3D Printed Chuff Magnet Cam - NICE!!

Looks good.  Do you run into any issue with the four magnets so close together?

I have yet to try it so it could be a total fail at this point. The idea is to adjust the reed switch position so as not to pick up a false chuff like you’d do with any other setup. Magnet spacing could be adjusted with tweaking the outer diameter of the cam. The other option is to use a Hall effect sensor. I’m always charmed by how well reed switches work.

Making the part itself was a great way to play with Tinkercad and to get the printer set up. Lots of stuff to play with and discover.

I know the ones on the tender wheel when I used two were frequently pretty tricky to get right, these look even closer.  You might get away with a less sensitive reed switch close to the cam to allow for the spacing of the magnets.

Smaller magnets, Hall effect sensors, 3D printed parts that take 10 minutes to produce, there’s nothing insurmountable here. I have been collecting reed switches in different sizes for a while now. I suppose one could print 4 lobe cams for microswitches too.

Do you have a 3D printer? I can post the .stl and you can give it a try as I’m not sure when I will get to. This part was just to do the initial printer setup and prove out the cad to real part pipeline.

Norm, I think it would be easier to just print cams. No magnets or reed switches needed. If the space for a cam is wide enough you can use two micro switches for chuff and smoke fan, though I know you don't care about smoke.

I machine mine but obviously you could print them as well.

Pete

Norm, before I decided that optical sensors were easier and was still using reed switches I discovered that the magnet did not need to pass by the glass envelope with the reeds but that the leads were steel and a magnet passing by a lead could close the reeds.  I am not sure if this is the case on all reed switches but it was on all I ever bought.  I did all sorts of shaping of the leads to adjust the timing of the closure of the reeds from bending them into a U to twisting them into a spiral or even an L shape . These configurations allow for a very sharp rise and fall of the magnetic field. One configuration I liked was the L where the magnets circular path was tangent to one leg of the L and you cut the length of the leg to adjust the duration of the closure.  The reed switches can even be anthwartship between two wheels on an axle with magnets passing by both leads.          j

Are those stock magnets that come with an upgrade kit? Or could you use smaller magnets if you needed to?

I think this is a great idea for a print though. No doubt about that.

@Norm Charbonneau posted:

Do you have a 3D printer? I can post the .stl and you can give it a try as I’m not sure when I will get to. This part was just to do the initial printer setup and prove out the cad to real part pipeline.

I don't have a 3D printer, I've been avoiding that as another giant time sink that I can't afford to get involved in!   Besides, I happen to have a product that I use for the task, the Chuff-Generator.

I have also had this idea. Similar to Norm I have printed mine, but instead of using magnets I am using them with a cherry switch. I had my buddy print them up in resin.

John, I like your board but quit using it because I kept getting inconsistent chuff rates. It just wasn’t worth the hassle and cost after awhile, sorry.

In any case I think you guys have sort of missed the point of this first exercise. I needed a first part to run through to completion to test the setup of the printer and to see what a simple design might look like once brought to fruition. I consider it a success even if the part serves as nothing more than a magnet holder. This will be one of many parts I plan on using for my DIY projects.

@BillYo414 posted:

Are those stock magnets that come with an upgrade kit? Or could you use smaller magnets if you needed to?

I think this is a great idea for a print though. No doubt about that.

There are quite a few different magnets out there nowadays. The ones I used here are pretty close to what you’d find in an ERR kit. The cams could be tweaked very quickly to host any size or shape available.

@Norm Charbonneau posted:

There are quite a few different magnets out there nowadays. The ones I used here are pretty close to what you’d find in an ERR kit. The cams could be tweaked very quickly to host any size or shape available.

I really like the idea of making a holder like this. It would almost be like the old magnets on the axles of older 3rd rail models like the Mercury and Santa Fe Texas.

@Sid's Trains posted:

I have also had this idea. Similar to Norm I have printed mine, but instead of using magnets I am using them with a cherry switch. I had my buddy print them up in resin.

I may try something like this for my older Lionels like my J1a that had the nylon two-lobe cam. The nice thing about these parts is that you could adjust them to synch the exhaust with crankpin angle.

@Norm Charbonneau posted:

I may try something like this for my older Lionels like my J1a that had the nylon two-lobe cam. The nice thing about these parts is that you could adjust them to synch the exhaust with crankpin angle.

Oh yeah totally. I made these originally for a Weaver I5 Hudson, but plan to install them in some older tmcc models. 4 Chuffs makes an engine 100 times better.

@Norm Charbonneau posted:

John, I like your board but quit using it because I kept getting inconsistent chuff rates. It just wasn’t worth the hassle and cost after awhile, sorry.

WOW, I don't know how that happens.  As long as the tach sensor spacing is right, the chuff rates should be rock steady.  No need to be sorry, if it doesn't work for you, then it's clearly not worth the money.

Sid, I am on a side quest to get all my engines to a proper synched 4 chuffs whenever they come into the shop for maintenance. I’m hoping these 3D parts will help. I made the decision to get a printer after making my last scrap styrene Kadee drawbar on the 5011 Class project. I want better looking parts even if they won’t be seen. Lots of other stuff to make too - roller mounts, truck bolsters, board mounts, speaker adapters and maybe even housings. Watching the first print materialize got me pretty stoked!

@Norm Charbonneau posted:

There are quite a few different magnets out there nowadays. The ones I used here are pretty close to what you’d find in an ERR kit. The cams could be tweaked very quickly to host any size or shape available.

I have used McMaster Carr to get some pretty tiny magnets for holding doors closed. I was just curious if the ones you have are stock in case you needed to go smaller because of space restraints.

@Norm Charbonneau posted:

Sid, I am on a side quest to get all my engines to a proper synched 4 chuffs whenever they come into the shop for maintenance. I’m hoping these 3D parts will help. I made the decision to get a printer after making my last scrap styrene Kadee drawbar on the 5011 Class project. I want better looking parts even if they won’t be seen. Lots of other stuff to make too - roller mounts, truck bolsters, board mounts, speaker adapters and maybe even housings. Watching the first print materialize got me pretty stoked!

Yeah Bruk has been printing shields for the boards we use for a while and the smoke unit funnels as well. I look forward to using 3D printing more as well. I'm working on printing a full tank engine as well. Lots of things can be done with a printer.

Bill, eBay has some 1.5mm and 2mm magnets, 1mm thick. I just used some for sticking to my one of my Decapod’s drivers. Something I hope to quit doing!