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Author Topic: Square engine anyone?  (Read 201 times)

Offline A7er

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Square engine anyone?
« on: October 02, 2026, 11:47:58 pm »
I installed Freecad version 1.1 to see if I could get on with it. I have used Freecad a lot in the past but now mainly use Design spark or Solid edge.
I started to design a single cylinder simple IC engine. 25mm bore and stroke with some fillets to soften some of the edges. After drawing the cylinder I decided to section it by drawing a 26mm square on top of the cylinder and pocketing it through the cylinder to create a sectioned view. Several attempts later I realised Freecad still had problems with fillets, so I deleted them. I could then section the engine to examine the interior of the cylinder. I then pressed CTR Z to undo the section to restore the cylinder, deleted the now not needed drawing of the section square, and this happened. (see attached image).

Each time I tried to delete or alter the drawing of the square Freecad turned my round engine into a square one.

A square cylinder might just about work, but a square crankshaft? or a cam with square lobes?


Offline crueby

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Re: Square engine anyone?
« Reply #1 on: October 02, 2026, 11:59:16 pm »
There were engines with square cylinders, but square crankshaft would be tough to spin!  Reminds me of the square tire episode on Mythbusters.   :zap:

Online Jasonb

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Re: Square engine anyone?
« Reply #2 on: October 03, 2026, 07:18:07 am »
You just need one of those ball races with with a square hole hole in the inner race ;D

If you are having to draw squares to get section views then it would seem Freecad is also rather lacking in the ability to section a single part let alone selectivly section parts in an assembly. I suppose you don't get what you don't pay for.

 

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