Metric Screws for Brass Locomotives?

Model Railroader General Discussion (Model Railroader)
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Hello. I thought I posted this earlier today, but I do not see it showing up anywhere. Anyway, lifetime model railroader but I just signed up for this forum today. Recently I have bought a few old brass locomotives online. These are the classics that were made back in the 1970s or so. Mostly from Japan or Korea. Most of them need some work. One thing I am curious about is the screws used in these locomotives. I suspect they are all metric. I am going to need to find some replacements for some of the screws that have gone missing. My queston is, does anybody know the specifics of some of the screws that were used in these old brass locomotives? I have a screw checker on order, but it only will go down to M1.6 screws on the metric side, and 0-80 on the inch side. I have a feeling that some of the screws used were even smaller than that. I plan to get a reasonable assortment of miniature screws once I can identify what is missing, just want to know if anybody knows the specific sizes of screws the makers of these older brass locomotives were using.

Thanks, from an old newbie.

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[#welcome]to the forum. Newbies are in moderation for their first 5 or 10 posts.

I know Micro Mark sells a metric screw assortment

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McMaster-Carr and Antrim, to name two, stock down through 0000-160, in stainless fillister-head no less. So there are likely sources for anything you identify on the metric side, too. But be advised that Japanese practice in particular involved a number of screws made to non-metric standards. There are posters here who can inform you specifically.

I have not researched a screw plate for the smallest sizes, but you wouldn’t lose by finding one. The counterpart is the real issue: you need one screw or threaded rod of each size and pitch, hard enough to act as a practical chase in bad threads, to appraise just what’s in a particular empty ‘screw hole’ – or determine if a press pin or rivet was in there to begin with. At one time I had a set of cheap pin vises set up with an appropriate screw in each one, with a slight bevel machined to ease starting and then assure alignment in chewed-up threads, as a counterpart to screw plates – but that might be overkill.

Perhaps some of the experts in brass will either know the appropriate fasteners, or can experiment on some of their engines to see what they use. It occurs to me that a ‘sticky’ here somewhere might be a guide by engine or manufacturer to the screws commonly encountered – we’ve already had the discussion for truck screws and coupler boxes…

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I don’t know exactly what you want to know, but I’ll refer to what I know. First, in Japan, the screw standard was changed to ISO metric screws around 1970 (1965-1975). The ones up to that point are called “Old-JIS screws”. Generally, the head of the ISO machine screw is just smaller than the old-JIS screw. But M3, M4 and M5 are not compatible because the thread pitch has changed. These may have been used for weight mounting screws.

For metric screws, “2” of M2 is called “nominal diameter”, which matches the thread diameter of the male screw, so it can be judged by measuring with a caliper. The model railroad is only coarse and no fine pitch are adopted, and there may be one type of screw pitch for each. What I have experienced is M1, M1.2, M1.4, M1.7, M2, and M3. I think M1.7 was special and used by Kumata (KMT). Brands imported from Kumata include Alco, CB, E&P, Fairfield, GHB, Gem, Hallmark, Key, LMB, Lambert, MTM, NKP, Soho and Trains Inc.

And there are machine screws called Micro screws, which heads are smaller than the ISO. Micro screws are used for glasses and cameras. Please note that this may be used in models. However, the pitch is the same. By the way, there are four types of pan heads for each micro screw: #00, #0-1, #0-2, and #0-3.

If you want to know more than the above, please ask. I will ask friends.

Kotaro Kuriu

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Doug,

From the few brass locomotives (Alco Models, NJ Custom Brass) and cabooses (Alco Model & OMI) I’ve picked up over the past few years, M1.4 (x 3mm & x 4mm) metric screws have fit both gear covers and draft gear/coupler box “ears”.

Tom

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Micro Fasteners is my go-to for my model railroad.

https://www.microfasteners.com/machine-screws.html

[#welcome]

Welcome aboard, we’re here to help as well as to be helped!

Mel

My Model Railroad
http://melvineperry.blogspot.com/

Bakersfield, California

I’m beginning to realize that aging is not for wimps.

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Like Mel, I get my stuff from Microfasteners. They offer these;

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Thanks for the help. The current project is a United Sierra 2-6-6-2. I bought it online. It looked great in the photos, but it had some issues when it showed up. Somebody gave it a nice paint job, but when they reassembled it after painting, some parts went missing. Of course a lot of the screws are custom, having various shoulders on them so standard screws will not fit. I am well aware of McMaster Carr, but thanks for the link to Micro Fasteners. The screws offered by Micro Mark are pretty limited.

Sierra 2-6-6-2

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In some cases, another option would be to drill-out the existing holes, then tap them for SAE-type screw sizes.

Wayne

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Yup. The threads are stripped in at least one hole. I may wind up doing that.

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i kinda got frustrated with the literally dozens of metric screw sizes and types and just tap it for 00-80,90 or whatever is close. Had very good luck and saved a lot of har pulling doing this when I have to.