Recent content by vbk

Thanks for all the help. I misspoke about the threaded hole being in 1/4" thick steel, it's in 1/2" so not great but better. Today I torqued these to about 200 ft*lbs. I have them in small patterns of 4 screws loaded in shear with about 7500 lbs of shear force on each group of 4.

thanks. Yes, that's a theory i often use when fastening fairly thin flanges with large moment loads. The situation here is that some of this was designed by another engineer & now it's left to me to recommend torques on the screws.

Hello, I'm specifying torque values for screws on a steel assembly (using standard torque tables). For some, i reduced the torque values where the screws are large relative to the materials being clamped & the holes threaded, e.g., when a 3/4" bolt is clamping a 1/4" thick steel plate to a 1/4"...

Thanks Mike, Another detail that makes this tough is that I'm planning to have the potential to hinge this open so discrete plastic pins are more attractive. The speed will be ~2 rpm & the torque will be ~200 ft*lbs. VBK

Hello, I'm attempting to design an all-plastic, low speed 2' dia rolling cylinder. This is a 1-of-a-kind & I want to drive it by way of roller pins instead of involute machining. I'm curious if anyone can shed light on how i should handle the tooth profile geometry. An example is Nexen group's...

Thanks btrueblood, I'll check out the site & seek their guidance. I see McMaster has some but they say they're not intended for a lot of cycles.

Hi, I'm looking to design a piping system for about 4 coolant lines (3" dia each) carrying ethylene glycol to a shelter resting on an Azimuth turntable. Because the turntable will need less than 3/4 of a rotation, I want to stack 4 swivel fittings over the center of rotation. The expected...

I have a slipping HTD timing belt. We use custom length endless timing belts that we can't get in neoprene. We've found the polyurethane more subject to slippage/climbing teeth. I sprayed some aerosol glue & it seems to help. Is this common practice or is there anything better? Thanks, VBK

Thanks for all the input. I think I have a pretty clear picture. I'll try to weigh these factors each time.

Thanks, Since this is an antenna measurement application & geometric bulk is undesirable, I'm leaning toward steel, at least for the vertical section. We've made variations on this in the past with heavier & lighter loads. Typically we use sandwich type steel construction with channels or...

I'm comparing the merits of using steel versus aluminum for an L-bracket. It is to be mounted on a motorized turntable oriented perpendicular to the ground. It'll be about 5' x 6' & have about 300 lbs at the end. Although I can use cntr-weight, I prefer to minimize it. Deflection is my main...