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Scratchbuilding a side discharge rotary snow plow

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Posted by Track fiddler on Thursday, April 28, 2022 10:35 AM

Hi Dave

Haven't visited your project for a while and discovered you went back to blade ellipses remanufacturing your hubs.  I didn't see much of anything wrong with your first ones.  You must be one of those perfectionistic type of guys eh? Huh?  Your new bladed hubs are looking quite exceptional I must say.  I also think that was a great idea of yours using copper plumbing caps to make your soldering go smoothly.

Don't you love re-doing things sometimes?  I'm serious.  Some people hate when they have to re-do something while being unsatisfied with the prior one.  Sometimes I love re-doing something as your craft always becomes more refined the next time around, making it more enjoyable to do as the discovery phase is eliminated.

That's cool how using a bigger diameter radius for the blades fit the hub correctly.  I can see how that worked, being that the ellipse only increases more drastically as it nears the halfway point of the cylinder.

Always found geometry the most fascinating part of engineering way back when and still do.  I remember how interesting it was dissecting the function of a U-joint.  How fascinating it was that two rotating right cylinders also created an ellipse in motion at the angle of transfer.

I hope you don't mind me posting a geometrical diagram I found illustrating exactly what you did creating your plow hubs.  Geometry is part of the reason I find your thread so interesting.  The rest is the illustrations of you putting it to good use, custom manufacturing itSmile

 

Blog courtesy of David B.

 

 

Spectacular job on those Plow Hubs DaveBow

 

 

TF

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Posted by BATMAN on Thursday, April 28, 2022 10:56 AM

I knew there was no reason for all the HUB-BUB Dave.Whistling

Very cool what you are doing, and I agree with TF, nothing wrong with taking another crack at things.Yes

Brent

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Posted by Overmod on Thursday, April 28, 2022 11:10 AM

Since you're making it again...

Go back and read the description about how the blades make a 'true helix' as they run.  Then look at the blade shapes in the front view.

They spiral like a screw thread, and I think the blades bend 'laterally' both backward and forward relative to the line of the flanges on the hub...

Just sayin... Whistling

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Posted by hon30critter on Friday, April 29, 2022 5:46 AM

Overmod
Since you're making it again... Go back and read the description about how the blades make a 'true helix' as they run.  Then look at the blade shapes in the front view. They spiral like a screw thread, and I think the blades bend 'laterally' both backward and forward relative to the line of the flanges on the hub...

Hi Overmod,

I think I already have a pretty good idea of what the blades should look like.

I have soldered one blade to each of the hubs and they fit reasonably well. The challenge will be firuring out how to solder the other blades to the hubs without melting the the joints on the previously installed blades. I'm going to try using very damp paper towels as heat sinks while I try to get the hub hot enough to melt the solder for the next blade. 

As I mentioned earlier, I am pinning the blades in place so they can't fall off completely if the solder melts, but the pins aren't solid enough to prevent the blades from going out of alignment. If I get the hub too hot I'm worried that the whole thing will turn into a floppy mess. If I can't get things to work, I will make a third set of blades with the mounting tabs as part of the blades so there will be one less joint to go soft if there is too much heat.

Wish me luck!

Cheers!!

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by richhotrain on Friday, April 29, 2022 6:03 AM

richhotrain

I don't know anything about welding as I ask this question, but would welding make more sense than soldering in an instance like this?

Rich 

I still think that welding is a better long-term answer than soldering these blades in place. I was Googling this issue, and "micro welding" seems to be a solution to welding small parts together. At least around me, there are lots of shops that offer micro welding services for those who choose not to do it themselves.

Rich

Alton Junction

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Posted by hon30critter on Friday, April 29, 2022 7:28 AM

richhotrain
I still think that welding is a better long-term answer than soldering these blades in place. I was Googling this issue, and "micro welding" seems to be a solution to welding small parts together. At least around me, there are lots of shops that offer micro welding services for those who choose not to do it themselves.

Hi Rich,

You are trying to take all of the fun out of assembling the blades!Smile, Wink & GrinLaughLaugh The risk of having them collapse in a pile of molten solder and parts is just part of the game.

