Advice wanted on a tender drive

andrewnummelin
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Advice wanted on a tender drive

Postby andrewnummelin » Wed Dec 01, 2021 7:53 pm

I am currently planning the acquisition of the bits needed to start work on a kit that has been on the “to do” shelf for several years and I’d appreciate thoughts on how to go about some aspects. It’s a straightforward 0-6-0 so a good opportunity to try a few things that will be new for me:
- split frame pick up using Gibson cast brass loco wheels (already bought)
- tender mounted motor (Highlevel gear box and tender- riser already bought)
- flexible drive shaft
- stay alive capacitor to go with DCC chip.

The questions that come to mind are:
- do I go for a silicone tube drive, a proper pair of universal joints or simple wire in slot as often used in 2mm?
- would it be a good idea to have pick-ups in the tender? If so, what’s the “best” way? ( I don’t like the idea of wipers as that’s adding brakes. Turn down Markits cast wheels or short Gibson plastic spoked ones"?)
- compensated or sprung suspension for the tender? (Would the motor torque give problems with a sprung suspension?)
- outside (pin point) or inside bearings (Gibson wheels came with pointed and plain axles.)
- are miniature plugs and sockets reliable enough for the connection between loco and tender?

Thoughts of sound or radio control crossed my mind but they are for the future...
Regards,

Andrew Nummelin

nigelcliffe
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Re: Advice wanted on a tender drive

Postby nigelcliffe » Wed Dec 01, 2021 10:14 pm

If you're split-frame on the loco, do the same on the tender - its easier :-) I'd short the Gibson wheels, but any method will do. That said, if you use a high-capacity stay-alive (such as the fairly small Lais units from Digitrains), then the run-time will be a second or more, so is the extra pickup needed ? I'm starting to wonder if its worth bothering with pickups onto bogies because of the hassle when there is a massive stay-alive.


Plug-socket is fine for loco-to-tender wiring. I've done many that way, with DCC and stay-alive for over 10 years. Make sure your pin-arrangements can't short-circuit things if swapped left-to-right, or the plug/socket prevents wrong orientation connection. That includes avoiding left-pickup/right-pickup crossed if you're also have pickup on the tender.


Wiring loco: I find it is MUCH easier to use a modern decoder socket, such as Next18 (plenty of current capacity for Mashima or small coreless motors) or Plux (bigger, but allows more powerful sound decoders with 3W output or more). With those, you can buy a socket for a few pounds with wires or solder pads for motor, pickups, lights, stay-alive, speakers, and other extras. So, wiring the loco is easier onto a pre-made PCB (and if the wiring is a mess, replace it, start again, for a few pounds). Then, when fitting the (expensive) DCC decoder, just clip-in. Next18 standard specifies the decoder maximum size (need Next18S for sound - its bigger than Next18), so its possible to plan exactly how much space is needed (make a plasticard mock-up to check). So, easy to plan for a "sound upgrade", which will be: just add speaker, and replace the plug-in decoder with a sound one.



- Nigel

davebradwell
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Re: Advice wanted on a tender drive

Postby davebradwell » Thu Dec 02, 2021 9:15 am

I'm sure we've done this before. All my tender locos have the motor in the tender and I go for minimum noise. This means motor mounted using sticky pads, double sided tape or just glue, 30 or 40:1 HL 'box in loco with single point restraint, Zimo decoder and 2 preferably plastic couplings in drive shaft. If you put a spur gear on motor shaft as first stage it will make more noise, although HL boxes are very good. There's a poor choice of couplings at the moment - Branchlines do a double universal with splined shaft and there's ball, socket and pin types from Markits and Ultrascale - either of these could have the shaft replaced by piano wire to make them more discreet. I've used the last of my moulded Dynadrive couplings and although an equivalent is made by NWSL for a few dollars, they charge an exorbitant amount for shipping overseas. If you can show me a piece of silicaon rubber tube that will lay in a straight line on a bench, I'll support this type of coupling but all tthe stuff I've seen has been curved which will give a coupling a preferred set, no matter how slight. All my tenders have springs in the outside frames arranged like wagons.

