Designs that won't work

David K. Smith wrote:
It's called a joke. I suppose I should have put a smiley there, but I can't stand them. (Sorry!)

Meanwhile, the motor is running and the gear train seems to be working. If it weren't for a prior obligation for the afternoon, I might have had it running tonight.

Yes... I know you were joking. Hence, my use of the embarrased smiley and the use of "Gee". No need for an apology, because I took no offence. It takes a lot to hurt my feeling.

Good news about getting 'it' running. I'm sure many folkz are looking forward to seeing your first video of 'it'.

Well David,

You have dashed my dreams to such an extent that now I'm very depressed and I figure the counseling sessions to put Humpty Dumpty back together again will likely run me about the same amount as your loco so I guess I lose all around.

I think I'll go find the highest pitcher's mound, climb up on top of it and throw myself off head first. Life is so unfair

Actually I kind of knew in advance that this was sort of a one of a kind project to begin with so I think I'm going to manage to cope with Monday after all.

Still, the challenge of the project and seeing someone bring it to completion, whether it runs like a scared rabbit or a drunken sailor is reason enough to be excited......sugar or no sugar Alex

Loren

David,

Outstanding!!! 4 grams on top eh? I haven't recieved my GE 25T from Shapeways yet so I don't know, but do you have any idea how much the shell weighs?

John

Dashing Dan wrote:

I haven't recieved my GE 25T from Shapeways yet so I don't know, but do you have any idea how much the shell weighs?

Just a guess, since it's RP resin, probably a very, very small fraction of a gram--may as well make it out of paper.

The only way this could come close to anything resembling a functional model is if the shell was lost-wax cast in brass.

Hello, I am not certain but it appears to me that the rear wheels are not perpendicular to the sides and not parallel to the front wheels. This could be a result of the angle of photography. It could also be the cause of the jerking motion. You may want to check it with some calibers. I think it is great, good luck with it.

TerryH

TerryH wrote:

Hello, I am not certain but it appears to me that the rear wheels are not perpendicular to the sides and not parallel to the front wheels. This could be a result of the angle of photography. It could also be the cause of the jerking motion. You may want to check it with some calibers.

You are right, one of the axles is not perfectly perpendicular to the sideframes. This is a consequence of having made it entirely by hand. However, it's not the cause of the jerking motion. Stalling and jerking is a result of being so lightweight; jerking at the end of the forward/backward travel is due to the fact that I did not throttle it down before reversing direction. I have been thinking of making a second mechanism using more sophisticated tools, since I now have a prototype from which to work; it would be much more accurate.

I think that the jerking with no weight charge is mostly a problem of the power pickup on the axles end. Nickel-silver would bring better result than brass at this point.

Cleantex wrote:

I think that the jerking with no weight charge is mostly a problem of the power pickup on the axles end. Nickel-silver would bring better result than brass at this point.

The wheels and track were not as clean as they could have been; after I'd shot the video, I did a more thorough job of cleaning, and it ran somewhat better. Having said that, I agree with respect to using brass, and future designs will utilize NS for any parts responsible for current transfer.

David, thanks for the feedback, this is a learning process for me. I always appreciate learning new things I am looking forward to your next mechanism.

TerryH

David,
Just wondering if the slightly angled wheel set would would tend to make the loco more prone to derailment in either forward or reverse direction?

I had noticed the slightly off wheel set also. That's the trouble with not having all the sophisticated tools that make building more accurate. Still though a great accomplishment.

tealplanes wrote:

David,
Just wondering if the slightly angled wheel set would would tend to make the loco more prone to derailment in either forward or reverse direction?

I don't think it would have made much difference. But if I do complete a new one, it won't matter because I have the equipment needed to "make it right," and the guts of the first one will get recycled.