Seemingly basic drafting question

[HCb]

I read it that the OP wanted something like this, so that all the braces could be cut square.

 

Yes! Exactly! Thank you for the reply.

 

The idea is that, yes, I could cut the pieces to the precise angles to fit...easy to draw, but it would mean I'd have to reset my cut off tool for the angles back and forth and do it precisely each time. If I cut them square like that I don't have to adjust my cutting equipment from one cut to the next (or every other cut if I cut two ends at one angle and then cut the middle at the other angle). Then I'll use some 10ga steel plates to tie the three parts at each junction together.

 

And I can draw what you've shown...if I monkey with it for a bit, making little adjustments here and there. But it's not just this project I would want to do something like this on...and I won't learn if I just rig things and go on. How did you draw that? Is there a way to do it without guesswork? Back to my original post...if you want to find the center of a line on paper (or in CAD if you felt like doing it) you can simply scribe some marks with a compass (or circles in CAD) and connect the crossings above and below the line and find the center. Quick, easy, and it works well. Is there some method for doing what you've shown here (which is my goal) without just guessing at what it should be and then monkeying with it until it looks right?

 

Thanks again.

 

--HC

[HCb]

Those added braces, if cut square like that would have to be applied to the outside of the truss, covering the existing joints to have any structural value at all.

 

Hey, Dana, thanks for the reply. In a later post I mention that I will use plates of 10ga mild steel to cover the junctions providing the structural tie-in you very accurately notice would be necessary to give structural value.

 

--HC

[ReMark]

Those added braces, if cut square like that would have to be applied to the outside of the truss, covering the existing joints to have any structural value at all.

I agree. Another option though would be to use gusset plates at each connection where a brace would be required.

[HCb]

Oh, OK. Then what you want is a dynamic block of the part you need. This block would have a lengthwise stretch action. You could insert the block, stretch it, then rotate it into place, or add a rotational action to the block too. Another way would be to simply draw a rectangle of the required size, and rotate it into position.

 

Hey, Dana, I hadn't thought of the blocks and making one dynamic. I'll try that. It will still require some monkeying but it would give faster results than what I've been trying. Not to be a smartbutt , but I don't know what the length will be ahead of time...I'm doing the design, not drawing a pre-defined/engineered structure. The point of drawing it in CAD is so I can learn the length of the piece.

 

Thanks for the idea of dynamic blocks, I'll try that.

 

--HC

[HCb]

I agree. Another option though would be to use gusset plates at each connection where a brace would be required.

 

Hey, ReMark, yes, that is the intent. I didn't mention that in my original post because it was just a drafting question at the time. Since then, to reply to some other posts, I've mentioned more about the final design/intent. I did not know a technical term for the plates (gusset plates). But that is exactly what I've done in the past and will do here...cover the junctions with plates (both sides) and weld it into place, tying all the members together.

 

Thank you.

 

--HC

[ReMark]

What types of buildings are you using these trusses on?

 

If you are going to use the same 2x4 light weight tubular steel shapes for the braces then cut their ends square, notch them and through bolt them to the gussets. That should work.

[eldon]

And I can draw what you've shown...if I monkey with it for a bit, making little adjustments here and there. But it's not just this project I would want to do something like this on...and I won't learn if I just rig things and go on.

 

How did you draw that? Is there a way to do it without guesswork?

 

It was trial and error for me, as I only have basic AutoCAD.

[Jack_O'neill]

The length of that brace may need to vary according to the skill of whoever is building the truss. If they happen to miss the location of the verticals by a quarter inch, you're gonna have a hard time getting the brace in there. If you are going to build a lot of these, you might think about some sort of jig or fixture to make sure they are the same.

 

I got into this a few years ago while working for a company building chicken houses (yes, this is Arkansas, chicken houses are everywhere). The trusses were made at a local truss company, and would vary as much as a half inch, sometimes more in over all length. The houses were 50' x 500', so there were lots of them in each one, and we'd have to sort them to get it to work properly.

[Dana W]

Hey, Dana, I hadn't thought of the blocks and making one dynamic. I'll try that. It will still require some monkeying but it would give faster results than what I've been trying. Not to be a smartbutt , but I don't know what the length will be ahead of time...I'm doing the design, not drawing a pre-defined/engineered structure. The point of drawing it in CAD is so I can learn the length of the piece.

 

Thanks for the idea of dynamic blocks, I'll try that.

 

--HC

You don't need the length of the piece ahead of time for a dynamic block.

