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Whats on your 2mm Work bench


nick_bastable
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Since I'd received so much helpful advice on remedies for my bendy Pannier replacement chassis on my Any Questions Answered query, I though it only right that I should post a few photos of progress. And given my glacial rate of progression in any of my modelling projects, it's exceptional to see anything happening anyway. These might be of interest, but on the other hand are just as likely to elicit howls of derision or detailed explanations of why not to do it that way. 

 

I decided early on that I wasn't keen on silicone tubing or similar to drive the worm from the motor and wasn't very confident that I could align a motor mount accurately enough to get an adapter sleeve to work very well (it's occurred to me later that a silicone sealant base would probably have solved the problem). So I designed a motor mount, but then had the problem of soldering it together accurately. I came up with a mounting jig consisting of a bit of scrap brass turned to the match the worm-bearing-to-motor-bearing distance  with a step on the end to match the motor bush hole in the mounting plate - this was then drilled and tapped 6BA and a screw soldered in place and drilled at one end for the worm shaft. A 6BA packing washer also had to be drilled out to the bearing diameter (4mm, I think) to ensure that the nut applied its force in the right place. The whole lot was set up square and the PCB base soldered to the mounting plate successfully.

 

I'd decided that I was going to use a dog clutch drive and turned up a couple of brass plates with pins and corresponding holes (subsequently open out to be slots). I know this can be done with only one pin but it offended my symmetric sensibilities, but time will tell whether one of the pins will be sliced off in light of experience. All has been assembled loosely and looks like it will work, but power has not yet been applied - so it's all going well, at least from a cosmetic point of view...

 

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This shows the mounting jig set up to hold the motor mounting plate in position to attach to the PCB motor mount base - yes, it looks crooked because it's just stuffed in place for the photo. 

 

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The various bits on display with the chassis. The right hand hole in the PCB was a mistake from an earlier effort and serves no purpose...

 

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Dog clutch parts

 

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The clutch and motor set up in the chassis.

 

Just occured to me that the 3-112 Frame Bushes (the large ones)could be used to make a dog clutch. They can be mounted on a 1.5mm shaft, clamped together then drilled for the pins and slots.

 

Mark

Edited by 2mmMark
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very clever although I confess I normally just put the  worm on the motor shaft

 

Nick

 

Most of this comes from my paranoia about being able to disassemble and reassemble things to correct previous errors. How much of this is counterproductive in introducing new errors is another matter!

 

 

b

 

 

Interesting idea. And something else I can think about 3D printing.

 

Is that motor mount clear of the wheels though?

 

Chris

 

 

Is it, just - but there's plenty of non-functional meat across the bottom of the brass mount that can be filed away to give better clearance.

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Just occured to me that the 3-112 Frame Bushes (the large ones)could be used to make a dog clutch. They can be mounted on a 1.5mm shaft, clamped together then drilled for the pins and slots.

 

Mark

 

That could work. But in this particular case I think one half of the clutch needs to fit a 1mm diameter shaft. The dog clutch is a neat solution to the problem that otherwise needs sleeves on the motor shaft. But it is a bit bulky in certain circumstances. 

 

I also feel Henk might at this point be making comments about issues getting it truely concentric with the shafts to avoid vibrations.

 

Chris 

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 I'm not sure the large axle frame bushes would be suitable. They are a very easy running fit on 1.5mm axle shafts (as you might expect) and also on the motor sleeves. Although the use of Loctite 601 or similar might centre them on the shafts I would worry about any vibrations caused by any excentricty as already stated.

 

Izzy

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That could work. But in this particular case I think one half of the clutch needs to fit a 1mm diameter shaft. The dog clutch is a neat solution to the problem that otherwise needs sleeves on the motor shaft. But it is a bit bulky in certain circumstances. 

 

I also feel Henk might at this point be making comments about issues getting it truely concentric with the shafts to avoid vibrations.

 

Chris 

 

Eileens  and Squires both sell accurate 1.5mm od/1mm id tubing.

 

Nigel Lawton offers turned shaft adapters.

http://www.nigellawton009.com/PayPalMotors.html

 

There is also 1mm id silicone rigging tubing (used by fishermen) which can link up shafts as it's stretchy enough to slip over 1mm & 1.5mm diameters.

