JohnGi

Hi, Instead of Metcalfe you could consider scalescenes (print-your-own-kits) who tend to have

editable signs in their kits. Here is a link to one of their products, they also have low relief ones.

https://scalescenes.com/product/t022c-corner-shops/

I also just noticed this blog.

and the new forum software has added a nice picture and link. (I just

pasted the URL)

Follow the link and there is a guide to making your own signs e.g. what

fonts to use etc.

Hope someone finds this interesting.

Bearing in mind that brass is about 28% as conductive as copper, does the collective RMWeb mind think that either of the brass rods will be conductive enough?

 

 

Hi,

Resistance = (resistivity)*length/area

The droppers will be much shorter than the rails themselves. You're picking brass wire similar to, or slightly less than the cross section of the rail. Therefore the majority of the resistance will be in the rails themselves. I'm sure this will be OK.

John

When used on card, probably at least two coats, it can be sanded with fine wet & dry to give a 'steel like' surface.

 

I mainly use is for coach sides which are then fixed to clear Perspex. I gives a near flush window.

 

The coach side is drawn on the card and the windows cut out. Shellac then applied one coat on the rear and two on the front. Front surface rubbed down and painted.

 

Walter Lishman wrote a couple of articles [scalefour news issues 126 and 127] on panelled coach construction in card. After the shellac dried, methylated spirit was used as a solvent glue to attach the panelling overlays to the sides. I haven't tried this myself but it looks like a slower and less aggressive technique than attaching plastic card layers using solvent glues - more time for adjustment and less chance of leaving fingerprints.

As the previous poster said you can sand the shellacked card. Mr Lishman also filed the window openings with a round file to form the corners - useful to be able to do this if you find accurately cutting on a curve problematic.

John

PS I have seen superglue mentioned as a alternative (to shellac) if you just need to harden card edges for filing.

An excellent piece of work. I don't see any clear mention the scale - and buyers may be better encouraged if that detail is included. Hope it gets a decent price.

4mm. See http://www.rmweb.co.uk/community/index.php?/topic/74067-show-us-your-scratchbuilt-building/page-15?hl=millhouses#entry1287193

I like that on rmweb you can click "Thanks" or "Agree" or "Informative/Useful" or "Friendly/Supportive" plus a few others to show your appreciation of someone's contribution. This avoids cluttering up the flow of the thread with lots of +1s and so on which you see in other forums. On the whole rmweb is a very friendly and well designed forum.

I've acquired a length of 3/4" square section balsa wood and have started to bash it in to shape for the domed roof section 

 

<snip>

 

Then it's adding all those strakes . . . . 

 

Hi Grahame, I always follow your excellent work but don't post often.

I expect if I glued plastic strips to a curved piece of balsa they would straighten out and pop off. Did you pre-curve the plastic strip, and what glue did you use?

John

Hi,

"The Engineer" for 8th July 1921 has an article, photos and detailed scale drawing for two Drewry railcars supplied in 1921.

This has been digitised by Grace's Guide. http://www.gracesguide.co.uk. Registration is now required for download. Here are two low res previews.

You can see some of what is available here https://gracesguide.co.uk/Drewry_Car_Co. There also seems to be a 1927 article about the preserved car which a previous poster supplied photos of. 

Grace's Guide now charge for downloads, I don't know how much as I had some free credits due to registering a while ago.

Hope someone finds this helpful

John

PS

This thread http://irishrailwaymodeller.com/topic/5699-dampbcounty-donegal-drewry-railcar-interior-query for some info on other 2-4-2 railcars.

It's not working for me for some reason, and I have chrome, so idk, also any chance of them picking up the Backwoods 009 kits, like the Garratt & Double Fairlie?

Sorry I model Irish 00n3 so I haven't followed what happened to the 009 kits. Maybe someone else does, or you could ask on NGRM.

John

Well, N-Drive Productions' site is no longer accessible, so I don't know what the status of the deal is now.

Their site works for me. (just checked, using Chrome browser). There's a thread on N-Drive Productions here http://www.rmweb.co.uk/community/index.php?/topic/135024-n-drive-productions. 

[EDIT

This was posted recently on NGRM by Colin Rainsbury

At the larger wagon works there must have been mass-production methods - probably including the use of templates and jigs - rather than individual marking-out of components. 

 

.....

 

No two items were precisely identical but very large numbers of items were identical within acceptable tolerances. That wasn't luck but judgement.

 

Hi,

If I may belatedly add to the above comment, people may be interested in this memoir by Albert Wright entitled "Wagon building in the 1930s" http://www.wrightsaerials.tv/annexe/wagon-shops.shtml.

Isn’t a feedback controller usually a pwm controller that senses back emf during the spaces between pulses?

