Questions regarding fitting brasses to passenger car axle journals in situ, without removing the wheelset from the journal boxes:

- Does anyone have "tuning fork" gauges (see attached photo) to measure actual journal diameter (nominally 5-1/2") while still inside the journal box?

- Does anyone have a set of dummy axle journals to fit brasses to, for the range allowed by the spec for 5-1/2 x 10 journals?

If you have something we could borrow for a week or so, please contact me. We'd be glad to pay for boxing, shipping & handling.

Thanks! - Doug Debs
Niles Canyon Railway
cell 650-704-1487

Why not just use a caliper? Not too expensive and very accurate when used correctly.

That looks like more of a go/no go or use/condemn gauge (pass through the first point is new size, second point is condemn the axle as too worn.

all you need is an old style friction joint caliper, most people have no idea how to use them: http://www.mcmaster.com/#1962a36/=13ys6h0 They tend to be common enough that up here any large flea market will have 3 or more vendors with a pair on the table, as they used to be as common as dirt since almost every mechanic, machinist, engineer and cabinet maker had multiple pairs in their toolbox.



Measure the distance between the points after you bring the tips close enough that they just barely drag on the axle. Usually easiest when you keep one leg in constant contact and them rock the other leg into contact. If the leg deflects at all you are still too tight.

Rich C.

Greetings:
The legs of a typical set of calipers won't fit inside a journal box when open, hence the "tuning fork" design.
Doug: we have a set of these and would be pleased to lend them.
J.David
PS: I have never seen or heard of "dummy axles"... JDC

Doug, the riding diameter of the brass will be determined by the mandrel on which you pour the babbit. So, just make it to suit the axle - very slightly larger than the measured diameter. Ride it in with Time Saver lapping compound by shoving the light truck around the shop a bit - you'll get a great final fit.

JDC, a dummy axle is one used on a steam locomotive dressed up as a streetcar. Don't see them much these days unfortunately - they would make city life a bit more interesting.

Thanks to this thread I now know what these are for. They have been in my office ever since I got them off the P&LE in the mid 90s. Never really paid much attention to what they were. 5x9, 5 1/2 x 10 and 6 1/2 x 12 sizes.

David,

I normally would not disagree with you on a lot of things RR, but as a Machinery Designer, part time machinist and Yan-kee tool task redefiner, I will have to disagree with you on this item. Of course you wouldn't use it in the normal orientation, the caliper would oriented parallel to the centerline of the axle (so the pivot is outside the journal box opening). I know it works as I have done this exact method (when sizing a coupling for an installed machine, only access point was from the removed pump's location and bolts holding guard were frozen) and depending on the design of the journal box, there maybe enough room between the axle and the sidewall so you can measure with the waste and old bearing brass (or temp wood blocking) in place, just measure across an angled line (as compared to horizontal or vertical). Otherwise you will have to jack the journal, remove the brass and waste to measure a more vertical line.

Those feeler gauges will only tell you the diameter is between dimension A and dimension B. Whereas the caliper will tell you within a few ten thousandths of an inch, depending on how careful you are.

Rich C.

[quote="crij"]


Those feeler gauges will only tell you the diameter is between dimension A and dimension B. Whereas the caliper will tell you within a few ten thousandths of an inch, depending on how careful you are.

Rich C.

[quote="J.David"]

Of course, you can always use the "tuning fork" gage and a feeler gage to measure the size within a thousandth... plenty close enough for this class of bearing.

.

Those pass-fail gages seem like they'd be ridiculously easy to make on a waterknife.

Kelly, do you realize the OD calipers come in multiple lengths? Here is a 6" (Pivot to tip) size one on both a 1957 6X11 and a 1937 4.25x8 journals (brassy colored axle). If the brasses or packing of the 4.25" were removed then the calipers would slip out, as it was since the wedge and packing were missing on the 6" there was plenty of room to remove for measurement.





[/quote]

The reason I was mentioning getting accurate measurement was because the OP was looking for a mandrel (dummy axle) to cast the Babbitt. Since he was going to have to make one, might as well do it the proper way and make the correct size shaft that will be a few thousandths undersize to compensate for the Babbitt shrinkage, and not have to spend time scraping it into proper size (I am assuming he doesn't plan on running the car for miles on top of miles to wear it into fit).

Does anyone know the shrink percentage for high strength/high speed Babbitt?

Rich C.
(Would have replied earlier, but couldn't get hands-on with photos until Sunday)

Kelly,

If you want to go into tighter places then you will need to find a pair of the articulated or triple jointed calipers. (brass one is an old shop made pair, and the ones on the blue are Starrett [stopped listing them ~1910])





Rich C.

Where the right hand knoweth not what the left hand is doing ...

SRC has an empirically-derived plain bearing car journal protocol where the journal is measured with friction calipers diagonally in the box opening without removing anything. The replacement bearing babbitt is custom fly-cut 0.015 larger. This dimension has given the lowest average heat across a range of journal sizes and axle loadings.

The old go, no-go gauges are anachronistic.

Your mileage may vary ...

What do we do that isn't anachronistic? It's part of what I love about our business.