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Class 31 conversion

 

 

Some while back I posted details of a 2FS conversion I had undertaken on the new version Farish Class 31 using the 2mmSA 'drop-in' diesel conversion wheels. This loco uses different sized wheels in the bogie as per the prototype and so required the use of 7.5mm geared wheels and 7mm un-geared ones. These were very slightly larger in diameter than the Farish originals at 7.35mm and 6.75mm respectively but otherwise the conversion seemed fine, the difference in overall diameter seeming small and something which it was supposed would make little real impact. The use of the non-geared wheels with their smaller diameter axles (1mm v 1.5mm) did mean however that the centre carry wheels needed springing via fine wire to ride properly on the track

 

 At the time a question was posted as to whether re-machining the Farish wheels to 2FS would be an easier/better route. Later on I acquired another new version 31 and machined the wheels to see if this was indeed a better solution for this particular model. With a lathe it was, for me, an easy task to undertake and the results proved that it did work well.

 

Without a layout at the time a couple of differences between the conversions went unnoticed and have only recently come to light under the testing of a newly finished layout, (well the track is built/laid/wired and it all works but that is all).

 

The re-machined wheels converted 31 works fine, it sits at the correct ride height and the body is firm and upright on the chassis. The original 31 using the 2mmSA wheels however, while it ran fine, had body issues in that the ride height was about 0.5mm more, and the body would keep leaning/listing to one side or the other.

 

A complete strip-down of the chassis did not reveal any reason for this. The springing to the carry wheels was removed in case this was the issue, lifting/raising the chassis/body. It made no difference. Finally the original wheels were re-fitted. This cured the problems, the loco now sitting at the correct ride height with a stable upright body. I am now currently machining these wheels as per the second 31 conversion.

 

I have no idea why fitting the 2mmSA wheels gave these issues as it doesn't seem logical - especially the increased ride height since the whole diameter difference was only 0.15mm - but there we are. Finding these problems I thought it best to warn others wishing to convert their 31's.

 

regards,

 

Izzy

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Class 31 conversion

 

 

Some while back I posted details of a 2FS conversion I had undertaken on the new version Farish Class 31 using the 2mmSA 'drop-in' diesel conversion wheels. This loco uses different sized wheels in the bogie as per the prototype and so required the use of 7.5mm geared wheels and 7mm un-geared ones. These were very slightly larger in diameter than the Farish originals at 7.35mm and 6.75mm respectively but otherwise the conversion seemed fine, the difference in overall diameter seeming small and something which it was supposed would make little real impact. The use of the non-geared wheels with their smaller diameter axles (1mm v 1.5mm) did mean however that the centre carry wheels needed springing via fine wire to ride properly on the track

 

 At the time a question was posted as to whether re-machining the Farish wheels to 2FS would be an easier/better route. Later on I acquired another new version 31 and machined the wheels to see if this was indeed a better solution for this particular model. With a lathe it was, for me, an easy task to undertake and the results proved that it did work well.

 

Without a layout at the time a couple of differences between the conversions went unnoticed and have only recently come to light under the testing of a newly finished layout, (well the track is built/laid/wired and it all works but that is all).

 

The re-machined wheels converted 31 works fine, it sits at the correct ride height and the body is firm and upright on the chassis. The original 31 using the 2mmSA wheels however, while it ran fine, had body issues in that the ride height was about 0.5mm more, and the body would keep leaning/listing to one side or the other.

 

A complete strip-down of the chassis did not reveal any reason for this. The springing to the carry wheels was removed in case this was the issue, lifting/raising the chassis/body. It made no difference. Finally the original wheels were re-fitted. This cured the problems, the loco now sitting at the correct ride height with a stable upright body. I am now currently machining these wheels as per the second 31 conversion.

 

I have no idea why fitting the 2mmSA wheels gave these issues as it doesn't seem logical - especially the increased ride height since the whole diameter difference was only 0.15mm - but there we are. Finding these problems I thought it best to warn others wishing to convert their 31's.

