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Locomotive control extension

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terry callaghan16/02/2020 13:34:15
209 forum posts
7 photos

Hi chaps. I need to add an extension to the reverser, as the tender is 3 foot long and there is know way I will be able to operate this control. I will need to add a few u/j joints to the hex side of the reverser to allow me to operate this control from behind the tender. As anyone some good idea of the best way to do this, thanks. Michael bd10cf05-6b29-4bca-9adc-0b57919b2f92.jpeg

Simon Williams 316/02/2020 13:56:39
465 forum posts
75 photos

Piece of flexy drive out of a brush cutter? (The kind with a droop snoot instead of a bottom gearbox)

terry callaghan16/02/2020 14:53:35
209 forum posts
7 photos

Hi simon, will take a look, thanks.

duncan webster16/02/2020 17:30:36
avatar
2437 forum posts
39 photos

Geared electric motor?

Nigel Graham 219/02/2020 00:38:37
523 forum posts

I think you can still buy flexi-drives for electric drills. One of those might be suitable, with appropriate adaptors.

terry callaghan19/02/2020 09:37:30
209 forum posts
7 photos

Thanks chaps, some good ideas. I don’t think an electric motor will work Duncan as it’s too near the firebox door. My worry with smaller flex cables is that they bend up if there is too much torque applied. The reverser does take some effort to move. I am going to a garden machine repair shop today to see what’s available. Will get back.

Clive Foster19/02/2020 10:14:17
2032 forum posts
73 photos

UJ rather than flexi shaft if there is any significant load / stiffness.

By the very nature of things flexi shafts tend to wind up a bit under load which will probably give poor feel and make operation imprecise. The one garden machinery flexi shaft I have had anything to do with seemed quite springy and had significant wind up. We concluded that this was a feature not a fault as it would act as a drive line shock absorber. Good idea for a brush cutter or similar where the blade is almost certain to hit something pretty solid several times during the machines life.

Seem to be a decent selection of affordable UJ joints around from various suppliers. Once used a socket set one for a quick'n dirty temporary job. Worked but not particularly wonderful in operation compared to proper UJ joints. Clearly made for strength not smoothness. When you are trying to teach a stubborn nut or bolt manners an extra ft lb or two to drive the joint is pretty inconsequential. But a control needs to be smooth.

Clive

terry callaghan20/02/2020 09:09:59
209 forum posts
7 photos

Hi, yesterday I looked at a few flexi cables, but they all had torque bend, bar the very large ones. So I had a look in Halfords. I picked up a few 1/4 inch uj joints and think that in the end this will be a better bet. Will update as I go along with the project. Thanks for input.

Derek Lane20/02/2020 10:02:19
avatar
307 forum posts
70 photos

Have you thought of a couple of long model boat prop shafts and the UJ joints that you can get to suit they would be OK for most of the joints but not the one near the firebox as they have plastic in them.

terry callaghan20/02/2020 10:07:07
209 forum posts
7 photos

Hi Derek, yes I know the ones you mean. Will take a look, thanks for that input. Good idea.

Derek Lane20/02/2020 10:30:43
avatar
307 forum posts
70 photos

HERE are some long props that I found up to 508mm long. I drilled a hole in some of mine and soldered an upright tube to it and then fixed a small paint tin to the top of that this allowed for lubrication of the tubes. Granted your use of them will not involve the same rotation speed a model boat needs.

terry callaghan20/02/2020 13:38:26
209 forum posts
7 photos

Derek, I think you have hit the nail on the head. But one thing remains to be looked at to make this work. As the locomotive turns a bend so the cap between it and the tender gets wider or shorter. This could be around an inch or more on my loco. So to allow for this movement some sort of movement most be allowed in the extension. I have been thinking of a slide made up of two flats around two inches long. One slide would have a slot in it, the other two pins that run along the slot allowing for the reduction of length needed or the increasing length due to the movement of the locomotive as it takes the bend. I have ordered some uj joints that can take 6mm rod. Maybe a bit overkill but I don’t want torque bend. It’s not the rotation speed that worry’s me, it’s the torque that is needed to move the reverser.

Derek Lane20/02/2020 14:04:13
avatar
307 forum posts
70 photos

A square tube with a square bar that slides inside and an UJ joint at either end will allow for the narrowing and expanding of the gap but still allow for it to be rotated

terry callaghan20/02/2020 14:19:47
209 forum posts
7 photos

I like that idea. Will have a think on that. Thanks

duncan webster20/02/2020 15:12:19
avatar
2437 forum posts
39 photos

to eliminate the need for telescoping as you go round a bend you could let the long rod slide through a spherical bearing, so it just goes in and out ( no rude jokes! ). I can't imagine it moves much

terry callaghan20/02/2020 16:36:44
209 forum posts
7 photos

Hi Duncan, interesting idea, but it’s becoming more complicated. I like to keep things simple, like me.

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