Technical A question for the garage tool making gurus

A tree limb makes a wonderful pry bar if you are stuck in the middle of nowhere depending on what it is you need to pry on.

 

As I recall, in years gone by KD tools was mighty partial to making their tools out of laminated steel strips riveted together. Nary a forging to be seen. The plies were always oriented parallel to the load.

Nowadays Sears seems to be the only proponent/hold out with their RoboGrip line.
https://cdn.protoolreviews.com/wp-content/uploads/2013/04/clench-wrench-angled.jpg

 

May knot be.

 

Instead of bolting there are some good epoxies out there.

 

Even if it would work save yourself some time and find a good steel supplier with a good drop pile. I'm not sure how I would get through life without my supplier and you never know what you will find. I enjoy going there and usually bring home more than I plan on getting.

 

For a sheetmetal lever, I would make the cross section look like this.


C's or U's
the corners will help keep it from buckling.

 

Lol, i tried that once, be sure the rope pieces your using is strong enough to hold your weight. You'll end up getting out the window, but it could be a REAL fast descent...lol

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These are the kinda tools I've based my idea on. Not saying they are superior, ive always thought it was a cheep way of making something... usually a cheaper tool like a yucky know no lol


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Yeah I was considering that also

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Nice idea, i might try that also

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So heres what i ended up with. I havent bolted it together yet, but i will when i get back out there

Herschel

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That last pic does kinda look like a sword

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How long is a rope?

 

Usually about a foot shorter then what I need...lol

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Your rolled sheet metal will hold up to some pry/leverage, but probably only to about 1/3 or less then what a solid bar would be. The weak point is the loose ends at the sides of each loop. The only strength you will have will be about equal to the width of the metal that is solid at the center. Drilling holes would weaken this "tool" even if the holes were used for bolts or rivets (unless the bolts/rivets could be forced through the holes without leaving a gap around the hole) because it will reduce the core strength and would create a place for the core to collapse (and bend) along its length. Filling to voids would only be as strong as the substance you are filling it gap with. Once you reach the breaking point of the fill material, it will not add any strength to the "tool".

Had you have bent the sheet metal like covered earlier (into the channels and held close tolerances the sheet metal would have been stronger then the rolled metal of the same thickness. Even a group of L or V shape sheet metal would have been stronger then the rolled metal, if you could find a way to attach them all together without drilling holes. Four 1/8" bars laid flat against each other would have been stronger then the sheet metal and two 1/4" bars laid flat against each other would have been stronger the the four 1/8" bars, but none of it would be as strong as a 1/2" bar. If the thinner bars were to be welded into a "T" the resistance towards bending would have been stronger then the same size bars laid flat against themselves.

The length of the lever has more effect on the amount of strength required to resist bending then the power doing the lifting/prying. Gene

 

Gimpy, as an engineer, you should know that the length of a rope is 2x the distance from the center of the rope to one end.

vic

 

Thank you Gene,
As luck might have it I was already started on folding the sheet when the neater way was posted. I do like that idea and will give it a try too. It's hard to see in the pic but the center of the folds were really pretty tight, and as the "bar" got thicker it was harder to hold tightly onto it while i hammered and the sides opened up...bummer... im thinking i might take it to work,where i can use a press to really flatten it before i fasten it together. I don't have high expectations for it's strength... although at the worst i think i proved to myself why i should probably upgrade my sheetmetal brake...lol

Herschel



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As to your riveting question there are formulas to calculate how many rivets per inch depending on your base material, the rivet type & diameter and rivet material. Check the aircraft industry, they have books on riveting.

 

Cool, thanks. Didn't know that

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I always forget that, for some reason. I should put it on a sticky note.