Custom Steam Locomotive Rods

[LEGO Train 12 Volts]

WOW black rods ...wise choice! :wub:

[wondermonkey]

Yeah, black would be a HUGE selling point for my EN.

[Locomotive Annie]

Very nice Emerald Knight, Zephyr's rods are the icing on the cake alright.

[zephyr1934]

Finally I can read the tread,and,my God,you made really a good work,

the perfect size of every rods,i'm not skilled to made steam loco,but the day i start...i think we get in touch!

but...inside me...a smal voice tell...is not Lego...is not lego...

i can close one or two eyes,because is really something of excellent what you have made!!!

All the best for your future works,i wait for some surprise!!

And if you want to hit the top,you know what you have to do....long,straight.....monorail!!!!

Thank you for the kind words. It is flattering to think that I am giving a purist pause and having them doubt their conviction (insert evil laugh here). You know you want to buy them. Then soon you will be cutting up lego bits to make your eccentric gears just so and...

In all seriousness though, I have total respect for the purists (I love going one step further and I try to come up with clever constructions out of basic bricks, but that's a different story). I made the first batch of rods for myself simply because I was not happy with any of the available alternatives. If there were longer technic half beams I might never had even attempted this, but now I am glad I did.

Heh heh, Monorail! I don't think it is viable in the present. Early on I had contemplated custom PF track geometries, while feasible they would be insanely expensive and the fabrication precision is not yet tight enough to give consistently good studs/receivers. However, I hope that costs will come down and precision will go up in the next few years. I'll also scratch my head about a hybrid solution for monorail tracks that might be cheaper.

Sorry for crossposting, but I thought this image belonged here as well...

The rods are really nice. I hope it will be possible to order black again. I don't mind doing some drilling and deburring myself.

As I mentioned in the other thread, she looks fantastic. Expanding on that, however, I really like all of the subtle improvements you've made on the EN design. That looks like you are using black tile clips for the lower 3mm hose, did you know that they are now available in dark green? The EN looks so much better with the rod connecting to the middle driver (even a purist can make this improvement using a 7 long technic half beam).

Now as for black rods, yes, if a customer understands that the rods may need to be drilled out before you can fit a pin in the hole and they are willing to do it themselves, I would be happy to fabricate in black again. I was doing drilling the holes out by hand and it took me way too long to do in quantity. I will also keep searching for a viable solution to drill the holes quickly and accurately.

[Cale]

I've been using Benn's new rods on several of my engines. I'm really pleased with the looks and performance of them. They're so much better that the Technic half beams I previously used. Anyway I'm finally getting around to taking some photos of my engines with the new rods.

By little Reading shop switcher #1251

My Baltimore & Ohio #4500 USRA Light Mikado

I can highly recommend the rods. They run very smoothly and look great. And Benn's customer service is excellent!

Cale

[zephyr1934]

Hey Cale, these are looking great and glad to hear the rods are working working well for you. Keep building those fantastic steamers.

[LEGO Train 12 Volts]

Another great work Cale!

Amazing new rods!

[gauge22]

Where can i find the red train wheels in this forum, i have looked everywhere

[UrbanErwin]

Nice rods zephyr1934 they seem very usefull

Where can i find the red train wheels in this forum, i have looked everywhere

official from LEGO

http://www.bricklink...em.asp?P=85489b

and Big Ben Bricks

http://www.bigbenbricks.com/

which site doen't work for me

Edited January 30, 2013 by UrbanErwin

[Duq]

I'm working on a new engine that should be using the custom rods. I've already got the rods in the correct length but now it turns out that my design doesn't work...

Let me try to explain. What I'm trying to do is like Cale's Reading above but with four axles. The connection between connecting rod and piston rod sits beside the coupling rod, rather than in front like on the Reading. As a result the smooth toggle joint goes on the outside of the connecting rod.

Now the problem is that there's enough play in the connections for the connecting rod to wobble a bit and catch the coupling rod, jamming the whole thing. I can't think of a way to stop the connecting rod twisting. I could go for a setup like Cale has on the Mikado but that would make the train 10 wide on the cylinders and that would keep it from running on most layouts.

