4-Chuff sound for K-Line Scale Hudson (Update 01/31/24)

The engine has a 2 lobe cam and micro switch to create the chuff sound. It also has a puffer unit for smoke. There are various ways to change the chuff rate to 4 chuffs per rev. Most here use GRJ’s chuff switch which senses and counts lines on the flywheel. A few of us swap out the 2 lobe cam for a 4 lobe. A third option is to paint white lines on the back of a driver and use a optical reflector to create the 4 pulses per rev.

These signals can the be coupled to a fan smoke unit with additional circuitry.

This is mine with cam replacement and fan smoke unit.

This in an example of a photo detector.

And the result.

So you have choices.

Pete

Thanks, those engines chuff rates sound like what I wanted. What would be a good source for the cam, and how involved is the swap? Any other modifications required for just the chuff sound (not the smoke, which I'll often have turned off)? I've rebuilt a fair number of postwar Lionel and Marx locomotives, but this is my first experience with newer scale stuff.

I make my own one piece cams but you can also 3D print them in halves so its much easier to install. You should at least lift the boards so you can see the micro switch as it will likely have to be adjusted. To replace a one piece cam all the rods have to come off and a driver pulled. If you mark the drivers location before removing you shouldn’t need a tool to requarter it.

Pete

I'm lazy, I use the Chuff-Generator.

Thanks, I saw in one of Norm Charbonneau's posts about 3D printed cams that the old ones can either be snipped off or melted off, unless the drive wheel can be unscrewed rather than pulled. I guess I'll just measure the axle diameter, then modify the file I found for the cam in the forum's 3D printing area. I assume this should also work with the K-Line scale Mikado as well.

@gunrunnerjohn posted:

I'm lazy, I use the Chuff-Generator.

I might be looking into a motor swap in a couple years, so I'd prefer to wait to do the flywheel tape method until I start that process.

@mattp.426 posted:

Thanks, I saw in one of Norm Charbonneau's posts about 3D printed cams that the old ones can either be snipped off or melted off, unless the drive wheel can be unscrewed rather than pulled. I guess I'll just measure the axle diameter, then modify the file I found for the cam in the forum's 3D printing area. I assume this should also work with the K-Line scale Mikado as well.

The 3D printed cams can work in the Mikado as well, ….be advised, there is few different cam lift sizes. They are not all the same. Some of the ones Norm uses will never fit in the cam well of a Kline, ….the Kline doesn’t give a lot of room for error, it’s a pretty tight cam well,…….you can carefully slice through the base circle of the cam lobe in two places, and harvest the halves for measurements,…..Pete’s one piece cam is absolutely bulletproof, as it can never fail,……you have to think about the two piece cam before just slapping it in there,….the axle obviously has to be super clean, & scuffed to hold the cement well,……

Pat

If you change the cam, it can also operate the puffer smoke unit to match the chuffs.  Harmon yards put the new cam in for me while getting some other work done.  Prior to this, I did not realize the cams were plastic, which will change how I upgrade future engines.  I feel like the puffer the smoke unit is still fun to use and just enough smoke for me to enjoy it being on all the time.  I can post video if interested.

Funny as I was listening to Pete’s video, i hear the 1 out of 4 chuffs being off sound wise when run slow.   My engine makes the same odd 4th chuff like it is cut off early.  Initially I thought it was the micro switch but replacing it did not resolve it. It must be something with the sound system.

Mike

@Hump Yard Mike posted:

If you change the cam, it can also operate the puffer smoke unit to match the chuffs.  Harmon yards put the new cam in for me while getting some other work done.  Prior to this, I did not realize the cams were plastic, which will change how I upgrade future engines.  I feel like the puffer the smoke unit is still fun to use and just enough smoke for me to enjoy it being on all the time.  I can post video if interested.

Funny as I was listening to Pete’s video, i hear the 1 out of 4 chuffs being off sound wise when run slow.   My engine makes the same odd 4th chuff like it is cut off early.  Initially I thought it was the micro switch but replacing it did not resolve it. It must be something with the sound system.

Mike

The event duration, ie; how long, & how quickly the cherry switch is closed can affect how the chuff sounds. You can get into the dynamics of it, but it’s can be a time goblin, ….I have a few like yours Mike, that spit one odd chuff, ….not out of timing, just an odd sounder, ……but once all of them are up above 5-6 SMPH, they do rhythm out, ……that’s why Pete’s one piece cam has us beat!!…he can guarantee his lift and lobe separation, where the split cam has to be fiddled with….

