D869's Workbench Thread

[D869]

11 minutes ago, Ian Smith said:

I can't see the photos Andy.

Ian

 

I just added them again so hopefully all OK now

[Caley Jim]

I can see the pics OK.  I had the same problem of a post appearing twice recently, but I couldn't find any way of deleting the duplicate other than reporting the post.

 

Jim

[Caley Jim]

26 minutes ago, D869 said:

 

I just added them again so hopefully all OK now

Ah!  That explains why I can see them!

 

Jim

[Chris Higgs]

On 16/02/2020 at 22:35, D869 said:

Thoughts are also turning to the cab roof. This has a rib all around the edge plus another that goes across the centre from one side to the other. At the moment I havent figured out a good way to do do this, so suggestions would be welcome.

 

I once used fuse wire to form the rib around the roof of a GWR Star in 4mm scale. Its surprsingly easy to solder it straight.

 

Chris

[D869]

14 minutes ago, Chris Higgs said:

 

I once used fuse wire to form the rib around the roof of a GWR Star in 4mm scale. Its surprsingly easy to solder it straight.

 

Chris

 

Yes a very under rated modellng material. For some reason all of my cards are devoid of the 5A variety... odd, that.

 

I still managed to buy some last time I tried but the shop person had to dig around a bit to find it.

[Chris Higgs]

3 minutes ago, D869 said:

 

Yes a very under rated modellng material. For some reason all of my cards are devoid of the 5A variety... odd, that.

 

I still managed to buy some last time I tried but the shop person had to dig around a bit to find it.

 

Just type fuse wire into ebay

[DavidLong]

5A fuse wire. How much do you need?

 

https://www.ebay.co.uk/itm/5-amp-fuse-wire-36-SWG-Tinned-Copper-Wire-40-meters-FUSE-WIRE-5-AMP-0-2mm-/113965764804?hash=item1a88e390c4

 

My reel already has a place in my will . . . 

 

David

[Kylestrome]

9 hours ago, DavidLong said:

My reel already has a place in my will . . . 

 

That's just like my tin/lead solder wire. I bought a half kilo reel of the stuff, when there was a scare that it would no longer be available, and I still haven't touched it!

 

David

[bécasse]

2 hours ago, Kylestrome said:

 

That's just like my tin/lead solder wire. I bought a half kilo reel of the stuff, when there was a scare that it would no longer be available, and I still haven't touched it!

 

David

Only one reel - I've got three, albeit different solder types!

[D869]

14 hours ago, DavidLong said:

5A fuse wire. How much do you need?

 

https://www.ebay.co.uk/itm/5-amp-fuse-wire-36-SWG-Tinned-Copper-Wire-40-meters-FUSE-WIRE-5-AMP-0-2mm-/113965764804?hash=item1a88e390c4

 

My reel already has a place in my will . . . 

 

David

 

Ordered now

 

I shall miss needing to smooth out the kinks from where it wrapped around the card every 2 inches or so though. I guess I could put them in for old time's sake.

[Caley Jim]

An easy way to straighten out any copper wire is to roll it between two hard surfaces. e.g a steel rule and a brass block.  Just roughly straighten it out and start rolling it a short length at a time until you can roll the whole length.

 

Jim

[pete_mcfarlane]

On 22/01/2020 at 17:57, D869 said:

The bits. In spite of appearances here, the frames are 0.5mm phosphor bronze. I'm trying out the Dave Holland 'keeper' style of chassis and so far it's proving very handy during the mechanical fettling stage. The front spacer is solid brass to get the weight forward with a PCB insulating layer. The rear one is Tufnol.

That looks quite an interesting way of building a chassis, and not one I'm really familiar with as a 4mm scale modeller. Is the rear axle fixed (by the shaped block to the left of the driving wheels)?

[Kylestrome]

1 hour ago, Caley Jim said:

An easy way to straighten out any copper wire is to roll it between two hard surfaces.

 

Alternatively, hold one end in a vice and pull the other end with pliers until it stretches a little. It works with most soft wire, but you'll have be very gentle with 5 amp fuse wire.

 

David

[D869]

2 hours ago, pete_mcfarlane said:

That looks quite an interesting way of building a chassis, and not one I'm really familiar with as a 4mm scale modeller. Is the rear axle fixed (by the shaped block to the left of the driving wheels)?

 

Hi Pete,

 

Dave Holland described his method of chassis construction some time back. It was published as an article in MRJ No 34 in 1989 and subsequently by the 2mm Association as a small booklet called 'Build an 0-6-0 in Two Millimetre Scale'. The booklet is unfortunately out of print but a PDF scan is available to 2mm Association members via the web site.

