ER Models Sharknose motor help

[Carolina Northern]

A little more info.

I got some time off today, with nothing waiting at home and the wife suggested some train time (bless her).
I reassembled the chassis, but the body still set too high. Back apart and some shaving off the "shoulders" of the chassis.
Another cleaning and reassembly and it sits just a bit lower than on the ER chassis.

For grins, I tried it with the last of my V-Line shells. I still have one set of unopened ones that I cracked open for this test.
The chassis would take a great deal more cutting to fit the front of the V-Line. This may be a case for the RS chassis in these.

I think I'm done with the chassis, now to the body mounted couplers.

Once I've got the first one the way I want it, my plan is for an A-B-A set.

[pennsyfan1361]

I have four units with the white gears and two units with the black gears. Is there anything to prolong the white gears from cracking like lubing the gears?        Rich

[victor miranda]

ummmm

I am not sure how effective this may be.

I read of a RC car racer who said he boils his new nylon racing rims
to keep them from cracking and breaking during the first few times out.

I know that one can dye nylon by boiling the part with the dye
so hot water must have some effect.

other than that, I can't think of anything that will save them.
it MAY be possible the keep the crack from starting
if the axle is the cause of the cracking,by
putting brass collars over the stubs.

[Alwyn Cutmore]

Caroline Northern,

Sounds like a good deal to me. I guess it is off to the bay to find some split frame FA2s.

Regards

Al

[NYC1956]

I have four units with the white gears and two units with the black gears. Is there anything to prolong the white gears from cracking like lubing the gears?        Rich

No. The nylon gear shrinks as it ages. Because it is constrained by the axle, stress builds until it cracks. It will be a crack running from the axle out to the teeth. Two teeth will now have a space between them, so the gear can no longer mesh with the next gear. That causes the clicking and binding.

The idea of boiling the gears (before they age enough to crack) is an interesting concept. I don't know how that can affect the nylon, but it could be worth a try. If that can soften the material or otherwise relieve the stress, it might work.

[pennsyfan1361]

Thanks for the tip on the white gears, I wonder if  boiling them would save them from cracking?   Rich

[Hornwrecker]

I just checked my two pairs: one has black gears and the other white.  I'll keep a close eye and ear on the five striper, white gear pair.  Surprised that they run the same speed and are at the same noise level.  I'll run them all separated for awhile and see if I notice any differences between them after running for a good amount: put them on a loop about a foot apart after a warmup.

[cgw]

No need to boil them.  Nylon is a hygroscopic material it needs a little moisture,  just needs to be soaked about 24 hours for the plastic to get its full strength back.  When nylon dries out, it gets to be brittle and has a higher probability for it to fracture (crack).   

[pennsyfan1361]

cgw thanks for the idea of just soaking them.    Rich

[pennsyfan1361]

What about soaking the white gears in Glycerin  to keep the gears from cracking? I know that soaking Lichen in Glycerin  keeps it soft so it does not get brittle.   Rich

[cgw]

It would only make an oily mess. That would gum up the gears overtime.  Nylon needs a little moisture in it to have optimal properties.  When it dries out it becomes brittle.  It does not age and shrink.  When it dries out the stress of the friction fit on the shaft is enough to cause it to fracture.   

[pennsyfan1361]

CGW, How often do you think the gears would need to be soaked in water?  Once a year or more often? I thought the Glycerin would help keep moisture in the Nylon. After soaking the gears in water would lubing the gears help in keeping the moisture in them?   Thanks Rich