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Hi, I am simply looking for a resource to look up the Maximum Allowable Stem Torque (MAST). We use stainless steel round bar with ACME threads cut into it. I know the MAST will vary depending on the exact configuration of thread but unless I am misunderstanding something, I believe these would...

Hi again, I have a follow up question. Our gate valves normally operate with the stem being under compression forces to seat the door.In some cases, we build the valves like weir gates (open downward). This means the weight of the door will allow the door to freely open and when closing, the...

Hi Again, We needed this answer ASAP so we contacted our engineer and he confirmed that we had been calculating this right all along. Ill leave this post up in case anybody else ever wonders the same thing.

Hi, We manufacture slide gate valves which are operated by a stainless steel (304) round bar stem. Since I have started this job, I have been calculating the slenderness ration by taking the round bar diameter and dividing it by 4, then multiplying this number by the specified maximum...

LittleInch If the weakest link in my stem has something to do with the threads then what you have sent me probably has the answer somewhere in there. I do not have the time to give it my full attention right now but I did take a few minutes to quickly read some sections which resulted in myself...

MJCronin, I agree with your opinion. Yes we are aware of our competitors stem diameters and we are definitely the largest. We do require far more torque than other slide gates to operate to begin with. This may not lead to any savings at all, but at least we will have some mathematical reasons...

LittleInch, From your response, It seems like I was doing my math right however as you say these may not be the limiting factors in this whole scenario. If the first thing to fail during gate operation is the threads because of a bending or shear force created by applying force to the threads...

Unless I am missing something, I feel like this should be a fairly easy calculation if you know the numbers to use. Please look at this example and tell me what diameter of stainless steel (304) round bar could handle these forces. Thrust required to operate gate = 5,726 Lbs Torque = 93 ft/lbs...

"LittleInch" Thanks for the response. I think you are understanding what I am trying to get at. In the end I will most likely be adding an additional safety factor to my calculated stem diameter however I still need to calculate that diameter. If I could just get someone to tell me a formula...

Hi All, I must say I truly do appreciate anybody willing to help me with this however I feel like I may have lead everybody down the wrong path. I should never have mentioned any sort of economic value for a spreadsheet to dictate our stem diameter. Ensuring we have at least the minimum...

Hi, I appreciate any input I can get on this however, I have done all other necessary calculations for thrust and torque based off a maximum rim pull of 40ft/lbs. I only require assistance for putting together a spreadsheet that will spit out the stem diameter required to receive these forces.

Mike, Thank you for posting. Your assumptions are correct in some cases however you'd be surprised how often the stem weight meets or exceeds the valve weight. The machining costs also add quite a deal to the associated stem costs. Also, economics is not the only reason. There is also a chance...

Hi, I am brand new to this forum and this is my first post so please bear with me! I work for a company that manufactures gate valves. These are not exactly your typical gate valves but for my purposes I don't think it will change anything. I have been tasked with creating a spreadsheet to...