Drewry O4 in 7mm

[Nicktoix]

Nice work

Nick 

[Bucoops]

5 hours ago, M51625 said:

Whilst gearing up for a bigger project, i thought i would bump this one up the build queue..

 

All seems to be going according to plan, etches all fit nicely..

 

Wheels and rods are the next step, i don't like the slaters crankpins as supplied so will be tapping then 10BA.

 

Funny you should say that - I'm not planning on building mine yet but have gathered the bits (I wonder if Slaters have noticed a "run" on 04 wheels?!

 

I took one look at the crankpins and thought "nope" - too much like 4mm ones. Bit of googling and I saw people use 10BA quite often so ordered some from Eileens.

[Nicktoix]

10ba is sure the way to go. Also tap the crank and use them there as well.

Nick 

[M51625]

14 hours ago, Nicktoix said:

10ba is sure the way to go. Also tap the crank and use them there as well.

Nick 

yep thats also getting the same treatment, hoping to have a rolling chassis this coming week.

 

Holding off starting the body until the chassis is finished

[Bucoops]

Something has been bugging me about the front - noticed what it was yesterday - it appears there are two radiator grille sizes and the one I was considering building has the other design (which is much closer to that used by 03s:

 

https://en.wikipedia.org/wiki/File:D2325,22-9-2018..jpg

 

Might have to be a bit of tweaking done

[M51625]

Ok, so i'm happy with the rods, and the cranks are all fitted and quartered, this is the first 8 coupled engine i've built and quite pleased with it, rolls nicely with no binding or tight spots.

 

Crank pins to trim and tidy up, and then onto the body.

 

Couple of minor issues, ride height seems a little high, and the running plate over hangs the buffer beams, so might need trimming down. 

[Nicktoix]

The running plate should overhang the buffer beams but only by a small amount

Nick 

[M51625]

chassis buffer beam - buffer beam measures 155.5mm, running plate is 158mm, overhang a little excessive looking at photos, therefore its been trimmed, i now have approx 0.5mm overhang and i'm ok with that.

 

ride height, check against quite a bit of my stock (various manufactures) but it does seem the buffer centre line is high, not going to do anything about it, on with the bonnet.

[Bucoops]

I know nothing about 7mm but the "Gauge O Guild" standard says 40mm apart, 24.5mm from top of railhead to centre line - how does it compare to that - if that's even the standard to use!? I can see through the tissue that they are 40mm apart.

 

https://www.gauge0guild.com/manual/01_1_standards.pdf

 

Edited April 11, 2019 by Bucoops

[Michael Edge]

The BR standard buffer height above rail is 3' 5 1/2", 5' 8 1/2" centres.

[Nicktoix]

16 hours ago, M51625 said:

chassis buffer beam - buffer beam measures 155.5mm, running plate is 158mm, overhang a little excessive looking at photos, therefore its been trimmed, i now have approx 0.5mm overhang and i'm ok with that.

 

ride height, check against quite a bit of my stock (various manufactures) but it does seem the buffer centre line is high, not going to do anything about it, on with the bonnet.

Don't forget the hooks on the buffer beams for the shunter's poles. I did until I painted up and had to go scraping paint off.

Lightly scribe across them from the half etches on the body of the etch gives a guide to the fold lines.

Nick 

[M51625]

13 hours ago, Bucoops said:

I know nothing about 7mm but the "Gauge O Guild" standard says 40mm apart, 24.5mm from top of railhead to centre line - how does it compare to that - if that's even the standard to use!? I can see through the tissue that they are 40mm apart.

 

https://www.gauge0guild.com/manual/01_1_standards.pdf

 

Hmmm 27mm measured....

[M51625]

on with the build.

 

Forming the bonnet, straight forward enough, a little flimsy in places due to the different thickness but unavoidable, i decided to build a frame internally for strength and to add a little weight so box structure made from 4x2 (thats 4mm x 2mm brass) inside, still plenty of room for the motor and probably a little extra lead weight in due course.

 

Picture shows progress and work has halted due to the soldering iron bit falling apart, unlikely to get a replacement before going away at the end of the week, so a deep clean and workbench tidy and a resumption at the end of the month.

 

 

[M51625]

steady if not rapid progress, everything has arrived for my next big project which awaits completing this.