 

As with most 2FS chassis, Dave's design uses split frame pickup. The important points for the O2 are the use of a now somewhat old-school construction with 20 thou phosphor bronze frames and solid spacers. Instead of having captive driving axles the axle holes are slotted and a separate 'keeper' with upwards facing slots is used to stop the wheels falling off.

 

The chassis is not compensated or sprung in a way that most 4mm folks would recognise but uses a more recent technique called 'Simpson springing' in which the axles normally bear on the tops of their holes in the frames but are allowed some downward movement. A piece of springy phosphor bronze wire is arranged to rub on top of them to ensure that electrical contact is not lost when they find a dip in the track. Calling it springing is a bit of a misnomer because it doesn't do any significant weight bearing.

 

Coincidentally if you read Mick Simpson's original 'springing' article in the 2mm magazine, he credits the inspiration to... Dave Holland. Dave's article/book describes the use of a similar technique but he only used it on the tender axles (maybe just the centre one).

 

The shaped block in the photo is a brass frame spacer. It has a PCB layer on one side for insulation and a Delrin bush to insulate the frame fixing screws. It doesn't play any role in the suspension arrangement.

 

Regards, Andy

[pete_mcfarlane]

Thanks for that explanation. I need to dig out MRJ34 from the pile of MRJs and have a read. 

[D869]

The splashers are on...

 

After a bit of pondering and trying to make them as a several sided box I ended up making them with a 10 thou outer layer with the rest of the thickness of the sandboxes done in solid brass...

...done on the MF70...

 

There was a bit of a gap between splasher and footplate because the (deleted) N Brass splashers were slightly further out than my versions. I filled the gap with a bit of 5 amp fuse wire and solder. This left a bit of a messy solder fillet...

 

I really needed to get to the point where I had finished applying lots of heat to the splasher area before I could clean up the fillet which meant making and fitting some twiddly bits to go on top. These were done with a hand graver on the watchmakers lathe. They looked almost non existent when I was making them but they look quite big on the loco...

 

The curved tops are strips of 5 thou which I have not managed to photograph.

 

Next up is fitting the rear panels. These were made a while back but left off to allow better visibility around the motor and fixing screws. The bunker rear panel is 5 thou brass and so far the only main panel cut out by hand.

[D869]

Coal rails... pleased with those... a bit of a shot in the dark in terms of how I made them but I think it's worked pretty well.

 

[D869]

It's about time I said a bit more on this. The postponement of the DJ expo has rather taken the deadline away and I've been ticking off some jobs from my (lengthy) lathe tooling 'to do' list which is not really about my 2mm workbench.

 

Before all of that happened I was getting on with the boiler fittings...

 

The roof (10 thou brass, annealed before bending) is also balanced in place but as yet unfixed and lacking its ribs.

 

The chimney is the N-Brass one, cleaned up in the lathe and drilled so that it looks more hollow.

 

I didn't think the N-Brass dome was a good likeness. The real thing is quite tall and has a rather undernourished flare so I made a new one on the watchmakers lathe in the Nick Mitchell approved manner (well, more or less).

 

The N-Brass safety valve casting comes up too tall as well as lacking the 'shroud', so I made a new one. The base was done in a similar fashion to the dome but this time I decided to make the MF70 cut the base profile...

 

 

before doing the lathe work... at this point it was visiting the Unimat, probably for drilling the spigot hole

 

 

The top was cut from brass strip on the MF70. It took a lot of cuts to do this and it needed a good deal of cleanup but it got the job done...

 

 

[D869]

The main job since the previous posting has been the beading around the tank tops and cab opening. The cab side handrails are also done... as a kind of practice for rather more tricky boiler handrails.

 

 

The handrails are 0.2mm Albion Alloys N/S rod. Ths 'knobs' are split pins made by filing down 8 thou P/B wire as recommended by Pete Wright's article in the April 1992 2mm Magazine.

 

The cab door should have been simple but turned out to be a right faff - it needed some packing to provide clearance behind the handrails and getting all of this soldered into place inside the cab was not easy. I'm definitey at the stage now where it is easy to do things in the wrong order and snooker myself. The cab roof will be staying off for a bit longer.

 

The beading was done with 5A fuse wire. It is overscale but I chickened out of trying 0.1mm wire. Maybe another time. I was also pondering leaving the beading off completely but that would have left the cab door handrails and tank front handrails with no means of support at the top.

