Dunitrong Locomotive Works

A place for discussing battery-electric locomotives, whether they're diesel, steam or even electric outline
User avatar
philipy
Moderator
Moderator
Posts: 5033
Joined: Sun Jan 30, 2011 3:00 pm
Location: South Northants

Re: Dunitrong Locomotive Works

Post by philipy » Thu Jun 30, 2022 9:52 am

metalmuncher wrote: Wed Jun 29, 2022 10:08 pm
The wheels have a slight wobble but the quartering is easy and strong, seems to be working OK.
Image

It's looking good Richard. I do like the varnished wood effect.

I always end up with wobble using printed wheels. I guess with me it's from using a bench vice rather than a proper wheel press.
Philip

User avatar
GTB
Driver
Driver
Posts: 1550
Joined: Sat Mar 05, 2011 2:46 pm
Location: Australia

Re: Dunitrong Locomotive Works

Post by GTB » Fri Jul 01, 2022 1:47 am

Looking good. I wouldn't worry about the passengers having to duck to enter, most early railmotors were tiny things, look at the size of the Wee Donegal's first one........

Laser cutting has a lot to recommend it for model making, especially flat panels.
metalmuncher wrote: Wed Jun 29, 2022 10:08 pm the idea was to hold the wheels with superglue, but it wasn't very strong and was difficult to keep everything free. The slightest knock and the quartering could go.
As you found out, superglue is useless as a retaining compound. I use Loctite 601 for fitting metal wheels to axles on live steamers, but I've no experience of using it with plastic wheels. The current equivalent is Loctite 609, I think.

The d shaped axle is self quartering and probably as good as anything else you could use.

I don't like the look of the wheel flanges though, too thick and what looks like a ridge on the front face. I'd be giving them a skim in the lathe, which should reduce any slight wobble as well.
metalmuncher wrote: Wed Jun 29, 2022 10:08 pm So that's where we're up to today, tested ok pushing one of the coaches up the section of track clear of vegetation, just needs a bit more traction, some lead weights might help.
Plastic wheels won't be helping traction, but lumps of metal for the cab control panel and drivers seat will sit over the power bogie and should do the job.

Regards,
Graeme

metalmuncher
Cleaner
Cleaner
Posts: 95
Joined: Sat Oct 20, 2012 4:15 pm

Re: Dunitrong Locomotive Works

Post by metalmuncher » Fri Jul 01, 2022 4:39 pm

Good points there Graeme.

The wheel profile is mostly to the 16mm association spec, so 1.5mm flanges:
Image

They are only 20mm diameter on the treads, so that might be causing the flanges to look a bit big compared to more standard sized wheels.

These were supposed to be test pieces, printed at a coarser layer height resulted in that step in the flange.

I did actually try turning some of these plastic wheels. The surface finish left a lot to be desired. The form tool has clearances but no top rake, not very sharp, so probably not ideal for plastic.
14.jpg
14.jpg (65.98 KiB) Viewed 4049 times
This was with some matte black filament though. Turing the grey stuff seemed to go a bit better. Might give it another go this weekend. If the wheels are painted black before turning, the turning will expose the grey on the treads and flange, might look a bit nicer for not much effort as well.

User avatar
GTB
Driver
Driver
Posts: 1550
Joined: Sat Mar 05, 2011 2:46 pm
Location: Australia

Re: Dunitrong Locomotive Works

Post by GTB » Sat Jul 02, 2022 4:13 pm

Sounds like a plan......... ;)


I use the G1MRA coarse profile, which is pretty much the same as the SM32 one you use. I use a simple rounded tool to turn the tread and form the flange root radius, then a file to chamfer the back and round the outer corners of the flange. Form tools and I don't get on well.

I've never machined any printed plastic parts, but FDM prints are effectively sintered plastic, so I wouldn't be surprised if they won't machine all that cleanly. I've seen solvent used to smooth out the surface on FDM prints, so see no reason why it wouldn't work to smooth out the tread of a printed wheel after turning.

Interesting idea to print wheels in grey plastic and leaving the tread unpainted. The only plastic wheels I use are Binnie curly spoke type on timber bogies. The wheels are moulded in black, so I paint the treads a metallic grey. They look good for a while, but the paint inevitably wears off.

Graeme

User avatar
philipy
Moderator
Moderator
Posts: 5033
Joined: Sun Jan 30, 2011 3:00 pm
Location: South Northants

Re: Dunitrong Locomotive Works

Post by philipy » Sat Jul 02, 2022 5:49 pm

GTB wrote: Sat Jul 02, 2022 4:13 pm
Interesting idea to print wheels in grey plastic and leaving the tread unpainted.
I tried this once, using the resin printer rather than FDM, and wasn't over happy. The resin is a bit paler grey than many filaments, and the black is only crudely applied, but it doesn't look realistic to my eyes.
file.jpg
file.jpg (223.12 KiB) Viewed 4010 times
Philip

User avatar
GTB
Driver
Driver
Posts: 1550
Joined: Sat Mar 05, 2011 2:46 pm
Location: Australia

Re: Dunitrong Locomotive Works

Post by GTB » Sun Jul 03, 2022 2:31 am

philipy wrote: Sat Jul 02, 2022 5:49 pm I tried this once, using the resin printer rather than FDM, and wasn't over happy. The resin is a bit paler grey than many filaments, and the black is only crudely applied, but it doesn't look realistic to my eyes.
The light grey looks more like aluminium than steel. In the distant past there were aluminium wheels avaiIable in HO, which were all I could get at the time. They looked awful and I rapidly changed to blackened brass........ :roll:

Treads need to be dark grey, metallic if possible and I now use Humbrol #53 when I paint log bogie wheels. I tried Humbrol #27003 'polished steel' from the Metalcoat range, which looked good when newly applied, but wore off too rapidly to be useful when run regularly. The bogie in the first photo was done with Metalcoat, but I couldn't find a closeup of a more recent build. The second photo shows wheels painted with Humbrol #53, but out on the track.

Image


Image

Paint sort of works for rolling stock, but I'm not sure I'd use it for locos. I think it would be gone the first time the wheels slipped.

Graeme

Post Reply

Who is online

Users browsing this forum: No registered users and 5 guests