 

Just draw the piece in the block editor at or less than the minimum you will ever need, and add a stretch parameter and action to it. I would ignore the rotation parameters myself, although you could do it. The angles in a truss are going to infinitely varry all over the place from one truss to another, but should stay the same within one truss.

 

You might want to make sure your truss drawing has two points in it to attach the block to, one for insertion on, and one for rotate to. that would probably be a point at each intended end of the inserted piece on the center line of the piece.

Once you have one copy of the block inserted and positioned properly, you can simply copy the block to the next location and stretch/squeeze it to length again.

[Dana W]

The length of that brace may need to vary according to the skill of whoever is building the truss. If they happen to miss the location of the verticals by a quarter inch' date=' you're gonna have a hard time getting the brace in there. If you are going to build a lot of these, you might think about some sort of jig or fixture to make sure they are the same.

 

I got into this a few years ago while working for a company building chicken houses (yes, this is Arkansas, chicken houses are everywhere). The trusses were made at a local truss company, and would vary as much as a half inch, sometimes more in over all length. The houses were 50' x 500', so there were lots of them in each one, and we'd have to sort them to get it to work properly.[/quote']

 

I used to hand draft truss drawings for a company in Easton MD many many years ago. They were made of 2x lumber. The pieces were machine cut, layed out in a jig, punched plates layed out, then rolled through a huge press. They'd still vary as much as an inch in overall size when done. Most of ours went into people coops though.

 

Chicken coops? You've been to the Eastern Shore, I'm sure. Waddaya think them things we have out here are? The people ride bicycles up and down the center isles of the coops out here. I wonder if they have special chicken poo treaded tires?

[Jack_O'neill]

I used to hand draft truss drawings for a company in Easton MD many many years ago. They were made of 2x lumber. The pieces were machine cut, layed out in a jig, punched plates layed out, then rolled through a huge press. They'd still vary as much as an inch in overall size when done. Most of ours went into people coops though.

 

Chicken coops? You've been to the Eastern Shore, I'm sure. Waddaya think them things we have out here are? The people ride bicycles up and down the center isles of the coops out here. I wonder if they have special chicken poo treaded tires?

 

LOL...no bicycles in use here, but they do use tractors and 4-wheelers (at clean out time, anyway). 1 bird per square foot here, you can barely walk through them.

 

I just remember trying to hang the fascia and having to bend it round those long trusses. Fortunately I didn't have to fool with that stuff much, I was inside hanging feeders and fountains most of the time.

[Dana W]

LOL...no bicycles in use here' date=' but they do use tractors and 4-wheelers (at clean out time, anyway). 1 bird per square foot here, you can barely walk through them.

 

I just remember trying to hang the fascia and having to bend it round those long trusses. Fortunately I didn't have to fool with that stuff much, I was inside hanging feeders and fountains most of the time.[/quote']

Wow, and I thought I had already done all the crappy jobs there are. You and Mike Rowe have topped me good.

 

Yeah, the trusses were pretty much hacked together. Even though thay tried to use big jigs to hold them still, the 2x stuff was just twisted enough to bounce all over the place during nail up. After the crew threw all the 2x's into the jig, they'd lay the nailer plates on the joints and whack 'em a couple times with a BFH. The other end of the web, rafter or whatever would give a little reflexive jerk as it bounced up in the air. Then they's slide it down the table to the monster roller downer thingy. The parent company also built houses all over the DC metro region. I did drawings for them too. I've seen rooflines with the shingles in place that looked like the ocean. Well, that's an exageration, but they were wavy. Framing carpenters don't sort trusses by length, I guess.

[Jack_O'neill]

Wow, and I thought I had already done all the crappy jobs there are. You and Mike Rowe have topped me good.

 

 

The new ones aren't bad. It was my brother in law's company, and I'd go help on weekends and some evenings when he'd get behind. All steel trusses, btw, made from angle iron. The truss company would measure with a tape, mark with chalk and cut with torch.

 

I let him con me into helping with a refit on an old one once....never did that again. The new ones are really kinda fun to work on. Well, at my age now it wouldn't be much fun, but at 20, it was good way to make some extra money.

[HCb]

What types of buildings are you using these trusses on?

 

If you are going to use the same 2x4 light weight tubular steel shapes for the braces then cut their ends square, notch them and through bolt them to the gussets. That should work.

 

Hey, ReMark, yes, all members of the trusses will be the 2x4. I want to cut the diagonal braces square to save time and gussets to achieve the intended tie-in/strength. Bolting would work but I can weld a lot faster than I can drill and punch holes and run bolts.

