# Quick project, I need a 1/2 ton portable gantry for tomorrow.



## Ben-NSW-au (Sep 8, 2015)

There is a little afternoon project, turning this pile of steel and a 12v winch into a portable gantry that I can take apart and transport in my ute. It has to be able to lift a pianola onto the back of the ute.










I'll post tomorrow what I'll come up with.


----------



## Hoodoo Valley (Nov 14, 2006)

Well this out to be an interesting build!


----------



## Ben-NSW-au (Sep 8, 2015)

The only thing I'm not sure about is the ability of the 4" 1/2 diameter, 3/16 wall pipe to handle the 750lb hanging in the middle of a 6' span (will be braced, probably at 2' from the ends)

I don't have the knowledge needed to calculate that so I'll do a rating test at 1 ton (or more if the rig doesn't flex) and put a clear signe "No overhead lifting" on it


----------



## Hoodoo Valley (Nov 14, 2006)

Ben-NSW-au said:


> The only thing I'm not sure about is the ability of the 4" 1/2 diameter, 3/16 wall pipe to handle the 750lb hanging in the middle of a 6' span (will be braced, probably at 2' from the ends)
> 
> I don't have the knowledge needed to calculate that so I'll do a rating test at 1 ton (or more if the rig doesn't flex) and put a clear signe "No overhead lifting" on it


I've found them to be somewhat stuffy, but there are many engineering forums that would help you out with those calculations.


----------



## Ben-NSW-au (Sep 8, 2015)

Thanks for the advice but I think I'll stick to the empirical method for today. I'm expecting the answer of an engineering forum to be something like
"Seen that this situation may endanger someone's health or life, we can not give you a formal answer to your question. 
But we can give you the formula to calculate the young's modulus, stress, ... of this particular pipe at a particular point, ... at the condition that you have the apparatus to measure the actual strength of this particular bit of steel..."
No offense to the engineers, I'd like to go back to school and do that.

I'll get a course one day about the calculations involved in structural designs.


Edit:

Just to make things clear, I am not criticizing the engineers. I know that there are too many parameters to answer whether or not it is going to hold, especially where one's safety could be compromised by a failure. We are not talking about dropping a hammer on your little toe.


----------



## Ben-NSW-au (Sep 8, 2015)

First leg put together (just need to weld the bracket at the top for the beam)










And disassembled:


----------



## Ben-NSW-au (Sep 8, 2015)

Well, it worked quite alright. I just have a little improvement to make and eventually paint it one day.
It took me about 3 hours to make it and it take about 4 minutes to put it together and I can lift up to 8'

I he'd trouble putting photos on yesterday but I'll try again this evening.


----------



## Ben-NSW-au (Sep 8, 2015)

I finally got the photos working. Here it is in action. I didn't put the bracing on because I forgot them home but it's light lifting anyway.
I just need to make some pins to hold the legs together if I want to move it. And a "no overhead lifting" in case someone else was ever using it. 










It makes working alone a lot better. The only"flaw" is that, being high, it's not easy to lift into position. There is room for improvement.


Edit : 

And once the job is done :


----------



## Hoodoo Valley (Nov 14, 2006)

Nicely done Ben! I like it!


----------



## Ben-NSW-au (Sep 8, 2015)

Thanks! I just got an idea to make it easier to lift into position. I'll post back when it's all finished.

I also ditched the electric winch and used a chain and tackle block instead simply because it's not always practical to feed the winch 12v 20A


----------

