Flak 36 recent addition

[Jerry Carducci]

Hello just added the Flak 36 to my little collection. This was a model recently offered here on the forum. Looking over the older threads regarding this model I'd like to make some of the upgrades I've seen however as they are old there are often missing photos ( haven't tried the 'Wayback machine' archive yet). Are there detail upgrades yet available for this model, I particularly liked the upgrades for dials and the like.

I was provided the original Armortek documentation however I don't have much by way of books on the machine. Suggestions for best of breed books?

Jerry

[Paul Wills]

Hi Jerry,

Try Tim Cattons, he did a lot of the upgread parts for the Flack36 https://erkennungsmarken.smugmug.com/Bu ... -upgrades/

Paul.

[Chris Hall]

There’s a Haynes Guide on the Flak 36. And probably an Osprey ….. there’s always an Osprey ……

[Jerry Carducci]

I've begun to delve into this model. I've chosen the gun and cradle to begin with. Besides knowing who the owner was immediate to me I don't know
much about when this model was built or how it was stored although I suspect it was partially kept where it was exposed to changing environmental
conditions as the top most surface of the barrel, recoil cylinders and other components show degraded paint and mild corrosion.

So far I've removed the upper mount and barrel assembly and since taken the barrel/slide assembly completely to pieces. I found 3 screws that were broken on the fronts piece and painted over so correcting that was the first fix. The original assembly had pretty much been 'by the book' as to what I can see with some fasteners left out due to what seems misaligned components - I'll try to correct these. There is some damage to parts but mostly minor and correctable; nothing so far of a structural nature. Force was clearly applied to some parts, I assume in an effort to improve alignment....

The cradle was mostly glued together according to plan. I have reduced the carriage to it's basic components; I plan to actually rivet the parts back together instead of gluing the rivets in their respective holes; the ease in which these parts came to pieces tells me gluing these together isn't a good long term approach. I've tried to save as many of the original rivets as possible; I have a selection of rivets here but may not have enough steel rivets of the correct size and head type. I would prefer not to use copper rivets here.

Fortunately there are quite a few very good build threads for this model which I've been scouring for ideas as to have improvements I want to make on this one while I rebuild it.

Jerry

[Jerry Carducci]

As I now have a pile of parts where the gun carriage on my Flak gun used to be I'm looking over the parts. One piece kept bothering me;
ok I'm often slow on realizations... I realized the gun breech block didn't look at all like the photos and others I've seen. Long story short
it seems the/a previous owner, in order to facilitate using those blank firer thingies cut a slot into what would be the strike channel on the full sized gun.

If you've seen those things they use a string to activate the firing mechanism but they're essentially a dummy 88 round designed to hold a .38 blank cartridge. A clever design, several of them came with the 88 when I got it (no I won't sell any) however I have no plans to use them. In my other hobby I'm a arms enthusiast and get enough noise 'over there'.

It made me rather sad to recognize that the breech block had been altered in this way. I was faced with either making a new one or attempting a repair
on the existing one. Fortunately aluminium in not something I'm short of; I imagine between raw aluminium I use for my foundry work and sheet, rod and plate stock I easily have 500-600kg of the stuff. (Now whether or not I've the right type, size or shape at any given moment is another story).

I opted to attempt a repair. My approach was to make the cut slight wider but straight and without jaggedness to it so I ran a .250" mill through it.
Next I repaired an insert of dome 7000 series scrap I had that was slightly longer that the cut and ~00015" thicker requiring a press fit. Next I drilled
2 holes from the top down through this new plug and pinned it with 2mm hard steel dowels. One of these will be hidden under the rack and the other
will never be seen as the breech block operation does not expose that section. Thanks to an array of end mills, 4 jaw chucks, dial indicators and mini boring bars I was able to restore the original shape reasonably, passably well.

I've included a few before and after shots. My plan is to make a striker insert and other breech block details to spruce this up a bit.

[Jerry Carducci]

I worked today a little on the gun carriage lower section. The one with the many rivets. As I may have mentioned previously my intent
is to assemble this piece with the rivets being functional.

I saved and cleaned as many of the original rivets as possible. I also annealed them; basically I gathered them up in a pile on
a firebrick and heated them up with a MAP gas torch to a pleasing cherry red. I had cleaned and removed any rust on the structural steel
parts involved and primed them.

I made a double ended rivet tool to correspond to the small rounded heads of the tiny rivets used.

I identified two separate operations and two different methods to be used for the rivets on the bottom of the "U" shaped
channel and those on the sides. For those at the bottom I kept the round head on the bottom outside of the work and compressed
the inner portion of the rivet by support the rounded head in the appropriate end of the tool I made and flattening the protruding
rivet pin at the inner bottom of the channel.

For the rivets on the sides I reversed the orientation. I kept the head on the inside of the work and formed a secondary round head
from the protruding pin on the outside of the work. The pin was initially formed by using the ball end of a ball pein (peen) hammer.
The rivets need to be trimmed slightly as too long a pin will result in a malformed compression and too short will not allow a properly
formed head. It takes one of two rivets before I get the length right when starting a new set of parts but after that it moves quickly.

