Scale Model Nuts for Model Steam Engines

[divb]

I am looking for some smaller nuts for a model steam engine that are scaled to the smaller size of the engine. Standard American sized nuts are rather large and don't really fit the scale of the model.

I am building a PM Research Model #3 Steam Engine that uses 5-40 screws. I want to make some better looking black oxide studs with black oxide nuts on the end to bolt it together.

Unfortunately typical 5-40 black oxide nuts have a rather large diameter across the faces that doesnt really fit the scale of the engine.

Can anyone recommend a source of black oxide 5-40 nuts that are smaller and more scaled to model steam engines?

 

[IanN]

Hi,

In the UK we have BA size bolts with "one size smaller" heads, I have no idea whether the same sort of thing is available in the "Colonies". See:

https://www.ba-bolts.co.uk/smallhex.html
Alternatively, just drill, tap and use smaller bolts - I doubt if any bolt on a model engine is stressed at the limits of its specification (you can always do the sums if you are worried)

If you are really bothered by this you can always follow Cherry Hind's (Hill) approach - she made all the nuts and bolts in her models by hand to the required scale size. She is on record as saying that if she dropped one, it was quicker to make another than to scrabble on the floor looking for the one she dropped....

Have fun,
Ian

 

[Jasonb]

Assume you are in the US as using 5-40. These people do small hex UNC though I don't know of any source for black oxide so probably have to black them yourself.

https://godshallscustommachining.co...ws-steel-screw-sizes-0-80-1-72-2-56-3-48-4-40https://godshallscustommachining.co...screws-steel-screw-sizes-5-40-6-32-8-32-10-32

 

[cheepo45]

I just finished making a batch of 4-40 scale size nuts for a Parcell and Weed engine I'm working on.
A bit tedious, but they came out well. You can blacken them with cold gun blue.
Scott

 

[R Degen]

mcmaster carr has small pattern nuts Randy

 

[IanN]

:
You can blacken them with cold gun blue.
Scott

An alternative is oil blacking

Ian

 

[Master]

Needed about 100 square head bolts and nuts for a replica Wells Fargo stage coach and under carriage. I just machined them from square brass bar stock. There are several methods of changing the brass to color of choice.

 

[divb]

Thanks very much for all of the great suggestions.

As a bit of background I'm building a PM Research kit that is very nice and very well machined but they supply 5-40 chrome plated Fillister head screws that don't seem to look really great on the model. I saw a really great technique for making studs with bolts in the Keith Appleton Youtube:

MINIATURE STEAM HACKS - PART #10 - MAKING GASKETS AND STUDS

Using his technique all of the bolts are at exactly the same height on the studs and it really looks great. Unfortunately the standard size 5-40 nuts are large and out of scale for a model steam engine.

All of the suggestions here are fantastic. Those of you in the UK have engines designed around BA screws and you are lucky they look really great. Basically that is what I am trying to do here. Your suggestion to just take a size smaller nut (4-40) and drill and retap it for 5-40 is a very good idea.

Thanks for the reference to godshalls live steam locomotives and parts. I had never heard of them before but they manufacture parts and screws sized perfectly for model engines. I will order a few screw lengths from them and see how they look on the engine.

As was suggested I also considered machining nuts out of hex stock and blackening them after machining.

Since this is a learning project I probably will try all 3 of the ideas. I think studs with nuts look much better on a model than chrome plated screws and Keith Appleton's technique seems really simple and able to produce a very consistent look.

Tonight was spent trying to cut a perfect gasket. I finally got it looking good with gasket material. I have some Teflon sheet of the same thickness. Does anyone have any opinions on whether Teflon makes a good (or better) gasket on model steam engines than the standard paper gasket material?

 

[IanN]

Hi,

I my experience the material generally used in model engineering circles in the UK is “Oakenstrong”

Ian

 

[Richard Carlstedt]

A little old maybe , but works great for gaskets is the covers on the old 5 1/4" floppy discs. The paper material is very uniform and consistent.
Rich

 

[comstock-friend]

Godshalls is the successor to American Model Engineering Supply for the scale nuts and bolts. These are a little on the expensive side, but are the best proportioned hardware for small engines and locomotives. I think they look a lot better than the BA hardware sold with Stuart models.

 

[Apprentice707]

I made the two-cylinder version of your engine some years back and used BA hex head nuts and bolts. I just think they look better and I have a stock of them, so no brainer I guess. A good supply of suitable hex bar is always good in these circumstances, after all, there are not hundreds of fasteners on these engines. Good luck with the build

 

[Mike Ginn]

Regarding Teflon gaskets. I have used Teflon, rubber and various polyx materials. They all suffer from creep since they are not stable under mechanical pressure in a gasket situation. You might be lucky depending on the size of the gasket and how thin the border is. In my experience a thin gasket material is always the best and stable and has the advantage of you being able to cut it using a craft cutter such as the Sihouette Craft Robo using a design from AutoCad or similar in dxf format.