Recent content by DTM

Thanks everyone for the replies. So it sounds like the only spec we know, ANSI/ASME B1.2 states that the NOT GO (Hi) thread plug gage may not enter more than 3 complete turns. My question to any of you reading this post is: HOW DOES THIS MAKE ANY SENSE? The common rule of thumb for fasteners...

After over 25 years of engineering, designing and analyzing bolted joints, I just learned this little fact. According to ASME B1.2, Gages and Gaging for Unified Inch Screw Threads: "The no-go gage should not pass over more than three complete turns when inserted into the internal thread of the...

Our company has made our own shaft keys for many years, grinding them on the 4 loaded surfaces. For example, let's say the pulley and shaft key seats are .5005 +/- .0005 wide. We've made ground keys that are .4995+/- .0002 with a flatness of .0004. We now are considering purchasing keys with a...

So differences in principal stresses is what makes ductile metals fail. That does make some sense and is somewhat intuitive. Thank you.

The formula for von Mises stress for a plane stress (2d) condition with no shear stress is: So if S1 = 1000, S2 = 0 , then Svm = 1000. If the S2 is now increased from 0 to 500. The von Mises stress will go from 1000 to 866 I understand this is how the equation works, but can someone give me...

Interesting thoughts. We'll have some discussions EHS and the assembly department.

Very good point. The caster may be the weak point. We may need to test one to see what kind of load causes failure and what that failure looks like. Thank you.

I like this analysis, and I can see if the rear of the cart did hop up, that would be one way of dissipating the kinetic energy over a longer period of time and lowering the impact load. However, the exact geometry of this cart/machine is actually lower than shown in the sketch and I think this...

Looking at this line of thinking, and putting these equations into a spreadsheet, I've come across a common engineering dilemma regarding impacts. The stronger you make it, the stiffer it is, the higher force of the impact, and the stronger it needs to be. I've come to the conclusion that...

The machine on the cart is about 4.5 feet tall. If someone is moving it from the assembly department to the shipping department, I can see them accidently hitting something low on the ground. For example if they are going around a building column and cut it too close. They're usually pretty...

The machine is complicated, but pretty robust. It's been tipped over on it's side (about a 4 foot fall) by shippers and survived. So I think it could handle a 2g shock load pretty easily. But the bumpers is not a bad idea. As for pushing around 3,000 lbs machine, we do it by hand all day...

Yes. Agreed, the cart must be elastic as it can't stop instantly or that would take infinite force. The cart would actually not be too hard to calculate the elasticity of, but the part ON the cart (The 3000 lbs load) is actually a complicated machine that I think might be very difficult to...

I would say worst case, I imagine they could hit a step in the foundation around a building column. I would say that is easily 10x more ridged than the cart and load. So for the purpose of calculations we can assume the thing they hit is immovable, and the cart and load will stretch/flex as it...

I'm designing a cart holding a 3,000 lbs load that will be pushed around the shop floor. One structural load I am concerned about is if the operator pushes the cart into a rigid stop, how much load will that impart to the cart? I realize calculating the g-load is a very complicated problem...

Very good analogy. Thanks DaveC.