Britannia 70047 "Derek Stokes"

[JonL]

Re-reading some of the notes it would appear I'm missing the critical part; does the cone fill the top of the chimney? I think I can state that as categorically no. Damn.

EDIT I wonder if I should fit some form of choke?

[simplyloco]

Jul 9, 2019 15:11:21 GMT JonL said:

Re-reading some of the notes it would appear I'm missing the critical part; does the cone fill the top of the chimney? I think I can state that as categorically no. Damn.

EDIT I wonder if I should fit some form of choke?

Page 677 NOVEMBER 20, 1952 shows the drawing of the smokebox. The flared part is straightforward. Do you not have this?
John

[JonL]

I'll have a look, I've got most of them but I don't recall seeing this drawing, thank you for the tip.

EDIT Quite right, its missing from my lineup. I thought it was a bit vauge! I've ordered a copy from eBay. Thank you.

[JonL]

Just a quick update, my embryonic Britannia is watching my work on William enviously, but I'm finding reworking and repair on an existing locomotive has been easier for my education than doing things from scratch. It's not the end of the road, but the project is paused until I've finished the William. I'm still very much in love with the design and will be doing odd bits here and there as I crack on with the other locomotive (which I have less of an attachment to as there is less of "me" in it).

Merry Christmas all, thanks for all your support when I ask questions.

Jon.

[JonL]

Almost exactly a year later!

Laid all the components I have out today, cleared the bench and re-assessed where I am. It's looking like motion work is my next port of call. This time last year I didn't have my Mill, and I feel much more confident about making the motion brackets now.

The William has given me a boost; I feel like the last year has been a huge leap in understanding and skills for me. I'm still a novice, but a better prepared one. I've also got a better eye for some of the things I'd like to redo which previously I would have been quite happy to leave be.

[JonL]

I had two options for making the motion brackets, use the castings, or the steel plate versions I bought in a batch from Malcolm at MEL last year. I measured up the right hand casting, it was slightly too small, possibly doable but would have left a few rough edges. I considered maybe adjusting some of the other components to suit to get the measurements right. Measured up the left hand, more complex casting (both of these were gunmetal. The left hand casting has the reverser worm on it so is a bit more interesting) and it was seriously undersized. As they came with the locomotive originally I have no comeback with the original manufacturer as I've no idea who it is. I machined the left hand one anyway as practice. It came out ok, however one thing I hadn't considered was that the casting would spring to slightly different proportions when metal was removed. It was only done for fun anyway.

So plan B it is, the laser cut steel versions. These solder together, and I'd already made the right hand one last year. I was not conviced if they would be strong enough or look the part, but as I already had them I figured I would attempt it and if I didn't like it I've only lost some solder.

As it happens they went together a treat and look quite tidy. They triangulate quite well so the measurements are very tight with minimal fettling. With a coat of black paint they look very "scale". Now I have to do the part I'm not looking forward to; the expansion link bushes. My plan is to make them undersized and then ream them in situ to get them as square as possible. I want them to look pretty close to the Prototype as they are a very visible part of the motion work.

[mbrown]

Reaming them through after final assembly would be my preference - although on one set of brake shaft bearings I discovered that there wasn't enough clearance on either side, once it was all assembled into the frames, to allow access for a standard reamer - so I had to cut a bit off the tail end of the reamer, file a new square on the end and drive it with a small spanner....

Malcolm

[JonL]

I ended up doing the expansion links next as once those are made I'll have a better idea of dimensions available etc. Just waiting for the case hardening to finish doing its thing, LBSC specifies the lowest bush to be hardened after reaming to 1/8.

[JonL]

I was a bit worried about making the brackets for the expansion links but ended up just taking my time and doing things to the best tolerance I could. In the end they have turned out in a way I'm happy with.

The pins in the side of the brackets are silver steel, I reamed the hole in the bracket undersized, heated the bracket up and pressed in the silver steel rod. Once cooled the rod was immovable, so I believe this should hold well. The alignment looks bang on, but I won't know until its all assembled. Awaiting Rivets for the next stage.

LBSC gave the option of sleeving the eye of the expansion links with bronze or reaming and hardening (1/8th). I did the latter.

[barlowworks]

Nicely done Nobby. 👍👍👍

Mike

[JonL]

My rivets have to pass through three thick pieces of steel before being rivetted, does anyone have any top tips on how this should be done? I'm about to search SimplyLocos thread to see if it's mentioned there.

