Mikado axles

[Yampa Bob]

When I'm quartering or aligning the rotational crank angles on a side, I like to pull the motor worm gear away from the drive wheel gear.  Then I can lay the wheels and side rod assemblies in the bearings, rotate them and watch the action.

If one wheel on a side is off a bit, the axles will rise and fall accordingly.  The actual quartering, where the left side cranks lead the right side cranks by 90 degrees isn't critical on a model, but as you've noticed, all wheels on the same side need to be exactly aligned.

Easiest to line up if the cranks are at top or bottom, then lay a straight edge along the crank pins.

Well, gee, if it works you can name the engineer "Bob".   

[grumpy]

Find a supplier of plastic industrial pipe and ftgs . You can purchase plastic welding rod of various diam . I would suggest CPVC It should be of sufficient hardness and stuctural strength to do the job . It is also machinable.
Don

[Yampa Bob]

I have also seen listings for ABS, Butyrate and Acrylic but I don't know about the hardness or brittleness.  It would be nice to have delrin or celcon rod for wearability.

[Woody Elmore]

Yampa- NWSL makes (or used to make) a great quartering jig. For the HO engine tinkerer it is a great investment. Also, over the years MR and RMC magazines have run articles on making one from scratch.