Yes. The confusion which sometimes arises with model railways is because the pulse frequency of the first feedback controllers was quite low (mains frequency I think) which led to problems with coreless motors. Feedback/pwm control of coreless motors is possible at higher frequencies - that is how DCC decoders do it.

:

Out of interest, how long did that style of uniform last after WW1? I am looking for 4mm military figures that would suit the late 1930's.

 

The new battledress, blouson instead of tunic and gaiters instead of puttees, came in in 1938 I believe.

 

 

Not all branches abandoned the puttees in 1938 so you could probably find an excuse to mix both uniform styles in some early war settings. I saw this a while ago on figure sculptor Andrew Stadden's website, concerning his father's military service.

RASC troops in puttees in 1942 https://static.wixstatic.com/media/ec935c_9370d36444b148fdae1982d5eb1c6bfe~mv2.jpg

Link to Charles Stadden bio https://www.acstadden.co.uk/c-c-stadden

Can I have a source for that please? I'm pretty sure I bought some from the model shop only a few days as Plastic Weld...

Not to be used in paint strippers sold to consumers following a number of reported deaths. Other uses e.g. degreaser still allowed.

https://www.paintsquare.com/news/?fuseaction=view&id=7328

Acetone will also weld PVC.  

 

Methylene Chloride seems to be freely available without certification

 

https://www.chemicals.co.uk/methylene-chloride

That looks like a useful and informative site but you may have to complete a declaration before purchase. They also have a separate page for dichloromethane (even though its the same chemical!). That page does mention a ban on DIY use.

I spoke to somebody today who uses Autodesk123 for 3D design and printing... but not for model trains. Has anybody tried this software ? It looks like it would be easier to learn than Blender.

Autodesk discontinued 123 a while ago

We are making some changes to simplify our Autodesk portfolio and workflows for people everywhere who love to make things. We are consolidating these tools and features into key apps such as Tinkercad, Fusion 360, and ReCap Pro.

 

I personally use Fusion 360 for 3D design, it is free for hobbyists and small businesses. I haven't used Tinkercad, it looks like its easy to get started and learn some principles of 3D modelling but when you want to model real pieces of engineering (locos, wheels etc) you may find fusion 360 is more satisfactory- it is designed and used for real mechanical engineering work.

There is a dedicated thread here http://www.rmweb.co.uk/community/index.php?/topic/125135-the-great-fusion-360-thread/ and this guy  has worked out a clever way of making loco wheels

http://www.rmweb.co.uk/community/index.php?/topic/122847-any-wheel-any-size/ I created a Fusion 360 wheel generator just tap in the diameter, spokes crank throw etc. and Bobs your uncle, I need to refine it but the principle works.

Re-ran the test with new percentage settings

 

5% 0mA

8% 4mA (laser running)

11% 7

14% 12

17% 14

20% 16

23% 18

26% 19

30% 20mA

 

I’ll re-run the tests - I suspect the limits are something like 6% and 27%, and I now need to work out what needs to be changed in the configuration to get the range to be more like 1%-99%.

 

 2mm MDF cuts cleanly at 6mm/s and 13%

 

Hi Simon, 

Did you change the configuration to be between 1 and 99%?

John

Alternatively, a 6.8v Zener diode with a suitable series resistor will shunt any voltage in excess of 6.8v away from the motor.

Assuming a 500mA load @ 6.8v, the resistor needs to drop 12-6.8=5.2v. From Ohm's Law, R=V/I = 5.2v/0.5A = 10.4 Ohms. The power dissipated in the resistor will be VxI = 5.2v X 0.5A = 2.6W. Choose a 3 or even a 5W to be on the safe side.

 

Edit:-Ha ha, that's not going to work is it? It won't work when you reverse the polarity! Stupid boy! That's what happens why you try posting late at night when you're tired.

Try two opposed zeners in series, one will drop the zener voltage, the other will drop the normal diode forward voltage (approx 0.6V).

My last post seemed more negative than I intended. What I meant to convey was that electroplating directly onto the lead seemed to be discouraged for hobbyists, but there's no reason why you couldn't follow a process using an intermediate step as suggested by an earlier poster.

I cannot say why I am not surprised about the poor response of the lead, but I am not. Maybe one of the electroless processes would work, the sort that will coat even plastics and used as a precursor to electroplating. I am familiar (a long time ago) with electroless "strike" to provide a base for further plating

If you google for "electroplating copper onto lead" you get a lot of hits where people ask about copper plating lead bullets. The general consensus is that electroplating onto lead is not something which should be done by the hobbyist. 

e.g.

Everything except for the plastic spur gear and crown wheel is part of the unit as bought. I have seen these units on sale, listed as 200rpm and 300 rpm. The voltage at which those speeds are produced isn't mentioned and some are sold as 3-6v and some at 6-12v. This particular one was advertised as being 200rpm and intended for credit card type door locks. Others mention being for car door locks.