Pat

Here is a 3D split cam next to a one piece machined cam and a stock two lobe cam. Hard to tell its two lobe due to the sidewalls but it may actually be the one from the K-Line Hudson. Note too the machined cam is for another engine and if you used this one the micro switch bracket would have to be moved. If you have a 3D printer the first thing you would want to do is measure the major diameter if you planned to cut the old one off.

Pete

The beauty of printing your own mechanical chuff cams is that they can be sized to fit any engine. I glued the one in my J1a then made one for my S1 that used screws:

If I were to make more they’d come out quite a bit nicer now that I switched over to Cura for cleaner slicing.

Whether they are glued or screwed, the nice thing is that the chuff can be phased to match crankpin angle during setup, something that I seem to be obsessed with. I put a slight radius on the rising edges to actuate the switch smoothly. Keep in mind I’ve never made one to actuate a puffer lever but I’m sure a PLA printed cam would be durable enough.

Don’t get me started on my magnet cams, that’s probably my favorite way to trigger chuffs now. There should be a thread or two on the 3D forum.

PLA is plenty durable for these, ….I had my doubts when my son ran me off a batch, so I did a test with a puffer lever, and the PLA cam on a drill,….I zip tied the trigger on the drill and let her rip for 15 minutes, …..virtually zero wear,…..

Pat

@Hump Yard Mike posted:

Funny as I was listening to Pete’s video, i hear the 1 out of 4 chuffs being off sound wise when run slow.   My engine makes the same odd 4th chuff like it is cut off early.  Initially I thought it was the micro switch but replacing it did not resolve it. It must be something with the sound system.

That is part of some of the sound files.  I see that with my Chuff-Generator, and there's no variation of the timing of the chuff pulses.

One of the manufacturers used two cherry switches mounted ninety degrees apart to generate 4 chuffs from a two lobe cam.  I think it was 3rdRail.  Someone else on the forum may know for sure ?  As for some chuffs sounding different it happens on real steam locos The valve linkage can be less than perfectly synchronized from one side of the loco to the other and one or two beats may be fractions of a second shorter or longer than the opposite cylinder. The timing, controlled by the eccentric crank, may be perfect from one side to the other however the cutoff can be slightly off. Such as, one cylinder can be at 40% cutoff and the other side at 45%.   That was one of the reasons the Baker valve gear was designed to eliminate the uneven ware on the Expansion Link of the Walschaerts valve gear.        j

@gunrunnerjohn posted:

That is part of some of the sound files.  I see that with my Chuff-Generator, and there's no variation of the timing of the chuff pulses.

Yes, some sound cards, like the Lionel generic steam have that odd chuff when you set them to 4 ……some of the RS4, etc, ( the better cards ) you can play with the switch activation, and get it cleaned up, …..from my practices, the quicker the on/off event is, the more pronounced the individual chuff is,…..

Pat

I used model airplane wheel collars flattened on opposite sides to activate a cherry switch.

Examples: One on a Hudson and two for a cab forward.

@gunrunnerjohn posted:

I'm lazy, I use the Chuff-Generator.

Hi John, what's the pricing on the CG's, and do we get them direct from you or thru Hennings?

You can get them from Henning's, and I suspect they even ship to Canada.

@mattp.426 posted:

I'm wondering about converting my new-to-me K-Line scale Hudson to have 4 chuffs per rev. Does this locomotive have physical cams on an axle, reed switches, flywheel tape, or chuffing handled completely by the electronics? I was only worried about the sound, I will probably leave the smoke alone until I get brave enough for a motor swap. Also, why does it have two 9V battery terminals inside of the tender? I replaced the battery that was in there since I run on conventional, but didn't plug anything into the other one.

This engine is a real beauty, too bad I don't have a proper passenger train for it...

It is not well documented but K-lines cruise electronics also had the ability to generate 4 chuffs. It probably was not used because of the puffer smoke unit that is driven by a 2 lobe cam so they just used a micro switch. I converted my Hudson to 4 chuffs with a simple wiring and program change . I wish I could remember how I did it as I have lost the instructions I used. Of course the smoke only puffs every other chuff. I need to put a fan driven unit in to fix that.

@Rod Stewart, You’ve asked a great Question, I’m not sure that your aware the Harmonyards, the Harmon Shops, can take your K-Line scale TMCC Hudsdon, to a far superior level making it a stump puller, a huffing, Puffing, Chuffing, Smoking, exceptionally beautiful Locomotive. He can make the headlight look like the real thing… He can also put a Pittman motor and MTH Chassis under the boiler and then, my friend, you have the most powerful hudson on the planet… It takes him some time, but it’s well worth the wait. Here’s mine… Happy Railroading Everyone

My Hudson has a lot of added scale detail.

Scale trucks front and rear, generator piping and all appropriate air pipes.

