Help with radius print reading

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Trying to build a go kart for son.. Bought some plans, they are pretty good, but everything is metric..  I understand radius, diameter, etc.., but on the attached plan it shows a radius of 105mm on two sides and a radius of 10 (R 10) on the end..Where is the center point I use to measure outward the radius dimensions??   Really appreciate any clarity on this one.. Thanks
Reply:Start at the corners with a compass set at the called out radius, and make crosshairs in the center. Start there, you should be good to go.City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:the 'R10' at the corners is centered on the centers of the holes at the corners.The 'sides' ('R105' and 'R110') are tangent to the corner radii.When laying it out, lay out the hole centers first, then the three corner radii using these centers (I would put about half the circle on the layout), then do the sides, making them tangent. You may want to make up curves of the specified radii for the sides... makes finding the tangent easy.My suggestion for procedure:Coat the surface completely with ink and mark the layout with a scriber. I would use layout dye, but a permanent marker will work. Centerpunch the centers for the holes. If you are doing the large hole and outside profile by hand, set a divider for the radius (31mm), put one point in the centerpunch mark, and scribe the circle for the big hole (even if doing it on a machine, I'd scribe it, since it helps with setup). Cut inside the line and finish with a half round file. Rough out the outside profile, and file to finish. Drill the small holes.
Reply:Easy, open the pdf file Attached ImagesVisio-Drawing8.pdf (17.2 KB, 121 views)
Reply:R110 and R105 - center of big central hole (D62).R10 center of mid size holes (D8.2).Mid size holes are dimensioned by linear dimensions.Part is horizontaly symmetrical, which is indicated by centerline...Fairly decent drawing and dimensioning. Missed tolerances and material...
Reply:Thanks for the info.. something is still not adding up.. when I draw a radius of 105, it seems way too big.. I've tried the suggestions by laying it out this morning, but something still isn't adding up.. wondering if the drawing might be off?  i usually catch on to stuff pretty quick.. but this one has the dense factor on me..
Reply:Then drawing simply incorrect.I checked - indeed incorrect. What is missing - dimensioning of the radii. Here I am attaching the correct one. Attached ImagesLast edited by Nomand; 12-16-2009 at 08:29 AM.
Reply:Originally Posted by NomandR110 and R105 - center of big central hole (D62).R10 center of mid size holes (D8.2).Mid size holes are dimensioned by linear dimensions.Part is horizontally symmetrical, which is indicated by centerline...Fairly decent drawing and dimensioning. Missed tolerances and material...
Reply:Thanks DSW. You're absolutely right...That's my "weak spot" (or natural stupidity) - missing dimensions...Made me wander - did I dimension that drawing in the first place?....
Reply:I had to lay out 30 columns that were spread out all over in a basement one time. Just could not get things to look right no matter how many times my boss and I pulled the tape. Colunm A to D would work, but A to H wouldn't, D to H would!After 2 days of sitting there beating our head we finally figured out the engineer dimentioned half the basement from the right side wall, half from the left wall going column to column not wall to column. All the measurements marked on the print started from the right however on one dimension line. In the middle the 2 groups overlapped and he was missing 5 feet from the column totals. Wall to wall 135', column total 130'!Oh and the engineer on the job had been one of my colege profs for this sort of thing! .No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Thanks guys.. I'm still a newbie and was beating my head on the wall trying to figure out what I was missing.. lesson learned.. because it's on a plan doesn't always means it's correct.. thanks again..
Reply:Just a thought, but do you have to have radiused edges?If you get the hole pattern correct, could it be a on a square plate?
Reply:I don't have to have the radius edges... The drawing is a bearing mount for rear axle for a go kart.. Don't think my 10 year old will care if the corners have radiuses.. As long as it goes when he pushes the pedal he's okay.. I'm also using it as a learning exercise.. Do a lot of weekend welding/grinding/fab'ing but not print reading..  I noticed after the responses today, there are some other drawings that seem wrong now also.. so, this looks like it will be part drawing and part winging..
Reply:Plans? We don't need no steenking plans!
Reply:use what they gave you. they did not give you the centers for the 105 and 110 r sections. they gave you the locations of the small holes.locate those holes. draw the r=10 circles.cut out a section of a r=105 and r=110 circles for a pattern and draw them in tangent to the r=10 circles. then cut it out with a trch and get it within an half inch...
Reply:beware the magic pencil..its easy to draw stuff that can't be built.
Reply:Originally Posted by NomandThen drawing simply incorrect.I checked - indeed incorrect. What is missing - dimensioning of the radii. Here I am attaching the correct one.