 

--HC

[HCb]

It was trial and error for me, as I only have basic AutoCAD.

 

Eldon, well, thank you anyway, it was still helpful. I'm going to try the suggested idea of dynamic blocks that I can stretch.

 

--HC

[HCb]

The length of that brace may need to vary according to the skill of whoever is building the truss. If they happen to miss the location of the verticals by a quarter inch' date=' you're gonna have a hard time getting the brace in there. If you are going to build a lot of these, you might think about some sort of jig or fixture to make sure they are the same.

 

I got into this a few years ago while working for a company building chicken houses (yes, this is Arkansas, chicken houses are everywhere). The trusses were made at a local truss company, and would vary as much as a half inch, sometimes more in over all length. The houses were 50' x 500', so there were lots of them in each one, and we'd have to sort them to get it to work properly.[/quote']

 

Hey, Jack, Arkansas is cool...some very pretty areas there. I understand about the precision of the assembly, and you are absolutely correct. First, Me is the designer, Myself does the labor/assembly, and I act as the shop foreman. That said, I'll get the parts pretty darned close. It's then a simple matter of a minor allowance for variance (and maybe a clutch-throw trim cut) to make the parts fit. The gusset plates will provide the necessary tie-in. Mostly this is an academic endeavor to learn to do CAD better. I can, as suggested, set it up and measure it in real life. I've done that on other projects. I can monkey with it a bit and get it designed in CAD. I've done that. I am just trying to learn if there is a better way to do the drawing so that, in the future, I can do it faster/better.

 

Thanks for the reply. Interesting that your quote is from Robert Heinlein. I used to have a quote from him (probably in a book he wrote) about that a human should be able to con a ship, take orders, give orders, comfort the dying, die valiantly, butcher a hog, and so forth and that specialization is for insects. I always liked that quote...kind of embodies my attempt and desire to do a lot of things across a lot of disciplines in life.

 

Anyway, thanks for the reply and the insight.

 

--HC

[Tankman]

Eldon, well, thank you anyway, it was still helpful. I'm going to try the suggested idea of dynamic blocks that I can stretch.

 

--HC

 

Drawing, the DLINE lisp routine might be of use.

[HCb]

You don't need the length of the piece ahead of time for a dynamic block.

 

Just draw the piece in the block editor at or less than the minimum you will ever need, and add a stretch parameter and action to it. I would ignore the rotation parameters myself, although you could do it. The angles in a truss are going to infinitely varry all over the place from one truss to another, but should stay the same within one truss.

 

You might want to make sure your truss drawing has two points in it to attach the block to, one for insertion on, and one for rotate to. that would probably be a point at each intended end of the inserted piece on the center line of the piece.

Once you have one copy of the block inserted and positioned properly, you can simply copy the block to the next location and stretch/squeeze it to length again.

 

Dana, I played around with dynamic blocks. I had to hit the help file since I've not used dyn blocks since the tutorial but I got it working pretty well. Thanks for the tip.

 

--HC

[HCb]

Wow, and I thought I had already done all the crappy jobs there are. You and Mike Rowe have topped me good.

 

Yeah, the trusses were pretty much hacked together. Even though thay tried to use big jigs to hold them still, the 2x stuff was just twisted enough to bounce all over the place during nail up. After the crew threw all the 2x's into the jig, they'd lay the nailer plates on the joints and whack 'em a couple times with a BFH. The other end of the web, rafter or whatever would give a little reflexive jerk as it bounced up in the air. Then they's slide it down the table to the monster roller downer thingy. The parent company also built houses all over the DC metro region. I did drawings for them too. I've seen rooflines with the shingles in place that looked like the ocean. Well, that's an exageration, but they were wavy. Framing carpenters don't sort trusses by length, I guess.

 

Before I became a welder/fabricator/draftsman and whatever else I do these days, I was a network admin (WinNT, Win2K) and a programmer (VB apps and DTS web components). When I was doing programming, I'd joke with my colleagues, "if it'll compile, it'll ship". Sounds like the same mentality about the trusses...if they'll stick together, they're good enough to go.

 

I think must be an interstate operation there...my house in Texas built in the 70's has a roof like that.

 

--HC

[HCb]

Drawing, the DLINE lisp routine might be of use.

 

Hey, Tankman, thanks for the reply. However, I can spell LISP if I look it up...I've never written code in LISP and never written any routines for AutoCAD. I wouldn't know where to start at this point.

 

--HC