Sd Kfz 7 Sprocket question and partial model rebuild..

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Jerry Carducci
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Re: Sd Kfz 7 Sprocket question and partial model rebuild..

Post by Jerry Carducci »

I haven't been making leaps of progress primarily because I'm just slow and I want to do things just once.

I spent quite a bit of time on the rear doors. This area had needed some attention from the time I received the model as neither the doors nor hinges were attached. I was first going to make my own, smaller hinges or use a pre-made piano hinge from Micro mark although I'm sure there are others around even more suitable. What influenced me most was the existence of all those holes on both the doors (steel), hinges (brass) and rear aluminium body casting. What I decided was to fill the holes on the doors and the hinges but only on the side that engaged the doors. The holes in the body I decided to drill out and tap with SAE 1-72 threads so I could use small_ish hex head screws. I like the ability to take things apart if needed and at least so far as the hinge/door assembly is concerned this does it. I made new holes on the hinges and doors so I could rivet the two together with functional 1/16 (~1.5mm) copper rivets. These two choices seemed to work ok and are similar to what I could see in photos of the full size machines albeit not quite scale in size.

I've decided that my goal is what may have been termed -semi 'standoff' scale when applied to aircraft. I want any of the detal parts I add or make to
look appropriate if not exacting in scale or construction to the original. I like things to be functional where possible which is why I tend to use steel and brass so much. This is the approach I took with regards to the latching mechanism for the doors.

I could see what these latches looked like and how they worked from the books I have. Their function seemed somewhat integral and dependent on how the full sized doors were constructed. I knew I wasn't going to nor could I with the constraints of what was there already -duplicate the door structures. However I wanted latches that would work rather that gluing, using magnets (although I considered this) so I sketched out what I thought I could do.
Using some of my favorite materials, construction nails, scrap sheet steel and some thin steel rods I had rescued from the roadway some years ago while walking I set about making these. Basically I did what amounts to miniature forging of these steels to make everything for these latches with just minimal drilling and lathe work. They seem to work pretty well. I recognize that the originals are flat- again an artifact of the overall construction; still mine are actually a hair over 5mm deep. I needed to make thin slots on the inside edges of the cast body parts to give the latching mechanism something to latch onto... I spent a few days making these. The latch mechanisms are held in place by 1,2mm hex head screws. The brass angles are held in place by a row tiny ( 0.0250" /0.6350mm) brass rivets for which I made a tool to maintain the integrity of the round heads. Drilling the tiny holes in steel was fun. No drills were harmed during the making of this scene... I need to make covers for the latch mechanisms so that only the 'arms' stick out.

I'm working on the tail lights which will be functional. They are cast of pewter.

Next on my radar is the dashboard. I've roughed out a replacement dash in steel, I still need to trim it down to the right length and cut out the holes for the instruments and such. I've attempted to see if the diameter of these dashboard instruments has been documented but I have yet to find it. Does anyone on the forum have these measurements they could share? I have a copy of the dial faces that someone kindly posed elsewhere on the forum - if these are the right size if I remove the outlines I can work from these. My plan is to illuminate these instruments and whatever else needs illumination... I haven't cut the holes in the dash as I search for the right dimensions.

I have lenses now for my headlights but I'm thinking I want to cast new headlight bodies in brass.

I've reached out to several fellow forum members regarding parts, hoping to encourage my inclination to be lazy and not make all the parts myself...
Attachments
rear and dash.jpg
latches.jpg
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Jeffrey Goff
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Re: Sd Kfz 7 Sprocket question and partial model rebuild..

Post by Jeffrey Goff »

Hi Jerry, when I built mine, I cut a slot below the doors to fit the spare wheel, easy to do while the back is not attached
F52A0BFB-D26C-49C6-905F-5CA6868C2F0B.jpeg
5FA7557D-CED1-4CF8-A382-1CE3305B3CE4.jpeg
B7D7EF66-1868-4B19-A4A7-C417F1C18AAE.jpeg
823CAC16-CBE0-4A7E-9B3C-5B54E615D93E.jpeg
Regards Jeff

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Jerry Carducci
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Re: Sd Kfz 7 Sprocket question and partial model rebuild..

