Hi folks,
So I've had my 11200 for a few days now and I've been itching to try out an idea I had even before I got the crane, so I got to work on Saturday and have put in a considerable amount of time on these boom cylinders. These are very much a prototype and given what I've experienced with testing I don't think they'll be taken to a final state. They work perfectly and IMO look good, but there are problems with the size of the jackets (still smaller than on the real machine!) and they rub against the boom in transport mode.

Anyways, I've never liked how the model companies use very thick plastic cylinder jackets, not to mention that WSI, Conrad and even YCC do it with the top quality locking metal cylinders too. On the real cranes the jackets are very thin compared to the body of the cylinder, and it's possible (and not difficult) to do this to scale. It really adds to the look of power that these machines have.

I used 11.1mm diameter styrene tube for the jacket, and inside are two telescoping steel tubes mounted upside down with the narrower tube to the bottom. The jacket takes none of the strain and the steel is so strong that only one of the cylinders needs to be pinned in place to support the entire boom. The steel tubes come from a telescopic back scratcher that I got for £1 in Tesco (not a joke - really!). On one side I drilled an additional two holes to experiment with boom placement; IMO it kills the realism but the functionality is very nice for displaying the model, and I much prefer the look of the cylinders to any others that are currently available.

The pictures show the three height options I have chosen:





I also made a small jib for the whip line. This was tricky but not especially difficult, and instead of paying silly money for three brass pulleys I decided to make my own from styrene and they work very well.




The last thing I want to share is the poor quality of the last section of boom... I'm really disappointed this time in NZG because I don't feel that the quality of this 11200 is the same as my first one. If you look at the picture you can see that it is very badly off axis at the head of the boom. Does anybody else have this problem, and do you think I should get in touch with NZG about this?




Thanks everyone.

Nice cylinders man, and yes I would contact NZG about that issue. I have found the customer service to be one of the best and they helped me replace all the issues I had on my Denzai 11200.

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A Millwright..... in Alberta.

Thanks guys. As a matter of fact I just contacted NZG this morning and I received a reply within an hour asking me for my address so they can send a replacement part. That is simply outstanding customer service! It is just as well because I have also since noticed that one of the pulleys on the boom head is warped. At least now I have spares!

Re. the holes in the cylinders, I was in two minds about drilling them and I decided ultimately that the compromise of better display potential at the cost of making these marks was worthwhile - the cylinders are completely sealed so I can't position them from inside. I did consider other approaches and ultimately it's nice to have the flexibility without having to remove the cylinders each time. I'm still tempted to try the screw idea with a bolt inside, much like the outriggers, although I'm not sure if the threads would support the weight of the boom. It really is ridiculously heavy!

Thanks Victor!

I decided not to spend (or waste) any more time on these prototype cylinders and start again from scratch with a much better design, and here's the process. So far things are working really well and altough the cylinders have to be detached for height adjustment, they are incredibly strong and there are no holes!!

Lots of pics showing process:




















Crooked boom says hi!

Me too Paul - and thanks! I'm really taking my time with these as they are not prototypes, so all my measurements are as precise as I can possibly make them and I want the finish to be the best I can possibly get. I've already put a lot of time into them and will be spending many more hours with detailing and then painting.

I wanted to be sure of the load capability of the cylinders so in the test fitting phase I extended the boom a bit to put more weight on them, and they are completely solid even in this low boom position. I also did a test fit with the boom down, and in transport mode. Naturally, the cylinders would sit a bit higher because they are propped up with the blocks underneath, but even now I really like how PHAT they look.

Thanks Ian - it's a great idea and could be done with the right materials and equipment, but perhaps too expensive for any manufacturer to consider on a large scale? Maybe YCC will do it, or maybe we'll see more realistic cylinders like this on future scale models from the "big three"... one can only hope.

At first my idea was to epoxy the bolt inside the upper part of the cylinder so that it could be adjusted by twisting the exposed metal part, but I've decided not to because it's nice to have the option of removing the bolt altogether, and indeed adjusting it with a power tool for convenience.

Looks awesome!

Paul R

Thanks Paul and Don!

Don - I'm really humbled by your kind words, and I certainly wouldn't consider myself a master compared to some of the other guys on this forum. I just try to do the best I can each time and that usually means flying by the seat of my pants, but with several projects under my belt I've definitely picked up some valuable tips and tricks. I'll see what I can do about putting a tutorial together for my approach to jib building, but it may take a while as I'm pretty busy at the moment!

A couple of things I would mention now are as follows: 1) appropriate selection of quality tools (very sharp knife, metal rule & square, vernier caliper, and lots of grades of sand paper or nail files). I often work with extremely small tolerances and the only way to do this is with a vernier (or digital) caliper. 2) accurate measurements. Measure, measure twice and measure again.

It goes without saying that a fair bit of maths goes into structures like the jib above, and even simple-looking things can be really tricky to put together in styrene. It all comes with practice, and (you guessed it) A LOT of patience and frustration!

Victor - thanks for the help!

I didn't realise that Max Bogl used a different yellow as it looks almost identical from photos.

They are extremely similar, with the Max Bogl yellow being very slightly lighter than Liebherr yellow. I won't be doing any repainting, so perhaps it'll have to be Senn Ag again after all!

Very nice clean work there Davie82