Westlake Publishing Forums

Gentlemen, thank you - but this is quite normal model making?

@Bernhard

QuoteBy the way, can you tell me where you got the big sprocket?

I was able to rescue various large gear wheels from a scrap box (in exchange for €5.00 in coffee money). They were components of medium format lenses.

On June 09, 2012 I described the milling off the smaller gear rim:
click

Do you need one of these?

Zahnradringe (fspg2)

Many thanks Frithjof. I don't have a need at the moment, but it's always good to know where you can find something like this.

Bernhard

As I don't have any pictures of the roof structure of the Münzel crane, I will partly use a Hamburg harbor crane - now also demolished - as a guide, which I was able to photograph more closely in 2007.
The roof superstructure is attached to the housing by four bolts.

Bolzen 01 (fspg2)


Bolzen 02 (fspg2)


Bolzen 03 (fspg2)



Since I didn't have a 5.0mm MS58 round rod available, the thicker part was milled out of a 3.0mm MS58 plate and a 3.0mm rod was soldered in.

Bolzen 05 (fspg2)



The retaining lugs were then turned off - this gave me the required 2.3 mm height of the thicker part.

Bolzen 04 (fspg2)




A housing for the gearbox was designed to enable the boom to be raised and lowered.

Ausleger heben 01 (fspg2)


Ausleger heben 02 (fspg2)


Ausleger heben 05 (fspg2)


Ausleger heben 06 (fspg2)


Getriebe Ausleger 01 (fspg2)


Getriebe Ausleger 02 (fspg2)



It consists of:

two 2.7mm thick side panels...

Getriebe Ausleger 03 (fspg2)



... and two 5.3 mm thick middle half shells.

Getriebe Ausleger 04 (fspg2)



First, various layers were created in CAD for the successive milling and drilling steps.
Shown here as an example for the two half shells:

Getriebe Ausleger 05 (fspg2)



A DWG drawing derived from this was then created as a DXF file...

Getriebe Ausleger 06 (fspg2)



... to SheetCam and I entered the required parameters there.

Getriebe Ausleger 07 (fspg2)



Getriebe Ausleger 08 (fspg2)



After cutting through the four 0.4 mm thick and 1.0 mm long retaining lugs, I milled out the top and bottom corners so that the middle parts could be inserted into the two side parts with a perfect fit.

Getriebe Ausleger 09 (fspg2)



In the following picture, two washers for the threaded rod and four fastening screws for the four housing parts are still missing.

Getriebe Ausleger 10 (fspg2)


Getriebe Ausleger 11 (fspg2)

Yet another example of your usual meticulous approach and remarkable results. -- Russ

Awesome as always.

For my purposes though, I'm very glad to have the 3D printer!!

That little unit certainly turned out well. -- Russ

@Lawrence
The part looks great!

I bought an FDM printer a few years ago. After I had converted it to aluminum plate and magnetic foils and height sensor, etc., it remained with a few test attempts. The "coarse" fineness, even with the thinnest layers, didn't convince me for my small parts.
I don't want to buy a resin printer - I have enough projects waiting to be completed, not to mention the fact that I still have a few ideas lying dormant. So I have some parts that can't really be produced on the milling machine printed by a service provider.

The top of the gearbox housing still needs to be rounded. There is a small jig made from 6.0 mm Pertinax for this purpose.

Getriebe Ausleger 12 (fspg2)



Getriebe Ausleger 13 (fspg2)



The lower part is inserted into the guide groove on my small Böhler saw (today Kaleas) and thus determines the distance to the grinding wheel.
The upper part can be rotated around a 3.0 mm axis. The turning radius of 13.0mm was set to 13.3mm in the jig.

Getriebe Ausleger 14 (fspg2)



This allowed me to slowly grind the radius. Everything was held in place with my hands. Then the distance to the grinding wheel was reduced with two 0.2mm and 0.3mm thin strips of sheet metal inserted one after the other to achieve the final 13.0mm rounding.
The surface is currently still a little rough due to the 120 grit sandpaper used. This will be reworked with the finer sandpaper I ordered.

Getriebe Ausleger 15 (fspg2)




The four individual parts of the gearbox, which are currently fixed with M2.0mm screws, will later be screwed together with four M1.2mm steel screws. The 1.1mm holes already drilled on the milling machine in the side parts served as a guide for the corresponding 4.0mm deep holes in the middle parts. They were carefully machined with a thread cutter.
 