 

This proved not too impossible to attach neatly and without unsoldering anything else... although I'd hardly describe the job as easy either. Much scraping and sanding was involved. Here is a shot of a rather earlier stage...

 

 

To give myself a break from handrails I've now decided to have a go at one bit that I've been puzzling over for ages - the reverse curvy (valve?) cover under the smokebox door. I've been struggling to come up with a way to make this. It needs to be soldered to the smokebox so I want it solid. So far I've milled some steps in a bit of brass, the plan being to do the curves with a needle file. We shall see!

 

If anyone has any better ideas about how to make this then I'm all ears.

 

 

The milling was done on the Unimat SL... mainly because I've recently made the milling column for it (this was missing when I bought it). I'm not sure it makes the ideal milling setup but should be very handy for drilling.

 

 

Edited April 28, 2020 by D869
corrected Pete Wright reference

[CF MRC]

I often put details such as beading on over-scale and then file back to size.  
 

For the valve cover you could try using a scraper (e.g. ground up needle file / scalpel) to plane it to the shape you require. Brass is quite soft. Solder the piece you are working on onto something larger so that you can hold it easily in a vice. 
 

The other way to achieve the reverse curve might be to drill into a square

block of brass with the correct diameter drill and then file back the rest of the brass to the correct shape. 
 

Another alternative to milling steps might be to use a round ended tool in the mill. A large rose head bur might do the trick. 
 

Choices, choices...
 

Tim

[D869]

Thanks Tim - I'll keep those in reserve in case the current plan doesnt work out. I'm hoping that the steps will give enough guidance to a file so that the curve stays straight (if you see what I mean) but time will tell. I do intend to solder it to a bigger lump. Should really have done that before milling but resorted to some fairly iffy clamping arrangements instead and I seem to have got away with it.

A round nosed milling cutter would be very handy but at the moment I don't have any of those - one of those things that I keep intending to buy but when actually putting together an order I seem to forget again. I do have a few burrs that I bought years ago to use in a mini drill but never found that combination to be much use. I've never thought of digging them out again and putting them in the mill so will give that a go.

Regards, Andy

[richbrummitt]

8 hours ago, D869 said:

Should really have done that before milling but resorted to some fairly iffy clamping arrangements instead and I seem to have got away with it.

 

Go safe Andy. I clamped something tight once and it moved into the cutter! Only a smashed up cutter and a bent spindle that time.  I always wear safety glasses regardless but the forces are high even in a tiddly mill. 

[D869]

23 minutes ago, richbrummitt said:

 

Go safe Andy. I clamped something tight once and it moved into the cutter! Only a smashed up cutter and a bent spindle that time.  I always wear safety glasses regardless but the forces are high even in a tiddly mill. 

 

Cheers Rich. I think the job was pretty firmly held TBH but the clearance between cutter and vice was close to nothing.

 

The bigger issue with the Unimat is the weight of the headstock and motor and the lack of any kind of fine feed or dial on the 'Z' axis. It's just a matter of using your best guess for height and then clamping it up tight before starting the spindle. Even though I was being careful to avoid it, I managed to 'drop' the headstock a couple of times while setting up, fortunately without breaking anything.

 

I have other options so I don't think I will be hurrying to use the Unimat as a mill again but the lever feed and slower spindle speed should make it quite useful as a small pillar drill - much better than using the MF70 for drilling anyway... and compared to using a lathe... well it's just the right way up.

 

FWIW I always treat milling machines as if they are trying to damage me, themselves and/or the job and they usually have more tricks up their sleeve than you are expecting. True of all power tools but I find milling is particularly prone to unexpected happenings.

 

Regards, Andy

[richbrummitt]

Strange you say that: my milling vice weighs ever so slightly less than it once did: the chips are somewhere in the workshop or they went in the bin by way of the vacuum. That was when I was making the splashers for a 28xx. They're only 0.5mm tall so virtually nothing to clamp! 

 

Often I wonder if I should have bought a slightly larger mill. A lever feed would be desirable many times and I'm convinced we don't need more than 1k-2krpm. Peter Clarke once showed me a natty device for small drilling that used an adjustable weight on a four bar linkage where the drill was aligned and driven on the spindle but moved on a spindle of it's own directly below the spindle of the drill/mill. He'd made a few and possibly they have a 'proper' name. I don't know that it was his original idea but it was beautiful as an idea and in his execution. 

Edited April 26, 2020 by richbrummitt

[D869]

I hasten to add that the lumps out of my machine vice and drill holes in it happened before it came to me

 

There's still time though...