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gordon s

Forming/fitting pick ups to 00 locos

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I wonder if any of you loco builders can give me some guidance regards forming and fitting pick ups to 00 locos?

 

I have some phosphor bronze wire in 24, 26 and 28 AWG, but I'm unsure which is the preferred diameter. I've seen various types of fitting but most seem to be soldered to pcb strip underneath the loco.

 

What shape wire gives the best performance/least resistance? Wire with long pivot points or shorter wire length with an omega loop or coil in the wire? Should the pick up wipe the back of the wheel, along the rim or even a wiping action on the rim at right angles to the wheel?

 

Obviously there are loads of solutions, some good, some bad, but I haven't been able to find any articles specifically on pick ups on the web.

 

Your input/guidance will be really appreciated...

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Thanks David, that's a good start. Most of my locos are steam outline, but I'm sure a version of that may be possible. The first thing I've noticed is the 10 thou wire, whereas the thinnest I have is around 14 thou, so perhaps I'll need some thinner phosphor bronze wire. I was just guessing when I bought it....

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I use PB strip (I think it was from AG)

I bend it into a 'Z' shape with a long center length'

One end with a 90 twist soldered flat to the pcb on the chassis the other end acts like a knife on the back of the wheels.

 

I don't like the method of lacing the wheel contact on the wheel rim - it just acts like a glorified wheel cleaner/scraper.

 

I've not used wire so cannot comment - it is a case of what works leave well alone

 

I had a small experiment with plungers and just couldn't make them strong enough to keep contact - again probably me and not wishing to persevere with something that seems like too much trouble and no gain.

 

That CLAG stylus method just seems over engineered and remains quite visible (probably getting all tangled in the brake gear) not to mention it will be a great dirt scrape.

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I used .315mm phos. bronze wire on my Ruston which works very well working on the rims. Shown here: http://www.rmweb.co....roblems-sorted/

Hope thats of some help.

 

 

Thanks Paul, been playing around on the bench for the last half an hour or so. The first ones I made were too short and the pressure was too high. As you would expect, the longer the pick up from the fixed point, the less drag there appears on the wheel. Going at right angles across the rim also seems to provide good contact with minimal drag. Will the rim eventually wear through the wire? I suppose that's a small price to pay for lower drag on the rim and they can easily be replaced.

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I use phosphor bronze wire (from Mainly Trains) bearing on the rims. I think the stuff I use is about 0.4mm, although it might well be the same stuff as Halfwit mentions. I solder the wire to a pickup pad under the chassis and then put two gentle bends in it, about 1/3 and 2/3 of the way along. After final adjustment I nip the end of the wire to length using a pair of nail clippers. I think this is basically the Tony Wright recommended approach, and it does work well (for me). The pickup pressure can be adjusted so that pony wheels, unmotorised loco wheels, etc, are still able to turn freely. I did struggle with pickup solutions for years but I can safely say that switching to phosphor bronze has made them fairly pain-free.

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Thanks Paul, Kenton and Barry for your input. Barry, I'm assuming the pick up is then parallel to the wheel. Are you making contact on the back of the wheel or on top of the rim?

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Thanks Paul, Kenton and Barry for your input. Barry, I'm assuming the pick up is then parallel to the wheel. Are you making contact on the back of the wheel or on top of the rim?

 

Hopefully a picture speaks a thousand words:

 

post-6720-127961662002_thumb.jpg

 

This is the arrangement under a Lima diesel but it's much the same as what I use on steam. I actually trimmed the wires on the right a bit too short but they still work well enough.

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I would vote for simple wires or strips bearing on the back edge of the wheel rim, apart from anything else it helps control wheel side play as well, giving centralised springing.

  • The best wire of all is beryllium copper, it is available from specialist suppliers, or add a beryllium copper tip soldered to nickel silver wire, or phosphor bronze wires or strips. Beryllium copper is the material used for electrical contacts and relay arms/contacts, except where platinum or palladium is used in combination for the tip.

  • However the next best is phosphor bronze, it wears, but very slowly. Made in flat strips or fine wires in most diameters. Quite springy, and retains the spring well.