Stahlschraube 1.2mm kürzen 01 (fspg2)



As I only had 10.0 mm long screws in my stock, they had to be shortened to 4.5 mm. A small 5.0mm-thick Pertinax plate was drilled with corresponding holes (with a conical countersink for the screw head).
The screwed-in screws were shortened with a fine fretsaw and then sanded smooth on a board covered with sandpaper. I ended up with four screws of the same length.


Stahlschraube 1.2mm kürzen 02 (fspg2)


Stahlschraube 1.2mm kürzen 03 (fspg2)

Not bad. -- Russ

I'm always amazed and fascinated by your methods of solving each problem.

So far I have only used a placeholder for the drive to raise and lower the boom.

Münzel Montage komplett 1 (fspg2)


U-Profile Dach-Gruppe 1 (fspg2)


The green pulley with the "rubber band" will probably not work properly, as two fellow model builders told me.
I like the suggestion of using a miniature chain.

A test setup with the existing oversized pulley looks quite acceptable!

Antriebskette 01 (fspg2)


Now I have to modify the green disk a little so that the chain can engage properly.

After I had fixed the worm to the 2.0 mm shaft with Loctite 648, the gearbox was put together for the first time - and it creaked a little.
The edges of the worm were finely ground on the lathe - result: everything works quite well without lubrication.


Getriebe Ausleger 16 (fspg2)


Getriebe Ausleger 17 (fspg2)



During assembly, the roof frame is aligned at right angles using 0.4 mm thick nickel silver angle gussets (6.0 mm x 6.0 mm) and 1.0 mm wires in a Pertinax jig. Most of the ends of the wires have to be rounded off beforehand, because I can't reach the inside with the finishing cutter when assembled.

U-Profil Dach-Gruppe 01 (fspg2)


U-Profil Dach-Gruppe 02 (fspg2)



Some soldering was also carried out on the crane roof.

Münzel Krandach 01 (fspg2)

Stunning as always.

Quote from: fspg2 on June 07, 2024, 07:32:32 AMI like the suggestion of using a miniature chain.

That sounds prototypical.  Will you put teeth in the groove of the green wheel?

I've had the need for chains (cosmetic rather than functional) on a number of occasions.  Small chain is not too hard to find, but the correct link shape is more problematic.  Engineering chain is doubtless designed with weight, load capacity and form in mind.  Ex-jewellery chain does not generally represent it very well.

For small chain I've found model boat anchor chain to be about the best around (eg: https://kilokits.com/products/model-ship-anchor-chains?variant=36508136964251).  For larger chain (about the size you are using) I've found it very practical to reform the broadly elliptical links into something parallel sided by gently crushing each link with flat jaw pliers.  This sounds difficult and mind-numbing, but its actually very quick to do.  I hold the chain in tension, with some twist to lock the links, and just work my way along gently squeezing each link. To do that on your chain (if you though it needed) would possibly need a more consistent method, but would be viable I think?

Your model is really looking good at this point. -- Russ

Impressive as usual!

The roof frame has now been soldered together in the jig.
First, the cross members were soldered to the gusset plates and wire pins. After the 1.0 mm wire ends were rounded on both sides, the two long beams were soldered with their wires already rounded on one side.

U-Profil Dach-Gruppe 03 (fspg2)


All the parts were now inserted into the Pertinax jig and soldered together. Through the large round recesses in the jig, I was able to solder the connection cleanly from top and bottom with the resistance soldering tool using short 0.5mm pieces of solder and soldering fluid. The two pictures show the inserted parts before soldering.

U-Profil Dach-Gruppe 04 (fspg2)



To connect the rear cross-section to the longitudinal beams using four M1.0 screws, everything was fixed vertically in a vice and the four holes were drilled using a 1.0 mm drill. The existing holes in the cross profile were used to position the drill precisely.

U-Profil Dach-Gruppe 05 (fspg2)



Once the four screws had been soldered in, I was able to shorten the wire ends still protruding from the outside of the long beams and round them into rivet heads.

U-Profil Dach-Gruppe 06 (fspg2)



U-Profil Dach-Gruppe 07 (fspg2)

Superb. -- Russ