 

The plastic spur gear has a D-shaped hole to fit the output shaft and the crown wheel, which originally had just a 2mm hole, has been opened out and mounted on a turned brass carrier that is fitted with a grub screw to allow for the wheels to be turned for fettling the rods etc. The plastic gears were given to me, so I don't know the source but if anyone can find more I'd like to know. Searches on ebay do show these gears and wheels but they are always packaged with lots of other sizes of gears, which is a bit of a waste but I suppose the packages are still very cheap and the other parts can be used for motorising things such as level crossing gates, turntables etc..

I was also going to ask where you got the final gears from! I found one of the sets you mention on ebay.

https://www.ebay.co.uk/itm/Plastic-Gears-Pulley-Belt-Worm-Rack-Kits-Crown-Gear-Set-0-5-Modulus-60-kinds/162509200917?hash=item25d64d9e15:g:~38AAOSwlY1ZETZj

Containing 75 gears in total, with 11 crown gears identified thusly.

You can also search ebay for the other types, e.g C203A seems to be 20 teeth, fitting a 3mm axle. Hope this is helpful to people.

Thanks.

 

They're cast white metal. I purchased a lot quite a few years back from a trader at an exhibition. There's several styles but they come in sets of three on one sprue/feed. I can't remember the make and I've just got them in a plain plastic bag.

 

G

They might be from Langley models range of building details.

The amazon (US) link https://www.amazon.com/Langley-Models-Decorated-Corbels-UNPAINTED/dp/3598218575 has a picture. There's no picture on Langley's own website

let me know how your experiment goes!

 

Hi again,

Trying out York Model Making's suggestion that mylar coach sides can be attached to rowmark by flooding with butanone. I have butanone and mylar, but no rowmark so I used ordinary plasticard (polystyrene).

I had a piece of 0.15mm mylar in stock.

I cut out a 10mm square of mylar, and another 10mm "window frame" with an 8mm opening, so the edges of the window frame were 1mm wide. 

I then painted enough butanone unto the polystyrene so that it was all wet, and set the mylar on top. After a while it appeared to be attached, but you could see a dark patch in the middle of the mylar square which I suspected to be unevaporated butanone. I left it for 24 hours and the dark patch had almost disappeared.

I was then setting up to take a photograph when all the mylar fell off the plasticard! 

Perhaps I didn't use enough butanone.

Looking back through the thread there have been a lot of other suggestions.

Earlier poster had found acrylic down to 1mm, and observes that thinner sheets (below 3mm get more expensive).

"Precision" acrylic sheet is available down to 0.3mm. Swiss manufacturer, trade name Hesaglass.  One UK supplier is http://www.peerless-coatings.co.uk. Don't know about MOQ and prices. Also modulor in Germany http://www.modulor.de/en/precision-acrylic-glass-transparent-colourless.html, 5.60 euros for a 180x330x0.5 mm sheet. 0.3mm also available but more expensive. Acrylic laser cuts well and can be solvent glued by acetone.

John

May I ask how you stick Mylar to other surfaces? 

Hi, I recently came across your other thread and found it very interesting.

According to http://yorkmodelrail.com/community/docs/Laser-Cutting-Information-sheet2014.pdf

Very interesting and informative thread.

 

More troubling than the surface is the shrinkage of the part. The digital model has an outer diameter of 20.18mm, while the finished brass part is 19.8mm. Shapeways claim a shrinkage of around 1%, somewhat less than the almost 2% shrinkage I encountered. I also suspect that the part has been somewhat polished, even if I ordered a part in "raw brass"

Where did you get your figures? According to Shapeways website..

 

Your model may shrink about 0.15 mm plus 1.5% after casting and finishing.

For rings the inner diameter will be 0.125 - 0.15 mm smaller than your design. On average, the model shrinks about 1.5% after casting and finishing. Scaling up your model by 1% will make your design closer to your desired size.

Using their figures I calculated 19.7 mm for your finished wheel, pretty close to what you actually got.

Branchlines are still in business, under new ownership. I contacted them a

couple of months ago and got a quick response by email. The email address

is given on their site.

http://branchlines.blogspot.co.uk

.. model the flare on a chimney or dome, where it intersects with the boiler of a steam engine...

Use a method like the second post in this thread http://www.rmweb.co.uk/community/index.php?/topic/77750-drawing-a-loco-steam-dome-how-to-get-the-varing-flare/

John

PS I found with fusion 360 I had to make the two bodies which were intersecting into a single body, so I could select the edge to fillet (use Modify->Combine to do this). Then do Modify->Fillet and set Type to "Chord Length"