I'd create a cross-section and dimension the diameters on that. If they're external turned dimensions, then a side view would be used to put them on. The 7,00 dim you have would be best in the right view as you have it.

Reduce text & arrow size. See if your CAD will dispense with the arrows on the other side of circles.

Martin.

I'm not keen on showing diameters with the diagonal lines at all sorts of angles, I prefer to select "linear" dimensions for diameters which puts them as shown.

Does the program not allow you to space the elevations further apart? Alibre does and I can also alter text and arrow size and style.

Edited By JasonB on 20/03/2022 16:31:47

Does your system allow viewports? If so you can have dimension parameters to suit the paper size, but scale up the item. It's easier to put dimensions on something drawn twice full size. Once you've got the dimension parameters as you want them, save it as a template, or even as a blank drawing so you don't have to do it again.

I think a radius is used to dimension arcs, rather than circles.

You should be able to measure the dimensions shown on a drawing. If you can measure the diameter it should be shown as a diameter. If not, it is a radius. If you cannot measure it, it should not be dimensioned.

Dimensions SHOULD NOT BE CHAINED, an almost universal fault on model engineering drawings. They should be taken from a single datum.

JA

I think that the various posters above are just trying to be as helpful as possible with advice on drawing layouts, being basically what the OP asked for.

I disagree; you cannot make a bald statement that you "should not chain dimensions". If you have an important centre-to-centre dimension that must be held to within a tolerance, then using a common datum would double the permissible variation between your important centres.

What is wanted is a copy of the good old BS308, (now sadly obsolete). That tells you all about dimensioning!

Nigel

I stand by what I wrote. In your case one of the centres becomes a datum.

For those who think this is outside the topic chained dimensions take up less room on the paper so, seemingly, produce a less cluttered drawing. Which comes back to use a larger sheet or more sheets of paper.

JA

Edited By JA on 21/03/2022 08:49:26

Unchained dimensions are far more useful these days with the vast majority having a DRO on their mill which makes it easy to work from a datum be that a corner or ctr of a part.

Centred pairs or hole son a PCD are easily handles with the absolute and incremental settings by using absolute to get the ctr of the pair or group and then incremental from there.

Those still marking out by hand and using handwheels are better off dimensioning from a corner datum so all positions are positive so less faffing about allowing for backlash if a ctr datum is used.

I'd happily do the 1000 holes from one datum with the DRO on the manual mill or better still the CNC which only needs the one datum. This is probably about the most I have done from one point, a lot easier than all the chained fractional inches that were on the drawing.

Edited By JasonB on 21/03/2022 13:01:47

So taking circlips 8 holes, say a 4 * 2 array. With daisy chained dimensions the diagonal could be out by somewhere around 4 times the general tolerance. Of course if your marking out is perfect it doesn't matter, mine isn't. There might be places where one datum isn't appropriate, but this would be the exception. Ordinate dimensions make the drawing less cluttered.

And I'll echo the plea, can someone find a copy of bs308, send it to whoever does the drawings for ME and MEW

Edited By duncan webster on 21/03/2022 14:57:12

Time to settle down with beer, nibbles and a dictionary, pausing only to don appropriate PPE against flying toys.

Andrew