Circle Cutter

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OK I have been talking about building a Circle Cutter for I don't know , 20 yrs or more but wanted something different. Here goes the explanation. I used Aluminum flat stock, 1/4 x 2. I drilled a series of holes that will accomdate my torch tip diameter. These holes are all 1" on center.  At each end I drilled 1/4 " holes at varioud fractional off sets and steel punched them to label them. I have a 1" offset and many other fractional off sets. This is the pilot hole or pivot pin.    I find the center of my circle and drill a 1/4" hole in it then I set up my radius to what ever fraction plus whole inches by counting circles. I can cut almost any size circle up to 4 feet without even using a tape measure. Just calculate the radius based on the diameter.  I did have to make a few of these flat stocks to get all the needed offsets but it seemed to work well.  Pictures left big so they are easier to see.  And I forgot to add, I use a hose clamp to keep the torch fastened but Zip ties would also work.  The second pictue is labeled + 1/4 that would mean the distance to the first hole is 1 1/4,   + 3/4 is 1 3/4 to first hole center.  On the other end of the flat stock are still different offsets yet.   The pivot pin is a grade 8 1/4 bolt set at the same height as the torch tip.Last edited by kolot; 08-09-2012 at 10:55 PM."Si Vis Pacem Para Bellum"Lincoln Idealarc 250 AC/DCMillermatic 251   Syncrowave 300   30A spoolgunLincoln MP210Hypertherm 45(2) LN 25(2) Lincoln Weldanpower 225 CV(4) SA200   1 short hood    SA250    SAM 400
Reply:Originally Posted by kolotOK I have been talking about building a Circle Cutter for I don't know , 20 yrs or more but wanted something different. Here goes the explanation. I used Aluminum flat stock, 1/4 x 2. I drilled a series of holes that will accomdate my torch tip diameter. These holes are all 1" on center.  At each end I drilled 1/4 " holes at varioud fractional off sets and steel punched them to label them. I have a 1" offset and many other fractional off sets. This is the pilot hole or pivot pin.    I find the center of my circle and drill a 1/4" hole in it then I set up my radius to what ever fraction plus whole inches by counting circles. I can cut almost any size circle up to 4 feet without even using a tape measure. Just calculate the radius based on the diameter.  I did have to make a few of these flat stocks to get all the needed offsets but it seemed to work well.  Pictures left big so they are easier to see.  And I forgot to add, I use a hose clamp to keep the torch fastened but Zip ties would also work.
Reply:Nice job, man.  Now that was worth waiting twenty years for!(Retired) Professional firefighter, amateur everything else I try to do...Oh yeah:  Go Big Red!   (You know: one of the 12 members of the Big 10 cuz we left the 10 members of the Big 12...)
Reply:Great tool.  Could you add a roller in one of the holes to make a stand off?  Like a steel roller skate wheel or something like that.Dan
Reply:could you use a large grounding magnet for holding one end in the middle of the circle , just bolt loose enough to spin on the magnet?..that would work for plasma cutter too....Of all the things I lost I miss my mind the most...I know just enough about everything to be dangerous......You cant cure stupid..only kill it...