Post by Jerry Carducci »

Jeffrey Goff wrote:
Thu Jun 09, 2022 6:59 am
Hi Jerry, when I built mine, I cut a slot below the doors to fit the spare wheel, easy to do while the back is not attached
F52A0BFB-D26C-49C6-905F-5CA6868C2F0B.jpeg5FA7557D-CED1-4CF8-A382-1CE3305B3CE4.jpegB7D7EF66-1868-4B19-A4A7-C417F1C18AAE.jpeg823CAC16-CBE0-4A7E-9B3C-5B54E615D93E.jpeg
Regards Jeff
Hmmmm nice. Then I s'pose I'll need a spare tire also! I might do that and worry about the actual spare later....

Jerry
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Re: Sd Kfz 7 Sprocket question and partial model rebuild..

Post by Derek Attree »

Hi Jerry
The spare tire was in the kit when I bought mine a few years ago from Armortek.

Regards

Derek
we must stop making stupid predictions

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Jerry Carducci
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Re: Sd Kfz 7 Sprocket question and partial model rebuild..

Post by Jerry Carducci »

Derek Attree wrote:
Thu Jun 09, 2022 2:16 pm
Hi Jerry
The spare tire was in the kit when I bought mine a few years ago from Armortek.

Regards

Derek
There was no spare when I bought this model, remember I purchased this as a previously owned model...

j
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Re: Sd Kfz 7 Sprocket question and partial model rebuild..

Post by Christoffer Ahlfors »

If it's just a spare, maybe you can print it?
//
A little too much is about right...

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Re: Sd Kfz 7 Sprocket question and partial model rebuild..

Post by Jerry Carducci »

Moving right along with changes albeit slowly. Making myself ill from eating too many apricots from my tree out back didn't help... but they're
soo good! Apricots for breakfast, apricots for lunch, apricot pie. Even after offering even more to friends.....

Anyway....

I made the tire stowage locker door and latch and begun work on the dash, cleaned up the plate and made the 4 major instruments from
aluminium with plastic lenses and dial faces found in another thread on the forum. The plan is to illuminate them. Not certain what else lights up on the dash but I see at least on lamp or indicator on the large rotary switch assembly on the left. I have a number of details left to do and the vent controls as well as the tachograph. It seems according to the (reproduction) SdKfz7 support manual the original tachograph had a range of 0-60km/h but I see mostly 0-70km/h versions used. I was fortunate for find a full sized tachograph (it still keeps good time) and I must find a way to shrink it! It may not be the exact type but it appears close to me.

This week if all goes to plan I hope to meet with a friend who was a paint chemist by profession who says he can make me up a batch of high quality paint in the appropriate German sand yellow /tan yellow. I'm not going to wait until I finish every last detail to begin to reassemble this. The windscreen needs to be upgraded and that tachograph needs to be made - I plan to allow for it but make and install it later- I also need one for my Famo.

Jerry
Attachments
tachgraph.jpg
sparelocker..jpg
dash.jpg
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Re: Sd Kfz 7 Sprocket question and partial model rebuild..

Post by Jerry Carducci »

More work done, repainting parts I've touched and modified. Used the paint my friend made and it works very well so far. I use a Devilbiss EGA series 502 to spray which is an oldie but it works very well; I keep the pressure at around 45psi (~311kPa) and get a nice satin -like finish.

Did a bit more work on the dash but there's still a good bit to do. Tried out the lighting of the dash. Debating with myself if I want to use two of the soft white leds in the tachometer which is a large instrument. I like the way it looks illuuminated so far.. Going to make the entire dash panel so I can remove it and work on it if need be although besides delaying making the tachograph until later I don't see much need to work on it once installed. I have to paint the back side of the leds to light doesn't 'spill' out through the led's body base as seen in the reflection from under the dash. I made caps for each instrument case that completely and tightly seal the instrument body with the led a press fit in the center- the leds being clear allows light to escape through the led base...and I don't want that..

Hope to begin reassembly soon.

Jerry
Attachments
painted_03.jpg
painted_02.jpg
painted_01.jpg
dash_notlit.jpg
dash_lit2.jpg
dash_lit1.jpg
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Robert E Morey
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Re: Sd Kfz 7 Sprocket question and partial model rebuild..

Post by Robert E Morey »

Good progress! Love those lighted gages!
Bob

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