I would suggest your split axles would be better on the tender than the loco as they have less impact on the construction. Scale loco chassis should have a cylinder block under the smokebox, a firebox under the firebox with frame spacer in front, motion bracket and weighshaft as a minimum and adding that lot without shorting is a challenge. It's a personal decision but the improved pick-up comes at a price. A miniature plug and socket is the best way of carrying power across the gap, especially if one end is fixed to a chassis. The wires can represent water feed pipes if separate pins are used each side. Don't forget to insulate whatever type of coupling you use if chassis is live.

andrewnummelin
Posts: 374
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Re: Advice wanted on a tender drive

Postby andrewnummelin » Thu Dec 02, 2021 12:16 pm

Nigel & Dave,

Thanks for the sound advice. (Audible, electrical, mechanical and reading!)

My O&S box contains a bit of tube (Exactoscale) that looks pretty straight (note the very old phone number!),
DSC04996.JPG

a Microdrive set-up (Scalefour Digest 41.7.1) that I think is too big for the current application,
a Mike Sharman two stage gearbox and universal couplings (much too big!).
And my files range from
Norman Dale in an old MRJ (date unknown)
Scalefour News 104 & 105
Barry Luck in MRJ in 1988
to
Steve Duckworth in Scalefour News 201 and
Mike Ainsworth in Scalefour News 217
not forgetting Dave in Scalefour News 140(?) p. 14.
You do not have the required permissions to view the files attached to this post.
Regards,

Andrew Nummelin

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zebedeesknees
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Re: Advice wanted on a tender drive

Postby zebedeesknees » Thu Dec 02, 2021 12:51 pm

Andrew, that tube night be the original Exactoscale neoprene, though the colour does suggest silicone. The neoprene was the beginning of a good idea, but is not flexible enough. In fact thick wall silicone tube can be too stiff, hence the critical need for a ball larger than the shaft, which causes a very flexible 'neck' either side of the ball.

Fwiw, I have been using silicone tubes for drive shafts since well before the date on this:- http://www.clag.org.uk/cv-couplings.html !

As Dave has repeated, they do have a 'set', or some do, but I have never noted any disadvantage caused by this. The sections used are so short that I contend that the effect is negligible.

For the shafting, the most common I use is 1/16" square brass tubing, which incidentally is 2mm across the diagonals, so in some cases can run through a 2mm id ball race. For telescopic cardan shafts, the inner I use is 1/32" square section brass rod, the diagonal of which fits smoothly inside 1mm id races; these are plentiful and cheap.

Incidentally, Puffers was close to my workbase in Stanmore for the decade of the 1980s... fond memories..

Ted.
(A purists' purist)

davebradwell
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Re: Advice wanted on a tender drive

Postby davebradwell » Thu Dec 02, 2021 1:17 pm

I used the old Exacto bits in my first loco but not the tube. Cross drilled the balls in a little jig, although they were quite tough, to take a pin and slit the sleeves to make the usual couplings. Your idea to use the 2mm design is interesting, although I suspect you won't be able to bend the enlarged wire tightly enough - it could be worth a try.

Anybody know an importer of NWSL stuff or know if the Dynadrive couplings are still available from another source as previous searches have failed.

DaveB

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Tim V
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Re: Advice wanted on a tender drive

Postby Tim V » Thu Dec 02, 2021 1:28 pm

You say 'turn down', so I assume you have a lathe.

It's quite easy to make your own flexible jointed coupling between engine and tender on the lathe. Much better than that Studiolith coupling - which is far too stiff.
Tim V
(Not all railways in Somerset went to Dorset)

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grovenor-2685
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Re: Advice wanted on a tender drive

Postby grovenor-2685 » Thu Dec 02, 2021 2:27 pm

davebradwell wrote:Anybody know an importer of NWSL stuff or know if the Dynadrive couplings are still available from another source as previous searches have failed.

