Best Of Spokane, Portland and Seattle (SP&S) 0-6-0 Project

[mmagliaro]

I am working on cutting out the frames now. 
First, we sandwich the two together, drill them, tap them, and screw them together so they will both
then be cut out together and will exactly match (and I mean cut out in the mill).

To get the rod hole spacing correct, I'll do what I've done when making replacement rods for other engines.
If you measure between corresponding walls of the frame slots from one driver to the next,
that should be the distance between the rod holes.   This can get you really close if you are careful.

Then, I make a "scratch" rod out of a simple strip of brass.  Put the drivers in, put on the siderods, and
check it.  If it rolls smoothly and all the quartering is good, then those scratch rods become drilling templates
for the real rods when I make them up with all the delicate curves and fluting.

If it is a little off for some reason, make another scratch rod, adjust,  and try again.   

[Lemosteam]

Max, an average measuring method is what I use.  Measure front edge to rear edge between pockets, then rear edge to front edge.  Add the two values and divide by two.  This will give you the dimension to the between the centers of each pocket and it takes the pocket width into account.

[Chris333]

I hold up my thumb and sight down it with one eye closed. 

[nkalanaga]

Another method used years ago was to solder the rod blanks to the frame blanks, then drill all four at the same time. 

[strummer]

Jeez....just imagine what this guy could do in, say, O scale!

Mark in Oregon

[mmagliaro]

And now I continue with the scratchbuilt SP&S 0-6-0.

Before cutting out the frame halves, I made some drawings of the axles, wheels, and bearings, so I could figure out
about how thick I wanted the frames to be.  I wanted to make them as thick as possible for strength, durability and weight.  I am also designing this engine with the intent that it is a short wheelbase engine, with small drivers, and thus will need only
minimal lateral play in the axles.  Everything can fit quite snugly without much wiggle and wobble for negotiating curves.

Here's my initial drawing for the axle and frame measurements.  The 2mm Association uses a drawing similar to this, but
I drew my own following their basic style (because I liked it!).  My dimensions are not the same as theirs.  I wanted thicker frames
and very little play.  Plus, my drivers are already made and cut to a certain thickness and that is what I have to work with.




And here is how I intend to fit the round clock bearings into the frame slots.  I machined two flats on the sides so
they slide right in, won't spin, and can still "float".



Here's the sequence of cutting out the frames...








A note here: 
I am using brass screws to put the frames together, but that's only temporary while I work on them.
Eventually, those will be replaced by nylon screws so the two frame halves aren't short-circuited together!










Now, I start using my wheel/axle assembly jig, which I've shown before in the thread on wheel making, to put axles and
muffs together.








Here's how I made those axle muffs.




Then I made a temporary styrene block spacer, just to put the frames together over something, drop a wheel in,
and see how I liked the overall width.  That styrene block will be replaced by a set of pieces of
printed circuit board, soldered to one side of the frame (not both).  I noticed the idea of using
PC board spacers in Gareth Ashenden's thread on his scratchbuilt engine.  It's a great idea and
I am happy to "borrow" it.   







Now, on to the nitty gritty of completing the frames and mounting the bearings and axles...

[mark dance]

wow

[CNR5529]

Incredible engineering and execution!

[wazzou]

What they said! ^
Top shelf stuff.  I can only imagine how satisfying it is to reach this point Max and the anticipation of each new milestone in this build.

[peteski]

You made some serious progress Max!  Impressive!  I see that you did make some changes to the original design (like not having channels in the frame to retain the bearings (like you originally wanted).

How did you quarter the drivers (or that wasn't done yet)?

I hope that the Delrin muffs don't crack on you (like the Bachmann or Kato ones do after being under stress for some time).  Maybe good idea would be to install a tightly fitting thin-wall brass tubes over them (like what Victor did to fix the cracked GS-4 muffs, but do it before cracking occurs).  You seem to have plenty of clearance inside the fraomes to do that.  Or maybe simply make the muffs thicker to start?  Again, there is plenty of empty space inside the frames for that.

