JasonPAtkins
Hot Rolled
- Joined
- Sep 30, 2010
- Location
- Guinea-Bissau, West Africa
I think my brain may not be running at full capacity this afternoon. This tube (with stub shafts welded into either end) is going to be the central shaft for a trommel sifting rig. Accordingly, it will have support arms screwed to it along its length to support the mesh screen.
In order to get things lined up, I need to get 90 degree marks on the face (end) of the tube, which i'll then transfer down the length of the tube by setting a stout piece of angle iron on the tube. The problem is, I can't figure out how I should be doing this, despite having what seems like plenty of measurement tools available.
First, let me say that what I've got is probably good enough for my application. However, I'm annoyed that I can't figure out the "right" way to do this, if it really mattered that it was perfect, which again, it probably doesn't here.
Starrett center finder gets me the first two marks (call them 0 and 180 degrees), that's easy. However, I can't figure out a way to precisely get the 90 and 270 degree marks. The basic problem is that adding a second tool perpendicular to that first one has one or both of two problems. First, most of the tools (like another combination square) against the blade of the Starrett aren't flat, so their rule doesn't sit against the tube on both sides at once, and since the body of the square isn't small enough to fit into the tube (5.5" OD), they rock. The second problem is that all of them are depending on measuring the center point by eye on the Starrett rule, from which to send the perpendicular rule. So, it's easy to get a pair of points perpendicular to the first two, but I'm not certain they're centered on the hole - so I'm probably marking 88 and 272 degrees instead of 90/270 by being a little high, or 92 and 268 degrees by being a little low. I also tried using the framing square against the Starrett, which is flat, but still depends on me eyeballing the center point on the Starrett rule for vertical position.
Am I missing an easy solution here? I also can't understand why I wasn't able to find a technique for this on google. Is it so obvious to everyone else that it didn't even need to be explained?
In order to get things lined up, I need to get 90 degree marks on the face (end) of the tube, which i'll then transfer down the length of the tube by setting a stout piece of angle iron on the tube. The problem is, I can't figure out how I should be doing this, despite having what seems like plenty of measurement tools available.
First, let me say that what I've got is probably good enough for my application. However, I'm annoyed that I can't figure out the "right" way to do this, if it really mattered that it was perfect, which again, it probably doesn't here.
Starrett center finder gets me the first two marks (call them 0 and 180 degrees), that's easy. However, I can't figure out a way to precisely get the 90 and 270 degree marks. The basic problem is that adding a second tool perpendicular to that first one has one or both of two problems. First, most of the tools (like another combination square) against the blade of the Starrett aren't flat, so their rule doesn't sit against the tube on both sides at once, and since the body of the square isn't small enough to fit into the tube (5.5" OD), they rock. The second problem is that all of them are depending on measuring the center point by eye on the Starrett rule, from which to send the perpendicular rule. So, it's easy to get a pair of points perpendicular to the first two, but I'm not certain they're centered on the hole - so I'm probably marking 88 and 272 degrees instead of 90/270 by being a little high, or 92 and 268 degrees by being a little low. I also tried using the framing square against the Starrett, which is flat, but still depends on me eyeballing the center point on the Starrett rule for vertical position.
Am I missing an easy solution here? I also can't understand why I wasn't able to find a technique for this on google. Is it so obvious to everyone else that it didn't even need to be explained?