Pikey Posted June 2, 2017 Share Posted June 2, 2017 So I ordered some German stuff From mikromodellbau, here: http://www.mikromodellbau.de/Shop/artikelauswahl.php?kid=102 Should be everything I need minus the transmitter and the receiver (and the battery). Seems a good way to ease myself into the daunting subject of teeny weeny RC conversions. I've previously bought a cheap RC lorry and a 00 gauge Eddie Stobart diecast model, the aim being to create some kind of hybrid between the two - the end result was not pretty and certainly didnt work. Its in about 6 pieces in a box in the garage somewhere. I checked the wheelbase of an Oxford Diecast Ford Transit (SWB) I have, and its within a millimetre of the 38mm suggested by the new chassis, so I'm hoping I can make it fit. The only thing I'm slightly concerned about it whether the servo will fit under the windscreen/bonnet, as its mounted vertically and quite far forward. Ultimately, the goal is to have some working 00 gauge vehicles with some more interesting movements ie articulated lorries, tippers, diggers, cranes, forklifts etc - but lets start with a basic van first and see what's what. 1 Link to post Share on other sites More sharing options...
cal.n Posted June 2, 2017 Share Posted June 2, 2017 Good luck, will be following with interest. Link to post Share on other sites More sharing options...
Pikey Posted June 2, 2017 Author Share Posted June 2, 2017 Here's the donor model before I hack it up. Four main components - a metal body, clear plastic windscreen and side windows moulding, black plastic interior moulding, and a plastic chassis loosely holding the axles, which is fixed to the metal body with 2 small screws. Initial plan is to bin everything but the metal body and screw the new chassis to it with the two screws. I suspect the servo will stick out through the windscreen though. Had confirmation (in English) that the parts have been dispatched today, within a few hours of ordering! Excellent Link to post Share on other sites More sharing options...
Pikey Posted June 2, 2017 Author Share Posted June 2, 2017 1 Link to post Share on other sites More sharing options...
BG John Posted June 2, 2017 Share Posted June 2, 2017 I'm glad I'm thinking of having a go at some vehicles in 7mm scale, and not given any thought to 4mm! It won't be until after I've got some RC trains running though. Link to post Share on other sites More sharing options...
Pikey Posted June 8, 2017 Author Share Posted June 8, 2017 Parcel arrived this morning: The 3D printed chassis has a rough texture, sort of like it was made out of salt. The servo and tiny motor are a perfect interference fit. I'll have a go at putting the steering together tonight, I think I've got a screwdriver small enough..! Link to post Share on other sites More sharing options...
Pikey Posted June 9, 2017 Author Share Posted June 9, 2017 Setting everything out ready for assembly: Adding the motor, servo and steering assembly to the chassis: As it sits now: Time to start chopping up the standard chassis so that it fits inside the van body. 2 Link to post Share on other sites More sharing options...
Robin2 Posted June 9, 2017 Share Posted June 9, 2017 Looks great. Presumably you could saw the front off the chassis to get a longer wheelbase or to turn the servo mechanism back-to-front if needed for a better fit. ...R Link to post Share on other sites More sharing options...
Pikey Posted June 9, 2017 Author Share Posted June 9, 2017 Yes, you're right, the servo would go in the other way round I think. Great idea Link to post Share on other sites More sharing options...
Pikey Posted June 9, 2017 Author Share Posted June 9, 2017 Needs a little more chopped off the front of the chassis in order to get the wheels further forward, and allow me to clip the front plastic bumper back on. Link to post Share on other sites More sharing options...
Robin2 Posted June 10, 2017 Share Posted June 10, 2017 (edited) Or scour the streets of London to find the prototype HobbyKing sell very small "linear" servos that might be a better fit. I don't recall the exact dimensions but they are for very light flying models. ...R Edited June 10, 2017 by Robin2 Link to post Share on other sites More sharing options...
otherplanet Posted June 10, 2017 Share Posted June 10, 2017 Just spotted this new topic and will be following with great interest. best of luck, its looking great. These 3d printed chassis must be new, i havent seen them on mikromodellbau before. It looks like a brilliant idea. please keep going and keep posting. Link to post Share on other sites More sharing options...
Giles Posted June 11, 2017 Share Posted June 11, 2017 (edited) Good stuff! Edited June 11, 2017 by Giles Link to post Share on other sites More sharing options...
fallen Posted June 11, 2017 Share Posted June 11, 2017 Nice! Frank Link to post Share on other sites More sharing options...
Robin2 Posted June 11, 2017 Share Posted June 11, 2017 I can see the value in the motor/gearbox and the steering parts but I suspect it would be easy(ier?) to make a simple etched brass chassis to hold them and position them properly for whatever body you might be using. ...R Link to post Share on other sites More sharing options...
