My Nemesis, The Perfect Circle.

[Gawdzilla]

Sometimes I get frustrated cutting that perfect circle. I know, I know, "practice makes perfect". I also know exactly how patient I can be.

This is forced me to make some cheaters. First, drawing circles to make sure I'm starting with a circle. When a compass is impractical I use, for the smaller circles, washers. You get two circles with each washer, outside and inside, and they're cheap so you can buy a whole range of them. I keep them on a dowel rod I set in a piece of scrap plywood. It's easy to arrange them by size that way. I scanned the whole collection at once and made notes on inside and outside diameters, then numbered them. One look at my sheet and I know which washer I need, and IF I keep them in order I can get to the right one quickly.

Bigger circles needed more work. I have scrap pieces of PVC piping that I've filed down to a sharp edge while watching TV. Two inches works for me. I put a PVC plug in the end and glued it in place. I can rap this on a piece of wet leather for a nicely marked circle.

I've also used the metal from hose clamps to make odd sized circles. Cut off the screw mechanism and use a wire tie or two to keep it in place. If the circle is going to be used regularly I fashion a wooden insert to keep it round.

Any other cheats out there?

[rickeyfro]

You can pick up a set of trammel points pretty cheap

Sometimes I get frustrated cutting that perfect circle. I know, I know, "practice makes perfect". I also know exactly how patient I can be.

This is forced me to make some cheaters. First, drawing circles to make sure I'm starting with a circle. When a compass is impractical I use, for the smaller circles, washers. You get two circles with each washer, outside and inside, and they're cheap so you can buy a whole range of them. I keep them on a dowel rod I set in a piece of scrap plywood. It's easy to arrange them by size that way. I scanned the whole collection at once and made notes on inside and outside diameters, then numbered them. One look at my sheet and I know which washer I need, and IF I keep them in order I can get to the right one quickly.

Bigger circles needed more work. I have scrap pieces of PVC piping that I've filed down to a sharp edge while watching TV. Two inches works for me. I put a PVC plug in the end and glued it in place. I can rap this on a piece of wet leather for a nicely marked circle.

I've also used the metal from hose clamps to make odd sized circles. Cut off the screw mechanism and use a wire tie or two to keep it in place. If the circle is going to be used regularly I fashion a wooden insert to keep it round.

Any other cheats out there?

[Gawdzilla]

You can pick up a set of trammel points pretty cheap

Thanks! Amazon has a nice set for $33.63 US. I'll have to check out the surplus tool stores in this area for those.

[gtwister09]

Gawdzilla,

You could also use drafting circle templates or radius master templates. These provide a bunch of sizes in a single sheet. Alvin, Timely and Rapid-design are some of the brands that I have. You can get some fairly large circles with the radius templates. I like these a lot because there are tons of sizes immediately available in a very small space. Likewise they also have ones for ellipse and other geometric shapes as well.

If using trammels, compasses (small or large) or beam compasses you can avoid the center line mark by using a small piece of leather to set the point down on.

Regards,

Ben

Edited January 29, 2011 by gtwister09

[Gawdzilla]

Gawdzilla,

You could also use drafting circle templates or radius master templates. These provide a bunch of sizes in a single sheet. Alvin, Timely and Rapid-design are some of the brands that I have. You can get some fairly large circles with the radius templates. I like these a lot because there are tons of sizes immediately available in a very small space. Likewise they also have ones for ellipse and other geometric shapes as well.

If using trammels, compasses (small or large) or beam compasses you can avoid the center line mark by using a small piece of leather to set the point down on.

Regards,

Ben

Thanks for the tips. I have a sheet of concentric circles in 1/2" increments, out to one foot in diameter. The maker's name got rubbed off years ago, before I inherited it.

[chainftw]

I took a adjustable compass with a sharp peg in the one side .

Took out the lead that was in the other side and flat sharpened a harness needle .

When I put the peg side in the center of the circle I use a scrap piece of leather

so I don't make a hole in the center than the needle cuts the circle so it's easy to

follow in the grove with a swivel knife .

Works great .

Chain

Sometimes I get frustrated cutting that perfect circle. I know, I know, "practice makes perfect". I also know exactly how patient I can be.

This is forced me to make some cheaters. First, drawing circles to make sure I'm starting with a circle. When a compass is impractical I use, for the smaller circles, washers. You get two circles with each washer, outside and inside, and they're cheap so you can buy a whole range of them. I keep them on a dowel rod I set in a piece of scrap plywood. It's easy to arrange them by size that way. I scanned the whole collection at once and made notes on inside and outside diameters, then numbered them. One look at my sheet and I know which washer I need, and IF I keep them in order I can get to the right one quickly.

Bigger circles needed more work. I have scrap pieces of PVC piping that I've filed down to a sharp edge while watching TV. Two inches works for me. I put a PVC plug in the end and glued it in place. I can rap this on a piece of wet leather for a nicely marked circle.

I've also used the metal from hose clamps to make odd sized circles. Cut off the screw mechanism and use a wire tie or two to keep it in place. If the circle is going to be used regularly I fashion a wooden insert to keep it round.

Any other cheats out there?

[seveneves]

The best way for me to cut circle is to take my compass and draw out my circle. Then I put a small nail through the center point into a board. Then take a pointed knife such as a utility knife, stick it on the perimeter of the circle and spin the letter around. It cuts a perfect circle. The only drawback is there's a small hole in the center.

[jestermg]

Why not take a metal pipe in the diameter you need and sharpen the outside of it to a sharp point. then you could take a small sledge hammer and actually use it as a punch?

[moeg]

Hi Gawdzilla,

I use scrap aluminum tail pipe 3 to 4 inches in diameter, from any shop. Just file the outside edge, use a piece of wood on top with a metal hammer. This way the leather doesn't have to be wet.

Moe

[Somawas]

Look at an Ufa circle cutter, from Michael's or Jerry's Art-O-Rama.

[320]

the olfa circle cutter is about perfect, just cut from the back side of your piece.

i also have a gasket cutter from harbor freight that is more rigid but clunkier.

heavy pyrex bowls are great templates if they are the size you need. pie tins, cake pans....

[Somawas]

Cheap on Ebay. http://cgi.ebay.com/Olfa-CMP-1-Adjustable-Circle-Cutting-Cutter-CMP1-New-/300544944026?pt=LH_DefaultDomain_0&hash=item45f9dfe79a#ht_3266wt_1396