The result I obtained are pretty good; makes for a very strong part so far. I'm waiting until an order for more rivets arrives so I can
attach the rails. I don't like mixing rivet types.

I made a video of the process but it isn't really very good or I'd post one of them here to further illustrate what I've done.

Jerry

[Jerry Carducci]

I must say that after 170+ rivets in such a small confined space I'm happy to see this job in the rear view mirror. I still find riveting two
pieces of metal together rather satisfying. The contortions I had to go through and the time spent on my machines making strange shaped tools
to facilitate this, and steel at that, wasn't the way I'd planned several recent evenings. Still it's done, not perfectly but looks decent and is strong
beyond expectations. I had to drill holes where there were none and change the approach to compressing the rivets several times as I got into it.
The rivets I purchased from Hansen's are slightly larger ( +.002-003") than the metric types originally used which wasn't the main issue; their relative hardness was greater (in my opinion) which was cause for the changed approach- more than once and was concerning due to the relative high force I needed to apply even after annealing these things. However all that said it's done, everything went together well without the slightest bit deforming of any part or damage to the anodized surfaces of the rails. I did mill out to shallow channels on the fontspiece to clear the rivet heads however these can't easily be seen especially when the gun is assembled.... In my photo I still have tape over the rails 'cause I don't want paint on them, inside or out.

I'm moving on to priming major parts and making some of the more fun little detail bits I want to add. Going to remake several parts that were made of what appears to be lead; in particular the equilibrator linkage pieces- hard to image these bits made of lead have survived under the force of those fairly powerful springs...

I was looking forward to making that retainer cover for the breech block striker channel; there's another similar bit off to the right on the breechblock.
I made my first one from a bit of scrap shaft rod once a part of an IBM 3890 check sorter! IBM didn't skimp on steel quality...

I want to attribute my 88 to Rheinmetall. I'm trying to determine which of their wartime plants assembled FlaK 36/37 pieces. I want to pick the proper ordnance code to stamp on the breech ring. Codes I have (I have others but I'm going with this set) are:

• aqx - Rheinmetall-Borsig, Tegel plant (Eventually replaced by 'hhg')

• bmv - Rheinmetall-Borsig AG, Soemmerda plant, Soemmerda

• bwo - Rheinmetall-Borig Borsig AG, Duesseldorf

• cpn - Rheinmetall-Borsig AG, Werk Apolda

• cpo - Rheinmetall-Borsig AG, Berlin-Marienfeld

• cpp - Rheinmetall-Borsig AG, Breslau plant

• cpq - Rheinmetall-Borsig AG, Gubeb Guben plant

Anyone have a link to what plants made these things?

I'm hoping I'll find that Mr. Catton or others still have some of their excellent detail bits to apply or I might be nearing completion on this this time next year...

Side note I just chanced into finding an appropriate steel chain for the lifting mechanism on the bogie assemblies. I had just waltzed into a local
hardware store when I decided to look at their chain offerings. Lo they had a spool of "clock work" chain - brass plated. I knew it had to be steel so sprung for several feet of it...and sure enough a few minutes in a HCL/H2So4 bath and 3-4 volts and that plating is no more!

I make slow progress but have fun along the way...

Jerry

[Jerry Carducci]

Work proceeds slowly, I find myself studying and staring at books, photos of originals and those of other modelers here on the forum...
So many, many parts!

As much as I'd like to add the nth level of detail to this model my initial intent when starting this was to repair the corroded areas, repair some things that weren't functional and the few broken or damaged bits I'd seen.

The bogie chain hoists were one such area. They were completely non functional. I've spent the better part of two weeks doing all the little odds and ends thus far and there's still more to do. At usable now. I took two different approaches with both hoists. I'm just going to list the things done:

• replaced or implemented proper bearings; bronze or ball

• realigned the shafts and pillow blocks

• made 2 each access covers, one functional another just decorative

• replace bolts

• machined flats on shafts for set screws

• pinned worm wheel to drive shaft

Still to do

• Turn input shaft to emulate prototype

• make chain guards

• make fold-able handles

• make third (decorative) access plate

I have no doubt there's much more to do with these That either I'll discover or someone will remind me of...

I worked a bit on the front of the carriage slide, made a number of square profile steel parts..

In my eagerness to try to straighten the elevation and windage controls handles I forgot the one immutable fact of zinc parts:
zinc doesn't take kindly to bending and so one of the handles bit the dust. Embarrassing AND annoying at the same time. I decided
to give it a go casting new ones in bronze. I was able to 1) glue the shattered example back together and along with the intact one
I was able to use them as patterns- I decided to ignore shrinkage which for a small part like this is immaterial. I also decided to have a go
at casting the base leveling mechanism handles at the same time. Of the 6 windage/elevation handles and 2 level adjusting handles
I cast I received 4 and 2 usable parts. The original deformities in all were reproduced in exacting detail BUT now I can bend the parts
within reason! I like the way they came out.

I'm at somewhat of an impasse as it's been raining the proverbial cats 'n dogs here or it's been near zero degrees- I cannot paint in these conditions.
My paint chemist friend strongly advised against it. (also why we aren't painting our F4 Phantom project on the Hornet).

