Default wrote:

The design will be a rectangle, length of 2.5 meters, height of 1.5
meters, with a brace running from the bottom of the hinged side, to the
top of the swinging side.

Why the brace the wrong way?

What type of material should I be using?

Steel :-)


I was thinking box tube of 20x20mm, or 50x20 if required.

20*20 is ridiculous. I would use a 40 * 40.
A 50 * 20 would be OK for vertical load (if the profile is standing),
but it will just warp and wiggle in the plane.


I guess I don't want a thin wall.

Yes. Then practice.

What wall thickness should I be looking at?

1.5mm, maximum 2mm


Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
DIY-DRO - YADRO - Eigenbau-Digitalanzeige

According to Nick Müller :
Default wrote:

The design will be a rectangle, length of 2.5 meters, height of 1.5
meters, with a brace running from the bottom of the hinged side, to the
top of the swinging side.

Why the brace the wrong way?

Exactly. The way you have it described, the diagonal member
will be in compression, and thus likely to buckle under load. And
*don't* bet that nobody would ever try riding the end of the gate.
Someone *will* do that.

Running from the top at the hinge end to the bottom at the free
end will put the diagonal member in tension, which will make it
stronger.

Aside from that -- I'll let the others comment on the size of
the material, as I have not made anything of that size.

Good Luck,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

That might be true for a steel gate but a wood gate works better in
compression. In wood, the joints fail long before the the crossmember
buckles.

DoN. Nichols wrote:
According to Nick Müller :

Default wrote:


The design will be a rectangle, length of 2.5 meters, height of 1.5
meters, with a brace running from the bottom of the hinged side, to the
top of the swinging side.

Why the brace the wrong way?


Exactly. The way you have it described, the diagonal member
will be in compression, and thus likely to buckle under load. And
*don't* bet that nobody would ever try riding the end of the gate.
Someone *will* do that.

Running from the top at the hinge end to the bottom at the free
end will put the diagonal member in tension, which will make it
stronger.

Aside from that -- I'll let the others comment on the size of
the material, as I have not made anything of that size.

Good Luck,
DoN.