It's dc and non sound. (Sorry but I'm old fashioned and started well before dcc!)
It's a great runner but a noisy one!
Does anyone have any ideas?
Thank you in advance.
My thoughts without answers. At a certain speed the chatter starts on both of mine, less in reverse. I've left one unaltered and have heavily messed around with the other one, 3004. I thought perhaps the motor was to blame but with a Mashima and non accurately bored out worm the noise was worse. I've had other variations of motors like custom skewed OEM and NWSL both using stock unaltered worms and the the chatter still exists above a certain speed.My Wombat 30T is back in its box, I took it out only to have a bopeep, and take the tail rods off the cylinders as mine is a Superheated version which did not have them, and I have not tried to run it yet.
There is tape underneath the OEM motor which I thought may dampen vibrations and I have experimented with a layer of squished blu tac and other tape to no avail. Then there are those four metal plates which I can't remember off hand exactly where they go, but I think they go between the sides of the metal gear housing and the body, and they might dampen noise. But from memory there was still noise before I took them out so i haven't put them back in.
Then there's the gears. I've only once disassembled everything. The worm, worm gear, reduction and drive gears (not sure of exact names), they all seem finely machined and mesh really well and the chassis finely machined to accept shafts in the right spots. I really can't tell where the chatter comes from except to say I think the gears cause the noise but I don't know where or why.
I've thought that perhaps fewer gears would make a difference. I've an unassembled FSM Z25 kit that has a fine pitched worm and drive gear without idlers. I look forward to seeing if that type of setup is noiseless. On the other hand a Lloyds C30 with worm, idler and drive gear in a NWSL gearbox is smooth and quiet. The major difference is it drives the middle axle which makes the gear box visible. So in that respect the Wombat does well to conceal the gears and any attempt to change the gears to a more direct drive setup would require major and accurate work I'm incapable of.
So I don't know. I'll have another look at this one day but the only thing I'd be prepared to do myself that probably goes against any advice of the more experienced and manufacturers is to liberally apply heavy grease to the teeth of all gears. I'm not recommending you or anyone to do it, but I'll give it a shot for the greater good. Soon.
Did a fair bit of testing over the weekend, results were negligible. I used INOX MX6 and MX8 on two mechanisms a 30T and Ixion 32. Briefly about the greases - MX6 food grade type, is synthetic PAO with PTFE. MX8 is lithium based with PTFE and much thicker.Oscar, looking at the last pic, I gather the gears are some sort of synthetic/nylon or something rather than brass gears that were more common in previous models as I have not purchased anyloco's for some time, the Wombat 30T being the exception, I wonder if brass gears may be better? Other thing I notice and maybe the photo's angle but the 3rd pic looks to me with the large gear to have minimal distance between the side of the gear and the metal side of the chassis/gear setting, could that mean the noise could be the gear rubbing against the metal, as the model increases speed?
The 30T always had a quieter spot which I said was around quarter throttle but after remapping the chip to a straight line to mimic a lineal DC like response, I discovered the mechanism was quieter between 50 - 90% throttle. I used MX6 first which had no effect. After trying to remove some I repacked the area with MX8 and whilst I thought there was some improvement, now I'm not sure.
The 32 had just MX8 applied, repacked twice and it made no difference. The 32 has the gear noise form zero to full throttle.
I videoed and compared everything but they don't capture what you can hear. It's a bit of hit and miss and sometimes unfairly exaggerated so I've not cut a video together. In short, overpacking with grease didn't really improve anything.
I will leave some photos of the mechanisms though because there's one more thing I'd like to try.
Before I greased the mechs I took photos of them just to check they were the same.
The 30T had a little more factory grease compared to the 32 but both were lubed enough IMO. With them appearing the same I wondered why they sounded different. The idler in both mechs can slide laterally and the 30T's idler could move more readily compared to the 32. Perhaps the 30T is more run in. But I would like to try and see if adding bushings, washers and a spring to keep the idler in place will make a difference.
