LGB point motors - rusting screws and source of replacements

OBBherr

OBBherr

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Last seeason I replaced several R1 points with R3. I failed to either cover or remove them over the winter (mea culpa.....). On preparing for this season I find that:

1. Three of the new R3 versions have rusty cover retaining screws (photo 1). I've disassembled one with some difficulty (due to collapse of corroded screw head) and the motor inside is untoched by corrosion.
2. Two of the new R3 versions (from same batch) are still bright and unrusted (photo 2 and 3)
3. My old R1 point screws are still bright after a number of seasons outside


IMG_0773.jpgIMG_0771.jpgIMG_0772.jpg

So if you will forgive a multipart question:

a. Has anyone else experienced problems with LGB point screws corroding?
b. Can you suggest a source for replacements, both for the cover screws, and more importantl the grub screws on the electrical terminals (also corroded)
c. Can you recommend something waterproof to drop onto the screw heads to stop a recurrence but which will peel off if needed? I'm thinking someting like a blob of Copydex or similar?

Thanks in advance for any insights and advice.
 
OBBherr said:
Last seeason I replaced several R1 points with R3. I failed to either cover or remove them over the winter (mea culpa.....). On preparing for this season I find that:

1. Three of the new R3 versions have rusty cover retaining screws (photo 1). I've disassembled one with some difficulty (due to collapse of corroded screw head) and the motor inside is untoched by corrosion.
2. Two of the new R3 versions (from same batch) are still bright and unrusted (photo 2 and 3)
3. My old R1 point screws are still bright after a number of seasons outside


View attachment 264342View attachment 264340View attachment 264341

So if you will forgive a multipart question:

a. Has anyone else experienced problems with LGB point screws corroding?
b. Can you suggest a source for replacements, both for the cover screws, and more importantl the grub screws on the electrical terminals (also corroded)
c. Can you recommend something waterproof to drop onto the screw heads to stop a recurrence but which will peel off if needed? I'm thinking someting like a blob of Copydex or similar?

Thanks in advance for any insights and advice.
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I encountered a little if this when restoring a few of these motors a year or three back. I think I left a little penetrating oil to do its thing overnight. When putting back tis worthwhile adding a small dab of grease to stop return of any rust, a useful tip for any steel screws that are likely to be left outside. So far this has had no effect on the LGB plastic.
 
Have had similar problems. The silver philips head screws have been particularly poor.

After having to replace a couple of motors as I simply could not shift the corroded screws, I've started unscrewing/rescrewing the screws on each motor every few months to make sure I could shift them if I need to. I also replaced the silver screws with some black-finish ones I acquired from Brian at Glendale a few years back. He sold me a big bag of screws of various sizes for LGB and i'm still working my way through them! (I think Champex-linded used to sell something similar as well).

I believe other folk have used some "weapons-grade" sealant to preserve the screws (worry, not sure of the name) and I know of others who have dispensed with the screws that hold the electrical wires in place in favour of soldering some fly leads directly to the point motor.

Hope this helps a bit.
 
I recall this being mentioned before. It seems at some stage LGB point motor screws were not stainless steel. The cover ones are usually blackened and don't rust.
I'm not sure where in the UK you get them but there is Micro Fasteners which is a good source for hobby sized fasteners.

Any white powdery stuff inside is oxidised zinc from the plating of the metal casing. Once this wears away rust (iron oxide) can build up inside and jam everything up.
Heavy lubrication can be an issue too because it clogs with dirt, dead bugs etc.
 
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If the terminal screws rust I find it is easier to replace the complete terminal block. They seem to be fairly standard types obtainable from electronic suppliers such as Rapid.
 
dutchelm said:
If the terminal screws rust I find it is easier to replace the complete terminal block. They seem to be fairly standard types obtainable from electronic suppliers such as Rapid.
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I must advise caution on terminal blocks. Many these days are made of cheep rubbish steel that rusts the minute you show it any damp air. If brass ones can be sourced they would be the ones to use. Also the wire exiting the commutator is extremely fine so it pays to take great care disconnecting it from a dodgy terminal block.
 
I've had, or been given, some of these motors with rusty screws.

I have un-soldered these terminal blocks and soldered in a flying lead.

I also cover the holes for the terminals and wires with mastic or silicon....
 
YES! Happened to three R3s I bought new about 4 years ago and just installed last summer. All the rest (5) show no signs of rust after multiple years exposure. Must have been someone's idea of lowering cost. Surprising and disappointing for a LGB product. If anyone knows the metric screw size I'd like to order some ss ones to replace those that need it. Likewise the terminal grub screws in these particular point motors. I covered the terminal screw holes with a piece of 3M electrical mastic to help minimize water ingress.

Decoder enclosures - 1 _5_.jpeg
 
Near as I could measure the cover screws are M2.2 x 6mm plastic thread forming. I've ordered some in stainless steel from Screwerk and will let the group know how they fit. Not cheap at $0.43 each when ordering 50-100 plus $15 postage. Had to tell a bit of a porky claiming my part time work affiliation as they "don't sell to consumers".

Learn something new everyday - a plastic thread forming screw is sized to fit a given hole molded in plastic. The threads are designed such that the plastic is displaced into the root of the threads when they are screwed in. This supposedly gives a more secure fit. Hence they are "thread forming" as opposed to self-tapping screws that actually cut a thread.
 
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The cover screws I just ignore but with the electrical terminal block I fix tails of thick (house mains) wire and then use a nylon block connector for transmission onwards. The terminal block may rust but I never intend to undo it. I have several motors that live out all year and to date they all work after 15 years.
I still put LGB gear grease on the terminal top though.
 
Got the M2.2 x 6mm plastic thread forming ss screws from Screwerk yesterday. They are direct replacements (thread pitch and all) to the current LGB points motor cover screws. This is the type and size screw if you need replacements.
 
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Phil, could you give me the Screwerk part number, something like this STP320220050E? There are a lot of options on the Europe website I given the cost I don't want to order the wrong thing!

Thanks, Adrian
 
I suggest ACF50. It’s used on aeroplane landing gear and doesn’t affect plastic/rubber like WD40. I‘ve used it for a few years and have found zero drawbacks! Available on eBay etc.
 
Modelfixings - I have used this company for many years and always had first class service from them. They stock a multitude of self tapping screws in various sizes and materials, but choose stainless steel for outside use. For those not in the know - silicone sealants often smell of vinegar - avoid their use anywhere near electrical connections or other metal, as the material and its fumes are very corrosive - use a type of sealant known as 'neutral cure', which is readily available from most suppliers. There's also a material called 'Corrosion X', which I use on all outdoor electrical equipment, either spray it on or douse the item - not cheap, but works wonders!
 
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