 

regards,

 

Izzy

 

Worth checking the number of teeth on the gears. Farish do not always use the same number. I am told the Farish 24 has 17 tooth gears whereas I think our axles have only 16. If the 31 has 15 tooth gears (which the prototype deltic does) and you put in a 16 tooth geared axle it would rock on the gear, assuming it ran at all.

 

Counting gear teeth is a bit of fun mind.

 

 

Chris

Edited by Chris Higgs
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Worth checking the number of teeth on the gears. Farish do not always use the same number. I am told the Farish 24 has 17 tooth gears whereas I think our axles have only 16. If the 31 has 15 tooth gears (which the prototype deltic does) and you put in a 16 tooth geared axle it would rock on the gear, assuming it ran at all.

 

Counting gear teeth is a bit of fun mind.

 

 

Mark a tooth with a black highlighter pen, then count from there.

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Thanks for the gear tooth thought Chris. Just double-checked this aspect - used a white gel pen as the gears are black - and the 31’s are 16 tooth, and so are the 24’s. Should also say there is nothing wrong with the 2mmSA drop-in wheels. The geared 7.5’s have been re-fitted into a recently bought Farsh 24 where it works as expected and they run absolutely fine.

 

It’s all rather bemusing. I feel I must be missing something quite obvious, but I just can’t see what. Thought it was the disparity between the geared non- geared wheels re the size difference error, but with the centre carry wheels removed it stayed the same. Ah well.

 

Cheers all,

 

Izz

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Measure the outside diameters of the gears and check they are not "corrected" diameters in some way.  That can be done with small gears, so the tooth count and diameter doesn't match theory. 

 

Or cross-check the class 31's original "N" wheels in the class 24.

 

 

I can't remember which way the tiny difference between DP and Metric gears goes, but its possible that the Farish is DP and the 2mm ones will be Metric. 

 

 

- Nigel

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Measure the outside diameters of the gears and check they are not "corrected" diameters in some way.  That can be done with small gears, so the tooth count and diameter doesn't match theory. 

 

Or cross-check the class 31's original "N" wheels in the class 24.

 

 

I can't remember which way the tiny difference between DP and Metric gears goes, but its possible that the Farish is DP and the 2mm ones will be Metric. 

 

 

- Nigel

 

Hi Nigel,

 

I have now checked the gears for any discrepency between them and can't find any, the overall OD and tooth depth being the same with all of them. I did wonder if this might be another area where the problems might be, given that gear forms can be over or undercut where needed for a particular situation. However, in going through all this I feel I might have discovered what might - I can't prove it now - have been the cause. It is simple, and leaves me feeling rather red faced. The P/B wiper pickups.

 

Those on the 31 are wide flat strips which run horizontaly along the bogie moulding. In fitting the 2mmSA 7mm carry wheels I had to modify them behind the centre axle to prevent shorting against the axles. Whether this was a contributing factor I don't know but the rear of the 2mmSA geared wheels have a large boss on which the wheel is fitted. I think the position of the pickups were such that their lower edges pressed down on the top edges of these bosses and allied with the slop in the axles in the bogie allowed them to act as springs, raising up the loco as a result. Mostly the weight of the loco compressed them, but not all the time. Had I realised this I could have tweaked them to stop it. It is noticable that the second 31's pickups sit slightly higher up, not by much, but enough to show. The original's ones don't seem to have been fitted/soldered on as well, the same level of quality, and I will now redo them. So another little lesson learnt.

 

regards to all

 

Izzy

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Yes

 

However it will take careful thinking to produce a design with the motor in the boiler tha can adjust the worm meshing.

 

Chris

 

Indeed. I had tried that on a Metro and it sucked so was keen to keep motor and chassis attached. It goes together with a satisfying click as the back of the boiler gets trapped by the firebox and the smokebox locates in a pocket behind the inspection doodah on the front footplate.

 

It now needs to go back in the gloat box for a few months until I can forget about the frustrating/annoying bits . . . might even clean the crud off first.

 

Andrew

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Its not on my workbench at the moment but Id like it to be. I'm after a Dapol N gauge 28xx 2-8-0 loco body to convert to 2mm finescale. Any condition considered as I don't need the chassis and will also be replacing the tender and cab to back date it to a 2800 rather than a 2884.

