Welding Bolts to Steel Block (Gate Hinge)

[meyco]

I'm new here. I am building a set of driveway gates here:

http://silverridge.org/yale/SR080711 RT31 Gate Question.pdf

The hinge is a prefabricated block and pin that I want to weld a 3/4-10 bolt too. The design is here:

http://silverridge.org/yale/Gate Hinge Assembly.htm

My welder doesn't like the hinge design; thinks its too weak.

I see that maybe using SAE-5 is not smart, so maybe I should purchase Nelson SS studs. Anyone see a problem with this design. I think maybe the real reason the welder doesn't like it is its too hard to fabricate. Anyone have another idea?

 

[evelrod]

I agree as I have done this exactly as you describe. It was a trash bin gate for the Kaiser computer facility. I think it lasted about a year. I'm guessing they went to the FOUR hinge design that was originally indicated until the bean counters got hold of the prints.

Rod

 

[meyco]

You have done this as I have drawn it and it broke? If understood you correctly, what broke; the weld?

 

[civilperson]

The post/hinge connection and the post itself seems under strength. More and bigger bolts on each hinge, more hinges on each post, and beefier post walls, (both width and thickness), is my recommendation.

 

[dvd]

Without the plan view of the hinge it is hard to know what is do-able. If there were no interference with the hinge pin, I would drill and c'sink through the bar that constitutes the hinge leaf. This would allow the flat head screw to be inserted from the opposite side with the hinge leaf material doing all the holding instead of the weld. The weld would on be required for preventing the fastener from turning when tightening the nut.

 

[evelrod]

Yes, it was for all intent and purpose "exactly" as you have drawn it.
First, welding was difficult in the field...we did not have access to TIG, which possibly could have made the welding at least, prettier and failure may have been postponed a bit longer. The failure was in the TS. The original specs were for four hinges and two gates. Someone did not like the looks of two gates and field change to one big gate but never addressed the hinges...That is a guess on my part as I did the "as builts" at a later date and noted the change. My crew did the fabrication and welding which passed the hospitals inspectors review. I only found out about the failure a couple years later because my daughter was a supervisor for Kaiser billing, then using the building.

Rod

 

[MadMango]

Is the 3/4 bolt for leveling the gate? I agree that a thicker wall post may be required, along with more hinge locations. Why all the nuts, washers? Can you just weld a solid steel block to the post and hinge half?

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of these Forums?

 

[meyco]

The gate post is sufficient to support the gate. In fact, according to the fabricators, who are experienced gate builders, the 6x6x.25wall posts are more than adequate. The hinge bolt hole is reinforced with a 2x2 tube as you can see on the drawing. The Elite hinge block is 1.5" thick and a pair of these are adequate to support a gate twice the weight of these gates according to the manufacturer. The normal procedure is to permanently weld the two halves to the gate and post. All of this is fine.

The question has to do with welding the bolt to the block. My experience has always been that welds are stronger than the parts themselves. If that is true, and we achieve full penetration of the weld as shown on the drawing, I don't believe the weld will break before the bolt bends. Am I wrong?

Evelrod: What is "TS"? MagMango: The purpose of the bolt is for adjusting the gate. Speaking with several gate builders, coupled with my own experience, over time, the gates sag, and the posts move requiring a welder to cut the hinges loose, shim and reweld. This is to eliminate that problem. The gate fabricators I have spoke with like the idea of an adjustable hinge.

 

[meyco]

FYI, here is the top view of the hinge and post:

http://www.silverridge.org/yale/Gate Hinge Top View.htm

 

[evelrod]

"tube steel" short hand, sorry. My feeling is the hinge joint failed because the gate was more than twice the weignt of the original design. Also, I can only imagine the added stress that may have been put on the system by the trash trucks, etc. I've not noted those guys possessing a lot of finesse.

You asked if anyone had done this...I never indicated your gate would have a problem. I feel my problem of years ago may have little to do with yours.

Rod