[mbrown]

I have just been doing some riveting through three thicknesses on the frame stretchers - two angles either side of the main plate. Keeping them all aligned is a bit of a pig, to be honest. I had marked out the holes in the plate rather than the angles, so I couldn't drill through all three at one go.

One way I have tried with modest success is to use an adhesive (Loctite of the right grade, perhaps) to hold things in alignment for drilling. Another is to drill slightly undersize - open one hole out and insert the rivet, hammering it in. Check alignment and adjust if necessary, then open out the next hole, in case the alignment is a wee bit out - the drill will then line it up properly - and insert the second rivet. After that it gets easier as two rivets hold things in the right orientation.

The key, I think, is check, check and check again.... and don't make a second move until you are sure the first is spot on.

Hope that helps a bit.

Malcolm

[ettingtonliam]

Is Loctite an adhesive? I've used superglue successfully in similar circumstances though. Yes, insert one rivet, but then maybe insert one at the other end before coming back and doing all the intermediate ones.

[92220]

Jan 3, 2021 2:25:04 GMT ettingtonliam said:

Is Loctite an adhesive? I've used superglue successfully in similar circumstances though. Yes, insert one rivet, but then maybe insert one at the other end before coming back and doing all the intermediate ones.

Yes Loctite is adhesive, though not overly strong. It is handy if you want to hold a couple of items together that will need separating soon. Use Loctite 222 is the best one for this. If you use any of the high strength Loctite Retaining Compounds, they can be a bit harder to separate. Incidentally, Loctite has a 'Use by' date. You don't actually need to take any notice of this. I have been using Loctite since it was first introduced in UK, when the company I worked for bought some to try, back in the 1960s. Actually, my bottle of 222 is from that time and it STILL WORKS FINE!! I also have some Loctite 648 from the early 1970s and that still works fine......so never throw Loctite out just because it is old!

Bob.

[ettingtonliam]

I usually have to buy a new bottle because the workshop elves have hidden the old one!

[JonL]

So the key thing here is check and check again, I will do my best. This may be a bit easier as I'm not riveting the frame, it's a discrete component

[Deleted]

Jan 3, 2021 9:32:43 GMT 92220 said:

Jan 3, 2021 2:25:04 GMT ettingtonliam said:

Is Loctite an adhesive? I've used superglue successfully in similar circumstances though. Yes, insert one rivet, but then maybe insert one at the other end before coming back and doing all the intermediate ones.

Yes Loctite is adhesive, though not overly strong. It is handy if you want to hold a couple of items together that will need separating soon. Use Loctite 222 is the best one for this. If you use any of the high strength Loctite Retaining Compounds, they can be a bit harder to separate. Incidentally, Loctite has a 'Use by' date. You don't actually need to take any notice of this. I have been using Loctite since it was first introduced in UK, when the company I worked for bought some to try, back in the 1960s. Actually, my bottle of 222 is from that time and it STILL WORKS FINE!! I also have some Loctite 648 from the early 1970s and that still works fine......so never throw Loctite out just because it is old!

Bob.

Like Bob, I also use Loctite to hold parts for drilling etc...I have also used it for permanent bonds. One such occurrence was the mainframe horn stay slots which had been incorrectly cut on my laser cut frames. To fix those I cut small strips of steel to be a good fit in the slot and bonded them in with Loctite, once cured they were filed down to size. For this, I used a retaining compound, can't recall the exact one but at that time most likely 238.

Regards

Pete

[JonL]

I bought a cheap rotary table on Amazon figuring even if it was poorly made I could probably tighten up the tolerances to make it acceptable for what I need (primarily things like evenly spacing the bolts on cylinder end caps and such, I'm so bad at it). However it turned up needing nothing really to make it useable for my needs. Here I'm drilling the bolt holes for the expansion link bearings. I was trying to avoid tapping the expansion link brackets but realistically it's my best option here.

[mbrown]

Looks like you have got a tilting rotary table there - very useful indeed, especially if you got it for a good price.

Nice work.

Malcolm

[JonL]

Jan 5, 2021 17:14:31 GMT mbrown said:

Looks like you have got a tilting rotary table there - very useful indeed, especially if you got it for a good price.

Nice work.

Malcolm

Thank you, very kind.

I paid £100. I figured if it turned out to be poorly made I might be able to improve things by remachining some components. It was a gamble, but for my modest requirements it paid off.