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I am having almost too much fun learning about 3D printing. I primarily wanted to make internal parts to help improve my engine and rolling stock projects. My beloved TMCC Lionel J1a always had something close to the proper chuff, with two magnets on one of the trailing truck wheels pulsing a reed switch, giving it 3.8ish unsynched chuffs. Even when it had EOB years ago, the chuffs were pretty proper but definitely unsynched. I thought it might be nice to try making a proper 4 lobe cam, which is just a square with rounded corners. Adjusting the cam rotation could get me synched chuff on the crankpin at 0, 90, 180, and 270 degrees. PSC sells a similar device in cast brass but it is probably more practical for smaller scale models. Turned out I needed a microswitch bracket too as the original is long gone along with the smoke lever for the postwar style puffer unit this had originally. After some trial and error, I got it all working a couple nights ago. I learned quite a bit about dimensioning parts and making slots for component adjustment. The cam halves are CAed together and to the axle. I like that the PLA takes to gluing. I probably made 3 or 4 different switch mounts and two cams. My next cam will probably be mounted with small screws like the original sketch shown below. The width of the cam (9mm here) and the placement of the switch are dependent on how much lateral axle movement there is, but this axle is pretty tame in that axis compared to a lot of 3 rail stuff.

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Pete, I snapped the old one out with some side cutters but I like the soldering iron idea better. I've had one or two of these split on me over the years and slip around. It probably doesn't help that these get soaked with smoke oil most of the time due to their location in most engines I've seen. It seems like this was probably an expensive way to actuate a microswitch from a manufacturing perspective. Gotta wonder how these were assembled in the factory.

Marty, I'm not too worried about it slipping at this point as this first one is an experiment. I was more concerned about one of the cam halves falling off and binding the drivers at speed. Being that they are CAed to each other I don't think that's a danger. Like I mentioned, the PLA seems to take to CA quite nicely.  I ordered some 00-80 screws to assemble the next one. The force it takes to actuate the switch is like ~40grams according to the tech sheet so with the height of the switch set correctly, I don't think the switch actuation will bother it. There's a lot of DCC cams out there in the market that go together like this.

@Allegheny posted:

Great job Norm!   Well done.  I don't understand why it wasn't built correctly originally.   Seems like a simple modification and most likely less costly.

Back in the day Lionel seemed to avoid the 4 chuff actuation even though their sounds always had a very nice full exhaust sequence with speed sensitive cutoff effects. If you listen closely to a lot of older RS4 sounds you can hear the cutoff shorten at speed.

The first TMCC engine I can recall with a proper cam-actuated 4 chuffs was the USRA 0-8-0 switcher.

I think part of the reason Lionel went with two lobe cams is many of the TMCC engines relied on puffer units actuated with a lever on the same cam. 4 lobes don’t give enough travel differential. Not sure why they didn’t use 4 lobes on the fan smoke units though. Most of those gave continuous smoke. Easy to upgrade though with a cam. If the cam well is wide enough for two micro switches you only need a full width cam. If only wide enough for one switch then a cam and DPDT relay will give 4 chuffs and puffs. Cost under a buck fifty and a few hours time..

Pete

I think the second run of the L2as had the 4 chuffs and puffing SSMU (maybe?) smoker. The 4 chuffed 0-8-0 I mentioned had a constant stream smoker.

Not sure the DPDT would work right as the RS4 board looks for a rising edge trigger. That's how all these simple chuff triggers (microswitch/cam, magnet/reed, magnet/Hall Effect, etc.) work so well. When making a cam you only have to consider the edges being rounded for a physically non-bouncy switch actuation and not an electrical pulse width/duty cycle consideration. I went with a 1mm radius edge to keep from slapping the switch around too much. This was just a guess really.

I did try to get a little cheeky and actually printed some experimental chuff lobes to epoxy onto the original 2 lobe cam. It actually worked but it was kind of a pain to get the lobes placed just right to get square sounds.