Please pm me if you can help.

Jerry

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I've dug out both my lathe and my M7 and I'm having a go at boiler fittings. I've made three chimneys, number two is the best but it still looks weird. I'll need to make at least one more. The first dome, however, came out really well. It needs to be soldered in place and then have the bottom edge formed, but one step at a time.

 

o01jX1E.jpg

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I've dug out both my lathe and my M7 and I'm having a go at boiler fittings. I've made three chimneys, number two is the best but it still looks weird. I'll need to make at least one more. The first dome, however, came out really well. It needs to be soldered in place and then have the bottom edge formed, but one step at a time.

 

 

Go on Gareth, show and tell all - show us yer "weird chimneys". A salutary lesson in turning to us all, perhaps...  :scared:  :derisive:

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Go on Gareth, show and tell all - show us yer "weird chimneys". A salutary lesson in turning to us all, perhaps...  :scared:  :derisive:

Here you go Phil. Left to right are chimneys 4,3,2,1. 3 was coming out pretty well, but I managed to break a drill in it. Funnily enough I did the same thing on number 1. On number 4 I remembered to oil the drill. I'm going to try to rechuck the dome, it's not quite round enough.

 

kLUvbzL.jpg

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Are you turning these fittings using the lathe dials and leadscrews Gareth? If so, that is very difficult. It is much easier to turn fittings using a graver and handle, resting on a bar: much the same as wood turning. The graver can be made from a ground up needle file, but do make sure the tool is supported near the work. This video is a bit drawn out, but shows the principles:

 

As an added bonus, it’s also in American.

 

Tim

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I have just installed my second tantalum stay-alive unit and would like to thank Nigel Cliffe for the all pioneering hard work he did on them along with Nick Mitchell for his recent posts giving the e-bay links to the parts needed.

 

Having had the privilege of seeing Nigel's 02 diesel shunter glide around a layout of mine some time back I knew the advantage they gave, but just didn't have the courage to attempt making one for myself until I read Nick's account of his coal tank adventures and the bits he used. It was the shove I needed to give it a go.

 

My first pack went into the Farish Jinty that is the subject of another thread here, and uses 3x220uf tantalums in a flat formation above the CT DCX76 so the cab is clear, while the second pack of 4x220uf's as a squarish block are fitted into the nose of my BR blue 08 with 2mmSA chassis & e-bay coreless motor. The Jinty has a 1st version (red) DCX76 while the 08 has a (green) version 2. The solder pads for connection are however in exactly the same places.

 

The improvement gained is immense, and would seem to be related to loco speed from what I can see. I had worried that just (!) three 220uf's wouldn't make much difference but this is what I have found. It is based around the use of coreless motors, and a third pack will be fitted when time permits into the BR blue 04 I have which is still not finished and again has a e-bay coreless motor so whether the advantage will be as much with ordinary non-coreless Farish type can motors I can't say.

 

Using 28 speed steps, and when power is completely shut off, on steps 1 or 2 about a spoke of movement is made. At step 5 this becomes about a 1/5th of a wheel revolution and at step 10 almost 1/2. Above this speed it's like having a bit of a flywheel action. This is about the same for both locos, and I presume the extra 220uf with the 08 is offset with the higher gearing of 49-1 against the 40-1 in the Jinty. But going by these results even fitting just 220uf or 2 x 220uf would seem to be worthwhile if space is at a premium. Working out cost-wise at just a few pounds each they are definitely worth the effort.

 

Here are a few shots,

 

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regards

 

Izzy

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Those Stay Alive installations both look really neat jobs, Izzy. I'm relieved my "encouragement" hasn't cost you a blown up loco, and pleased you're getting such good results.

 

Funnily enough, I've recently retro-fitted my Association Class 11. I knew there was a good reason for not quite finishing it off and painting it 10 years ago!!!

