Bridge Crane build

The spring loaded pin ejects the slug also, I love annular cutters.
 
Aukai said:
The spring loaded pin ejects the slug also, I love annular cutters.
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I was hit an miss on whether the pin worked to eject the slug, had to pick a few out. I didn't buy the highest quality set of cutters, so that may be part of the reason.
 
Mine will jam on occasion too.
 
rabler said:
As I mentioned to @woodchucker above, I purchased a mag drill to drill the beams. At 40 ft long, no way to maneuver them into a drill press ;)
First time I've used a mag drill or annular cutters. This certainly made easy work of drilling these 11/16" holes. One lesson I quickly learned, pecking with annular cutters doesn't work, as the chips lodge under the cutter in the circular grove. Better to just keep drilling steadily.

The mag drill, a Fein JHM shortslugger, has a small tank on the far side with a coolant feed down the inside of the cutter. A spring loaded pin, sort of like a tap follower, helps center the cutter. This drill has a "safety" feature that doesn't allow the motor to be turned on unless it is on at least 3/8" plate. These beams were not of sufficient thickness (W10x12), although the magnet held well enough. They include a jumper that you can place on the internal circuit board to bypass this safety feature. Would seem to me that a lower threshold would make more sense, as the safety feature would shut the drill off if it comes off the beam. Makes me wonder if it is more of a feature meant to reduce their liability?
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I don't understand the pin , it has no cutting edge right? So how does it keep it centered; just from the dimple of a center punch? I just thought it was for alignment and ejection.

I didn't know that about chip ejection good to know. I don't have/need one at this point. But if the need ever arises. Long ago when I finished my basement , I tried drilling the beams, but found it too difficult, I made no headway. So instead I used powder charges to drive concrete fasteners into the metal. I was putting up metal studs. It worked. If I had the mag drill, I would have put in bolts so it would have been removable at some point.
 
Now that you're at (past?) the point drilling the beams, it occurred to me how important it is to get accurate dimensions of the upright spacings. I'd be interested in reading about the process you used to get the uprights plumb (and tops level) as well as how you measured the hole-to-hole spacing between the installed uprights.

I have a faint memory about setting the upright base plates on nuts (on the J-bolts) for adjustment of plumb and height and then grouting after beam assembly. However, I'm not sure if that faint memory is from your project, somebody else's or my imagination.

Living vicariously. :)
 
woodchucker said:
I don't understand the pin , it has no cutting edge right? So how does it keep it centered; just from the dimple of a center punch? I just thought it was for alignment and ejection.
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Correct, Alignment and ejection only, just to get it set up on a drill center point before turning the magnet on. Otherwise you'd need to mark a circle on the beam and align the outside of the cutter to that circle.
 
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extropic said:
Now that you're at (past?) the point drilling the beams, it occurred to me how important it is to get accurate dimensions of the upright spacings. I'd be interested in reading about the process you used to get the uprights plumb (and tops level) as well as how you measured the hole-to-hole spacing between the installed uprights.

I have a faint memory about setting the upright base plates on nuts (on the J-bolts) for adjustment of plumb and height and then grouting after beam assembly. However, I'm not sure if that faint memory is from your project, somebody else's or my imagination.

Living vicariously. :)
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The uprights are not rigidly set at this point, so just drill on the same distance on the beams as the plates are spaced on the floor.

Hanging the beams will require supporting them safely until the entire thing is assembled with the corresponding cross bracing.
 
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rabler said:
The uprights are not rigidly set at this point, so just drill on the same distance on the beams as the plates are spaced on the floor.

Hanging the beams will require supporting them safely until the entire thing is assembled with the corresponding cross bracing.
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I was obviously imagining a very different approach. LOL
When you say "as the plates are spaced on the floor" do you mean where they will be placed or are base plates already fixed to the floor (uprights to be welded to base plates later)?
 
extropic said:
I was obviously imagining a very different approach. LOL
When you say "as the plates are spaced on the floor" do you mean where they will be placed or are base plates already fixed to the floor (uprights to be welded to base plates later)?
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The uprights are already fabbed with top and bottom plate, and mounted on the studs in the floor. I just need to bolt through the top plate into the overhead rail/beam. The bottom plate has 4 holes, with the j-bolts through those holes, and a nut on either side of the plate. Those nuts can easily be loosened to allow the upright to move around a bit.
 
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