Dasco Pro 1405 Giant Circle Beam Compass with Rod, 12-Inch

This beam compass includes a fiberglass beam about a foot long, but you can use the trammel points on any 1/2" dowel or round stock to make larger arcs. So for maybe a total of $15 for this kit and a couple dollars at the hardware store for a dowel, you can easily draw 3ft arcs or 6ft circles. I find it to be easier, more reliable and more accurate than using string on a pencil to mark a large curve. The marking trammel end will take a pen, pencil or marker up to about the diameter of a standard sharpie, but the larger the marking instrument, the more awkward it might be to mount it. However, once mounted, it works fine.

This beam compass worked great. It’s easy to adjust and quality design and material.

This works very well for drawing larger circles and arcs on wood. The bar is a smooth, round, solid chunk of plastic, 1/2" in diameter and a little over 12" long. It seems too smooth. The adjustments slide too easily, and you have to carefully tighten down the screws to get it to hold a specific diameter. It's also easy for the two ends to rotate around the bar, altering the diameter. The rotation issue would be better if the bar were square or hexagonal, but then it would be harder to use alternate, longer bars. I think I may replace the bar with a wooden dowel to reduce slipping. That will also let me use a longer bar for larger circles. The included bar is good up to about a 12.5" radius, ie a 25" diameter circle. The pencil holder accepts a standard, 1/4", office type, wooden pencil. It will not accept the larger carpentry pencils.

This is a nice tool to have in your shop, art studio or craft room. Sturdy, easy to use and affordable.

Works as described and while not high quality, with gentle use gets the drawing purpose done.

Perfect Circles!! I bought a 36 in dowel to go with this from my local hardware store. I needed really large circles for a VBS project and this gadget worked perfectly!!

Pros:- One of the few options for larger radius drawing tools that won't break the bank- You can replace the beam with a wooden dowel or similar material to extend this to even longer lengthsCons:- I originally chose this so I could easily swap out pens, however the diameter allowed by the the end clamp is limited to "pencil" size. It wouldn't be too hard to bore or carve the clamp to a slightly bigger diameter pen, but it would have been nice had it worked out of the box for what I wanted.- The pivot and clamp are a cheaper plastic that may not hold up over time.

Kinda flimsy. If I knew it'd be like that, I'd build one myself.