Building Don Young's Doncaster

[sonicspeed66]

wow nice job of them something for me to aim to replicate myself keep up the good work so i can keep getting inspired.

[davebreeze]

From my wee bit experience working on the railway I noticed that buffer heads are only slightly domed, and very often completely flat. Of course that was mostly modern stuff, maybe things were different in Flying Scotsman's era, but the B4 tank I'm building (from 1895) also has flat buffer heads.

[pault]

Hi All
Dave has raised an interesting point here. I was looking at some buffers that a friend has made who has worked on the full sized railways for a long time. The buffers he made had a flat in the centre and a radius on the outer part of the head which he says is how they should be. Looking at the full sized GA for the P2 tender they appear to be a radius across the head. Has anyone got a drawing of a full size buffer head, ideally from an LNER tender? I can see arguments for a flat/radiused head and a totally radiused head, which is right? If it’s any consolation Pete the buffers I made for my tender have radiused heads because that’s how I believe they should be. When you go to York take a straight edge and have a look at Mallard’s tender buffers. But then again were the buffers radiused when they were new and the flats were worn on them? I don’t know time for bed
Regards
Paul

[pault]

Hi All
Ok on a different note, Dave would like to see the B4 its different, the NE electric is very different, Locomotion, well I looked at it a few years ago thinking it would be a quick build boy was I wrong. For a very small engine with limited power there is a lot of work in it. I would love to have a go on a 7.25 gauge one but I don’t think I will be building one. Sorry for going off topic. now i realy am going to bed
Regards
Paul

[Deleted]

Thanks for all the input re the buffers guys, personally I like the domed effect on the buffers but I'm sure after use the centre would get flatterned out as mentioned here. After all something has to give when rammed by hundreds of tons day after day, the springs won't absorb all of the impact. Interesting info regarding flat buffers Dave, thanks for that...

Pete

[Deleted]

Pic206

Just a small update today, I decided to do the guard irons as mentioned. Here are the pair having been cut, filed, drilled (No.44) and bent to shape remembering to make opposites. Don mentions how these things tend to get knocked off and how his drawing states items that are probably a little overkill and could be made more to scale. I think you guys have realised now that scale is important to me so naturally I took that direction. I made these in brass perhaps if they do get knocked their more likely to bend than shear off, time will tell.

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Pic207

Guard irons fitted to chassis, the 8BA bolts have been left overlength as the steps will also fit here. Well I guess I have no excuses left now for not starting the suspension, this I believe is going to be a long haul..... wish me luck... lol

Pete

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[Smifffy]

It's all a long haul Pete, but good luck all the same :-)

[6233]

Hi Pete,
Looks fantastic. make me want to crack on with Tornado.

[9F]

Hi Greenglade
Sorry a bit of a hijack of this thread but I have been following your excellent write-ups and noticed that you have used Petseal in the FS tender. I have purchased 260ml of the product for my Black 5 tender and would like to know if you had any issues applying the stuff or have any hints or tips, and did it stick OK as it seems to imply that it leeches into the rust in a petrol tank, which will not happen in my shiney brass tank!Also will 260ml be sufficient as the two tenders are of a similar- ish size.
Thanks in anticipation,
Charlie.

[Deleted]

Hi Charlie

Thanks for the comments on my write-ups, much appreciated. Regarding Petseal IIRC there was a few types available and on reading the info I decided on the Ultra variant. I bought the 260ml Ultra petseal from ebay and followed the instructions although it's basically very similar to Resin A in both mixing and application. My tender holds 3 1/2 gallons of water so the 260ml seemed to be the correct size going by the info out there. I used petseal really just as a back up as the tender was soft soldered and i didn't want to take the risk of applying heat to run solder inside as is the normal method but there was a small leak around the belly tank before application and that is sealed now so i guess it did it's job. I only mixed up half of the tin after first doing a small test as described in the instructions to check curing time. I would reccomend a second pair of hands to help with this as slushing resin around in a heavy tank is to much for one person, well it was for me anyway especially as it does take a fair amount of time to cure (and you must not stop turning until it's set) although it's warmer now than when i did mine so may cure quicker now.
The reason I only used half is first I wasn't sure how easy it would be to reach the belly tank before curing , second the water gauge outlet is very small and of course very low in the tank and i didn't want to risk a build up around this thus blocking the outlet and finally if i still had a leak after curing I wanted some back up petseal to concentrate on such a leak. As things turned out the 130ml ( approx) did the job first time. regarding how well it sticks i don't think i'll know the answer to this until much later once it's being used on a regular basis but on reading articles on the web the future looks good.