Yes, getting someone else to do the work would be much easier, but I am determined to do it myself! Without wishing to disparage the 3D printing crowd (who's work I admire by the way) the satisfaction of doing it myself is the whole reason for getting into the project in the first place. I don't care how long it takes, or how many attempts. When it is done I will be able to say that I did the work. That satisfaction is one of the main reasons that I am in the hobby.

Thank you for your suggestions and your interest.

Cheers!!

Dave

 

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by hon30critter on Saturday, April 30, 2022 10:19 PM

Right now I am chuckling to myself because I made the new set of blades a bit too big.Bang HeadDunceLaughLaughLaugh

I increased the inside radius by 2 1/2 scale inches thinking that that would be about the right radius to fit the hubs properly. Alas, they are a bit too big.Bang HeadBang HeadBang Head

I also discovered that the blades are too wide. They are 36 scale inches wide. They should be 22". I don't understand how that happened. I must have changed the printer settings by mistake.

When I make the next set (note that I'm not assuming they will be the 'final' setSmile, Wink & Grin), I think I'll test fit the first one before cutting out the rest.

Oh well, lessons learned. At least I'm getting good at cutting blades!Smile, Wink & GrinLaughLaugh

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by hon30critter on Tuesday, May 3, 2022 12:05 AM

Apparently I have run afoul of the gods! I mentioned a while ago that I had ordered a Bachmann Spectrum 4-6-0 to push the snow plow. On the 21st of April a UPS driver showed up at the door and presented me with a customs brokerage invoice for $41.01 Cdn. He told me to pay the invoice over the phone and then they would deliver the parcel (the invoice clearly said that the driver was to collect the money). I dutifully paid said invoice over the phone and waited....and waited.....and waited for the locomotive to arrive.

On April 25th I started to ask questions and was told that everything was fine and they would ship the parcel asap. I was told the same thing on the 26th, and the 27th, and, you guessed it, the 28th. Finally last Friday I decided to launch a complaint. Fortunately this time the young lady was professional enough to do some digging before brushing me off. She discovered that someone had said that I wanted the parcel held at the distribution center for pick-up. I had said no such thing. Then she also discovered that my payment had not been credited to my account.

As it stands right now, I have an email stating that the payment had been credited properly and that the warehouse had received instructions to ship the parcel. I haven't seen it yet so I won't count my chickens.

Unfortunately the pusher locomotive saga doesn't end there! I spotted a Model Power 2-8-0 in Canadian Pacific livery on eBay for a really good price. I know the quality won't be up to that of the Bachmann, but for $25.00 plus shipping for a supposedly new locomotive, I thought 'why not'. I unpacked the locomotive tonight and was quite happy with it. There were a couple of loose parts but it was all there. "Great!" I thought. Then I noticed that the drivers rotated with almost no resistance. I said to myself "that shouldn't be!". I opened it up hoping to find a broken drive link but what I discovered was that the model was a factory dummy! There was no motor. There had never been a motor!!

I went back to the listing. There was no mention of the unit being a dummy. In fact, the seller said "I took it out of the box... and it does run." Downhill maybe!?! Sending it back will be a waste of time and money so I have asked for $20.00 USD back in compensation. I don't want to cause a hassle, but if he ignores me I will take it up with eBay.

I firmly believe that all of my recent misfortunes are a direct result of me changing the way I spell 'plough'!Smile, Wink & GrinLaughLaughLaugh

Cheers!!

Dave

 

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by hon30critter on Tuesday, May 3, 2022 12:09 AM

I'm going to try a different approach to mounting the blades on the hubs. I'll let you know how it works.

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by BATMAN on Tuesday, May 3, 2022 12:57 AM

Dave! LaughLaughLaughLaugh

Just keep ploughing away, I mean plugging away.Smile, Wink & GrinLaugh

Brent

"All of the world's problems are the result of the difference between how we think and how the world works."

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Posted by Overmod on Tuesday, May 3, 2022 3:43 AM

hon30critter
I opened it up hoping to find a broken drive link but what I discovered was that the model was a factory dummy! There was no motor. There had never been a motor!!

