Radius curves from drawings (example R66)

[Alex Gibson 1Participant @alexgibson1]

Hi all

Sorry if this is a silly question.

How do you put the radius from a drawing into your practical work, ai am a little stuck with understanding the process or how to measure and mark onto a work piece, for example the drawing is showing R66 (measured in mm).

Thanks inadvance

Alex

[Alex Gibson 1Participant @alexgibson1]

Not sure how to take the measurement and transfer to work piece

[Nigel Graham 2Participant @nigelgraham2]

If you mean from a centre off the work or its stock material, one way is to clamp the work to a marked-out surface with the centre on that. If the workpiece is thick you would need mark the centre on a block or something to reduce the triangulation error introduced by the height difference.

It may help obtain a better answer if you can supply a photo of what you're trying to achieve.

[JasonBModerator @jasonb]

A photo of that part of the drawing would help us give some more specific answers, details of how to add photos here or say what the drawing is for

If for example a large flat plate has a R66 corner I would measure in from each of the two edges and lightly mark a line 66mm in. Where the two lines intersect put a light dot punch mark and then set your dividers to 66mm place one point in the dot punch mark and then draw the corner radius with them like a compass.

As for cutting to that line then rough sawing and filing is one way and there are several other options depending on what tools you have available.

[duncan webster 1Participant @duncanwebster1]

It all depends on how important the R66 is. If it matters then use the methods above, if it is cosmetic find a saucer/plate/tin etc can of the approximate dimension and draw round it

[Alex Gibson 1Participant @alexgibson1]

An example from the drawing:

Mod edit:  for convenience here it is, and the right way up!

Edited By SillyOldDuffer on 23/06/2021 17:37:02

[JasonBModerator @jasonb]

More or less as I said above draw two lines 15mm from each edge of the "tee" shape as you mark out the sheet of metal. punch where they meet and then draw a circle of 15mm radius.

When it comes to making the part you may want to make a 30mm dia hole in that location first and then cut the straight lines or simply file the radius after machining of filing the two straight edges

 

Edited By JasonB on 23/06/2021 18:17:14

[old martParticipant @oldmart]

In the case of the drawing shown, the exact radius is not vital,and could vary. I notice that the material is not vital either, (ALU/MS).

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