So I've two questions (or three actually):

Ben, why are your rods narrower than the technic half beams? I think that I wouldn't have this problem if they were the same width.

Could you make them thicker/wider?

Does anyone have any other suggestions to resolve this problem?

[zephyr1934]

So I've two questions (or three actually):

Ben, why are your rods narrower than the technic half beams? I think that I wouldn't have this problem if they were the same width.

Could you make them thicker/wider?

Does anyone have any other suggestions to resolve this problem?

Hi Duq,

sorry to hear that things are not working out smoothly.

The rods plus the cuff on a pin should be pretty close to the thickness of a technic half beam. So there should be very little extra slop when using just a 3/4 pin and a single rod. However, when you use two rods on a full pin, you now have an extra "pin cuff" of slop that wouldn't be there with technic beams.

I'll get to trying to solve the problem in a moment, but first let me give the logic behind the unusual rod dimensions. I made the rods thinner than a technic half beam for several reasons. First, I wanted to be able to paint the rims of the train wheels without a risk of the rods rubbing the paint off. Having the rods float on the pin cuff provides this option. Second, in case I got a batch of rods that came out too thick from the fabrication I wanted to be able to sand them down if I had to. If I had a full cuff I wouldn't be able to do that.

Now for diagnosing your problem, I have two ideas to try and see if either solves the problem. If so, then we know what to do to fix it. First, try flipping the connecting rod over so that what should be the backside is now facing outward (and the side with the groove is facing inward). It will look horrible but we are just testing the spacing. With the rod flipped over like this, the side rod + connecting rod should be comparable to two two technic half beams in width on the pin (excluding the pin cuffs, which are holding the rods in place). If this doesn't make sense, let me know and I'll get you a photo of what I am talking about. Oh, and this tweak will add slop where the connecting rod meets the piston- the pin will now be loose there.

Second, try replacing the the connecting rod with a technic half beam (or if it is longer than 7 studs use a couple of them pinned together like the side rod in the top of this photo). Again, don't worry about looks, this is just to test the dimensions. Be sure to keep the custom side rod on the engine for this test.

I had anticipated that in some cases one would not want the slop, that is why I initially made the 2mm thick washers (now listed under the valve gear bars). I THINK a pair of these has a good chance of solving your problem.

Otherwise, we could bring out the big guns and make a connecting rod that meets you specific dimensional needs, i.e., make it the thickness of a technic half beam by adding a ring on the back side, kind of like the following (meant to skip one rod), only not nearly as deep,

Let me know the results of your diagnostics testing and then we can figure out how best to get you the long term solution.

If none of the above works, I could also try to build up possible cylinder designs that meet your needs while eliminating the current conflict. For this, you'd need to send me photos and/or more details of your specific design (off line or on, whichever you prefer).

Thanks much,

Benn

[Daedalus304]

Hi Duq!

I actually had the same problem at first with my 2-6-6-2 mallet, but I managed to fix it. Zephyr's got a lot of really helpful tips there, but I figured I would share what I did because it's really easy.

What I did was take the connecting rods, and very gently bend them "outwards". Do be careful not to break or visibly kink them, just a wee bit will do. The other thing I did was turn my technic half pins around backwards, so that the stud portion of the pin was hooked into the rod. I don't know how to explain it clearly, so I'll share a picture.

That engines runs beautifully now without issue, and way better than it could have before. I hope this advice can be helpful to you!

Edited April 4, 2013 by Daedalus304

[Duq]

Benn, thanks for taking the time for a detailed reply. I tried both your troubleshooting setups and both work, allthough with the custom rod facing the wrong way it feels like it would take very little to make it snag on the pin cuff that now sticks out the back of the rod. With the full-width technic beams there's no room for twisting as the rods are touching along nearly the whole length (hope that makes sense).

Reading back through the thread (which I should have done before...) I noticed you explained the reason for the width in your opening post. Oops.

