1:48n3 Lima Shay #122

[michael mott]

Hi Paul just managed to get to this thread Great to see how you are tackling this model. Yep I think that drilling out the threaded part so that you can insert .020 phosphor bronze rod is just shy of eccentric I don't know why you didn't just machine off the whole bolt and put in 0000-160 bolts Just kidding.

It will be interesting following your progress.

Have you checked out this source. http://www.newmantools.com/taps/micro.htm#threads for anything small that you might need I am always amazed at what is out there when you go looking for it.

regards Michael

[RoughboyModelworks]

Michael:

I'm not shy of eccentric, I'm totally eccentric and proud of it  . To prove it, I've threaded the phosphor bronze rod and machined square-head bolts that will actually fasten the pear-wood pilot beams to the frame. I'm working on some photos showing how I made the bolts that I'll post here and on my blog shortly.

Thanks for the link, I'll check them out. I use J.I. Morris Company http://www.morris01550.com/ for most of my miniature fasteners, taps and dies. They provide an excellent, though rather pricey product. There are some photos elsewhere on this forum of some 000-120 flathead screws I use to fasten bearing retainers on a 1:48 Kodama K-27. For this project I had the time to make them so I figured "why not," plus it saved money.

Paul

[michael mott]

To prove it, I've threaded the phosphor bronze rod and machined square-head bolts that will actually fasten the pear-wood pilot beams to the frame.

Brilliant!
Thanks for the link, I actually have an old Small Parts Catalogue circa 1973 ish but it is buried in the boxes of books in storage, i would imagine the prices will have gone up a bit

regards Michael

[RoughboyModelworks]

I found that picture of the K27 pedestal block I referred to in the post below.

Paul

[RoughboyModelworks]

I just published Part 3 in the Shay construction series on the Roughboy blog http://www.roughboy.net/shinola. I've included a couple of teaser photos here.

The first is a picture of the end beam brackets mounted on the frame rails showing the .018" dia. x .100" L. phosphor bronze pins that lock them in place.



The second picture shows the finished scratchbuilt, square-head bolts used to bolt the pear wood end beams to the frame. The bolts are threaded as are the corresponding holes in the brackets. I had to fabricate an adaptor for my Emco lathe to fit my Boley Jewellers collets in order to bore and turn these bolt heads. The collets afforded me the ability to bore the stock at absolute centre. The bolt shank is .025" dia. phosphor bronze rod. The heads were fabricated from .040" sq. brass rod.



The third shows a finished bolt temporarily in place in the frame.



Paul

[John McGuyer]

I do like those bolts. I'm after the guys at Scale Hardware to make 00-90 square head bolts and nuts for us to use on these era engines and rolling stock. They are suggesting a metric size that is close as most of the interest seems to be coming out of Europe and not the US. Incidentally, they do some smaller thread sizes, but only as hex head and not square. Oh the lonely life of a rivet counter that wants things correct.

Meanwhile, keep up the good work.

John

[finescalerr]

Most satisfactory. -- Russ

[michael mott]

Nice work on the bolts Paul, didyou soft solder or silver solder them?

regards Michael

[RoughboyModelworks]

Thanks guys.

Michael I used Stay-Brite silver bearing solder. It's an alloy of silver & tin with a medium melting point, not so high that you risk damaging tiny parts such as these but high enough that you can build-up assemblies of smaller soldered parts into more complex groups using lower melting-point solder.

Paul

[michael mott]

Paul, Thanks for the info on the solder I will have to try and find some.

Michael

[John McGuyer]

Micro Mark has it. They also have the flux which can be hard to find.

John

[RoughboyModelworks]

Micro Mark is a source as John says. Stay-Brite is made by the J. W. Harris Co. and you should be able to find several sources on the internet. It comes in different diameters. I use the 1/32" dia myself. I also use the liquid flux, I find it easier to control and it works extremely well. You don't need much. A small bottle goes a long way. Just be careful not to get any of it on any steel surfaces as it causes almost immediate corrosion. I have an old steel vise that I've designated just for solder work, thus avoiding any potential damage to my better vises.

Paul

[michael mott]

John and Paul Thanks again for all the info .

Michael

[John McGuyer]

Michael,

For flux I use an acid paste I get from Rutland Tool. It works as good as Stay-Brite and as a paste, you can place it with a toothpick. It is also much cheaper.

John

[RoughboyModelworks]

Just a mini-update on the Shay project. I've cut the wood stock for both end beams and the foot-boards. I decided to use Boxwood instead of the previously planned Swiss Pear. Since these parts are more-or-less hanging out in space, I wanted to use a very tough wood that could withstand any unintended knocks or bumps. In addition I have a limited supply of Swiss Pear and another project coming up for which I'm going to need almost my entire supply. Unfortunately the photo doesn't really show the true color of the Boxwood, it's slightly lighter and a touch more yellow than shown. Having such a dense grain structure, it's much more difficult to stain, but more about that later.



The next step is to texture, drill bolt holes, split and carve years of wear into the boxwood. For that purpose, in addition to a sharp scalpel blade, I use some micro gravers. The main ones I use are shown in the photo below. I think I may have purchased these from Micro Mark many years ago, but I'm not sure. It's important that they be as sharp as possible, so before doing any carving work I sharpen and hone them. I have a lot of experience sharpening plane irons and chisels freehand but for these miniscule cutting tools (for reference the smallest round cutter in the photo is .035" dia.) I adapted a plane iron sharpening fixture to hold the tools at a constant angle while sharpening. With cutting planes this small, it's very easy to create a rounded or multi-angled cutting plane if you try to sharpen freehand which will render the cutter effectively useless. It's also important when sharpening any cutting edge to remember there are two surfaces that need to be honed to produce a working edge. The back surface of the flat cutters needs to be honed perfectly flat as well. The round tools need to have the shaft buffed as smooth as possible at the cutting edge.



Paul