Thanks everyone for the help, I'll start getting ready to perform the surgery once i graduate from my program in a month. I've decided to go back and get the matching K-Line scale Mikado, which will also need the chuff mod

@leapinlarry posted:

@Rod Stewart, You’ve asked a great Question, I’m not sure that your aware the Harmonyards, the Harmon Shops, can take your K-Line scale TMCC Hudsdon, to a far superior level making it a stump puller, a huffing, Puffing, Chuffing, Smoking, exceptionally beautiful Locomotive. He can make the headlight look like the real thing… He can also put a Pittman motor and MTH Chassis under the boiler and then, my friend, you have the most powerful hudson on the planet… It takes him some time, but it’s well worth the wait. Here’s mine… Happy Railroading Everyone

Thanks for the info Larry. I am aware that Pat does awesome upgrades and work. I have a K-Line 5343 Hudson that I upgraded to PS-2 a few years back including an MTH smoke unit. It runs great and sounds and looks great too. quite happy with it. If/when the motor fails I would need to go to Pat for a replacement.

The next thing I need to work on is a K-Line GTW tank engine that has a failed cruise unit. So I am thinking an ERR CCM, but not sure how to handle the smoke unit upgrade just yet. Need to take it apart and check things out. I know its pretty tight quarters inside and just not sure what will fit yet. If a CG will fit that might be the easiest way to create a chuff signal.

Great pictures of your 5343 by the way!!

Rod, you only need a Cruise M, not the full Cruise Commander. A GRJ Chuff generator should fit. Super chuffer may be a bit harder.

Pete

I've put the C-G and Super-Chuffer into the K-Line semi-scale Pacific and Berkshire, so I suspect it should fit in the Hudson.  I believe that's a scale model, probably larger than the semi-scale ones I mentioned.

Snap-fit cam experiment.

Great topic here. I find it interesting that once again the bay has a bunch of the K-Line Hudson's popping up, selling overpriced or sitting a bit before someone bites. I'm glad I got one when I did from a TCA member for a great price. Currently that one is at the Harmon Shops where the great mechanics, engineers, and other shop folks are working hard to get it back up to steam.

Also, I love seeing Larry's pics on his that went to the Harmon Shops as well. His was the inspiration for me to get mine.

@Norm Charbonneau posted:

Snap-fit cam experiment.

That's a very elegant solution, I like it! Once I pull the engine apart I'll need to measure the axle diameter.

I made a C-shaped cam to test snap-fitting over the axle of my EM-1 which is on the workbench for a slipped shaft repair. The snap-fit was good but the prob with the C shape is that the gap is big enough to catch the switch flapper in reverse. I could have printed a 'plug' to fill the gap but figured since this is now a two-piece solution, I might want to try splitting it on a 45 across the running face of the cam.

I was having some issues getting a clean print for my screwed-together cam so I thought I'd try this snap fit idea. Could be the PLA I am currently running. The black PLA I used in the photo a few posts above seemed a little better for the small details in this print.

Little update from this weekend, the Mikado runs pretty warm with a similar length train after only 10 minutes, where the Hudson was happy and cool for over an hour. Both have some fresh grease on the gears and oil on the siderods. Also we weren't able to get them to move at the same time as a "train" on TMCC, I'll have to look more into that when there isn't as many visitors.

I may have also devised a way to fit a larger motor into both of them, but I'll need to take a closer look, and get some measurements of the worm gear and wheel, along with the gearbox itself. No guarantee it would work of course, but I think it would be a fun experiment. Good thing I took classes about measuring, 3D modeling and machining for my Mech Engg Tech diploma...

Long time update here, recently got an Ender 3 V2 and finally took it upon myself to 4-chuff swap the Hudson and Mikado. Had them running for about 1 1/2 hours each at the club with a short train with no issues, haven't tried smoke yet. Sorry for the poor photos, the digital zoom on my iPhone 7.

Here's the cam halves after they were printed, black PLA doesn't photograph well I suppose.

Here is the cam well of the Hudson, after I used a pair of cutting pliers to remove the stock cam. I cleaned up any debris before continuing.

Now superglued in, they needed some sanding to get rid of the "elephants foot" from the printing process. That gap between the halves hasn't seemed to affect anything yet.

Here is the stock cam after removal. The only other way to remove it would be to pull the front axle, but I felt this was easier.

Here is the model of the cam in Fusion 360 before I split it and send it to the splicer.

On the Hudson, no further modifications were required, but on the Mikado, the smoke cam also triggers the chuff switch. Since the new cam has shallower low spots than the original, I had to bend the switch arm down slightly. Next steps, add fan smoke and ERR cruise!

Here is a couple videos of them running at the club, I'm quite pleased with the result!