I measured the custom rods at 3.2mm which would be the same as a plate. With the coupling rod 'floating on the pin cuff' I'm not sure the 2mm rings will fit. The second solution, with a ring as thick as the pin cuff on the back of the peg hole, would be more to my liking as it would also stop the pin cuff 'peeking out' at the front end.

Daedalus, thanks for your suggestion. There's a significant difference between our engines: you use M-wheels where the crank offset is smaller than on the L wheels. As a result the end of the connecting rod does not get above the coupling rod. I understand what you mean about turning the 1/2 pin around. I had tried that already but as it allows even more play in the connection with the piston rod it didn't solve my problem.

Just to make clear what I'm trying to do (and to show off ;- ) I made this picture:

Custom Rods by Duq, on Flickr

[1974]

The EN looked like shit before, Now it's approaching something good

You did well

[zephyr1934]

Hi Duq,

okay, that is good that you were able to make the problem go away with the two diagnostics. Yes, after I typed my last note I realized that I misspoke about the washers. Way way back in a prototype of the rods I tried a super thin version (basically no cuffs on either side of the rods) and in that case I needed the 2 mm washers for spacers. In this case you would need about a 1 mm thick washer from your local hardware store for the quick and dirty fix. You might also be able to fashion your own washer from paper, cardboard, or a plastic container.

If the washer solution is no good, then certainly a new rod design is feasible.

1. I personally like the aesthetics of an added ring behind one end of the connecting rod, but looking at your render (very nice btw) I am also a little concerned that the side rod could catch the backside of the half pin on the piston. If the piston is mounted securely then in theory the cylinder should always keep the pin out of the plane of the side rod, even though the back ring of the half pin is exposed.
   
2. On the other extreme, I could fabricate a rod that is roughly the same thickness as a technic half beam or play with the pin holes such that the cuff portion is on the back side and would protect the cylinder pin. The thing I don't like about this solution is that connecting rod would now rub against the face of the side rod and this wear might show on the side rod.
   
3. I could put a ring on one end of the connecting rod (as per #1) and on the other end try to taper the back side of the connecting rod so that it thickens to the width of a technic half beam and protects the backside of the piston pin. Though this option also has the risk of wear marks forming on the front of the connecting rod.
   
4. Again use the ring from #1 to stabilize the connection with the side rod. Then I could try to come up with a new connection for the cylinder end, completely eliminating that half pin. I know that I do not have the precision to fabricate something that would emulate a technic pin, but with the ladders, I also know that I can fabricate a bar. Perhaps have a thick bar on the front of the connecting rod for the technic connecter on the cylinder, and then drop down to a bar thickness so that you could push a 1/2 bushing on the end to secure the technic connector. The risk here is that I don't know how securely the bushing would grip the bar. It should work, but we would be flying into uncharted territory and the bushing would add 1/2 stud width to both sides of your locomotive.
   

If you have ideas, certainly let me know and I will also keep scratching my head for other things that might work.

Thanks much,

Benn

[zephyr1934]

Just to make clear what I'm trying to do (and to show off ;- ) I made this picture:

Custom Rods by Duq, on Flickr

While waiting for Duq to decide which way to go on the pin collision problem, a second customer just ran into the same problem. Now in my past haste, I forgot to give all the background, I had not anticipated that someone would mount the rods this way. There is no problem on the front of the rods because the pin heads are all protected by cuffs and in most cases there is no conflict on the back with the exposed pin head. I figured the connecting rod would always extend beyond the side rod. So if the backside of the pin poked out 1 mm, no big deal. As soon as the piston end of the connecting rod has to pass the side rod on a rotation... Houston, we have a problem. What should have been an innocuous tip of the pin now is sticking out there trying to catch the side rod on every revolution of the wheels.

As I mentioned in an earlier post, I deliberately made the rods thinner than a technic beam, and in 95% of the situations that is an asset (e.g., now one can paint the rims of the driver wheels if you are so inclined), here though, it is not. So as discussed in earlier post above, I can make a rod that is of similar thickness to a technic half beam and add a cuff to protect the end of the pin, but there is a risk that wear marks would arise on the side rod.

