Hi, I\'m in the middle of a mechE lab designing a wrench, and I\'m trying to fig

Question

Hi, I'm in the middle of a mechE lab designing a wrench, and I'm trying to figure out one calculation for the wrench. I don't need exact answers, (i didn't even provide any dimensions to start), I just need someone to help point me in the right direction towards solving the problem.

Consider the case in which the wrench is used to tighten a nut and bolt to a torque of 50 ft-lbs. Using methods of statics, calculate (i) the force that must be applied to the handle, and (ii) the magnitude of the two forces produced at opposite corners of the hexagonal bolt head. Include all calculations, and follow the same guidelines as you do in completing your homework.

for i) I know that the sum of moments must be 0, so that means 50ft-lb*d1 = (Force applied) *d2 if i sum the moments about the center, where d1 = distance from nut, and d2 = center to handle where i'm applying the force. But here's where i get confused, what exactly would d1 be? The bolt is hexagonal, and the wrench is 3d. So that means there is actually a whole plane of contact between the bolt and the jaw of the wrench. Should i use d1 as the center to the center of the bolt? would that mean i need to use Torques = force x area?

Thanks for considering, I know it's a handful to read, especially since i didn't include any useful numbers. I really want to figure this out on my own, and just need a slight shove in the right direction

Explanation / Answer

You could do all of it on a 4axis cnc lathe in about minute. You could use a 4 axis cnc mill in about 2 Looks like you could cast them then finish with milling the slot Could be done a manual machines. Main cost would be programming time and setup of the machine. As for the material it could be anything. IF i had to guess one would cost you 100 bucks (that's what i would charge you) then the price would start dropping. maybe 2-3 bucks if you started making them in the thousands. ******** For got to answer the design part. You really don't need much this is very simple all you need is a basic layout anyone could draw this up in solidworks,autocad in about 5 minutes. All they need is basic blueprint with dimension. Looks like you could get all the information in two views. One of the side. With the length and width and one of the front to say how wide the slots should be cut. You could go to any machine shop and have this tool made.

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