Saturday, April 25, 2009

Everyone Draws Rectangular Flanges, don't they?

The other day I got sick of drawing yet another rectangular flange.
I thought: get smart-someone else must have done a lisp for this.
But no. At least as far as I looked- which was not all that far.
There was one found but it did not perform the way I wanted, so
I decided to write my own. Needless to say it appears to have
taken a day and half out of my life.

It occurs to me now, that my time would probably have been
spent better watching TV or taking Rose for a walk.

Anyway, it was a vague sort of challenge, and it is finished now.
One of it's features is that it does produce 3D solids when it
has finished. It also flies in the face of "traditional" methods
of spacing of bolts. Normally in the old days a draftee would
work out the bolt centres (theoretical) then choose the nearest
value to make the centres. For instance, he might have calculated
137.5mm as the hole centres. To make the drawing not have the
dreaded 0.5 or the "hard to read" 137, he would have said
nearest is 140mm. Then the dimension between the end hole
and the next one in might have ended up at say 122mm.

I have suddenly had an epiphany: all the flanges I have been
drawing lately have been laser cut. So who cares if the hole
centres are 137.5mm? Not me. Especially when it
made this routine a lot easier to write. No doubt the
traditionalists out there will be pouncing on me for being
so outrageous!

Here is the dialog box - where you fill in all the variables.

It does make the layers "Front Flange", "Back Flange"
and"Gasket", otherwise it does not appear to do anything
drastic to your drawing. I have made it so that it can be used
in an existing drawing-ie you don't have to run it in a new drawing.
I have had the odd situation (which I could not make it repeat)
where it seemed to lose the plot and put the holes in the
wrong place-almost as it the snapmode had gone nuts.
When I checked osmode, I got something like 16477,which is
a strange one, considering the whole thing just uses
standard commands and hopefully does not reuse Autocad's
reserved commands like angle and so on.
An extension I did consider was to insert bolts/nuts and washers.

Monday, April 20, 2009

Filleting Polylines

Exciting stuff, huh! oh well....
In my ponderous progress towards writing a lisp that does steel handrails, I came across
a little corner of Autocad I had not realised was available: If you go Fillet, you are given the option to fillet a polyline. You just pick the polyline and it fillets every corner in one go. How often the average user would need this I'm not sure, but it sure does come in handy for my handrail routine!

Thursday, April 2, 2009

Not really Autocad...but where to put it?

One of my hobbies is to play around with a bit of programming.

I have looked at Basic, C, Autolisp, VB6, VBA and now I have downloaded
the freebie from Microsoft, VB 2008 Express Edition.

I can say that this represents an improvement of VB6, at least as far as the
small amount of things I have asked of it so far. I downloaded it to make a
small program, which, hopefully, will be needed where I work....

This post is essentially a repeat of my site at Analysis.html

This is the new program as it runs: it consists of two dialog boxes,and amounts to pressing buttons and selecting from lists. Once the program is run, it creates a text file-see listing below for that one.

This is the contents of a typical text file the program produces:

Task Analysis

Date Created:2009-04-02

The Task: Remove Beams

The Plant:Porana Rd

Permits: glass permit

Personal Protection: safety goggles

Equipment: gas sets

Step No: 1

The Action: Remove old conveyor
Hazard: gas

Type of Control: Eliminate

Means of Control: ,chemical isolations,standby personnel

You can see that this is site specific and could not be used on other plants. Why am I posting this here? To see if anyone is interested in such a program.You can email me at
A more general program would be identical, except the Plant and the Location boxes would extract their items from 2 separate text files, created by the user. I would imagine a fair price for the program might be US$20.
Another option might be a customised one that can only be used by your firm-the logo shown (mine) can easily be replaced by one that your firm uses.

Limitations are:

1. You have to make a directory c:\Task Analysis

2. The output is to a text file, which if you wanted to alter fonts and so on, then you would need to open the file in MS Word instead of Notepad.

3. At the moment the file output name is the same as the date. This means that if you do more than one on the same day, it just appends it to the file created before on that day.

4. It does not allow for multipages-for instance you might have Step No: 7 at the bottom of a page, then The Action on the next page.

5. It does not have "the smarts": for instance, if you chose say "welding"the program should suggest "welding helmet" and so on. It does not do this. Some might say the idea of this program is not the spitting out of a form, more the engagement of the person about to perform the task thinking about what he is doing.

All of the above limitations might be got around, but no gaurantees!

Wednesday, April 1, 2009

Everybody draws Handrails...don't they?

Handrails....A necessary evil, as the fun of drawing them soon diminishes.
Unless you are the type of draftsman that finds them relaxing,because it is the ultimate in blame free drafting: How can you possibly get them wrong?
Over the years I have come across many different styles of handrails. Once I created a very badly written lisp to automatethe process. It only drew the railings as a 50 x 50 square, to save on computing horsepower- it was in 3D.

With me getting Autocad Architecture, I was in hog heaven, because it had a very smart
system for drawing handrailing. You just decided on a style, and picked a few points and there it was.
Unfortunately, I am back in the mechanical world of vanilla Autocad,and there don't appear to be any such items on it's horizon any time soon. Not that I draw handrails very often, so when I do it is not a big deal.

My original plan was to get all the ducks in a row on this one, and present about 4 different types of handrails as "ways" of doing them.

So far I have only got this drawing:

Please excuse the image quality-I originally posted this as a jpg, but when saving it back I noticed that the text was unreadable. Hence the png file above, which might work better.

If not, I'll post it on my site: ....eventually!
It is for a food factory, so it is made from stainless steel. The good things about it are the lack of welding required and the ease of construction.The rails are just straight cut, and there is the theory that any sweeping to be done would just brushout through the 10mm gap in the kickplate.

The plan is you start sweeping at the top level and work your way down.
The bad thing is the little vee on the top of the stanchion, as this would snag sleeves and hands. It could be improved a lot by making the top rail continuous and not having the vee. This would mean that semicircular cuts would have to be made in the top of the stanchion, but with proper tooling, this might be a good thing.

I have a suspicion that this design has not been "engineered", so should not be trusted to conform to any standards.
This lack of "engineering" just highlights to me how bad a world standard is needed: We, as draftsmen or engineers, should never be choosing our own designs for such a mundane thing as a handrail. We could have a choice of very well engineered and thought out designs to choose from. For an engineer to be designing a handrail represents a waste of resources.
I hope to post further on this topic, with more designs and eventually putting on my website a series of drawings that could be used as a "semi-standard". I'm not an engineer, so these " semi-standards" would only be that.

Unless someone knows of a site that does?