Nonetheless, it is a perfectly logical way to want to mount the rods. So I've had the boys in the lab recreate the problem, here's a photo,

Rather than using a normal gray half pin, I chose blue to highlight the problem. In this case the pin is in the piston end of the connecting rod and the other rod in the picture is the side rod. Since the pin must cross the side rod in its orbit, it can catch. Argh! Why can't you get the lip of the pin out of there?

Yesterday I came up with what I think may be a better solution,

Take the construction from my first photo apart, flip the 1/2 pin over and push the stud into the piston end of the connecting rod. Then slip on the technic connector, then slip on a 2 mm thick washer (AKA a 1-1 2 mm valve gear bar as listed in my bricklink store). So the washer is on the outermost side of this construction, opposite the wheels. So now there is no lip sticking out of the back of the connecting rod (as shown in the far right) and it can pass the side rod in peace.

Don't have one of these washers handy? It should work without the washer, but there will be a little extra lateral motion in the connecting rod. One could also cut down a technic axle with stud (6587) and use a 1/2 bushing to get the same effect.

----

Doh, after posting this post, looking again at the history, credit for this brilliant idea should probably go to Deadalus304

The other thing I did was turn my technic half pins around backwards, so that the stud portion of the pin was hooked into the rod. I don't know how to explain it clearly, so I'll share a picture. http://www.flickr.co...157632187200464

Edited May 17, 2013 by zephyr1934

[alainneke]

... my black rods arrived earlier this week:

Emerald Night with Zephyr's custom rods by alainneke, on Flickr

Finally got rid of those Technic beams!

[zephyr1934]

... my black rods arrived earlier this week:

Emerald Night with Zephyr's custom rods by alainneke, on Flickr

Finally got rid of those Technic beams!

That is a slick looking EN! I like the rods, even in technic, it looks so much better with the connecting rod actually making it to the second driver. The smoke is the crowning touch.

[ScotNick]

zephyr1934 I have one question: did you think about making your own steam cylinder for the rods? Lego doesn't really have one (they had one about 30-40 years ago!?) and it is not always easy or takes much space to build one?

[zephyr1934]

Yes, I had contemplated building cylinders too. They are certainly doable, but so far I haven't, no one has asked for them. There are a lot of good options in lego already. Right now I am fond of this compact cylinder design,

It is 3 plates deep, with the real work being done by a tiny bracket,

Though you could easily use a technic lift arm with a couple of pins too, e.g.,

or

[rebelego]

Finally got rid of those Technic beams!

Nice!

Off-topic: What smoke generator do you use? Looks like it doesn't get enough power and cough and spit oil. (?)

[alainneke]

Nice!

Off-topic: What smoke generator do you use? Looks like it doesn't get enough power and cough and spit oil. (?)

The smoke generator is made by Seuthe. The smoke sometimes looks a little weird due to the load dependent output of the decoder: little power at standstill (maybe too little as in the photo ), full power at acceleration (nice chuffs, but I wasn't able to get them on the photo) and moderate power at steady spead.

[Duq]

While waiting for Duq to decide which way to go on the pin collision problem

Yeah, it's been a little while hasn't it? Been busy with lots of things lately, not just Lego. I've nearly got the engine finished, just waiting for the final parts before I can take pictures and post them here. A little more patience please. Trust me, it'll be worth it....

Just haven't had the time to put my solution into MLCad...

I had tried the reversed pin but without the ring there is too much play in the connection.

As for cylinders, I really like those 3x3 T beams on their side. They make it easy to have the centre of the cylinder at the same height as the drive axles.

[Duq]

The BR 55 is online so here's my solution for the pin collision/rod collision problem:

BR 55 See-through by Duq, on Flickr

[zephyr1934]

Fantastic build Duq! Looks like the half pin solution works without washers too (but remind me when you place your next order and I'll toss in a pair of washers for this engine).