I am not aware of any importer of NWSL stuff, but last I looked Branchlines had a similar range of U/Js.
I think Brimalm of Sweden dropped all the Dynadrive stuff years ago. Certainly nothing shows up on their website.
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Keith
Grovenor Sidings

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barrowroad
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Re: Advice wanted on a tender drive

Postby barrowroad » Thu Dec 02, 2021 5:18 pm

Wiring loco: I find it is MUCH easier to use a modern decoder socket, such as Next18 (plenty of current capacity for Mashima or small coreless motors) or Plux (bigger, but allows more powerful sound decoders with 3W output or more). With those, you can buy a socket for a few pounds with wires or solder pads for motor, pickups, lights, stay-alive, speakers, and other extras. So, wiring the loco is easier onto a pre-made PCB (and if the wiring is a mess, replace it, start again, for a few pounds). Then, when fitting the (expensive) DCC decoder, just clip-in. Next18 standard specifies the decoder maximum size (need Next18S for sound - its bigger than Next18), so its possible to plan exactly how much space is needed (make a plasticard mock-up to check). So, easy to plan for a "sound upgrade", which will be: just add speaker, and replace the plug-in decoder with a sound one.

Nigel out of interest have you a source for the sockets you mention?

Robin

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zebedeesknees
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Re: Advice wanted on a tender drive

Postby zebedeesknees » Thu Dec 02, 2021 5:32 pm

davebradwell wrote:Your idea to use the 2mm design is interesting, although I suspect you won't be able to bend the enlarged wire tightly enough - it could be worth a try.

DaveB


If this is a response to my posting Dave, I fear that we may be on different pages... I do not understand the reference to 'enlarged wire' nor 'bending it', tightly or otherwise.

My 2mm was referring to the diagonal dimension of 1/16" square brass tube which is (variably) 2mm, and therefore can be used as the outer of a cardan shaft running in a 2mm id ball race. The inner, sliding part of the cardan shaft can be made from 1/32" square rod, which is a sliding fit inside the 1/16" square tube. If required, the inner rod can be supported in a 1mm id ball race, or if there is room, a second piece of 1/16" square tube could be attached with a silicone sleeved 2mm diameter ball to the gearbox or other shafting. A picture might be a good idea...

Ted.
(A purists' purist)

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zebedeesknees
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Re: Advice wanted on a tender drive

Postby zebedeesknees » Thu Dec 02, 2021 5:39 pm

barrowroad wrote:Nigel out of interest have you a source for the sockets you mention?

Robin


Some options here:- http://www.micronradiocontrol.co.uk/conn_wiring.html

And here:- http://www.micronradiocontrol.co.uk/conn_pwr.html

Ted.
(A purists' purist)

davebradwell
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Re: Advice wanted on a tender drive

Postby davebradwell » Thu Dec 02, 2021 5:59 pm

Don't worry, Ted, I was referring to Andrew's first post although it would have helped if I'd made this clearer. The 2mm scale folk use a piece of piano wire bent into a cunning shape as a driveshaft although, of course, I can't find a photo easily and I'm going from memory - unwise really.

The last Branchlines catalogue I have is 2020 but he only lists the "universal jointed drive shaft at £3-75" (on last page) which I have seen used successfully and I have one in-stock.

DaveB

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Winander
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Re: Advice wanted on a tender drive

Postby Winander » Thu Dec 02, 2021 6:28 pm

andrewnummelin wrote:- do I go for a silicone tube drive, a proper pair of universal joints or simple wire in slot as often used in 2mm?

Silicone tube can be more discrete and are silent, I have components to use 1mm ball bearings

- would it be a good idea to have pick-ups in the tender? If so, what’s the “best” way? ( I don’t like the idea of wipers as that’s adding brakes. Turn down Markits cast wheels or short Gibson plastic spoked ones"?)

If you pickup from the tender, do you need a capacitor, especially as you are contemplating sound - will you have sufficient room to fit all that in? I am using split axles, same as the loco using Gibson wheels and CSB. Consider the benefits of devoting the space for a capacitor to a larger speaker.

- compensated or sprung suspension for the tender? (Would the motor torque give problems with a sprung suspension?)

Torque has been discussed before and the consensus is it must, but the effect is hardly noticeable provided you don't reduce the output in the tender.

- outside (pin point) or inside bearings (Gibson wheels came with pointed and plain axles.)

Pin points may be compatible with compensation, but (depending on system used) I don't believe they are with springing as most springing systems act on the bearing.

- are miniature plugs and sockets reliable enough for the connection between loco and tender?

Thanks for asking, I was struggling to find something suitable.