For a plow train... just build a couple of motor tenders for fuel and auxiliary water.  Then have fun with the prototypically lacy and elegant 'prototype' chassis appearance of an older locomotive of that type, without the issues of gears and towers visually getting in the way...

hon30critter
I firmly believe that all of my recent misfortunes are a direct result of me changing the way I spell 'plough'

No, it's karma for having spelled it differently from the way the prototype clearly did.  Actions have consequences, you know. Wink

 

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Posted by richhotrain on Tuesday, May 3, 2022 7:08 AM

hon30critter

I'm going to try a different approach to mounting the blades on the hubs. I'll let you know how it works.

Welding?  Smile, Wink & GrinLaugh

Rich

Alton Junction

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Posted by snjroy on Tuesday, May 3, 2022 7:57 AM

Hi Dave. Sorry to hear about your mishaps. Model Power did sell Frateschi engines, with a motor in the tender. As for UPS, I try to avoid them entirely!

Simon

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Posted by Overmod on Tuesday, May 3, 2022 9:27 AM

richhotrain
Welding?

Don't laugh so quick.  Very small resistance welding is a well-established 'thing' and very easy to execute (see the YouTube video on making Nixie tubes to see the equipment repeatedly used).  The situation with fusion-welding brass is a bit different (you'd want correct fluxing agent and shielding gas or CA) but not so much more difficult as to be hard.

I think I already proposed resistance soldering as a valuable potential technique (but the added cost of the rig was a sticking point).

Resistance soldering works the same way autogenous spotwelding or shotwelding does, but uses less heat to melt a 'spot' of what can be hard solder; this would affix the blades in alignment and he then heats the fluxed piece with a torch to wick lower-melting solder all along the fitted blade edge to secure it if desired.

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Posted by richhotrain on Tuesday, May 3, 2022 10:51 AM

Overmod
 
richhotrain
Welding? 

Don't laugh so quick.

That laugh was intended to be playful since I had twice before suggested welding to Dave.

Rich 

Alton Junction

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Posted by rrebell on Tuesday, May 3, 2022 8:55 PM

Yeah the Canadian thing with packages is a real expencive pain, lucily the cost is only to Canadians but things going to the states seem to take forever to get here, I get stuff from China much faster.

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Posted by gmpullman on Tuesday, May 3, 2022 9:23 PM

rrebell
lucily the cost is only to Canadians

I had to pay $75. to send a locomotive back to Rapido in Markham, Ont. from Ohio, about 311 miles by highway. That was two years ago before price increases.

Not to mention my package to Dave that took over two months and had a vacation in Sydney for a while. Actually that was a bargain for a trip of 18,900 miles.

Cheers, Ed

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Posted by doctorwayne on Tuesday, May 3, 2022 9:50 PM

hon30critter
Apparently I have run afoul of the gods! I mentioned a while ago that I had ordered a Bachmann Spectrum 4-6-0 to push the snow plow. On the 21st of April a UPS driver showed up at the door and presented me with a customs brokerage invoice for $41.01 Cdn. He told me to pay the invoice over the phone and then they would deliver the parcel (the invoice clearly said that the driver was to collect the money). I dutifully paid said invoice over the phone and waited....and waited.....and waited for the locomotive to arrive.

Dave, there is no duty on model train items bought in the U.S. and brought into Canada, in person, by the buyer.

Similarly, there is no duty on model railroad items bought in the U.S., and shipped via mail into Canada. 

However, shipped-in mail does go through Canada Customs, and they assess the value (in U.S. dollars) then convert it to Canadian dollars, and assess it for HST (the Harmonised Sales Tax - both federal and provincial).
 
I learned this last month when I purchased a brass loco for a friend and had it sent to me from Illinois, and was shocked when the price of the loco suddenly came to almost double of what I had paid in U.S. dollars.
I did have a good on-line conversation with a Canada Customs Official on this, and was pleased to at least be treated politely and with respect.

When I order model train stuff from the U.S., I normally have it sent to a very good and longtime friend in Ohio, then pick it up when I visit  (which hasn't happened for the last couple of years, due to Covid restrictions).

My stash waiting down there is, I think, below the allowable $800.00 duty-free limit.

The tariff number for duty-free model railroad stuff is 9503-10-10-10, and Canada Customs is well aware of it.

