent backwards movement of the assembly, as the front disk is prevented from moving rearward by a step on the main shaft.

But I would not think it would be wise to have the barrels press-fit into the front disk, as the barrels will grow in length during firing as they expand from heat.  Also I would worry about them coming loose.  

Or was this a shortcoming of the 1862 design?

I had assumed that the front barrel disk was a close but non-interference fit with the barrels.  

Thanks,
Steve