The first two pics show the 30T with idler in different positions and the last is of the 32 showing the same gear arrangement. Helical cut gear and attached reduction are easily visible in the last pic.
I can't believe that Nylon gears would be noisier than brass. I am also not surprised that packing grease makes no difference.Sugestion only
I have a re-motored Ixion C32 (similar mech to Wombat C30T) and it is quite noisy, particularly in reverse, but otherwise runs well since fitting a Mashima motor.
If there is a significant difference in noise between forward and reverse then one must suspect the helical gear that meshes with the worm, this will be thrust either left or right depending upon the direction of travel.
It's an interesting topic a6et that has been solved but we still struggle with it by making incorrect choices. A few youtube channels I follow like fishplatefilms, chadwick and model railways unlimited covered it over the past year with aussie made INOX MX3 getting some good exposure. I went with auto trans fluid prior to that but after not running anything for months, nothing would run. Rather than use ATF again, for this latest running session I revisited the old MRH article that listed kero as the most non-polar and a near empty bottle was behind me. So that choice was easy. CRC 2-26 rates alongside ATF as semi-polar, so whilst not the best, they still work remarkably well as you and many other will attest to. FWIW kero, WD40 contact cleaner and CRC contact cleaner rated in the top 3 along with other brands for being the most non-polar.Thanks Oscar, I had to change two taps the other day, and the water meter we have is one with a lever on the top, and you have to turn it 90 degrees to turn on/off, I could not budge it to turn the water lever off, I gave the lever a slight spray with the CRC, initially it did not want to move, a little more around the base & it opened a bit gingerly then close & open it, a 4 year old would find it easy.
Thanks for the heads up on OO Bill DJ. I watched a number of videos over the past few days and was amazed how noisy some of those worm drives are on those older hornby models. On the flip side, some with still coarse pitched worms but in newer models are very quiet and I reckon the difference between the old open frame and newer can motors must make a difference too. Worm meshing was something I considered early on as there doesn't seem to be much of the worm gear exposed for the worm to grab on to. I'm going to drill a couple of inspection holes to see how things line up but the shimming has definitely stopped the chance of the worm wheel/reduction combo gear from moving laterally.Oscar, you are doing a great job and makes for interesting reading.
But I agree poor worm alignment will cause noise and as I noted I think in the other thread and NSWRcars thought too, when we put Mashima motors in and rebored our worms to 1.5mm both ended up slightly off centre and added to the noise. To this end I may have good news. I've ordered some worms from Germany. A worm for N gauge Minitrix part number W0456. From what I can tell they're Module 0.4, 5mm diameter, 6mm long and have ID of 1.5mm. Wombat's were 5.3mm diameter but the threads are sharp so I'm conveniently ignoring that difference. Length is 9mm but the Wombat's only have about 6mm of actual thread. If these fit and work they are my missing link to an "easy" 5 pole skew wound Mashima makeover a couple years back.
As for the gears and my shimming attempt, 3004 has had a lot of running along with the other two and although I reckon it's quieter it's not as good as I had hoped. Slow speed is really good, much better than the other two but once there's speed there's a rattle and whir still. Reading the old NWSL catalogue about gears and the effect of vibrations causing noise, to my mind it's a result mostly of that idler and freeplay. The shim and spacers I put around it don't quite act like a hub extension like I wanted. I assume they hold the gear more perpendicular to the shaft but their inside diameters are slightly oversize like the gear's ID and since they're not attached to the gear they do nothing to stop the gear from moving up and down.
I'm still thinking of a way to prove this. I was going to glue some tube to the gear to form the hub but I doubt I can be accurate enough to avoid the gear becoming eccentric. I'm unable to find a replacement with hub or correct bore and commissioning a one-off is unlikely. So the next step is to make it myself but I doubt that'll happen. Lathe, mill, tooling. Three little things I don't own....yet. One day, maybe.