Wayne

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Posted by hon30critter on Wednesday, May 4, 2022 11:05 AM

doctorwayne
Dave, there is no duty on model train items bought in the U.S. and brought into Canada, in person, by the buyer.

Hi Wayne,

I misspoke. The brokerage bill was for the HST. Unfortunately, UPS added their own charges on top of that. The HST was $22.93. UPS added a $16.00 brokerage fee plus $2.08 HST on the brokerage fee so the total came to $41.01 which added 23.2% to the cost of the locomotive. None of that includes the shipping fee which was a ridiculous $59.99 USD. The total cost for the locomotive works out to about $294.00 Cdn. The Trainworld price for the locomotive was $139.99 USD. Just for comparison, a used DC Bachmann engine on eBay would have cost about $30.00 - $40.00 more all costs in because the auction prices started at around $235.00 Cdn.

I still don't have the locomotiveGrumpy. I will give them a couple more days and then I will go after them again.

Cheers!!

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by hon30critter on Wednesday, May 4, 2022 1:46 PM

I have succeeded in making a second set of rotary blades that look much better and were much easier to make.

This is a close up of the original blades. The veins are 0.005" brass. You can see all the creases. I couldn't get them flattened out:

The new blades are on the right. The veins (0.025" copper) are perfectly smooth, and they are closer to the thickness of the prototpye veins:

I used a different method for attaching the veins. Instead of trying to solder them to the outside of the hubs, I cut diagonal slots in the hubs and slid the veins into the slots. This picture is slightly out of focus but you can see where the veins protrude into the inside of the hubs. They will get ground smooth:

Installing the veins in the slots took 1/10th the time of trying to solder the originals to the outside of the hubs. They were easy to line up and keep in place.

The new blades are slightly smaller in diameter than the first set. The first ones were actually about 6" too wide. The new veins are 22" wide which is what the prototype was.

I still have to eliminate a bit of wobble. That will simply be a matter of trial and error.

Cheers!!

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by Attuvian1 on Wednesday, May 4, 2022 2:02 PM

Tremendous idea, Dave! Bow

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Posted by hon30critter on Wednesday, May 4, 2022 2:10 PM

Attuvian1
Tremendous idea, Dave! 

Thanks. It only took me 2 1/2 months to figure that out!LaughLaugh

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by BATMAN on Wednesday, May 4, 2022 3:13 PM

Lookin good Dave. Make sure you paint and weather the first set to prop up against the roundhouse wall.YesYes

Brent

"All of the world's problems are the result of the difference between how we think and how the world works."

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Posted by hon30critter on Wednesday, May 4, 2022 3:59 PM

BATMAN
Make sure you paint and weather the first set to prop up against the roundhouse wall.

Hi Brent,

Yes, and I can bend up a couple of the veins a little more to make it look like the plow injested something it shouldn't have.Laugh

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by hon30critter on Thursday, May 5, 2022 2:38 AM

I reassembled the gearbox this evening. I had ordered a 24 tooth delrin worm gear since that was what I had originally used (before I melted the first gearDunce). Before I cooked it it seemed to fit fine, but I never actually ran the gearbox. However tonight when I put the 24 tooth gear in place it barely touched the worm. Fortunately I had also ordered a 28 tooth brass worm gear and it fit perfectly. The gear box runs quite nicely. There is a bit of gear noise and some vibration at lower speeds, but at about 3/4 throttle it is fairly quiet. I ran it for about an hour and the motor was barely warm to the touch.

One thing that didn't work initially was the silicone drive link. When I first turned the power on the silicone tube twisted and buckled. I replaced the tube with a NWSL coupler and everything ran quite nicely. I suspect that the fact that the gears had not had any run time might have contributed to the silicone tube failure, but I think I'm going to stick with the solid coupling.

I also discovered that my gearbox is a bit flimsy. The slightest twist causes the bearings to bind. It took me about 1/2 hr. to get things lined up again. I don't want to risk soldering additional braces to the gearbox because that would risk having the bushings go out of alignment so I'll just have to handle it with care. Once it is installed it should be fine.

Cheers!!

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by doctorwayne on Thursday, May 5, 2022 10:24 AM

Using slots to mount the vanes was a better choice than trying to solder them in-place.