Last edited by Norm Charbonneau

Pat, I sent Mario (the original 3D Mario Parts!) the .stl files for my two versions.

Sid, I did NOT need to see the clear green resin available today! Man, think of all the awesome telegraph poles with clear insulators I could make!

Hahaha. The 3D printing is a crazy world. Tons and tons of options and possibilities.

So...telegraph pole insulator's 🤔🤔😂😂

Norm, both an R2LC and RS4 board only need a contact closure for chuff. They are open collector, 5v open circuit then to ground with the closed switch. Been doing these for a quite a while now. The relay is used only to separate the chuff signal from the 5v needed to drive the fan. I am sure you know but for others you can’t use the same pair of contacts for both chuff and fan power.

Pete

@Norton posted:

Norm, both an R2LC and RS4 board only need a contact closure for chuff. They are open collector, 5v open circuit then to ground with the closed switch. Been doing these for a quite a while now. The relay is used only to separate the chuff signal from the 5v needed to drive the fan. I am sure you know but for others you can’t use the same pair of contacts for both chuff and fan power.

Pete

Well if you didn't want smoke at idle, couldn't you do the old trick Bruk came up with by hooking the fan circuit ground up to the chuff switch with a buffer in line. Very old school and not ideal, but could be satisfactory to some.

Well if you didn't want smoke at idle, couldn't you do the old trick Bruk came up with by hooking the fan circuit ground up to the chuff switch with a buffer in line. Very old school and not ideal, but could be satisfactory to some.

Its not about continuous smoke at idle. With many of the TMCC engines the fan ran continously. No distinct puffs timed with the chuff sound. The get puffs and chuffs syncronized you need either two micro switches or a Double pole relay. I have used transistor buffers to do this but both my relays and micro switches cost me 50 cents. I found this to be easier.

This engine came with two chuffs and continous smoke. By adding these:

image

I ended up with this. Couldn't be easier or at least less expensive.

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Last edited by Norton

Back in the day Lionel seemed to avoid the 4 chuff actuation even though their sounds always had a very nice full exhaust sequence with speed sensitive cutoff effects. If you listen closely to a lot of older RS4 sounds you can hear the cutoff shorten at speed.

The first TMCC engine I can recall with a proper cam-actuated 4 chuffs was the USRA 0-8-0 switcher.

Correct on all points, Norm. We were hesitant about making a wholesale jump to four-chuffs, as the sound could become a "machine gun" at typical toy train speeds.

Nice to see everyone breathing new life into early 2000's Lionel!

TRW

@PaperTRW posted:

Correct on all points, Norm. We were hesitant about making a wholesale jump to four-chuffs, as the sound could become a "machine gun" at typical toy train speeds.

However, it seems that Lionel has made the leap with virtually anything new, even the LC+ 2.0 0-6-0 that really didn't need it.  Many of us actually reduced the 0-6-0 back to two chuffs as it was pretty bad audio wise with 4-chuffs.

You can also see the puffing smoke with only two chuffs on those little switchers.

Yep, I'm tempted to cut off another nub and get one chuff/rev for the little 0-6-0.  When it gets to any speed, even with two chuffs, the sounds suddenly get garbled, the sound set for that particular locomotives is not really done that well.

Todd, Lionel has been kind enough to recode some of the older RS4 PRR sounds that seemed to go out of stock, really happy to keep using them as long as they're available.

I didn't realize they were actually generating new stock for some of those, did you have to request specific models?  There are several that I'd like to get.

@Norton posted:

Its not about continuous smoke at idle. With many of the TMCC engines the fan ran continously. No distinct puffs timed with the chuff sound. The get puffs and chuffs syncronized you need either two micro switches or a Double pole relay. I have used transistor buffers to do this but both my relays and micro switches cost me 50 cents. I found this to be easier.

This engine came with two chuffs and continous smoke. By adding these:

image

I ended up with this. Couldn't be easier or at least less expensive.

This is exactly how I put sound cams and switches in  my locomotives with everything operating from tender axles.

works great!

