Scribing a cylinder

Kgaijin · Post by **Kgaijin** » Thu May 17, 2007 7:57 am

Wishing for some sage advice. I am attempting my first scratchbuild and this will probably not be my first post on this journey. The main body of my model is a 7.62cm cylinder with an approximate 22cm circumference. I need to scribe seams on the body to simulate seams, like 3 or 4 cylinder sections joined and riveted. Without a lathe, what would be my best bet to accomplish this?

Johnnycrash · Post by **Johnnycrash** » Thu May 17, 2007 9:30 am

Measure out the lines to be scribed from the top or bottom. Do this several times around the cylinder, at least in six spots. Use black electrical tape, wrap it around the cylinder with one edge lined up on your marks. Use this tape to guide the back of a #11 Xacto blade. Scribe away. The reason for the electrical tape is that it is thicker, and will be less prone to allowing the knife to hop in the wrong directions. Use light pressure, almost none for your first pass.

elmas · Post by **elmas** » Thu May 17, 2007 9:35 am

You can also use labeling tape. The kind you use in the manual press little machine. Available at your local office supply store.

elmas · Post by **elmas** » Thu May 17, 2007 9:37 am

You can also use labeling tape. The kind you use in the manual press little machine. Available at your local office supply store.

http://www.officedepot.com/ddSKU.do?level=SK&id=475544

Post by **TER-OR** » Thu May 17, 2007 9:04 pm

A height guage is a good way to go, too.

Warped Speedster · Post by **Warped Speedster** » Fri May 18, 2007 5:21 am

For cutting around the cylinder's radius I usually set the cylinder on its end on a flat surface and spin it by hand, and let the scribing tool cut around it. (obviously the cylinder's end has to be straight and true and square) Stack up spacers to get your scribing tool up to where you want the cuts to be. You can then hold your scriber in place easy enough to gently make the cut. If you're working with a straight and true cylinder this method will give a perfect straight cut just like using a lathe.

For lengthwise (north south) lines you may want to use a piece of angled metal to lay against the cylinder as a scribing guide. This method works really good. Again, if your cylinder is true and straight, your scribes will be too.

I use 1"x1"x6" long angled aluminum. Or whatever size and length you need to fit up against the size cylinder you're using.

Side note: Aluminum is sorta bright and the glare can make it hard to see marks and lines on your project when you set the angle next to a mark to be scribed. So you may want to spray paint the aluminum black to cut the glare down. I just put black electrical tape on the aluminum's edge.

Go SLOW SLOW SLOW, and use your close-up glasses and have a lotta light when scribing, it really helps.

I'm doing a cylindrical design too right now.

Good luck.

Warped Speedster · Post by **Warped Speedster** » Fri May 18, 2007 6:58 am

Just to expound a bit on the above mentioned scribing method. There was a discussion on this subject a few years ago. I figured I might as well touch on it again since someone has asked about scribing cylinders.

I mess around a lot with cylindrical shapes. I do a lot of cutting using X-acto blades superglued to short pieces of 1/4" evegreen strip (of various thicknesses). I usually cut a strip about three inches long as a "scribing handle" and as a "height gage." The blade's tip just extends out past the end of the strip about a quarter inch. The thickness of the strip depends on how tall the cut needs to be as I scribe around the cylinder wall. The flat surface of the evergreen strip lets it rest squarely on whatever spacers I'm also using to add to the desired height of the cut on the cylinder. (If you use spacers, use some big enough to be stable and wobble free) Then just spin and cut.

Again, this method works well if the tubes and cylinders you're using are true with straight ends. If they're not straight, just go ahead a get em straight,

it's worth it. It does give a lathe like accuracy to the scribing, and you can very easily duplicate the width of your cuts this way too.

Lt. Z0mBe · Post by **Lt. Z0mBe** » Sat May 19, 2007 10:07 pm

I had the same issue a few months ago when scratchbuilding propeller hubs. Here's what I did (some sage here told me

).

Get a big, thick book and place a hobby knife blade between the pages at the desired height, and close the book with the hobby knife blade sticking out. Place a heavy weight on the book or just press down on it very hard.

Butt the cylinder up against the blade and slowly rotate the cylinder to scribe the line at the desired height. When finished, move the blade to another height and scribe again.

I hope this helps.

Kenny

Mr. Badwrench · Post by **Mr. Badwrench** » Sat May 19, 2007 10:38 pm

Here is the method that ZomBe describes. I'm not too fond of it myself, but it works in a pinch.

Kgaijin · Post by **Kgaijin** » Sun Jun 03, 2007 8:56 am

Mr. Badwrench, amusingly, I am using that exact same plastic ornament dome in my project pictured in the link you posted, but I will be scribing pvc and not the dome. Nevertheless, that method may be ideal for what I am doing. I will have to assess all of the ways described in the above threads, thank you all for helping. Now, I just need the time to make some serious progress on this...