The Ship Model Forum

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Good job on the windows !

At some stage I also need to get myself one of those choppers - or make one.

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Eberhard

Former chairman Arbeitskreis historischer Schiffbau e.V. (German Association for Shipbuilding History)

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Thanks, yes, I have been aware of these products and identified various shortcomings in them from an engineering point of view. I also found them rather pricey for what they are. You essentially confirmed the feelings I had about them - I never had one in my hands. That's good to know.

I had tossed around mentally various designs and specifications. By making the design a bit less flexible, one could perhaps improve precision, There will be always trade-offs.

I would perhaps make the blade move vertically up and down, rather than pivotting. The latter movement creates a lateral force away from the backstop. With a vertical movement one can also eliminate more or less the side-play that comes from a pivotting arm with blade mounted quite far away from the pivotting point.

Rumour has it that there are blades with bevel on one side only, which would make alignment of the cut more accurate. I have also been thinking of square scalpel blades, rather than these heavy razor blades, but these would limit the width of strips one can cut, particularly at an angle.

Another weak point on these 'choppers' is the 'die', i.e. the cutting surface, which is soft and results in the material being pushed down and torn somewhat. A design more like the paper guillotines or shears, where the blade moves very close past a sharp and precise edge, would improve on that. One would need a sort of slot under the blade. However, then arranging for cutting angles is not so easy anymore. I have been thinking of a 'stage' rotating around a small guillotine-like structure.

The fact that I bought this little laser-cutter a good year ago, had led me to push the 'chopper' project onto the back-burner. However, in the next project in my mental pipeline, I will be using more styrene strips, I think, then the 'chopper' may become more urgent again.

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Eberhard

Former chairman Arbeitskreis historischer Schiffbau e.V. (German Association for Shipbuilding History)

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I see that you also use the NWSL chopper. Very handy for cutting pieces from Styrene or even paper. I also noted that you have rotated the cutting surface after the blade wears a trough in it, which leads to pieces having a slight fold at the cut end. I suppose eventually I may have to make a new cutting surface from one of the commonly available cutting mats after I do the complete set of rotations.

Very nice work and always very helpful to we lesser mortals to see your working methods. Yes, woodworking is a fun relief from the sometime tedious task of ship modeling in small scales.

Regards! Tom

Well, for purely selfish reasons I hope it will be a short woodworking project...
Enjoy it though!

Nice advertisement pic for glass covers BTW!

I had to move ship modeling out of the house for a number of years when the (ex) wife acquired somewhere around 6 plus cats. Not even high shelves are adequate hinderance.

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Sculpture using some discarded sound equipment ?

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Eberhard

Former chairman Arbeitskreis historischer Schiffbau e.V. (German Association for Shipbuilding History)

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Wow, nice woodworking! That looks pretty complicated...


Last time I was in a Klingon brothel, the speakers were not the most uneasy things on my eyes in the room ...


But I'm glad to see you returning to Hood. Already looking forward to the next update!

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Indeed, the limited clamping capacity of the 'Micromot'-system can be nuisance. On the other hand, operating a 6 mm cutter on this small machine at 10000 rpm could bring some rather dangerous torque down onto the worktable, even if the motor only has 100 W. Perhaps that is the reason, why they limited the clamping diameter to 3.2 mm (= 1/8").

I was not aware that such aftermarket spindles were available ...

For such small cross-drilling operation some sort of dividing head with tailstock might be useful. Or an ER11 collet block that can be held in the vice. The collet would recenter the material in a repeatable way.

As you now have a mill (and had a lathe already) you could make yourself a miniature machinist's screw-jack to support the outboard end of the parts to be drilled.

I am using an old watchmaker's lathe bed with the dividing head and its tailstock and made this sort of jack I was talking about:



The idea of the jack could be adapted to the Proxxon, but one needs to find a way to attach it to the table - on mine I simply used a couple of neodynium magnets, but the Proxxon table being aluminium this obviously would not work.

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Eberhard

Former chairman Arbeitskreis historischer Schiffbau e.V. (German Association for Shipbuilding History)

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Good to see you back on track EJ! The davit prototype is spectacular . i sense you're going to be unstoppable with your new weapon
Cheers,
SG

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http://www.3xblackcats.wordpress.com

Amazing work on that davit Evert-Jan! Wow!

And thanks for posting all that information.
I think I will also buy that ER11 check and collets. I want to be able to make fine grooves with microcutters of 0,2mm to 0,5mm wide, but I can only find these with 4mm shafts, that don't fit in the standard MF70 collets...

Eberhard, I'm also very interested in small machinist jacks for this kind of work. But I would prefer to buy them instead of making them myself, so I can maximize my time actually working on the model (and I don't have any thread-cutting experience or equipment...). My first online searches yielded no viable results, but maybe you know of some sources?
As for attaching to the table: would simply clamping down not work?

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By that standard my 0.4 mm diameter Davits seem coarse and simple

_________________
Eberhard

Former chairman Arbeitskreis historischer Schiffbau e.V. (German Association for Shipbuilding History)

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