There is also this on the CLAG site http://www.clag.org.uk/silicone-tube.html
Richard Hodgson
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davebradwell
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Re: Advice wanted on a tender drive

Postby davebradwell » Thu Dec 02, 2021 7:27 pm

Re silence of couplings, this is why I'm trying to find a further source of all plastic couplings although mixed metal and plastic will be ok. As regards being discreet, the couplings are hidden but with simple drives it's difficult to hide the shaft, hence use of piano wire - I've used 0.020" on 0-6-0s and 0-8-0s. Some of us like silicon tube and some don't - it's a choice you make. The Branchlines shaft is ready to install and cheap but has a significant diameter which might offend.

Wagon springing with outside pin-points is just as standard as inside framed loco springing. I don't get your point here and can't see what compensation has to do with it. Yes, outside plain brgs would be a nicer solution but in practice the pin-points are probably easier. The inside frame solution is, though, a very convenient and popular way of splitting a tender down into sub-assemblies. Another choice that's really down to personal preferences.

DaveB

nigelcliffe
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Re: Advice wanted on a tender drive

Postby nigelcliffe » Thu Dec 02, 2021 7:44 pm

barrowroad wrote:
Wiring loco: I find it is MUCH easier to use a modern decoder socket, such as Next18 (plenty of current capacity for Mashima or small coreless motors) or Plux (bigger, but allows more powerful sound decoders with 3W output or more). With those, you can buy a socket for a few pounds with wires or solder pads for motor, pickups, lights, stay-alive, speakers, and other extras. So, wiring the loco is easier onto a pre-made PCB (and if the wiring is a mess, replace it, start again, for a few pounds). Then, when fitting the (expensive) DCC decoder, just clip-in. ........


Nigel out of interest have you a source for the sockets you mention?

Robin


Assuming you mean the Next18/Plux sockets -
Digitrains have a fair range (other retailers probably have them too) some are Lais brand (solder pads on rear), and some are ESU (as wires from socket which attaches to an ESU micro decoder).


For tender/loco connections, I use various small electrical/electronics connectors. My usual is turned SIL pins which I find easy to solder and fit with heat-shrink, but I've used smaller when necessary.



- Nigel

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Julian Roberts
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Re: Advice wanted on a tender drive

Postby Julian Roberts » Thu Dec 02, 2021 10:22 pm

Hi Andrew

For what it's worth, after such great preceding advice, I have made a 4-4-0 tender loco with the tender picking up on one side only and the loco bogie picking up on the other, in addition to the conventional wiper pickups to the driving wheels. Shorting strips used, though not all the way to the flanges. I'm very happy with it, though so far the loco has had extensive testing only - very smooth running, so I don't need a stay alive capacitor.

The electrical connection between loco and tender is simply a piece of ph br wire sticking out backwards from the loco bearing on another one on the tender in such a way that coupling the two vehicles links the two wires. It could be bent to resemble a hose but is a bit thin.

The tender is compensated with an inside frame, Gibson wheels in Gibson hornblocks. If compensating I suggest you have the rear wheel as the fixed one, or single rocking one if all wheels are compensated - this makes rearward running more secure IMHO.

I recently acquired a Markits double ended UJ drive for a remote motor in an 0-4-4 tank loco and that works very well too.

bobwallison
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Re: Advice wanted on a tender drive

Postby bobwallison » Sat Dec 04, 2021 9:30 am

davebradwell wrote:
Anybody know an importer of NWSL stuff or know if the Dynadrive couplings are still available from another source as previous searches have failed.


Dave and all, you could try the universal joints listed here https://www.nbrasslocos.co.uk/nloco.html
Although listed in the N Gauge section, they look almost identical to the NWSL items. The item at top centre of the images is a steel shaft which you trim to length before mounting the collars at each end.
I have a couple myself, although I have yet to use them in anger.

davebradwell
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Re: Advice wanted on a tender drive

Postby davebradwell » Sat Dec 04, 2021 10:25 am

They do look the very thing, Bob, so many thanks for that - somebody had to be importing them. As a further giveaway, the NWSL bits had the short shaft to enable motor and gearbox to be separated.

Will get some on order.

DaveB


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