 

Chassis back together, motor fitted, rods currently being painted all will go back together when dry, just pickups needed.

 

Work has started on the cab, tricky bit coming up involving the cab side windows, seems a lot of pieces, so need to study some detail shots.

[Bucoops]

Looks very neat - love it!

[M51625]

finally, ready for paint, test run, loaded with lead, transfers ordered...

 

 

[M51625]

slowly but surely, this was parked during the summer while i concentrated on a DMU project, back on with this now, transfers have arrived too.

[Bucoops]

A lot of my 4mm stuff is still at work but I am not, but wanted to have something to do so decided to have a crack at this. Have got a rolling chassis so far, still a lot to do though of course.

 

 

 

I seem to have the biggest trouble with the laminations - getting them to look solid instead of the laminations. I'm hoping that perhaps high build primer may be my saviour

[Michael Edge]

Clamp the laminations together add flux and run solder all round the edges, nothing else is necessary it will go well into the middle by capillary action. Make sure that the solder covers all the joins in the laminations so that they can't be seen then file it all smooth. Keep the soldering iron away from the front face  if it has rivet detail though - if it doesn't you can sand the face flat as well.

[Bucoops]

52 minutes ago, Michael Edge said:

Clamp the laminations together add flux and run solder all round the edges, nothing else is necessary it will go well into the middle by capillary action. Make sure that the solder covers all the joins in the laminations so that they can't be seen then file it all smooth. Keep the soldering iron away from the front face  if it has rivet detail though - if it doesn't you can sand the face flat as well.

 

Thanks Michael - it's what I had been trying, but it didn't want to flow well enough - I may try a lower temperature solder perhaps - I normally use 179c with 7mmlocomotives.co.uk flux - you can see it has flowed nicely for the frame spacers. 

Edited April 29, 2020 by Bucoops

[Bucoops]

Whilst waiting for some more fiddly bits I've started on the body.

 

 

The side doors have a bit of a "realistic" ripple to them as I did struggle somewhat to get them attached. I think I need to invest in an RSU...

 

I've used the same bushes for the radiator fillers (?) as for the rocking part of the chassis compensation - Romford 4mm coupling rod bushes. I'm not sure what the rear ones are supposed to be - fuel fillers? Duplicates to the ones under the footplate?

 

 

 

[Michael Edge]

On 29/04/2020 at 13:47, Bucoops said:

 

Thanks Michael - it's what I had been trying, but it didn't want to flow well enough - I may try a lower temperature solder perhaps - I normally use 179c with 7mmlocomotives.co.uk flux - you can see it has flowed nicely for the frame spacers. 

I use 62/s solder - tin/lead with 2% silver, melting point is 179. It flows really well and changes soldering techniques a lot. Available from Warton Metals, RS and Hobby Holidays at least.

[Bucoops]

49 minutes ago, Michael Edge said:

I use 62/s solder - tin/lead with 2% silver, melting point is 179. It flows really well and changes soldering techniques a lot. Available from Warton Metals, RS and Hobby Holidays at least.

 

Thanks Michael, I do have some silver solder bit it's lead free. Haven't had much luck with it - I'll see if I can get some of the real stuff then and try that for the fiddly bits!

[Bucoops]

Little bit more done, and checking the fit on the chassis.

 

[Bucoops]

Thanks for the recommendation on the solder, @Michael Edge - I found in my soldering box a tube of Slaters Cream I don't even remember buying, and I bought some of the 0.7mm from Hobby Holidays (after RS refused to sell me any!).

 

Still not perfect but looking a lot better.

 

You may be able to just make out on the front buffer beam a strip of brass - when I soldered the buffer beams on, I tried to get the buffer mounting holes a little closer to the 24.5mm height spec. This meant putting them on slightly lower than intended. I need to do the rear as well, then clean them up but I think it's worked out OK.

 

 

The resin parts are held on with screws from behind. I'm sure i could have just glued them on but I went for a mechanical fixing. I will also glue them when totally happy with their fit. I've used photos of my intended victim to guide where they go. It has involved hacking the spacers around quite a bit, but with the buffer beams there's a lot of excess strength so I don't think I've harmed it, and it still passes the "push" test with the wheels revolving freely with the drive grub screw loose.