Boll Aero18 Drawings

[Clive Brown 1Participant @clivebrown1]

Perusing the on-line plans for the Boll Aero18, I’m puzzled by the use of a multiplier against some hole dimensions. An example for the press fitted crankpin is shown highlighted below. It’s not the number of separate holes, here there’s only one. Is it perhaps a CAD thing, can someone enlighten me please?

[DiogenesParticipant @diogenes]

It’s an error; a relic perhaps, as you say, of production – you are not ‘missing’ anything.

I think they were ‘de-bugged’ in days gone by, and although there may be other minor idiosyncrasies I don’t remember anything serious and a good runner may be produced from them.

[JasonBModerator @jasonb]

As all those blue arrowed noted are added by hand it is just a typo

[Clive Brown 1Participant @clivebrown1]

Thanks, what made me unsure was that same thing is to be seen elsewhere, eg the front bearing housing. Also, the drawings have revision notes, and this would seem to be a fairly obvious candidate for correction.

[David JuppParticipant @davidjupp51506]

I can’t be certain, but one way that the count for holes can report higher than the actual number is if there was an error in the production of the CAD model.  I’ve see both of the following happen;

• hole accidentally placed twice at the same spot (the system still counts 2 holes)
• an extra hole placed ‘out in space’ away from the model (perhaps an accidental extra click)

On several occasions I’ve handled reports of the CAD system getting the numbers wrong in the automatic hole callout, so far the error has always been on the part of CAD operator.  These things can be very tricky to find.

[JasonBModerator @jasonb]

David, as it looked like an Alibre drawing I tried placing two holes in the same place and setting the call out to on but only one callout showed on a drawing file. Also dragged it and there is not another call out under the first

[David JuppParticipant @davidjupp51506]

Jason,

2 nodes in the same hole sketch give this result

[JasonBModerator @jasonb]

Ah, I’ve got it to do the same now. Just a double click when one is needed puts the two holes in the same place.

I don’t usually have hole call outs ticked as 99% of my holes I just sketch a circle rather than use the hole tool unless they are to be threaded and I only use that for drawings that will get published.

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