Lessons learned re. David Smith 282R gantry crane article (Nov '09)

[lionelsoni]

Suggestions that might make soldering to a 1/4-20 nut easier (or even possible):

o  File or grind off the zinc plating that probably covers the nut, at the point where you want to solder.

o  Use acid flux (zinc chloride).

o  "Tin" the nut (and the wire if it is steel) first by coating the bare steel with a little solder, using the acid flux.  Then clean, reheat, and join the parts.

[dsmith]

Bob,

It's great to see someone who read my article and successfully made the crane operation.  You did a great job on yours, and you blended the crane into the layout very well.  Your layout looks fantastic and your video work is excellent.

watch?v=0iJPsdydgdo

[rha90272]

I retitled this earlier thread, to give some feedback on some lessons learned in applying the advice in David Smith's Nov '09 gantry crane article.

I found much of his advice to have great wisdom, the more I got into the project. Here are four things I did a bit differently:

1. I created an 8" slit in my layout, next to the track on one side, to allow the wire from the crane to slide along as the crane moved. I added a weight (actually, a metal measuring tape) to the wire below the layout to keep it hanging straight. (Cutting this slit through 1/2" plywood and 2" of blue foam was the most difficult part of the whole project.)

2. I decided to use a metal geared motor advertised to go 240RPM. I computed that would move the crane one inch in five seconds, which seemed about right. I found a small motor that had just those specifications (Tinkering Supplies, model H04468-01L) with a 100:1 gear ratio. It has the added benefit of a "D" shaped shaft, which made it easier to bond materials to it to build it up to 1/4" diameter, to match the 1/4" threaded rod it's joined to by a flexible tube.

3. I'm using a 3-way on-off-on toggle switch to control movement, with diodes in opposing directions placed on the two different "on" posts.

4. I couldn't solder the wire to the 1/4"-20 nut, because I couldn't get the wire and nut hot enough simultaneously. So I used a strong glue (E6000), and it does the job.

This project was great fun. I've posted a YouTube video (  http://www.youtube.com/watch?v=jCHkRcakRaY ) showing the results.  It's #13 in my series on my LCJ&I Lines layout.

   Bob A.

[rha90272]

Wow, David.  A rapid and thorough response.  Thanks very much for the additional information!

   Bob A.

[dsmith]

[quote user="rha90272"]

David Smith wrote an excellent article on creating forward/back movement for the Lionel 282R gantry crane, in the Nov '09 CTT.  I'm trying to apply the techniques and materials he used.  But this raises several questions:

1. I assume the threaded rod shown as 1/8" dia is really 1/4" dia, because he uses a 1/4" nut.

YES, 1/4 - 20  THREADED ROD IS THE CORRECT SIZE.

 

2. Motor: He specifies a Radio Shack 273-256 motor. But that motor turns 18,000 RPM, which is 300 revolutions/second. The threaded rod has 24 threads per inch, so without down-gearing, the crane would move 12.5 inches per second -- not very realistic or controllable!

THAT IS THE MAXIMUM UNLOADED SPEED AT FULL VOLTAGE.  USING ACCESSORY POWER AND THE DIODE PROVIDES HALF-WAVE D.C. WHICH IS A MUCH LOWER VOLTAGE.  THAT IS WHAT I USE AND IT WORKS OUT FINE.

 

3. He specifies Radio Shack 276-1114 1-amp 50-volt diodes.  But when I bought that item, the packet says they're 1.5-amp 1000-volt.  I don't know enough about diodes to know if this would make a difference.

1 AMP - 50 VOLTS IS THE RECOMMENDED MINIMUM REQUIREMENTS.  ANY VOLT OR AMP RATING THAT IS HIGHER IS JUST FINE.

 

I'd appreciate any clarification and guidance regarding these seeming discrepancies between the article's specifications, and what I find (and have already bought!) at the local Radio Shack. Thanks.

   Bob Anderson

BEING ABLE TO MOVE THE CRANE LATERALLY HELPS TO MAKE THE CRANE LOADING AND UNLOADING A LOT MORE VERSITILE.  IF YOU HAVE ANY FURTHER QUESTIONS, I WOULD BE HAPPY TO ANSWER THEM.  GOOD LUCK!

HERE IS A VIDEO OF THE CRANE IN OPERATION.

watch?v=9XMgh6U3yNM

 

/quote]

[rha90272]

David Smith wrote an excellent article on creating forward/back movement for the Lionel 282R gantry crane, in the Nov '09 CTT.  I'm trying to apply the techniques and materials he used.  But this raises several questions:

1. I assume the threaded rod shown as 1/8" dia is really 1/4" dia, because he uses a 1/4" nut.

2. Motor: He specifies a Radio Shack 273-256 motor. But that motor turns 18,000 RPM, which is 300 revolutions/second. The threaded rod has 24 threads per inch, so without down-gearing, the crane would move 12.5 inches per second -- not very realistic or controllable!

3. He specifies Radio Shack 276-1114 1-amp 50-volt diodes.  But when I bought that item, the packet says they're 1.5-amp 1000-volt.  I don't know enough about diodes to know if this would make a difference.

I'd appreciate any clarification and guidance regarding these seeming discrepancies between the article's specifications, and what I find (and have already bought!) at the local Radio Shack. Thanks.

   Bob Anderson