Feedback on first design

[fpk]

I am (slowly) working on building an unlimited gun and would love some feedback on the design I have so far. This is done in Autodesk Fusion 360, and borrows from a bunch of differ designs that have been posted.

I have tried to simplify the design as much as possible, so that it can be built easily. I have not added a sighter cam yet, but otherwise consider this a complete base. Thoughts or feedback on things that I missed or appear to be bad ideas?

 

[Wilbur]

What's that wheel in the middle, on the rear, of the base do?

 

[fpk]

What's that wheel in the middle, on the rear, of the base do?

Adjusts the elevation of the rear by raising/lowering threaded rod in the center. I have realized that using the horizontal screw as the pivot for the elevation table will cause horizontal shift when adjusting the elevation. I thought I had removed the need for the extra pivot rod, but alas, I now see I removed the independence of vertical and horizontal adjustment in doing so.

 

[Mike Bryant]

It will take a little more than what you are showing in the drawing to get the windage adjustment to work. Its pretty common to use a ground shaft that run in hardened bushings. The ground shaft will slide in the hardened bushings which will be epoxied into the upright on each side of your windage plate. The windage plate will be fixed to the shaft. Normally, you'll thread the end of the rod for an adjustment knob that bears against either the right or left side of the rest depending upon whether it's a right handed or left handed rail. You can either use a coil spring in between the uprights on one side or on the outside of the upright on the opposite side from your adjustment knob. That's for setting the rail gun up where one rod handles both the horizontal sliding adjustment as well as the pivot function of the rest. The most common method is to have one end threaded for the windage knob and the other threaded for a spring tension knob where you can add more pressure or even lock down the windage by applying more pressure to the shaft. This is the method used in the Jay Young rail guns. Some others like the Magnum Metals rail by Scott Hunter, have a separate pivot rod with a threaded rod that pushes against the windage plate. With the Young type you can use a right hand thread and have the windage work correctly for the way you want it to go. If you push against the plate with a separate pushing screw, then it will need to be a left handed thread to get it to push the way you want it to go. Either that or make them all right hand threads and just get used to the way that they work. It's better to turn the adjustment knob counterclockwise and have the crosshair move to the left on the target or clockwise and have it move right on the target.

Of course, however you want to make it is up to you as thats one of the appeals to making and designing your own rail gun. About the only one who I've ever seen who thinks outside the box when it comes to rail gun design is Jerry Hensler. I had built one years ago that was pretty unconventional and it worked well, but it was a pain to pick up and rotate benches with at the Nationals. Here is a link with some photos of it as well as a later rail gun I built. Rail Gun Photos and Various unique and commercially made rails

 

[geo.ulrich]

Mike, No need for prints here you go in the flesh or in the aluminum, important thing is to have no slop in threads

 

[Chism G]

How much does it weigh or will it weigh when finished. I have a rail Gun. Mine has a handle ,on the bottom and top, for easy lifting.

That is, easy lifting, for the Arnold Schwarzenegger's, I don't see handles in the photos. i know this is an early stage design but, Are there future plans to include handles? Just Curious.




Glenn

 

[geo.ulrich]

I have built with and without handles. I just lift and place in range cart not much reason for handles even though there is one on top. I think base is 35 #'s. not to bad to lift I've had a lot heavier. If you need a much lighter rail you might consider workout at gym....

 

[BillBrawand]

check this out

I have built with and without handles. I just lift and place in range cart not much reason for handles even though there is one on top. I think base is 35 #'s. not to bad to lift I've had a lot heavier. If you need a much lighter rail you might consider workout at gym....

at 85 your lucky to get pout of bed un less she rolls you out after a night of rubbing cheeks bill b