Technical Laying out a fishmouth cut in tubing

Thanks for the picture. With 1 3/4" roll bar tube it worked out real well if the flat was 5/8" across and the depth of the wedge 5/8". A little touch with the grinder to round the corners and it fits right up. Its been 15 years, but if i remember right, the way to cut angles was to draw the angle across the tube. Then measure up at 90* from that line to where 5/8" hits the front and back edges of the tube. Next at the fat part of the tube center a 5/8" line along the first angle line. Then it's connect the dots and cut the wedges, short and fat at the front and long and thin at the back. Minor touch up with the grinder. All we had was a saws-all and a hacksaw. A little playing around will adjust for different tube diameters.

 

You'll only do it once...

LynnW

 

What's your trick for laying out a curve intersecting with a cone?

 

This is the book you want. I've used it for 30 plus years and it makes pattern making simple.Easy to follow step by step instructions. Make t's and laterals at any angle, small pipe to same size or larger pipe.

 

I saw someone burn themselves with a torch, something you never forget. Off to the ER... I've set my pants cuffs on fire welding inside a race car.... what the hell is that I smell...

 

50 is a short sleeve shirt working day in the driveway in NY....

 

pretty cool stuff

 

it all depends, you could hold it and mark it by eye and keep trimming till you sneak up on it
or you just draw it up developing the template. figuring around a cone adds a slope to the lines you draw

 

COLD? In Sierra Vista?

Ben

 

Feels like -3

 

Log scribe. 3d transfer

 

if it isn't at least 70 degrees out, it's cold.

 

eyeball and freehand..?

 

That's Drafting 102, 45 years ago. Sheetmetal man in an old school heating and sheetmetal company could probably do it on auto pilot.

 

We are expecting a lovely 110 degrees today over here.

 

Gotcha!

Ben

 

Eyeball freehand and experience. You asked.

 

I am one of them tool usin' monkeys:

 

Or an overnight low, in San Francisco, in the middle of January.

 

..the problem is it's also a high in August!

 

It’s currently 5 here, yes 5! And this is not bad for Jan!


Sent from my iPhone using H.A.M.B.

 

Well, there is that.