Cutting Paterns for Sink Tubes

[Jagahati]

WALL OF TEXT VERSION

Hey guys.

Don't know if anyone else had run into this problem before.

Basically I draw out my shroud designs on a piece of graph paper and then wrap that around the sink tube I plan to cut up and use it as a pattern.

The problem with doing it this way is a problem of angles on rounded surfaces. A 45 Degree angle on the pattern turns into a sloping and curved cut when translated onto the 3 dimensional surface of the tube.

While this look may be OK if it is what you are after it is not desirable if you want to make nice clean angled cuts like those on some MHS pieces or like is done on the traditional Vader Saber.

It seems that the normal way to accomplish these cuts is to just use a miter box and a hack saw. While this works I was after a more controllable and more easily planned effect. That way I can plan the whole thing on graph paper and make a graph paper or card stock mock-up of the piece before i start cutting. This way I get a better feel for what I am doing before I do it and can more easily plan for things like screw holes switch locations cut-out sections etc.

At first I was trying to freehand these curves with relatively good results but not as crisp and precise as I would have liked.

Then after quite a bit of looking and trying to make my brain remember the math I am sure is involved in this problem I stumbled upon this:

Tube coping Calculator

If i set diameter of the second pipe to as large as it will go (10") then i get a very neat very precise pattern for cutting the sink tube with my Dremel to get the desired effect.

This works well IMO. does anyone else have a better or easier solution (that doesn't involve owning a C&C Mill and $1000 CAD software)?

Hope this helps somebody else.

TLDR VERSION

Check the link out. This lets you make 2d patterns for 3d cuts that look nice.

Tube Coping Calculator

[Jagahati]

Here are some examples to help you better understand what this little web widget does.

These are easily usable for sink tubes. And if anyone would like the properly scaled PDF images and can't figure out how to do them on the site just let me know and I can post those too or send them out to those who need them.

Examples:

[Sairon]

Great find, although the old graph paper and protractor work great too.

[Jagahati]

Great find, although the old graph paper and protractor work great too.

Sure for 2D images protractor is fine. But they don't remain straight lines when put on a 3D round sink tube.

[Sairon]

True, then you just copy the same thing on the opposite side onto the paper just like the tubing calculator alreadt does.

[Jedi-Loreen]

I've never really had any problems using graph paper.

I did this saber 7 years ago using that method:

[Jagahati]

yes you can do it that way Loreen. However see how you get a curved result when you view it from the side?

What if you want it to look like this?

45 degree blade holder

To do that the pattern must be curved so that the result is a straight line when viewed from the side.

The site I link to lets you make the pattern that ends out with a flat edge instead of the curved pointed one.

That is why I thought this was important enough to post.

[Sairon]

And it is a great find, I was just restating a older more common template. and you always could cut sinktubes with the saw blade on an angle.

[LordCyric]

yes you can do it that way Loreen. However see how you get a curved result when you view it from the side?

What if you want it to look like this?

45 degree blade holder

To do that the pattern must be curved so that the result is a straight line when viewed from the side.

The site I link to lets you make the pattern that ends out with a flat edge instead of the curved pointed one.

That is why I thought this was important enough to post.

Or, you could use a Metal cutting disc on your Compound miter Saw and not need a design drawn.

[Jagahati]

Yes you can. I just prefer to be able to plan out the entire build in mock-up so that I can solve most of the unforeseen problems before I have destroyed a couple of sink tubes or MHS pieces with inaccurate or unneeded cuts.

Maybe it is as worthless as you all seem to think but I thought it was a neat find.