Re: DAK Pz IV Ausf G Build
Posted: Sat Mar 05, 2016 6:32 pm
One of the problems that came from raising the sprockets is that the outer edge of the tracks were rubbing the edge of the fenders. I’m using Impact tracks and the have a rounded knob on the end of each link that creates the closed-pin feature. The fenders have a small vertical face on the outer edge that represents the metal being bent down on the real thing. But, because it’s plastic, there is more thickness to this lip than there would be if the fenders were metal. So, I’ve tried a couple of different ways to make this work correctly and still look right.
First thing I did was ask my brother to lathe the drive shafts in order to shorten them by 2-mm (original length: ~60-mm). That worked. The tracks were no longer rubbing the lip. But, they seemed to far from the edge of the fender. Photos of the real tanks showed that the tracks pushed a ways away from the hull. In fact they went all the way to being just inside the bent lip of the fender. So, the next attempt was order some more drive shafts from MatoMart (sold in sets of two) and lathe them down by 1-mm. To make the drive shafts work that only had 1-mm removed, I sanded down the inner lip. Stock it is 2-mm thick. After sanding, it is 1-mm thick. That should leave sufficient strength in the plastic and let the tracks come a little closer to where they are supposed to be. Comparison photos are attached. I like the second effort better (1-mm from plastic and 1-mm from the drive shafts).
One thing my brother did for me while we had the drive shafts in the lathe was to deepen the hole for the bolt that holds the sprocket in place. For whatever reason on all of my drive shafts (I have three sets), the M3 bolt that secures the drive sprocket won’t screw in all the way to the bolt head. It stops about 2/3 of the way into the shaft. It will still hold the sprocket as is, but I like to be able to screw it in all the way to bolt head. So, he drilled that out and tapped it all the way in.
One added benefit to lathing the drive shafts is that the sprockets seat better. The stock drive shafts have a slight beveling around outer edge of the shaft at the ends. It was just enough to let the sprockets wobble slightly on the end of the shaft, even if tightened down. Shaving off a millimeter or two eliminated the bevel leaving a sharp, 90o junction at the end. The sprockets don’t seem to have that slight wobble anymore.
First thing I did was ask my brother to lathe the drive shafts in order to shorten them by 2-mm (original length: ~60-mm). That worked. The tracks were no longer rubbing the lip. But, they seemed to far from the edge of the fender. Photos of the real tanks showed that the tracks pushed a ways away from the hull. In fact they went all the way to being just inside the bent lip of the fender. So, the next attempt was order some more drive shafts from MatoMart (sold in sets of two) and lathe them down by 1-mm. To make the drive shafts work that only had 1-mm removed, I sanded down the inner lip. Stock it is 2-mm thick. After sanding, it is 1-mm thick. That should leave sufficient strength in the plastic and let the tracks come a little closer to where they are supposed to be. Comparison photos are attached. I like the second effort better (1-mm from plastic and 1-mm from the drive shafts).
One thing my brother did for me while we had the drive shafts in the lathe was to deepen the hole for the bolt that holds the sprocket in place. For whatever reason on all of my drive shafts (I have three sets), the M3 bolt that secures the drive sprocket won’t screw in all the way to the bolt head. It stops about 2/3 of the way into the shaft. It will still hold the sprocket as is, but I like to be able to screw it in all the way to bolt head. So, he drilled that out and tapped it all the way in.
One added benefit to lathing the drive shafts is that the sprockets seat better. The stock drive shafts have a slight beveling around outer edge of the shaft at the ends. It was just enough to let the sprockets wobble slightly on the end of the shaft, even if tightened down. Shaving off a millimeter or two eliminated the bevel leaving a sharp, 90o junction at the end. The sprockets don’t seem to have that slight wobble anymore.