EM2 Pantograph pre-production.

[The son of Triangman]

As some of my friends here will know I have been working on getting the old Tri-ang EM2 pantographs made.  The costs involved are massive and most small top medium makers want minimum orders of 10,000 units at an average cost of £15 - £19 each, so I am going it alone.

Here is the base of the pantograph and the first 3D plastic proving print.  The project is an as an when project, the folding press block is the next job and micro refinements to the drawings.  A small CNC laser cutter and small CNC milling machine are on the shopping list next.

 

 

 

 

Edited September 8 by The son of Triangman

[The son of Triangman]

First 3D plastic proving print in the slicer

 

 

[The son of Triangman]

First 3D proving plastic print, the quality of print isn't important as this is just to check dimensions and see how it looks, changes to make.  The printer can do much finer work so a better print will be done later this week.

 

 

Edited September 8 by The son of Triangman

[Brew Man]

@The son of Triangman will you print on a FDM or Resin printer?

[What About The Bee]

I think the part of the pantograph is this one

Note the two large holes on centerline and the four 'legs'.

If not mistaken, I think the entire part conducts electricity, so this base part will be metal.  

Bee

[The son of Triangman]

It is indeed the base for the EM2 pantograph.   3D printing is just being used as a proving tool to check measurements and adjustments.  I need a better cad package that is easy to use and is free or inexpensive.  Once all is perfect I shall then design a press tooling for doing the folds. I will also look at materials.  The weak spot near the Pantograph skate will be slightly thicker to increase pantograph life.

Edited September 8 by The son of Triangman

[What About The Bee]

@The son of Triangman

While the learning curve is quite steep, the power of FreeCAD is amazing.

Totally free.  All models are local (on your machine).

Its a worthy contender

Bee

 

[Tony57]

Hi SoT

Thank you for remaking this important and much needed item.

I require a number of replacement pantographs for my 4 x Steeple Cabs, 6 x EM2 and 4 x Transcontinental Electric Locomotives. So I am looking forward to hearing more on its development.

 

[Rana Temporia]

They will certainly look more authentic than the Jouef and Lima ones I have replaced some of mine with on my Transcontinental locos. Both my EM2s have their original ones. I think the Lima ones are slightly better but neither are big enough being made for HO locos. The Jouef ones also seem to be up or down with no springing in-between. It’s odd when you look at the complexity of assembling these and adding them to the loco body with the switches etc. and yet on one original price list I have the class 37 and the EM2 are the same price. 

[The son of Triangman]

A big thank you to Bee, I will be investigating freecad more closely as it is now on my design pc.  A thank you to you all, the pantographs are a long term project as I have other things going on such as new model railway business launch, speaking to the big wholesaler today about a trade account and are having a holiday for a weeks rest for my heart condition.  I am also doing a course on CNC programming after my holiday to get a recognised qualification and buying a CNC laser cutter and a CNC mini milling machine.  The model railway business won't be self supporting so I need a part time job to keep the bills paid, this is a challenge in itself!  Anyway, lots going on I digress.

The new pantographs will be accurate representations of the originals with a few important improvements such as the weak area where they always break near the pantograph head, the metal sides will be increased in thickness and height in the weak area to strengthen it.

Edited September 10 by The son of Triangman

[Rana Temporia]

1 hour ago, The son of Triangman said:

A big thank you to Bee, I will be investigating freecad more closely as it is now on my design pc.  A thank you to you all, the pantographs are a long term project as I have other things going on such as new model railway business launch, speaking to the big wholesaler today about a trade account and are having a holiday for a weeks rest for my heart condition.  I am also doing a course on CNC programming after my holiday to get a recognised qualification and buying a CNC laser cutter and a CNC mini milling machine.  The model railway business won't be self supporting so I need a part time job to keep the bills paid, this is a challenge in itself!  Anyway, lots going on I digress.

The new pantographs will be accurate representations of the originals with a few important improvements such as the weak area where they always break near the pantograph head, the metal sides will be increased in thickness and height in the weak area to strengthen it.

I have freecad on my home computer and for a freebie it’s a massively powerful programme, as evidenced by Bee’s excellent work in it. However, I have been trained in Autocad and automatically go to use the commands and shortcuts I would when using that, which don’t work so I end up getting frustrated with it which isn’t the programmes fault but my familiarity with another software package. I also only use 2D for work so learning 3D is a bit of a stretch. There are some excellent tutorials online and when I had time to spend with it I was making good progress but unfortunately things happen and it’s fallen by the wayside. 

I would recommend keeping a manual of what you find useful in the commands for freecad. I still have my training manual for Autocad 95 and it’s amazing how relevant it still is in the 2023 version. Any changes or new commands that I use are in there with explanations on how to achieve some of the newer commands that I use less frequently.  

I think I can produce .dwg files in Autocad and import them into freecad, and use an elevation and plan 2D drawing to produce a 3D solid object, but I have never got round to trying. So much to do and so little free time to do it!

[What About The Bee]

Rana

In FreeCAD, you sketch in a 2D plane.  XY, XZ and YZ base planes.  You can draw in any arbitrary plane (datum), but setting that up at first can be daunting. 

Example: this mock up of a Hornby Finescale Chain took 11 sketches, 9 sketches in datum planes, to match the link orientation.  The remaining sketches were one in XY and the other in XZ . The sketch in each datum plane was a simple oval, representing one link along the arc. 

When drawing in the plane that you select, you want to achieve a "fully constrained drawing".  Meaning the lines, arcs, points, circles and ellipses have been defined and fixed.  This is very important, as FreeCAD will recompute your model periodically and unconstrained sketches can move about.  FreeCAD can be made to tell you what is uncontrained.

Once the sketch is done and saved.  You either extrude it to transform that sketch into a solid or use the sketch to cut through other solids.

In the case of the finescale chain, each link was padded symmetric to the sketch.  It extruded on either side of the datum, with the thickness I measured off of the real part.

You go from the 2D world in a sketch, and extrude / cut the part in the 3D world.

I have barely scratched the surface of FreeCAD.  The power is simply amazing.  The negative with FreeCAD I have read about is that compared to things like Solidworks, the commands are clunky, that it takes longer to set things up.  Maybe, but I am not running a department with Mechanical Engineers on the clock.  It is just me, playing.

Bee