PDA

View Full Version : How to check for parallel across distances?

Linepipe
11-16-2009, 07:33 PM
I am putting in new double doors for my shop. Hole is 10' wide. Using 3" angle iron for the door frame, welded to 2 7/8" upset tubing (shop's frame is made of this). Hinges will be welded to the outside of the angle iron.

Pipe is plumb, so we are good there. Put the pieces up tonight and its looking good, but how do I make sure that these opposite pieces of angle iron are parallel to each other and dont end up "offset"?

Like this, only 10' apart, vertical: __I I__

If I could get it that perfect, top to bottom, I would be a very happy human.

Alternatively, how would you guys go about doing this right?

Thanks for the help.

transit
11-16-2009, 08:05 PM
Simple, if the two vertical sides are equal in length, than measure the diagonals, right top to bottom left and bottom right to top left. If the diagonals are equal the sides are parallel and square. Try it on a smaller scale to get the technique.

denrep
11-16-2009, 08:19 PM
. . .Pipe is plumb, so we are good there. Put the pieces up tonight and its looking good, but how do I make sure that these opposite pieces of angle iron are parallel to each other and dont end up "offset"?

Stretch a string line (or two) between any two points, probably on the building's frame or fascia, then at two points measure and mark an equal distance perpendicular to the string line; when these two mark points are connected, that will form a second line which is parallel to the string, and in your case, parallel with the building's wall. Kapish?

You may have to space the string line away from the structure to be sure it's free and clear.
Of course you could substitute a laser for the string.

Good Luck

Bob
11-16-2009, 08:23 PM
Use a level and a tape measure.

Linepipe
11-16-2009, 08:24 PM
Got it. Thanks.

Is there a specific way to spot weld this in place without causing any shrink movement, etc? In the past when I have had something lined up and welded it would warp somewhat and throw everything off. Will be using 6011 1/8" rods.

transit
11-17-2009, 12:15 AM
Stretch a string line (or two) between any two points, probably on the building's frame or fascia, then at two points measure and mark an equal distance perpendicular to the string line; when these two mark points are connected, that will form a second line which is parallel to the string, and in your case, parallel with the building's wall. Kapish?

You may have to space the string line away from the structure to be sure it's free and clear.
Of course you could substitute a laser for the string.

Good Luck

Kapish is spelled Capish, there is no K in the Italian alphabet. Ca is pronounced as a K.
Capish is pronounced Ka-peesh. The spelling of capish as Kapish or Kapeesh is the angloized version.

And don-t for-get a-bot it.

JohnnyWelder
11-17-2009, 12:44 AM
I am putting in new double doors for my shop. Hole is 10' wide. Using 3" angle iron for the door frame, welded to 2 7/8" upset tubing (shop's frame is made of this). Hinges will be welded to the outside of the angle iron.

Pipe is plumb, so we are good there. Put the pieces up tonight and its looking good, but how do I make sure that these opposite pieces of angle iron are parallel to each other and dont end up "offset"?

Like this, only 10' apart, vertical: __I I__

If I could get it that perfect, top to bottom, I would be a very happy human.

Alternatively, how would you guys go about doing this right?

Thanks for the help.

Just pay me to do it.

JohnnyWelder
11-17-2009, 12:46 AM
Got it. Thanks.

Is there a specific way to spot weld this in place without causing any shrink movement, etc? In the past when I have had something lined up and welded it would warp somewhat and throw everything off. Will be using 6011 1/8" rods.

tack it all together first. then call me to weld it up. I only charge 75 per hour. A few weeks later, ill have those things hung in no time. I am currently doing some fence work. As soon as im done bleeding that sucker, i can get to work on yours.

transit
11-17-2009, 12:51 AM
Simple, if the two vertical sides are equal in length, than measure the diagonals, right top to bottom left and bottom right to top left. If the diagonals are equal the sides are parallel and square. Try it on a smaller scale to get the technique.

This should help

denrep
11-17-2009, 05:50 AM
Kapish is spelled Capish, there is no K in the Italian alphabet. Ca is pronounced as a K.
Capish is pronounced Ka-peesh. The spelling of capish as Kapish or Kapeesh is the angloized version.

And don-t for-get a-bot it.

Capish :laugh:

Speaking of angloized...

Simple, if the two vertical sides are equal in length, than measure the diagonals, right top to bottom left and bottom right to top left. If the diagonals are equal the sides are parallel and square. Try it on a smaller scale to get the technique.

Maybe I no Capish Linepipe; eh? I thought he was aksing how to be sure that the new door panel would be parallel to the building's wall, not how to square the opening.

But anyway, while the math of comparing diagonals is technically correct, sometimes with all of the variables in building work and materials, it's just too difficult to confirm an accurate square by comparing diagonals.

For example, if Linepipe's 10' door opening had sides which were 2" out of plane with each other, that would probably only show about an 1/8" difference on the diagonal measurements. Which would leave me wondering if the 1/8" difference was in the jamb, or the tape measure anchor, or the viewing angle.

With building work, to me, the eyeball sighting a square, level, or string, are most accurate. Even then, there are usually compromises to be made. After all, what good is perfect level, square, and plumb, if it doesn't fit or visually match the rest of an existing structure.

So Linepipe - The pull of a shrinking tack weld on sheet metal building work, won't mean diddley. Get it done.

Capish?

Linepipe
11-17-2009, 09:24 AM
Denrep, thanks for that little bit of wisdom on compromise there. And the slap upside the back of the head. I'll get it done. :)

I do hate it when things don't fit perfect. My gates around here open with one finger because I spend time up front making sure everything is the way it should be, including properly made hinges. I'll take the advice and let the OCD monster go somewhere else....

JohnnyWelder, I think I see your joke. However, that is exactly how I started teaching myself to weld some time ago - an expensive welder. I now do it all myself, including rebuilding what I had originally paid him to do. Dont get me wrong, there are some REAL GOOD welders around here though. No way I could even hold a conversation with them.

Transit, thanks for the pdf. That explains it very well.