What is becoming my "standard" configuration of 4 x 220uF wouldn't fit: 

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There is room in the bottom of the cab, but because of where the body attaches to the chassis, that room is unusable. Perhaps the fixing point could have been moved when building the kit, but not now. Besides, it is nicer to keep the cab empty - especially when it has a pretty light in it :)

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I managed to fit 3 tantalum caps and the other components round the gear tower - 2 vertically at the side, one on top. I had to cut some gaps in the PCB base (now hidden from view). When gluing the unit to the top of the gear tower, I put some card packing between the worm and the vertical capacitors... I didn't want to end up with them rubbing together.

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Soldering to the DCX75 decoder was interesting. The warning on Carsten Berger's 1001 Digital website (via Google Translate) concerning the smallness of the pads on this particular decoder is as scary as it is hilarious:

Who has no sensible soldering equipment - keep away! Who quickly gets the shaking - Do not do it! Who is half blind - Switch to H0! ;)

 

Anyway, I survived. And so did the decoder. It fits nicely back under the motor, with room above the motor for a block of lead.

post-14390-0-04835100-1527174169_thumb.jpg

Everything is quite a snug fit within the resin cast bonnet.

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This was a really sweet running chassis when I first built it. Adding the decoder took things to a whole new level, but it did still stall occasionally. Stay Alive is the icing on the cake. Because the cab light is connected to one rail (rather than the decoder blue wire - it didn't have one when I installed it at first) it doesn't stay alive. There is something oddly satisfying seeing the cab light flicker, indicating a bit of dirt on the track, but the loco smoothly carrying on.

The little springs at the front of the chassis you can see in one of the photos above transfer the 2 function outputs to pads on the underside of the PCB footplate, so the chassis can be removed completely without having to unsolder any wires. The 3D printed chassis in the new style of kits will make this sort of thing more difficult (but the bits that sane people want to do much easier)... With the second function output I want to install some working marker lights.

 

Nick.

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Are you turning these fittings using the lathe dials and leadscrews Gareth? If so, that is very difficult. It is much easier to turn fittings using a graver and handle, resting on a bar: much the same as wood turning. The graver can be made from a ground up needle file, but do make sure the tool is supported near the work. This video is a bit drawn out, but shows the principles:

 

As an added bonus, it’s also in American.

 

Tim

I was doing it by hand, but I was also kinda making it up as I went along. I have since bought some small tool blanks, including a round one, which should make a difference.

 

I soldered them in place, but I think I will now need to make chimney number 5. The top flange is too big, which didn't really show up until I took a picture of it...

yidGiyE.jpg

 

 

In other news, I built a new underframe for a Dapol CCT which is a vast improvement over the original.

VvyGkXv.jpg

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"Those Stay Alive installations both look really neat jobs, Izzy. I'm relieved my "encouragement" hasn't cost you a blown up loco, and pleased you're getting such good results."

 

Thanks Nick. I do think it's soldering the wires onto the decoder where the nerves really jangle. Probably I'm quite lucky here as my normal/standard iron these days is a 15watt antex with a 1mm tip - I often file an oblique flat on the very end of them - and the pads on the DCX76 are huge....in comparison with those on the DCX75, as you can see here. I believe those on the latter are about the size of the four small ones between the wires..........

 

I do like Nigel's assessment - use another decoder.

 

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Cor, your class 11 install really is what could be called 'nip & tuck' isn't it ? Good job it's the association job with the resin body. As mine is the Farish body on the etched chassis conversion I did rather go to town with the masking tape to make sure there were no shorts. A smaller motor was also a big help here.

 

cheers,

 

Izzy

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I was doing it by hand, but I was also kinda making it up as I went along. I have since bought some small tool blanks, including a round one, which should make a difference.

 

I soldered them in place, but I think I will now need to make chimney number 5. The top flange is too big, which didn't really show up until I took a picture of it...

yidGiyE.jpg

Do you turn up a deep base with the chimney / dome Gareth? This helps to give you material from which to make the flare. Your dome looks a bit impoverished in this area. The thick base can then have the diameter of the boiler / smokebox filed in to it so that the best fit is achieved - sometimes useful to use bar of the same diameter as the boiler for checking. Finally the sides of the flare are filed in or ground in with a bur/stone/abrasive polishing tip in the Dremel. I always use 24 hr Araldite to fix boiler fittings, soldering is far too tricky to get them in the correct place.

 

Tim

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