Bridge Crane build

rabler said:
The uprights are already fabbed with top and bottom plate, and mounted on the studs in the floor.
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That's what precipitated my original question.
"The uprights are not rigidly set at this point".
Hmmm?
Clearance holes? Precisely level concrete? Precisely parallel plates, precisely perpendicular to the posts?

More specifically, I'm wondering what your plan is to accommodate tolerances. I hope you'll be clear about it as the project progresses.
 
extropic said:
That's what precipitated my original question.
"The uprights are not rigidly set at this point".
Hmmm?
Clearance holes? Precisely level concrete? Precisely parallel plates, precisely perpendicular to the posts?

More specifically, I'm wondering what your plan is to accommodate tolerances. I hope you'll be clear about it as the project progresses.
Click to expand...
The posts are not yet grouted.

IMG_4987.JPG

The holes in the beam are drilled 11/16" for a 5/8" bolt, so there is tolerance for deviation in the 4-bolt plate and mag drill layout. The plates were drilled using the DRO on the mill so they're accurate to within a few thou, the tolerances on the mag drilling will be slightly sloppier.
 
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Just a suggestion, bolt everything together before tighten all the bolts. This allows some wiggle room while assembling. Also use A325 structural bolts and washers and then torque to spec. of the bolts size used.
 
aliva said:
Also use A325 structural bolts and washers and then torque to spec. of the bolts size used.
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Just curious, why the A325 vs. grade 5, or A490 or grade 8?
 
The company I retired from had a construction dept. which I was part of for 9 years. We did a lot structural steel erection. Our engineers specified 3/4" A325 bolts and washers. The torque was in 350-425ft/lb range. This was back in 2003 2004. Things have since changed. A490 has a higher torque depending on weather it's dry or lubricated. We never lubed the A325 bolts.
Below is a quote from Portland Bolt and manufacturing website.

"In 2016, ASTM A325 was officially withdrawn and replaced by ASTM F3125, in which A325 now becomes a grade under the F3125 specification. The F3125 specification is a consolidation and replacement of six ASTM standards, including; A325, A325M, A490, A490M, F1852, and F2280."

So A490 and A325 seem to be the same so either would be acceptable in my opinion.
Grade 5 wouldn't meet the specs, it also has a longer thread length. Structural bolts have a shorter thread length ,the bolt head and nut are larger than the standard 3/4" bolt I believe they are 1-1/6
You've gone to a lot of trouble to build this so don't skip on the bolts.

www.portlandbolt.com

Specifications - Portland Bolt

Summaries of technical information on common ASTM Specifications used in the construction fastener industry.
www.portlandbolt.com www.portlandbolt.com

Also once you've leveled the post base plate, build a wooden form around the base and fill with non shrink grout to the top of the plate
Be sure to add a piece of wood on the inside of the form to taper the edges around the form to create a sloped edge, this reduces chipping of the grout edge.
 
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aliva said:
So A490 and A325 seem to be the same so either would be acceptable in my opinion.
Grade 5 wouldn't meet the specs, it also has a longer thread length. Structural bolts have a shorter thread length ,the bolt head and nut are larger than the standard 3/4" bolt I believe they are 1-1/6
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I'm agreeing, certainly use the right bolt! I would never suggest skimping on something like this!

However, I would disagree that the A490 or A325 are the same. One is a 170ksi UTS bolt and the other is 120ksi UTS.
Grade 8 or grade 5 SAE J429 bolts are also 170ksi UTS and 120ksi UTS respectively also.

Head size not withstanding, the a A490 is specified similarly to a SAE Grade 8, in proof load, UTS, and yield strength. The A325 is again analogous to a Grade 5.

www.portlandbolt.com

Fastener Identification Markings - Portland Bolt

Information regarding the head markings on bolts manufactured by Portland Bolt. This is broken down by grade based on the specification of the fastener.
www.portlandbolt.com www.portlandbolt.com

I'm genuinely curious as to why in this application an A325 or A490 would be preferred over an a SAE Grade 5 or Grade 8 bolt. Not that it matters here, but the SAE grades in many instances have tighter tolerances. As far as I can tell, the difference in specification is simply use case: Structural steel (F3125) vs. Machine building (J429), etc.

Again, not disagreeing. Just trying to understand why one would be chosen over the other.

(For example, around here grade 5 and 8 hardware are available by the pound in stock. The other stuff is a minimum order shipped in. For the cost difference, grade 5 hardware can be upsized and still be had the same day.)
 
sorry to hear about this Randal, I hope you recover soon.
 
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