Welded bush on taper pole

[greencircle]

Hi,
We build taper poles for street light. Taper varies a lot depending upon pole height, bottom diameter and top diameter.
We weld 2 bushes on the pole for installing banner arms in the field. It's challenging to keep the bush axis perpendicular to the pole axis. At times when it is not, the banner top/bottom edge looks tilted upwards.

Is there a easy way to maintain bush axis always perpendicular to pole axis when welding?

I don't want to stock welding fixtures for every possible taper ratio, pole height and pole diameters. Any easy way around?

Please share your thoughts.

Thanks
GC

 

[bljnv]

Is it possible to drill holes with a counter bore to suit the diameter of the bushes. The bush should register inside the counter bore on the taper pole such that the face of the bush butts against the counter bore bottom. The bush face and counter bore face should be machined with reasonable accuracy and trueness.

 

[greencircle]

Good point, but not practical in my application because the pole wall thickness is 0.188in.

The bush size is ID=1.0in, OD=1.312in, length=2in. Need to but weld to pole tapered surface. Theoretically, it's like bush touchs pole at only one point and get welded all around.

 

[StoneCold]

Sounds like you need a welding jig that the alignment is only based on pole axis. The jig will allow the bush to slide up and down, and in and out to fit any pole, but the bush must remain parallel to the axis of the pole. I imagine needing some aligning holes in the top of the pole to slide the jig in to get it to work. I tried to find an example for you as I know this explanation is not good.

Goodluck

StoneCold

 

[bljnv]

Oh! Can you try this. Have a ring of suitable outer diameter and thickness. The inside should have a taper matching the pole, with larger and smaller end dismeter matching the diameters of the pole at locations where you need to have the bush. The bush shall be fixed to the outer diameter surface of the ring. The perpendicularity of the bush axis to the ring axis can be maintained easily. The ring and bush as assembly can be passed over the pole and oriented in the direction you want. The ring assembly can be further secured by weld

 

[MintJulep]

Alignment jig based on the concept of a sliding bevel gage.

http://en.wikipedia.org/wiki/Sliding_T_bevel

If you trust that your poles are installed plumb, just set horizontal with a bubble level.

 

[dhengr]

Greencircle:
I assume you make many of these poles, of varying top and bot. O.D’s. and lengths and tapers. You should develop a spread sheet which will make all the pertinent calcs. and develop some critical dimensions for each size of pole; in particular its support elevations above some datum. I would place the pole in two stanchions, each with a single pipe or sq. tube vert., 10 or 15' apart. Atop these pipes is an angle opening upward, hinged (pinned) perpendicular to the pole axis (maybe a plate with a V notch, then no need for pinning) , which supports the pole and aligns it in one direction, a vert. plane, including the pole’s longit. axis. The pipe stanchions are adjustable vertically to bring the center axis of the pole into a predetermined horiz. plane. This horiz. plane matches the horiz. plane which contains the two central axes of the banner arms. I assume the banner arms are of only a few O.D’s., lengths, and the spacing btwn. them doesn’t change much; and they would fit into upward opening angles on their own stanchions, for vert. adjustability. When the banner arms are all the same dia., these stanchions don’t need vert. adjustment and the center axis of the arms forms the horiz. datum plane. These four small banner arm stanchions would be on a common sliding table which could be moved up and down the pole for height location. Your two bushes (banner arm support points/fixtures) fixed to (threaded onto) a std. banner arm would locate properly w.r.t. the pole when pushed into side of the pole, and ready for welding.

 

[Tmoose]

What is the range of pole diameters at the point the bushes are added?