help please franks s problem

stevedenver

stevedenver

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ive sheered off a screw in the driver axel-

in the past few three of four runs, the screw has unwound a bit, always blocking the drive rod and stopping the engine dead-
and it came off completely today while running,
found it and took it to the bench to clean off debris, cleaned out the oil in the axel hole with meths and a pipe cleaner and used a bit of thread lock ("Lock Tite" -removable type )
and i re tightened it, using some lock tite on a tootpick-
i felt a bit of resistance near the final depth of the insertion-but the screw still had a bit of a way to go before things were flush and fitted as they should have been, the resistance felt but only slight. I thought it was the lock tite setting up, as the screw felt well seated in the threads and not like it was out of alignment, and i didnt use brute force but off came the head -needless to say ive cocked up somehow

-ive added penetrating oil but dont know if it will actually get in due to the close fit and fine threading

but if i cannot get a replacement axle -id appreciate some guidance on how to tap out the screw shaft
or the name of someone in the US, if you know, who can repair it as ive no machinist experience

needless to say, im bummed
 
Steve,
In larger, car type, jobs, it would be a case of drilling centrally into the remaining bit of screw, and then using a reverse threaded stud extractor (known as an "easy-out") to cut its own thread progressively into the drilled screw until it grips and unscrews it.
These extractors are widely available, but I don't know about model engineering sizes.
Failing all this, it's a new axle.
 
yes i was afraid of this-
the screw body is less than 1/16" roughly
im looking into a new axel

and have found a LS fellow in FLA who may help if no axel is available
im hoping that a new axel is a rarely sought part and one remains with Aster in Japan
 
The loc-tite will, by now have a grip. That can be eased by heating the part up to above 120C ish. if the screw tail can then be wriggled out with a point (scriber?) well and good, if not, things can get a little complicated.

Drilling it could be fun, as I suspect it is very small. In an ideal world you would use a drill of the core size of the thread and drill the centre out, leaving just the threads, which could then be picked out, or a correct sized tap run into the hole to clear it.

If the screw is large enough and you can drill a smaller hole down it, an easi-out can be made from a small pice of piano wire filed to a tapered square on one end and GENTLY tapped into the screw and used to rotate it backwards.

Another method which required speciallist equipment is a 'spark eroder', try a small engineering firm locally (might not be cheap).

Failing that, the easiest route is..................................another axle!
 
the screw is quite flush, and possibly ever so slightly counter sunk, unfortunately-not a chance
and i think i could not actually drill anything out by hand due to the requirement of precise, perpendicular drilling as the area is very tight....if i could back out the screw a bit, then i might have a chance, but i havent been able to get anything into the stainless shaft-its quite hard and harder to center and get purchase at all, no less with the friction and the lock tite......
i think i shall sit and wait two weeks for word from Japan
i am hopeful

then if need, I shall lool into sending the thing to the expert LS repairman/machinist in FLA-and if an option, ill have a goodall valve added, and perhaps the burner poker mod (mesh and stuff)-there is enough area for a drill out and re-tap for a slightly larger screw

worst case-failing all-frank will become and 0-4-0 and ill utilize the center driver set for the rear, as it appears that all drivers are identical, including counterweights and all

or, ill reset the center with the damaged rear axel and let it free roll, unattached to the rods and hope no one will notice when the counter weight is off (either figuratively or literally, as i may later determine)

good lessen in being very very careful-i should have know better but hindsight is only that
 
Steve, even though the Loc-tite you used is the removable kind it still has a good grip on the tail. Try heating it in a flame, not enough to discolour it, but pretty good anyways, way hotter than you can touch. That should destroy the Loc-tite and at least give you a fighting chance, unless the screw bottomed out in the hole.
 
Steve ,
You should try contacting Marc Horowitz here in Denver. With his contacts across the US , I am sure that he can direct you to the right party to help. He is going to be at the Colorado Railroad Museum this weekend hosting the SideStreet Banner Works Small Scale gathering. The 13th and 14th the same as last year. We will start at 9:00 A. M . and run until 5:00 P.M. Maybe you could come out.

Charles M
 
thanks charles i will keep marc in mind
thanks for your interest too
ive contacted aster usa to order any old spares and screws-actually ive ordered 2
hans didnt know if any were still around-id imagine that they may be as this had to be rather freakish and i cant imagine a high demand for drivers
-should know in about 2 weeks
steve
 
well ive drilled out the screw -pretty straight and seeming without damage-but now i need to rethread
will try to find the ultra fine tap-otherwise will consider a self tapping metal screw with a very flat head to clear the counterweights

any suggestions????



woull anyone know of a complete axle and driver set from a junker frank s that i could purchase???
 
Steve, if you've drilled out big enough then you might be able to pick out the bits of the old tread with a sharp point, like a small scriber or a darning needle. then run a new screw in, gently back and forth till it goes the whole way.
 
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