[SOLVED] Learning...

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NGoode
Newbie Member
Posts: 5
Joined: Wed Nov 10, 2021 1:14 am

[SOLVED] Learning...

Post by NGoode » Wed Nov 10, 2021 1:24 am

G'day All,

I am using QCAD Professional 3.26.2 on Windows.

I need to draw up the drawing attached. Any help as to the best way to draw the varying radius/curves and how best to set the holes out would be much appreciated!

I don't mind drawing rectangles etc but this one is a bit harder!

Thanks in advance.
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20211110_105230.jpg
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Last edited by NGoode on Wed Sep 07, 2022 6:46 am, edited 1 time in total.

CVH
Premier Member
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Joined: Wed Sep 27, 2017 4:17 pm

Re: Learning...

Post by CVH » Wed Nov 10, 2021 4:20 am

Hi,
NGoode wrote:
Wed Nov 10, 2021 1:24 am
Any help as to the best way to draw the varying radius/curves
In the early days boat builders used wooden splints that they bent for 'natural' curves under tension.
They also heated or steamed the splints more or less as required.

The mathematical counterpart these days are splines.

QCAD PRO supports 2 kinds: fit points (SP) and control points (SL).
The first kind is easy to fit but may require (too) many points.
The other kind is more natural and will be a bit more harder to fit.

Remind that if you cut or trim a fitpoint spline QCAD will return a spline with control points.

The idea is now to insert your picture in QCAD as a bitmap (IM) and trace over the contour.
Remember that dxf only stores a link to that picture file.

Fitting straight lines ... circles as holes and trial circular at end rounding with 3 points (3C) or with the tangent tools ...
... and finally splines where nor lines, nor arc/circles really match.

The best way for the holes is to put it in a T-square and record dX-dY.
In this way those positions will be more exact than those placed on the picture trace.

Eventually splines need to be approximated with arcs for CAM, called explode (XP) in QCAD.
See for the XP settings under App.Prefs (Ctrl+,) .. Modify .. Explode

Regards,
CVH
Last edited by CVH on Sat Sep 10, 2022 6:16 am, edited 1 time in total.

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Husky
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Location: USA

Re: Learning...

Post by Husky » Wed Nov 10, 2021 6:23 am

G'day NGoode,

what a nice exercise - isn't it? :wink:

In short: Best and most accurate way would be to trace it in QCAD. Insert the bitmap in your drawing on its own layer, fade it to 60(?), lock the layer. Then trace on top of it ...

You need the scale tool, Circle (3 Point), Lines and maybe one rectangle - then trim tools + common sense.

I don't recommend to gather the x/y coordinates from the template - that is not precisely enough in this case.
No need to think about splines - none is used.

Use common sense! Try to think like the manufacturer of this Alu template. e.g. If you find a drill hole with 10.1358 mm diameter most likely it was meant to be a 10 mm hole.
... if you have 3 holes in a row most likely they should have the same distance to each other and be on the same orientation. This template is built by a human - ask yourself what is more important to you: To copy the template built by a human with all shortcomings as it is or to come close to the original drawing which was used to built the template.

I hope you have just as much fun as I had to draw the template. e_surprised

Husky-2021.11.09-02.png
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NGoode
Newbie Member
Posts: 5
Joined: Wed Nov 10, 2021 1:14 am

Re: Learning...

Post by NGoode » Wed Sep 07, 2022 6:45 am

Sorry guys, just wanted to thank you all for your help on the above! Worked out great :D

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