[mmagliaro]

Thank you, folks.  It is indeed satisfying to have brought it this far, even though there is so much more to do.
This is the first mountain to climb in a whole mountain range before this thing is a finished, running engine.

Pete, I only quartered them by eye in these pictures.  I still need to pull them out, put some Loctite in there, put them back
in and quarter them for real.   I plan on doing that also by eye.  But first, I'll make a set of temporary side rods
(by drilling 3 holes through the bearing holes into a strip of steel or brass) and putting them on.
Then, I'll know I've got the quartering right when I twist and adjust the drivers in those muffs.

It rolls like a dream on the track now, so it if doesn't still do that with my rods on, I'll know my quartering isn't right.
The Loctite retaining compound I'm using has plenty of setting time for me to fool around with them.

I hear you about the cracking axle tubes.  I had originally planned to sheath them with thinwall brass collars (like Victor's
GS-4 repair).  There really isn't much clearance in a few spots for any more thickness.  I could spin them in a
chuck and take off .006", and then put the thinwall K&S tubing (which is .006" thick) over them.  I would then
not gain any more size.  However, just judging by feel, these muffs are not that tight on the axles and I really
doubt they are under enough stress to crack.  They certainly aren't so loose as to be "slip fit".  I do have to gently rotate/twist
the drivers as I push them in to get them in.  But I can do it just by gently nudging them in that way by hand.
I don't have to really press them hard to get them in like Kato and other axles I've felt.

From earlier discussions we have had on this subject, you know that this is a design feature that makes me nervous: counting
on those muffs and Loctite to really hold those axles and not let them slip.  I am going to test it on a spare axle and muff,
and see just how tight it gets with the Loctite (i.e. when I tried it with brass/brass and brass/styrene, they were both
so strong I could not get the tube off the axle.  I had to cut it off, which was a good sign.  But that's not steel and Acetal.)
And I know from chucking these in the mill by their axle so I could widen the tread area on two of them,
that the axle-to-brass-hub Loctite joint is so strong that it did not fail even under the stress of cutting back the flange.
So I'm confident in that hub joint.  The muff one... ewwwwww, I still don't know.

Of course, the Loctite expands as it cures, which might put more stress on the tubes.  Well, look at it this way.
If they do ever crack, I know the guy that made them    so I could make a replacement and address the strength problem
then.

[Chris333]

I like that you made the brass sides to begin with instead of strip brass.

What vise is that? I have a similar one, but the locating pin (in your photo) is on the inside and is a pain to get it set into the next notch. This is the one I have:
https://littlemachineshop.com/products/product_view.php?ProductID=2356&category=

[narrowminded]

Very nice!  A lot of thought, time, and patience exhibited in that device.  

[mmagliaro]

I like that you made the brass sides to begin with instead of strip brass.

What vise is that? I have a similar one, but the locating pin (in your photo) is on the inside and is a pain to get it set into the next notch. This is the one I have:
https://littlemachineshop.com/products/product_view.php?ProductID=2356&category=

Thanks Chris. Strip brass, like from K&S, is all like "dimensional lumber".  As in a 2x4 varies wildly in its width and
it's warped.  But I'm sure you knew all this.    It's not machined, so although it's pretty good,
it's not perfectly flat and uniform thickness.  So I started with a bigger heavier piece and milled it down on both sides
to get it really flat.

My milling vise came from Micro Mark.  But Little Machine also sells it.
https://littlemachineshop.com/products/product_view.php?ProductID=1145

I think I know what you mean by the locating pin, but I don't see that it's
hard to use.  I turn the handle and a steel "track" of teeth just slides one way or the other and a locking
claw drops in and then clamps.

[Chris333]

The 2 vises look similar, but all the workings of mine are under the vise. Sometimes I stick my finger down the jaws and reach under to hold the pin while moving to the next notch. If not I might un-thread the bolt out if it and 

This video shows a 3D inside view of my vise.