I've another little update, this time showing gears in action. My assumption is the difference in the diameter of the gears' shafts and the gears' oversized bores allow vibrations. Some vibrations might be against the chassis and others on the shafts. I start with the helical worm wheel/reduction spur combo, then add the idler spur, than the drive wheel. Each gear will dampen some of the previous vibrations but not eliminate. It seems the cast gears including the fixed one on the wheel don't rotate perfectly round or may be out of round adding to changes in mesh and initiate vibrations.When choosing to replace gears, choose machined Delrin gears, do not consider 3D printed or cast gears, as you will find the rough surface on those gears will cause you just as much noise.
This is all came about during fitting a 1015 mashima to one of the locos so it has a non OEM worm which I've detailed in the other thread I started and needs more updating which is in the works. It's open for criticism that this worm may affect the lateral movement of the worm wheel more than the OEM wheel and I could put an OEM setup in there again to prove it doesn't matter but we'll see. The main point is to demonstrate how the gears past the worm intereact and my aim now will be to replace the two main gears with either 3d printed, milled or cast replacements that have hubbed centres whose bores match the shafts more closely and will hopefully eliminate lateral movement and vibrations without adversely inducing a lot of drag.
The chassis is filmed upside down and level with camera over the top. The gear housing and motor are firmly clamped on the table which echoes the motor making it sound like R2D2. Whilst the noise from the gears is the rattle and chatter that you'll be able to pick up, plus embarrassingly, some nose whistle which I'm blaming on the magnifiers pinching on my nostrils, or age.
When choosing to replace gears, choose machined Delrin gears, do not consider 3D printed or cast gears, as you will find the rough surface on those gears will cause you just as much noise.
As far as I am aware, you cannot print Nylon or Delrin, so I do not see much point in trying. The best solution if you do not want to pay machining costs are the packaged gearsets from North Yard.When choosing to replace gears, choose machined Delrin gears, do not consider 3D printed or cast gears, as you will find the rough surface on those gears will cause you just as much noise.
I agree GG. Must admit I've neglected delrin. I've been consumed with using nylon as per original that I've forgotten about alternatives but I may have a rethink as delrin would be better.
Regarding machining, there's a couple of issues for me. For third party machining I put out a couple of feelers last year about getting 1.5mm bored replacement worms made but was told it was uneconomical for a one off or limited run. I assume the same would go for machining the helical and spur gears but since then I've been looking to tool up and go it alone and have been agonising over how to go about it and to what cost but it's an interest that's grown from a general interest in making stuff.
But the helical worm wheel/reduction spur gear combo has been a sticking point as I doubt they could be machined from one piece. And if machined separately, I don't know how I'd attach them together securely with adhesive be they nylon or delrin. 3d printing is an attractive option to make that combo gear but I don't know if they'll still need machining to refine surfaces or how accurate the bore will be in size and centering. Depends on the quality of the printer and as is typical in getting what you pay for, I go from looking at cheapies to chasing accuracy and high resolution at a few thousand dollars and start back at the bottom again.
Same goes for the lathe and mill plus accessories. I'm not in a position yet to buy all the gear I want and settling for the mini cheap everything will drive me nuts in frustration I'm sure. So although I agree with you, right now in the shorter term for the sake of prototyping a couple of modified gears I'm going to go down the printer path and see how that goes. Plus the printer will get a workout making some other projects no doubt.
I've no experience but the generic materials like PA and acetal or POM are printable from what I've read but have their own issues to print correctly on more expensive printers compared to the more common filaments. In that regard it might be a better option to outsource the job once I've drawn the gears. Still researching.We tried moulding gears in Acetal once. The die for the gears was produced using spark erosion, and the surface had lots of fine bumps in it, so the gears whined atrociously when assemble. 3D printing would be worse. The only way to get good gears is to machine them.
I looked up Northyard a while back and didn't find what I need. Same as Northwest Short Line and RS components. Nothing matched the specs exactly. I did very briefly think about cutting the gear tower off and gutting that area to fit a NWSL or Highlevel Kits gear box but I'd probably have to drive the middle wheel. The original layout does a great job of hiding the gears and motor whilst allowing a detailed cab layout and under boiler clearance, something I want to maintain.