Nees help - Non flame cut hole in 2.5" plate

[Inkomodius]

Its a 6 meter, 12x87 Wide flange with 1" thick 180mmx120 repads on each side of the web with a 75mm hole going through each repad and web. This is a lifting point when all the steel is erected and a 2.75" shackle will be used at this lifting point. We do not have a water jet near us, and from the time we get the prints to the time they get erected we wouldn't have enough time to outsource it and get them back. I know I may not find a solution I am looking for but I will try haha.....
I love engineers.....

 

[mjncad]

That's a manly beam you're working with. No wonder you are using a magnetic drill-press.

OK, since the holes are for lifting the beam; how about just welding on temporary or permanent lifting eyes and be done with it? That way you're not compromising the web of the beam with a large hole, and the eyes can be easily dilled prior to welding onto the beam.

Without seeing the drawings, and knowing the engineer's intent; that's how I would take care of the problem.

 

[Inkomodius]

The lifting points aren't for erection. We are building the steel for pipe rack modules, and once each mod is assembled and loaded with the pipe they are trucked to site and flown in by crane, so the lifting points are for lifting the entire structure and the hole has to be below the top of the column so other mods sit on top and mate to the column. Its an awkward problem.

 

[muddstopper]

I have cut 4in holes in 1 in plate using the lennox's brand of hole saws. I try to do this in a drill press when I can, but have done it with a 1/2hp hand drill. Go slow and use plenty of oil. The tip about drilling a lot of smaller holes around the inside edge of the cut line helps a lot. It gives the chips someplace to go and also helps keep the holesaw from heating up. For a pretty good cutting oil, I have used dextron mixed with water. To me it seems it keeps the bit cutting better so the holes go a little bit faster. In fact, I would like to hear a littl e feed back on others preferred cutting oils.

 

[lostcause]

i'm sure you can't share the drawings due to legal issues, but it would be helpful to see what is going on. i've worked as a steel detailer for the last 2+ decades and i'm wondering why the holes weren't drilled, unless the shop fabricating them is very small? i've seen holes this size and larger in base plates quite frequently. i can see where using a boring head could be tedious, but there might be ways around that. carbide tooling can be (and likes to be) turned much faster than hss tooling - often double the speed. also, when you are dealing with interrupted cuts (what you have when you are transitioning from the plate to the web) a grade of carbide that is meant for cast iron or aluminum will be more forgiving. carbide for steel is harder, but also more brittle. also, watch the feed rate as you switch materials - don't try to dig too deep on an interrupted cut.

 

[Brad_Blazer]

Go back to flame cut with a skilled operator using a circle guide.

 

[lostcause]

Go back to flame cut with a skilled operator using a circle guide.

based on the title of the post, i'm assuming that it isn't allowed. there are steel construction standards that prohibit flame cut holes where bolts are used, and i would assume that this pin condition is the same. even if that isn't the case, the engineer of record is likely to give it a thumbs down and say no way.

 

[Todd727]

Maybe you can get some ideas here: Official Site of The Line Boring Book

 

[Inkomodius]

Yeah its a big negative on the flame cut holes. I am going to pick up a boaring head and see what I can come up with. And as far as the blueprints thats a no go as well. I will try to get a pic next time I do one on my stands and give you a better idea. Thanks for all the help guys!

 

[deereman75]

I would probably try a big, slow t-handle drill, and a hole saw. I have found you can't beat a big t handle with a good length pipe screwed in the handle hole. Keep in mind I have never dealt with holes this big outside the wood shop, really just thinking out loud here. I guess that with how grabby hole saws are, there would be a very high chance of breaking a wrist, or smashing a knee with a drill as torquey as a big t handle.