So while I'm waiting for more favorable painting weather I could make a few more detail parts...

Jerry

[Jerry Carducci]

I'm skipping around a bit on the model. I'd been looking forward to making changes to the breech ring so I decided to jump into it. I've been using
Uwe Gerstenmayer's beautiful work as inspiration. I'll return to the chain hoists just after. I plan to finish up the few detail bits, one or two other changes and repainting and I'll call it done until I can obtain additional detail parts at some time in the future.

So far on the whole I think the breech is looking a little better than when I found it. There remains several things to do and a touch more contouring.

Jerry

[Jerry Carducci]

Since I've most of what I want to do done on the breech ring I went back to the chain hoists.

I've been staring at photo of these things so long I believe I could make one by memory. I studied the mechanism of the crank handle
and believe I understand how it works. Required some modifications to the kit parts. I machined square sections on the input shafts
to the hoists in order to simulate the ability to extend and retract the crank shaft in order to clear the fender when it's in use. It's enjoyable
work with the 40:1 gear ratio of my rotary table though making the inner square receiving sockets and handles took some planning.
I believe it all turned out respectably and I'm pleased with the work so far and it actually works well. I used steel wherever possible and the original material where feasible. I have got to the point where I've made the rough handle that attaches to the shaft that extends to the outer edge of
the fender but have yet to make the collapsible part of that handle. I don't expect any difficulty but I've been duped before!

I've attached a few photos of the progress.

Jerry

[Phil Woollard]

Nice work keep it coming, I have one to detail in the future and your work is excellent inspiration!

[Jerry Carducci]

Well, I should have known better that to assume I'd just breeze through making a functional chain hoist crank handle!

In researching these it appears that either they are missing from many museum exhibits or in some cases they've been
replaced by recreations. It would seem the originals are a bit more complex than may be seen from the photos I've
found. I originally assumed that the handle pivoted at its base between detents that were engaged by some sort of spring loaded
pin or rod. From the photos I've seen I cant see how the base can pivot in what I'm assuming are the surviving originals.

Here is an example of what I'm referring to:


I'd love to have 5 minutes with an original to see how it works!

I can make something similar but my goal is to have a functional part.

If anyone has better detailed information and can pass it along I'd appreciate it...!

Jerry

[Jerry Carducci]

Well. I have a handle. Tested my patience and my ability to machine tiny parts in steel. Using SAE 1-72 taps and 2mm endmills in steel
makes me wiser and older; older as I have even less hair than I began with and wiser cause after I finish the second one I don't want to do a third.

And they're not exactly the way I'd envisioned nor perfect but they work well and seem fairly sturdy. I think they look the part. They look ok.

I had to cheat on the spring- I used a stretched expansion spring instead of the compression spring I tried in the first iteration. The first compression spring was so strong once I assembled the handle I couldn't compress the spring comfortably and in one instance It fired the detent plunger across my shop. So the gentler action of the spring I used is bordering on weak but it works ok. I just don't have a wide array of suitably small springs nor thin spring wire to wind one...

On to whatever other details I can torment myself with.

Jerry

[Jerry Carducci]

Moving right along... I'd seen where Uwe Gerstenmayer had modified the base of his FlaK gun to use a ball bearing race - he mentioned he'd had a Panther turret in hand. I knew immediately whet he meant as I have * Panther models from the late Jochen Maier and all of them used a type of built -in
bearing race. I made one identical to these for my scratch built King Tiger this design works very well.

I used about the same size bearing balls as Uwe cited just shy of 4mm - I believe they're actually SAE 5/32" bearing balls which are about 3.968mm or 0.156". Anyway it's what I used on my KT build and what I had on hand.

I didn't use my mill to cut the bearing race I ground a lathe tool to give me the profile I needed and used that. The worst part of this was determining where on the lower section of base plate to make the cut. This is critical because of how the upper section is formed- there's a relatively narrow area that will support the circle of bearings. I sighed in relief when I was finished with the cut!

Now the base truly does rotate with minimal effort.

One other thing I did was to replace the OEM 10mm bolt that was used to secure the base together. I made a special part that will screw into the
central part of the pedestal but cinch up against a shoulder eliminating the need to screw in the bolt and locktite it in place so as to not bind the movable parts. I finished off the head of this piece with a rather fanciful octagonal face - I have no idea what was done on the full sized machines.

Nearly finished with what I'll do with this model. My goal was to improve its appearance a bit so hopefully that will show.

Waiting for the opportunity to begin painting.

Jerry

[Jerry Carducci]

I keep telling myself 'this is the last thing I'm going to do to this model'.

It never seems to be.

The latest thing was to make replacement stowage boxes for the wheeled units. I used steel to make the box and lid, silver brazed together.
I used sections of the piano hinge available from Micro Mark.

The hasps and that annoyingly deceptively difficult little catch that engages the hasp. After much wrangling, fretting and colorful language I got something that will work. I have to mount the retaining pin and chain but otherwise they are pretty much done. Finally!

A few photos follow.

Jerry