The Home Machinist!

To keep up the interest in loco construction, here are the first of the Hudson suspension construction photos.

These are the first of all new parts made as I think that have finally corrected all of the deficencies found in the original model.

The work pictured now comes from the Josslin Hudson design/drawings.

Note how I center machined rectangular work using a chuck jaw stop set on the lathe bed and an indicator. Note also the two flat spacer stiffiners placed between two of the jaws and the eyelet slot. The other two jaws only have brass strip pieces to protect the work. This came out of the school of hard knocks. One must also have tailstock support to turn the long stem of the eyelet down to finished size(1/8").

The construction photos.

Looks very good to me. Keep it up!!

Very Nice!
Jack

Carrdo,

How did you center drill the tail stock side of the work? By simply chucking it up (with only a short bit sticking out) and indicating it in the 4-jar?... then center drilling?

Keep up the good work!

Thanks,
Dan

Dan,

The way I do it and it is just my way in this case is:

The work was first centered in the 4 jaw and then the stem end was carefully center drilled at full extension with a small center drill after the chuck jaws had been tightened. The blank previously had had its ends milled square.

This way, the tailstock center is put in with the work in its natural extended position. The tailstock center may not come exactly on center on the blank but the tailstock support then does not force the free end out of its natural line. The stem, when turned down, stays straight i.e. it doesn't bend to the side when the taistock support is removed.

A delicate feed on the center drill and a sharp cutting tool is definitely required.

In order to form the half round radius where the stem meets the eyelet (this was put in by hand with the same round nose cutting tool used to turn down the stem), the eyelet itself has to project out quite a distance beyond the chuck jaws or the cutting tool will foul when forming the radius. So there is not a lot of jaw support at the chuck. That was the reason for adding the stiffiner pieces due to the school of hard knocks lesson.

The first one I tried holding the eyelet directly in the chuck jaws whipped and bent the blank.

Here is the start of the suspension fulcrums. Normally, these would be bronze castings as seen in the previous photos but since I don't have any of these castings for the (Josslin) Hudson, they are being made from the solid.

I quite often use cheap tracing paper for a lot of my rough outlining instead of layout dye. The outline is made by taping a piece of tracing paper directly over the print part and then tracing the outline. This is just my way as I find I can be quicker.

The end and center plugs are there to hold the paper outline onto the metal surface. One can also use paper glue which, these days, comes in handy spray cans. Unfortunately, the spray cans tend to plug up even if one follows the cleaning instructions.

The end plugs are also used as guides when contouring the ends of the fulcrums. I do this by belt sanding.

I carefuuly drill and ream the center pivot and end holes in the first blank and then carefully mill the blank outline down to the print outline. This piece is then use it as a quide for the remaining fulcrums.

The layout photo is a shot of how the center pivot is used as a reference point to keep it central with the finished outline. In this case layout dye was used.

Don, very nice. That bandsaw helps a lot, you are taking off pretty big chunks of meat there. I was kind of surprised how big those pices are for a 3.5" model. But, perhaps, I do not have a big picture in my head as to where exactly this goes, and how it is integrated in the loco. Thanks for keeping us abreast. It is always interesting to see how other people do things. Good luck with the rest of the suspension. Take care. Vic

I often model put the parts into 2D CAD, like Turbocad or Autocad. You can plot it with lthe ploter set to .010 wide line width and either glue it or tape it to the part. A freind plots it on over head projector slide film and uses that. you can even use wood glue, and soak it off the part after.

You can dimension all the demensions form any datum you want to machine form, so critical dimensions are dialed in on the mill, and the template helps to insure the handels are turned the right number of turns.

I got one of the of the cheep Asian mills with 1/16 of an inch dials. So I always lay out the part to make shure I am not a turn off on the cranks. Ploting on my injet printer is as almost as good as I can lay it out buy hand, and a lot quicker.

Another advantage to putting it on the CAD is sometimes you uncover mistakes form the older hand drawings as well.

Rob

Hey one thing I fogot to mention is the CAD will find center center lines corodiates of fillets, even a fillet between two intesecting arcs and such, very usefull and a lot quicker then doing it with trig.

Rob

Vic,

Here is a photo of part of the Josslin print so you can see what is being made. Hope it helps to better explain the previous construction photos.

Rob,

Yes, you can do the layout exactly as you describe but I am stuck in the sixties with my loco construction methods.

Richard is pushing me to get more involved in CAD/CAM but my brain goes into memory overload when I get 10 layers deep in the CAD commands even with a drafting tablet so for the time being I am planning to stick with my working museum ways.

Don, many thanks. That makes it clearer. Take care. Vic