The story so far...

Several weeks ago- getting on towards months now - I set myself the task of scratch building a couple of 15cm Self Propelled artillery pieces - Hummels.  I was given some of the bits: guns, running gear, lower hull, ammo racks and other small items, all from ESCI kits that had presumably been adapted to other purposes.  The upper hull and fighting compartments had to be built. 

The front drive sprockets having been glued previously needed to be re-fastened with reinforcing.  I drilled a hole through the centre of the sprocket right through the hull and shove in a brad.  The solution is OK, but better would have been thickish wire (about Nr 16 gauge) right through.  After all my effort, the sprocket still sticks out a bit...

The alignments aren't great, I have to admit, though
the top plate over the driver's compartment looks worse on
account of the skewed ink streak at the front edge.

 Here's my progress thus far: none too impressive, I have to admit.  I've not used plasti-card for modelling to any extent before, and I'm finding it not very forgiving.  Getting things right is hard enough, but with a glue that grabs, it's hard to get things properly aligned as well, as these pictures show.

I'm hoping, therefore, that the final painting will disguise the less perfect aspects of these models.

Alignment problems and poor measuring left a gap
that you see in the centre.  Time to try out what
can be done with Green Stuff.

The grey pieces are from the ESCI 1:72 kit.  From the above picture I've mocked up how they should fit together.  The front of the fighting compartment has certain peculiarities I haven't yet figured out how to model: the slight inward bend edging the embrasure; and the cylindrical/frustum-shaped piece that forms the gun-shield(?) attached to the gun.  I'll also be making and fitting the hydraulic arms involved in elevating the gun in action.

A quick mock up with the bits assembled so far.
H'mmm... could be worse...

 The way things are going, I think the final product will at least be recognisable.  I'll be keeping one: Evil Uncle Brian (who provided the ESCI parts - Thanks Brian)) will be getting the other.

 Below is an ESCI kit made up many years ago when it was just about the only German ordnance (with the Wespe) that one could find in plastic that was not an Anti-tank or FlaK gun.  I still haven't figured out how to do the louvres at the sides, just above the tracks.

I have the crew figures.  I just need to glue them in...

 About the time my daughter was born (twenty years ago, now)  I used the ESCI model as a template for making a towed 15.0 cm gun/howitzer.  I've since removed the shield I had fitted, and I believe there are additions to be made.  The legs are too short, too, though I hope to disguise that by adding spades.  

Needs finishing: hydraulic elevating gear and spades; some crew figures.
Then finish off the base.

The whole thing was made from cardboard, balsa and plastic tube.

I never did finish the thing...

Finally, a couple of 7.5cm PaK40 Anti-tank pieces fashioned from the gun from the Airfix SdKfz234/4 Armoured Car kit.  The original kit was unsatisfactory from several points of view.  They will end up as fitted with scratchbuilt 75L24 guns as recon support vehicles (SdKfz 233).  One unfortunately I destroyed trying to fashion a Soviet BA64.  That experiment was not a success...

A use for the guns from the Airfix Armoured Car kit.
  I did at one point have a couple of scratchbuilt 7.5cm field guns
based on these, but dismantled them for other uses.
A bad decision!

The near piece has has the gun barrel replaced with plasctic tube, but the muzzle brake has been retained.  Not a wholly satisfactory solution.  I had shortened the original barrel to make 50L60 PaK38 AT guns - a mistake as I had no clear idea what the PaK38 looked like.  Oh well...