  • Nickel silver wire is the easiest to buy, handrail wire, but it does wear a bit, and is not quite as springy, going off a bit with age.

  • Brass is very poor, it wears, little spring, and corrodes.

A minor point is that wheels made in Mazak, most FE ones are, have a coating of pure chrome, and this is very hard and abrasive, and wears any wire or strip, so Beryllium Copper, or Phosphor Bronze really should be used if possible, as Nickel silver wears badly on chrome.

 

The most de-luxe pickup is to use a stripped relay tip made of platinum, or palladium, and solder it to a phosphor bronze wire, and cover with a fine black heat shrink sleeve except for the tip. Near indestructible!

 

Stephen.

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I simply use phosphor-bronze strip (Eileen's and Slaters supply it, among others) formed so that it bears on the corner of the back of the flange; on 'traditional' steamers (rather than BR Standards and some others) it's almost always possible to completely hide this set-up behind the footplate valence.

 

The 'stylus' pickup looks very neat, but personally I wouldn't consider anything that bears on the tread, as it's going to pick up dirt even more effectively than electricity. I think that Bachmann found that out with their early 08s!

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There have been some suggestions that the stylus type of pickup would pick up dirt. On the contrary the point cuts through the crud discourages the formation of muck on wheels unlike a flat strip bearing on the tread. Or at least that is the way my versions have been working..

 

Cheers,

 

David

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There have been some suggestions that the stylus type of pickup would pick up dirt. On the contrary the point cuts through the crud discourages the formation of muck on wheels unlike a flat strip bearing on the tread. Or at least that is the way my versions have been working..

 

Cheers,

 

David

 

Thanks, David - that's very helpful to know. Maybe I'll give them a try and see if they work for me.

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I use PB strip (it bends in the desired direction only) with small brass pads (etch fret offcuts) as the contact point. Rear/edge of the flange or on top of the tread (usually on tank loco) seem to work equally well. Direct PB and steel tyres contact is not considered a good mix as arcing/corrosion can apparently occur.

 

I have found that this version works well, even under exhibition conditions.

 

Jol

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I am very surprised about adding the brass pads to Phosphor Bronze, I had heard abut P/B causing arcing, and did some very long, (many weeks), tests on pickups, as I was managing a display layout where Tri-ang locos were left running for months.

 

I tried many combinations, including guitar steel wire, with and without tips etc. The steel wire is attractive as it is the most springy of the lot.

 

With steel tyred wheels:-(Triang, Gibson, Sharman, Some Ultrascale)

  • Beryllium copper wire and strip worked the best of all, no arcing or fast wear, but the wear on wheels running with a brass tip was excessive, the tips wore away in hours. P/B on steel tyres did not arc or wear much more than Beryllium copper.

With nickel tyred wheels....(Romford. Markits, Ultrascale)

  • Same as above, but brass tips wore much slower. No arcing. P/B worked fine.

With brass tyred wheels....(Hamblings, Some Ultrascale, Stewart Reidpath).

  • Best was again beryllium copper, brass tips work, but wore. Steel wire pickups on brass arced. P/B worked fine.

Stainless Steel tyred wheels...(no commercial, but the best ....)

  • Best was Beryllium, brass tips arc, as did nickel silver, P/B worked fine.

All chromed Mazak wheels worked best with P/B or Beryllium copper, nickel wore on chrome, as did brass tips. None particularly arced except a steel wire pickup running direct on the chrome finish, but see below.

 

All Chinese wheels are chrome or Nickel Chrome on mazak, and wear pickups a lot due to the ultra hard chrome surface. The backs of most of these wheels are not a good dead smooth finish, and sometimes arcs if the contact is poor.

 

Hope this all helps, pickups are vital to good performance, as many as practical, and more!!!

 

There was once a make, Poole Wheels, that used aluminium for the tyre, and it was difficult not to get arcing with any type of pickups, they left a miniature firework display as the loco moved down the track.

 

Stephen.

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Bearing on the flange as per Barry Ten's picture is my vote too. I sometimes put a few turns in to soften the wiping so it affects the springing/compensation less. Really must finish the 14xx off once i've got my wagons done as it was tricky to avoid the brakes on that!

 

Heat shrink anything near metal frames.

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