Now all you have to do is find some "snow" to see how well the plough works.

hon30critter
I also discovered that my gearbox is a bit flimsy. The slightest twist causes the bearings to bind. It took me about 1/2 hr. to get things lined up again. I don't want to risk soldering additional braces to the gearbox because that would risk having the bushings go out of alignment so I'll just have to handle it with care. Once it is installed it should be fine.

I've had a similar issue with a couple of brass locomotives locking-up, and used some sheet styrene, slipped between the gearbox and the loco's frame, to keep the gearbox from flopping around and locking-up.
I was surprised that it was so easy to correct.

Wayne

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Posted by Overmod on Thursday, May 5, 2022 12:21 PM

hon30critter
I also discovered that my gearbox is a bit flimsy. The slightest twist causes the bearings to bind.

To me, the answer sounds like simplicity itself, to quote Eli Gilderfluke.

Apply a little etching primer to the outside of the brass, with the gearbox properly aligned, and butter on some high-strength epoxy with stiff filler, like the steel-loaded JB Weld.  If this cures around several sides of the gearbox with good bond, it will provide good torsional and flexural stability without inducing any shape changes through volume change while 'drying'. 

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Posted by hon30critter on Saturday, May 7, 2022 3:27 AM

Overmod
To me, the answer sounds like simplicity itself, to quote Eli Gilderfluke. Apply a little etching primer to the outside of the brass, with the gearbox properly aligned, and butter on some high-strength epoxy with stiff filler, like the steel-loaded JB Weld. 

That sounds really messy! I think I'll pass.

I overcame my reluctance to mess with the gearbox so I was able to reinforce the gearbox frame with a couple of pieces of brass C channel. The gearbox and motor mount are all on the same frame which up until tonight was just a piece of brass strip. The strip was too flexible so that the slightest bending in the frame played havoc with the gearbox. I soldered the C channel along the sides of the whole length of the frame and the whole assembly is now quite stiff.

Here is the reinforced frame:

Here it is before the addition of the C channel. This is the first attempt, so you might notice a few other modifications made along the way:

I also decided to rebuild the gearbox. I was able to run the drive mechanism last night with the rotary blades attached. Before I put the blades on, the gearbox was relatively quiet considering that it is a brass worm gear on a steel worm. All that changed once I installed the blades. The gears started to make a lot of noise. I determined that part of the problem was that there weren't enough shims between the gears and the bushings. That was allowing the gears to slide back and forth, going out of alignment in the process.

In order to install more shims I obviously had to take the gearbox apart. Getting the shafts out of the gears was proving to be a challenge until I remembered that one of our fellow forum members had generously given me a set of drive pin punches (Starrett no less!), and the smallest punch fit the bill perfectly!

Once I had the gearbox apart I decided to correct a couple of slight missalignment problems. The input shaft for the gearbox didn't quite line up with the output shaft from the motor so that was creating an unnecessary bend in the couplings. I also played with the rotary blade shaft bushings to get them lined up as well as possible.

I will reassemble the gearbox tomorrow night. I'm keeping my fingers crossed that all the stuff I did tonight will be an improvement. So far at least, the shafts are turning very smoothly.

I also managed to get the new rotary blades straightened out so there is almost no eccentricity from side to side.

Speaking of tools, I was about to replace my old clamp on bench vice because the jaw assembly was starting to come loose from the base. I could see the allen bolt that needed to be tightened but I couldn't for the life of me figure out how to get the screw shaft out so I could get at the bolt. A few minutes ago I decided to turn the vice upside down and voila! There is another allen bolt on the bottom of the front jaw that will release the screw! So, when I was speaking of 'tools' I might have been inadvertently referring to myself instead of the mechanical kind. You decide!

Cheers!!

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by hon30critter on Sunday, May 8, 2022 1:18 AM

I have the gearbox and drive system reassembled and it works great! Here is a brief video with sound. Click on the 'Watch on YouTube' to get the full screen:

The recording makes it sound a lot louder than it actually is. Also, the blades are just sitting loosely on the drive shafts so there is a bit of wobble. When I do the final assembly I will use Locktite to secure the blades.

Dave

 

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Posted by Attuvian1 on Sunday, May 8, 2022 3:46 AM

Wondermous!! Bow

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