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Re: 1/16 Long Tom Project
Posted: Sat Apr 04, 2015 12:29 pm
by Woz
Try adding a R 10mm (h 0.2mm) circle to each corner.
Re: 1/16 Long Tom Project
Posted: Sat Apr 04, 2015 1:34 pm
by jackalope
The last time I was at Aberdeen Proving Grounds before the armor museum was moved I remember the thing as being HUGE so you probly got it right.
Re: 1/16 Long Tom Project
Posted: Sat Apr 04, 2015 7:58 pm
by wibblywobbly
Woz wrote:Try adding a R 10mm (h 0.2mm) circle to each corner.
I will give that a go, the other alternative is spinning it upright so that there is a smaller contact area.
@jackalope It sure is a big gun, I am just hoping that I can stay with this, and get it completed.
Re: 1/16 Long Tom Project
Posted: Sat Apr 04, 2015 8:38 pm
by jackalope
I have no doubt you can handle it.
Re: 1/16 Long Tom Project
Posted: Mon Apr 06, 2015 11:08 am
by AlwynTurner
Coming along great, following on. Alwyn

Re: 1/16 Long Tom Project
Posted: Mon Apr 06, 2015 7:24 pm
by wibblywobbly
Currently doing the undercarriage, which I have had to split into four sections to fit onto the print bed, but yesterday I did the recoil blocks and fitted them. Amazingly they slot into the recoil bed and the whole barrel/blocks assembly slides back and forth. Bit of a shame that the gun will be built in transport mode, so the barrel will be locked down in the rearward position.
Re: 1/16 Long Tom Project
Posted: Tue Apr 07, 2015 8:29 pm
by wibblywobbly
Did the chassis today, redid the front tow hitch to both shorten the length and beef it up a bit so that nothing snaps off when towing. It is now in three sections all made as solid as can be with plastic weld. Woz was right, that stuff works perfectly on PLA plastic, it's as if it is all one solid object. Any fine detail will be done with styrene as there is a limit to what it is worth doing with the printer.
Next task is the front bogey, it's quite simple to do, but the wheels and tyres are a challenge. I could print wheels, but would never find tyres to fit, so I may as well find some Lego wheels and tyres, and design inserts to make them look the part. I can also print wheel adaptors so that they will go straight onto a steel rod.
I am getting to grips with Openscad now, it took a while, but it was worth it.
Re: 1/16 Long Tom Project
Posted: Tue Apr 07, 2015 9:02 pm
by AlwynTurner
Fantastic work Rob, it's almost magical watching this come together. The part about printing bits to marry technics wheels to metal spindles sounds like modern alchemy! Watching not just with interest but total amazement. This is one of my sources of big technics wheels
http://stores.ebay.co.uk/bagsobricks?_t ... 7675.l2563
don't know if these are too big
http://www.ebay.co.uk/itm/Lego-Technic- ... 0889010727?
pt=LH_DefaultDomain_3&hash=item58aec11227
Alwyn
Re: 1/16 Long Tom Project
Posted: Tue Apr 07, 2015 10:17 pm
by wibblywobbly
Someone somewhere makes something that someone somewhere wishes that someone somewhere made.
http://proto-pic.co.uk/3mm-hexagonal-sh ... eels-pair/
Re: 1/16 Long Tom Project
Posted: Wed Apr 08, 2015 8:12 am
by AlwynTurner
Ooooh brilliant find Rob - this would have saved me enormous problems on the bedford build. On your long tom build though you could use technics axles to save the adapters, I did on the 5.5 inch howitzer. If you pm me what you need I may have some I can send you. Alwyn