Pikey Posted June 12, 2017 Author Share Posted June 12, 2017 In the future, I would like to develop my own 3D printed chassis, specific for the van (or whatever model I'm doing at the time), so I could make it line up exactly with the screw mounting points, hold the servo the other way round so it will go in behind the windscreen etc. I'm going to be ordering the receiver, battery, charger, and possibly transmitter from www.micronradiocontrol.co.uk in the next few days. I sent the chap an email over the weekend and he's replied very quickly with some very helpful information, which is starting to make the picture a bit clearer as to what I need to finish it off etc. So I'll hopefully be able to get it moving in the nearish future Link to post Share on other sites More sharing options...
Pikey Posted June 14, 2017 Author Share Posted June 14, 2017 Ordered radio gear and battery and charger today, fingers crossed to have them by the end of the week. The thing I'm pondering now is what to do about wheels and tyres. The rear axle and two front stub axles are 1mm diameter. The van's original wheels were pressed onto larger diameter axles, and so they dont fit tightly onto the new ones. I'd like to re-use them ideally, not sure how to do that just yet. Link to post Share on other sites More sharing options...
Pikey Posted June 14, 2017 Author Share Posted June 14, 2017 Just doing a bit of searching, found this image: Which looks exactly like what I need to do - on the left is part of an original Oxford Diecast axle with cross-hatch bit that the wheel pushes on to, with the remaining part of the axle filed down to a smaller diameter so it will fit in the hub. The part on the right is the original stub axle provided in the kit. But then how does it stay in the hub without a flange on the end? Link to post Share on other sites More sharing options...
Robin2 Posted June 14, 2017 Share Posted June 14, 2017 (edited) Can't you put some sort of sleeve to reduce the size of the hole in the wheel? You can get brass tubing where each smaller sizes fits inside the next larger. Some with a 1mm ID might fit the 1mm stub axle. (That's not a joke - you will need to check the fit). Another option for a sleeve might be some insulation from a piece of electric cable. ...R Edited June 14, 2017 by Robin2 Link to post Share on other sites More sharing options...
otherplanet Posted June 14, 2017 Share Posted June 14, 2017 concentric tube can work really well, If you excuse a little cross linking http://www.rmweb.co.uk/community/index.php?/topic/96611-radio-controlled-road-vehicles-on-upper-benllech/?p=1941736 you can get thick walled sizes from most model traders who specialise in tools and materials. for the really thin walled tube I have found albion alloys to be really good. https://www.chronos.ltd.uk/acatalog/Abion-Alloys---Precision-Metals.html Link to post Share on other sites More sharing options...
Pikey Posted June 15, 2017 Author Share Posted June 15, 2017 (edited) I tried filing/grinding down the original axle, it didnt work very well, so thats all in the bin. For the mk2 I simply put a blob of glue on the end of the axle and glued the original wheels on. It seems to have worked so far, but they might be a bit wobbly in use, and ultimately I suspect they will just break after a short time, so something along the lines of a metal or plastic sleeve for the centre of the wheels will likely be the permanent solution. I also noticed that I'd put the hubs on the wrong sides. They're very slightly eccentric, so putting them on the wrong sides caused the van to have about 10 degrees of toe-out (can be seen in the previous pictures), this has now been corrected. So, I now have four wheels on my wagon: The wheels dont fully turn left, I need to file a tiny bit more away from the front bumper to acheive this. Edited June 15, 2017 by Pikey Link to post Share on other sites More sharing options...
Robin2 Posted June 15, 2017 Share Posted June 15, 2017 (edited) I like the dash-cam I wonder if you could turn the servo body through 90 degrees would it fit? But maybe things are designed (at the moment!) so the shaft is on the centre line of the van. ...R Edited June 15, 2017 by Robin2 Link to post Share on other sites More sharing options...
Pikey Posted June 15, 2017 Author Share Posted June 15, 2017 I was thinking about turning it 180 degrees - but actually I think this may still foul the windscreen. I've since discovered that you can get a 'linear servo', which would lie flat, and may even allow me to reinstall the dashboard over the top of it Link to post Share on other sites More sharing options...
BG John Posted June 15, 2017 Share Posted June 15, 2017 You can also get linear or screw stepper motors (search for both, they're the same thing), that are cheaper, and I think can be much smaller. They need to be controlled differently to servos, but you can get very small motor driver boards to do it. I don't know if/how you would operate them from your Rx though, although I'm sure the information is out there in cyberspace. Link to post Share on other sites More sharing options...
Pikey Posted June 19, 2017 Author Share Posted June 19, 2017 Delivery! Transmitter, battery and charger, and a receiver smaller than my little fingernail! 1 Link to post Share on other sites More sharing options...
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