angle cutting small pipe

My neighbor came to me, and wants me to build some greenhouse supports.
Basically house shaped, out of galvanized chain link long pipe sections.
Make some purlins and connectors to support the water system, and rigidize
the whole outer frame. Put some simple gussets at all welded points.
He had thought of using PVC, and connectors, but I think the metal would be
a lot stronger and reliable.
I have a band saw and a wirefeed. My idea is to figure out the angles on a
scale drawing, and cut the pipe and weld together, laying them on a big flat
driveway. Trouble is, making the second cut, and getting them to match.
They would have to be cut with the pipe in the same orientation. I've done
pipe with the bubble center punch, but that would be difficult on the
smaller pipe.
My idea was to use a Irwin clamp, and weld a piece of angle on there that I
could put a magnetic level on. Put it in the saw and make the bubble level.
Then on the second cut, reverse, and have the bubble level again.
Is there a simpler way to do this? We may go to HF and get a pipe notcher
to make clean joints on those that saddle.
TIA
Steve
Reply to
SteveB
Loading thread data ...
Consider a design that uses cuts done with a holesaw and an angle jig. That's how they make roll cages.
Reply to
Buerste
Clamp the pipe to a flat surface. Set a surface gage or equivalent so its scriber point is exactly the height of 1/2 the OD of the pipe. Scribe lines on both sides of the pipe. Put the pipe in the band saw vise loosely. Rotate the pipe until a scribed line is the same height as the surface gage, then clamp and saw. You can rotate the pipe 180 degrees precisely, or flip end for end and keep the alignment precise. Make all 4 of your cuts that way.
Recall the excellent Web page
formatting link
(best opened in IE, doesn't work correctly in Firefox at any rate). For an example of this technique, see
formatting link
GWE
Reply to
Grant Erwin
I clamp scraps of angle near the cuts, aligning the second parallel to the first by attaching other bar stock at a right angle and sighting down the pipe, or blocking them up in the bed of my truck. Two Kant- Twist clamps hold the angle, one far enough from the cut that it can stay on when the pipe+angle are clamped in the saw vise.
When I welded some scaffold sections I jigged the first end frame planar by clamping the pipes to a diagonally-placed X of visually straight 2X4s with a spacer the thickness of the pipe between them where they cross.
That was awkward to set up, so for the second I arranged the 2X4s parallel to each other in Workmate benches and leveled them lengthwise. My driveway slopes so they weren't at the same height, but that doesn't matter as long as they are spaced the same distance apart at the ends, the tops still define a plane surface.
jsw
Reply to
Jim Wilkins
Any reason not to buy & use the bolt on clamps for holding these pipes together as would be done on a fence?
You could put a spot of weld on to make the clamp / pipe connection more rigid if you wanted. certainly a LOT less work if you can do it using clamps.
Reply to
Nector
They also make pipe cross clamps just for greenhouse use. If you go this route, I'll find you a source. Take a look at a local garden center greenhouse, you want to copy this proven design.
Karl
Reply to
Karl Townsend
This is a garden item - absolute accuracy is not required.
Assuming that you only have cuts that need to match at same, 90 or 180 degrees along the pipe - Clamp (don't bother welding) it to a bit of angle iron just shorter than your cut length; that'll let you cut your matching angles.
If you have no angle iron, or have a lot of different lengths to do - Drill a hole in a block of wood, the diamater of the pipe. Cut the block in half so you have two blocks. Slit one side of the blocks so you have a C-shaped hole in each. Clamp/screw the pipe in the blocks to a length of straight lumber (cheaper than angle, and easier to cut to the necessary just-shorter-than lengths).
After clamping and cutting, tack, and adjust with BFH as necessary.
If you need compound angles at something other than same, 90, or 180 along the pipe, the block and lumber way is better, because you can cut the block you drill to one part of the compound angle; you might have to clamp/screw the blocks to two bits of lumber.
Reply to
_
On Thu, 14 May 2009 22:50:26 -0600, the infamous "SteveB" scrawled the following:
Ayup, much simpler. Here ya go: Search
formatting link
for "greenhouse bender" or use this url
formatting link
. He has several sizes available. I've been threatening to get one myself. Sections of 1/2" or 3/4" conduit with flattened ends lagged into the pipe hoops provide stability. I've seen them made with 2x2s and 4x4s, too, and that's sturdy enough in non-hurricane climes.
For another bolted-pipe configuration, search
formatting link
for "geodesic" or use this url
formatting link
. It'd be simple to make those struts with a punch press. Nice, clean look, wot?
I used eBay because I'd seen both products there. Here is the guy's main website, the page with the vertical leg/house style GH linked.
formatting link
(Standard disclaimer applies.)
-- No matter how cynical you are, it is impossible to keep up. --Lily Tomlin
Reply to
Larry Jaques
And, I would have bet that you would have recommended assembling the pieces with boogers!
Reply to
Buerste
"SteveB" wrote in news: snipped-for-privacy@news.infowest.com:
Take a look at this. It works well on 1" tubing, just like using a bench shear and leaves space for the bead around the joint. Keep in mind that you are not doing pipe fitting here and a little extra daylight around the joint prior to welding is not a major problem.
formatting link
Doc
Reply to
Doc
Rolled sheet plastic for the green house roof and walls?
Sounds expensive.
Depends. UV would eat up the PVC, but in that environment the fence posts will start to rust pretty quickly too.
How about setting up an angled stop block that traps the end of the pipe? Cut one end. Put it in the stop block, and then cut the other end.
Sounds like you could get some cumulative error on sections with multiple miters. If you lay out each section on a jig before welding it probably won't matter as you can easily bridge any gap you might get that way.
Sounds like a good idea to me, and you have been looking for an excuse to buy one anyway.
Bob La Londe
formatting link

Reply to
Bob La Londe
=A0 =A0 =A0 =A0--Lily Tomlin
Larry knows not to be lured by your environmentally friendly "green" solutions to metalworking problems.
Reply to
guillemd
Flatten the pipe at the end then cut your angles. It is easier to weld the flat sections
Reply to
F Murtz
Cut the ends at the correct angle and then get someone with an Edwards Ironworker
formatting link
the pipe punch to cut out the ends in to circles that match the other pipe.
Reply to
Calif Bill

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.