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Wow, I’m looking at some of these last few posts and I’m glad I went the 3D route for making these parts. I have perfectly synched exhaust at the correct rate and I didn’t have to yank the drivers to put the cam on.

Norm, most of the cam swaps I do have bolt on drivers, so no wheel pulling involved,…it’s literally a bolt in affair….but, I really really like what you guys are getting into with the split cams,….I’ve beat up Mario last night, and intend to ding dong him to death today about it!l…I’ve got a project coming up this week, and that split cam would be a life saver!!…

Pat

Yep, I'm tempted to cut off another nub and get one chuff/rev for the little 0-6-0.  When it gets to any speed, even with two chuffs, the sounds suddenly get garbled, the sound set for that particular locomotives is not really done that well.

If you do that, please post a video of it in action.  I've been considering the same thing for mine.

Speaking of single chuffs, my TMCC Ten Wheeler from 2003 only has 1/rec because it is actuated by a bar on just one of the cylinder rods.  Sounds pretty terrible.  This thread has given me some inspiration to see if I can kick it up to at least 2/rev.

If you do that, please post a video of it in action.  I've been considering the same thing for mine.

Speaking of single chuffs, my TMCC Ten Wheeler from 2003 only has 1/rec because it is actuated by a bar on just one of the cylinder rods.  Sounds pretty terrible.  This thread has given me some inspiration to see if I can kick it up to at least 2/rev.

My guess there is no place for a cam in the engine unless you mill one out. You could do what RonH has done with a two lobe cam on the tender axle, use magnets and reed switch on a tender axle, or John’s chuff generator on the motor.

You will still only get one puff out of the smoke unit unless you install a new fan smoke unit.

Pete

@Norton posted:

You will still only get one puff out of the smoke unit unless you install a new fan smoke unit.

Actually, I'll get no puffs out of the unit because the **** voltage regulator burned out on that loco too.  Since it's a puffer unit, I might just try giving the smoke unit track power with a rectification diode and current limiting resistor.  But as for chuffs, I might see if there's room for a bar on the other siderod that could give me 2 chuffs and puffs.  Otherwise, a cam on a non-driving wheel it is!  Since the drivers are so large, I might aim for a 4-lobe cam.  There's already a reed switch for chuffs, I'd just have to relocate it.

As soon as the LC+ 2.0 0-6-0 gets going at any speed, the smoke is continuous.  There is a cam in the LC+ 2.0 Docksider, it triggers a hall effect sensor.  It originally had four nubs on it for 4-chuffs/rev.  Cutting two off gives you a better range of speeds before the sounds go south.



Sounds with 2 arms is okay at slow switching speeds, but the smoke is still basically continuous.  Hence why I am considering going to one arm on the cam.  But don't get me wrong, they did a great job on the 0-6-0, cramming a lot of stuff into a pre-existing small body.  And I paid only about $25 more for it than I would for one of Lionel's "new" 64' woodsided passenger cars

Actually, I'll get no puffs out of the unit because the **** voltage regulator burned out on that loco too.  Since it's a puffer unit, I might just try giving the smoke unit track power with a rectification diode and current limiting resistor.  But as for chuffs, I might see if there's room for a bar on the other siderod that could give me 2 chuffs and puffs.  Otherwise, a cam on a non-driving wheel it is!  Since the drivers are so large, I might aim for a 4-lobe cam.  There's already a reed switch for chuffs, I'd just have to relocate it.

Sounds with 2 arms is okay at slow switching speeds, but the smoke is still basically continuous.  Hence why I am considering going to one arm on the cam.  But don't get me wrong, they did a great job on the 0-6-0, cramming a lot of stuff into a pre-existing small body.  And I paid only about $25 more for it than I would for one of Lionel's "new" 64' woodsided passenger cars

That smoke unit is driven by a triac on the R2LC. Its a dollar part from an electronics supplier that can be replaced but shipping will add another ten bucks. I think R2LC replacements are up to 75 bucks now.

Pete

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