[Mikeover]

I'm laying out for mitre cuts on 2" square tube, trying to be precise. The issue is how to accurately extend layout lines along the sides of the mitre, since the side is what I'll use to align the tube for sawing. I mark the long point of the mitre, then try to sight along that @ 45 degrees with a combo square to mark the sides. Difficult (for me) as the radiused edges of the tube makes line up fussy at best.

Is there a good, simple way to do this accurately?

Thanks!

[Poland308]

Accuracy depends as much on the ax as the micrmiter.

[LtBadd]

What are you using to make the cut, it's normal that a 45* cut takes more time to line up, depending on the saw you use.

last shop I used a cold saw, and I'd use a 6" straight edge against the blade to show where the cut line would fall on the tube

[homeboy]

Simplest way I've found is mark your long point and use a triangular framers square for 45. The extended flange on the one side will hook on the flat and straddle the radius on the corner of the tube. For other angles a hinged digital angle finder works the same way.

[LanceR]

Look up "speed square" and you'll find what you want. The back on the square will span the corner radius and allow you to lay out the miter accurately. They come in different sizes and in plastic and aluminum.

[Toggatug]

Or there's he lasquare on Jody's site.
I bought one and definitely don't regret it. It's wide base goes behind he radius of tubing and even lots of pipe I've found.

If you can justify the extra money it's definitely a nice square/45 layout tool

Sent from my S60 using Tapatalk

[Mikeover]

And the speed square wins! I thought about cutting a small section of tube @ 45, then removing two adjacent sides, slide the top edge to scribed line then use side edge to mark the true cut line. But didn't proceed along that line of thought yet.

I'm using a abrasive cutoff saw, not the best approach but its what I have. Neighbor has an Evo cutoff saw which IMO is incredibly fast & accurate, and pretty much a joy to use by comparison - but hauling tubing there & back in the snow doesn't much appeal.

Great tip on lining up the blade w/cut mark using a straight edge!

Thanks to all!

[Louie1961]

I am going to take a different approach. I don't think the accuracy of the cut is that critical. What matters is how you lay out the pieces for welding and how you account for the weld metal drawing the pieces out of square. Watch some of Jody's videos on this. If you get it all square and tacked properly, little gaps in the metal won't matter. You just fill them in with weld metal. When I cut metal if it is within a 16th or so, I call it good.

[Mikeover]

I'm OK with a 1/16" gap, depending on the metal, material thickness & weld aesthetics. I'm not OK w/a 1/8" gap though on thin material, so measuring & layout as precisely as called for to minimize error is my goal. Aim small, miss small. The abrasive saw IMO leaves much to be desired as a weld related tool, the "blade" tends to flex & thus wander a bit much, good for parting rebar or such but with all the sparks/smoke/noise attendant with its use I somehow expect more accuracy. Although no doubt some are using it successfully - maybe it's just me?

I do like to clamp as much as possible & tack throughout, thanks for the reminder!

[Poland308]

All abrasive chop saws are pretty much equal when it comes to accuracy. It’s a necessity of the blade material composition, and use.