Best Regards

Pete

[9F]

Hi Greenglade,
Thanks for the information and fast reply.
Looks like I will give it a go next week, fingers crossed it all goes well.
Charlie.

[Deleted]

Afternoon everyone

Well I've made a start on the suspension spring hangers having previously discovered that the leaf spring material stated on the drawings is wrong. So while I wait for the correct material I'll cover the hanger build.

Pic208

Don suggested machining the hangers from 1/2x3/8 BMS bar as one but I decided to build them in two parts to save on material and time. In the picture is the hanger end which starts life as 3/16 bar threaded 2BA for 9/16 and then turned down to 5/32 for another 7/8". I left a small collar and then turned a 3.1mm spigot that would be a drift fit into the next part , that being the hanger grip.

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Pic209

Here we see the finished hanger end and also the grip end having first been cut into rectangular blocks and then drilled a No.30 hole for the top leaf to fit into. This block also had a 3mm hole drilled to a depth of 2mm for the 3.1mm spigot to be drifted into, with the collar acting as a stop to ensure correct overall length for the bracket.
.

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Pic210

With the parts fitted together they were then silver soldered and so two parts became one..

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Pic211

After retrieving the parts from the acid dip( note to self, don't leave things with fine threads in acid for to long as they get eaten away, although the threads are slightly damaged on doing a small stress test the threads are still capable of doing their job, live and learn) I cut a small template for the gripper and scribed around it for each hanger.

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Pic212

Now Don mentions about adding a touch of class by drilling a small hole in the gripper and tapping it 10BA for a bolt to be able to lock up against the top leaf to stop the spring from sliding out as on the prototype. The picture shows me doing this but on checking Mallards tender it was obvious that 10BA would be too small and that 8BA was the correct size to use so a 1.8mm hole was cross drilled to the No.30 hole drilled previously and then tapped 8BA.

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Pic213

Here is the finished spring hanger which involved an awful lot of hard work sawing, filing, sanding and polishing which is why I've taken a small break after doing just one to add this small update. Tomorrow I intend popping into work to use the bandsaw and 12" disk sander which should allow me to do the other 15 in the time that it took me to do this one..lol

Once these are done I'll do the spring buckles followed by the spring leafs once the new sized material arrives which hopefully will be soon.

Pete

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[drjohn]

Hi Pete

I was going to ask you about the spring hangers, but it seems that the Doncaster ones are completely different from the Black 5. See www.dr-john.org the Black 5 tab, third picture in.

I am faffing about trying to fabricate these little devils, but it's awffy difficult and I am seriously thinking of asking Abby to do me some lost wax castings.

On a slightly different topic, the box stretchers on the tender, are they similar to the Black 5 or completely different, as I am struggling with them too! Don says to hold the bits together with 1/16" copper rivets in 3mm steel for silver soldering - Lol!! I have loads of 1/16" copper rivets but only three 1/16" drills which are like hen's teeth on the island here.

Suggestions would be appreciated.

DJ

[goldstar31]

Dr J, Greetings- nice to have you back.

I'm somewhat baffled because you are drilling,rivetting and then silver soldering( what you said)
Again, you are using 1/16th copper rivets using 1/16th drills!- which you can't replace.
So the first principle in silver soldering is to allow for 'wicking' between the parent sheet and the rivet. Unless your drilling is shaking to go oversize, you are going to get a dry joint.

Now I'm no body's expert on locomotives but I can silver solder- so you must find a clearance drill above 1/16th inch- metric or imperial.

Regards

Norman