Pin size for shop press

[bgaidan]

I've been out of the books for too long and can't remember this shit...

I building a shop press and have some 1" grade 50 (50 ksi) steel rod that I was thinking about using for the support pins.

Can anyone quickly run through the calcs. for shear in this application?

[bgaidan]

NM...found the formula i was looking for.

Looks like it's good for 23.5k in single shear. Not sure if this would be considered double since it's going through the web of a 6" chanel. Assuming single shear x 4 joints it's good for ~94k pounds. Should be ok for the HF 40 ton jack.

[76scoutman]

I believe the pins would be in double shear since you have the 2 webs on either end and the press cross bar trying to go the opposite direction.

[braxton357]

Shear strength=60% of ultimate tensile strength. 50kpsi is pretty weak if that is the tensile strength...g8 bolts are rated at 150kpsi. (1"/2)^2x3.14=.785sqin x30,000psi=23550 x2 if in double shear. So shear strenght would be 47100lb. Compare that to a 1" bolt's 141,300lb. Go to fastenal and buy some g8 bolts. Though, I don't know how you're building your press so it could work.

[bgaidan]

My thought behind this is that I'd rather have a little flex or deformation using a lower grade than a catastrophic failure w/ something like grade 8.

You're getting ~ the same numbers I got, I just went about it a little different way w/ the double shear vs. non. Either way, it's 47k on either side so combined 94k. If the HF jack does indeed make 40 tons I *should* be ok assuming evenly distributed press @ 40k on each pin.

[ReadyMix]

You would have a catastrophic failure with that before the G8 even started to strain....

Why is that myth still floating around interweb. It's a retarded and dangerous way to go about life.