Brassmasters Blk5 45232

Dave Holt
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Re: Brassmasters Blk5 45232

Postby Dave Holt » Tue Apr 28, 2020 10:27 am

Right, sand pipes tweaked to an acceptable rail clearance and coupling rods re-fitted, just for appearances sake. Those pesky cinder guards still to face. Then on to the tender?
BM_Blk5_45284_115.JPG

BM_Blk5_45284_116.JPG

Black 5 faces its nemesis?
BM_Blk5_45284_117.JPG

Dave.

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johndarch
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Re: Brassmasters Blk5 45232

Postby johndarch » Tue Apr 28, 2020 11:07 am

It really is looking the business Dave. Looking forward to seeing it finished and painted now.

John

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Will L
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Re: Brassmasters Blk5 45232

Postby Will L » Tue Apr 28, 2020 12:34 pm

Dave Holt wrote:Will, I'd be the first to admit my lack of knowledge about CSB design, but I can't believe the deflections of the spring beam is not dependant on the total mass of the loco in some way or other. So, if the final mass isn't known at the design stage, nor can the deflections be known either?

Dave
Absolutely true, but because changing CSB springs is simply done and doesn't effect the way the weight is distributed across the wheels, you just need to substitute the size wire that gives the correct ride high when the final weight is known. Some (Bill Bedford) advocate doing this by trial and error, me personally, once the final weight is know, I put the weight back through the spread sheet to find the right wire size. Then if the design doesn't work quite as it should, and the ride height isn't quite right with the correct size wire for the weight, there is no problem going up or down a wire size or so to correct.

If I do a plot for somebody these days I'll give a table of wire size to weight. In practice the range of likely weights isn't that big and the range that suits a particular wire size is relativity broad so this table is usually gives no more than three options. If you guess 12 thou you're often proved right.

These days I actually build stuff with a very stiff (20 thou) wire in place so that when testing the bare chassis you get minimal defection so you can check that you have actually built it flat and square. The correct wire only goes in once I know the true weight.

Dave Holt
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Re: Brassmasters Blk5 45232

Postby Dave Holt » Tue Apr 28, 2020 1:12 pm

Will, that all makes sense and makes adjustment easy, assuming you can get the wires in and out of the finished chassis. Unfortunately, the Brassmasters coil spring suspension doesn't provide that facility, so the only options are to alter/move the weights or insert packers under the appropriate springs - virtually impossible on the drivers as the wheelsets are permanently built into the chassis.
Fortunately, in this case, it's all worked out OK.
Dave.

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Will L
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Re: Brassmasters Blk5 45232

Postby Will L » Tue Apr 28, 2020 2:15 pm

Dave Holt wrote:Will, that all makes sense and makes adjustment easy, assuming you can get the wires in and out of the finished chassis.

That is just a design issue which you can settle at the start
Unfortunately, the Brassmasters coil spring suspension doesn't provide that facility, so the only options are to alter/move the weights or insert packers under the appropriate springs - virtually impossible on the drivers as the wheelsets are permanently built into the chassis.
Fortunately, in this case, it's all worked out OK.

When I first started pontificating on CSB, I did suggest that I was uncertain about any system, like brassmasters, which relies on individual coil springs over which you had no control. See this post. I was reassured at the time by Russ Elliot (no less) that this was OK as as the Brassnaster spring was well calibrate to meet it designed use. I was not certain I believed it at the time, but I suppose I have just said the applicable range for a given spring set can be relativity wide. Brassmaster do seem to go in for nice big locos so perhaps it is less of a concern for them than for me and my small prototypes. That said their tenders tend to be CSB sprung these days. I know this as I provide them with the CSB plots and appropriate wire to weight tables.

davebradwell
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Re: Brassmasters Blk5 45232

Postby davebradwell » Tue Apr 28, 2020 6:37 pm

Why does it matter so much to you WillL? Don't you think Dave has enough experience to choose how he wants to build a loco? Here's a kit with a decent chassis that you can just build so what will you gain by changing it? You'll just end up with another kind of sprung chassis and you'd probably have to carve holes in frame spacers and generally make a mess of the design. Don't forget there's a sprung bogie there too which will trash your calculations requiring an guestimate. He's achieved a spectacular result and it's certainly better than anything I can build.

DaveB

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Horsetan
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Re: Brassmasters Blk5 45232

Postby Horsetan » Tue Apr 28, 2020 10:43 pm

davebradwell wrote:Why does it matter so much to you WillL? ....


A form of navel-gazing :?: :lol:
That would be an ecumenical matter.

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Will L
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Re: Brassmasters Blk5 45232

Postby Will L » Thu Apr 30, 2020 11:47 am

davebradwell wrote:Why does it matter so much to you WillL?

I've been trying to popularise CSBs for about 11 years now, its probably a habit. What I don't understand is why it bothers you so much.
Don't you think Dave has enough experience to choose how he wants to build a loco? Here's a kit with a decent chassis that you can just build so what will you gain by changing it?

And I didn't suggest he change it, that would clearly not be a reasonable or sensible idea. I am inclined to wonder how foolish you think I am.
...Don't forget there's a sprung bogie there too which will trash your calculations requiring an guestimate.

That's not true either. You can read here exactly how to deal with a weight bearing bogie on a CSB fitted loco, and you end up knowing exactly what the weight distribution will be. It may well be that its trying to dispel misinformation like this which is the answer to your original question.

For the avoidance of doubt I too think Dave is making a cranking job of this loco, and that finding he need to bend up the sand pipes a little bit is in no way a good reason to change anything, except the sand pipes.

Dave Holt
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Re: Brassmasters Blk5 45232

Postby Dave Holt » Fri May 01, 2020 7:36 pm

Well, no excuse now not to get on with the tender.
I have finally motivated myself to fit the cab-side cinder screen frames that I've been putting off for a day or two (in the vain hope they might fit themselves?). Of course, it proved far easier to do than I had worried it would be.
The chimneys I commissioned from Tom Mallard came today and rather nice they are, too. One has duly been attached to the smokebox using 5 minute epoxy.
BM_Blk5_45284_118.JPG

BM_Blk5_45284_119.JPG

Cab glazing, buffer heads, number and shed plates and cab roof to be fixed after painting.
So, to the tender......
Dave.

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45609
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Re: Brassmasters Blk5 45232

Postby 45609 » Sat May 02, 2020 6:53 am

Brilliant Dave. A great looking engine.

Cheers...Morgan

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johndarch
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Re: Brassmasters Blk5 45232

Postby johndarch » Sat May 02, 2020 7:42 am

Here,here!

Dave Holt
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Re: Brassmasters Blk5 45232

Postby Dave Holt » Sat May 02, 2020 12:55 pm

Thanks, gents.
Dave.

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barrowroad
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Re: Brassmasters Blk5 45232

Postby barrowroad » Sat May 02, 2020 5:30 pm

Looks really great Dave, keep up the good work and I look forward to seeing it on Barrow Road sometime in the not too distant - I hope - future.

Robin

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Craig Warton
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Re: Brassmasters Blk5 45232

Postby Craig Warton » Sat May 02, 2020 11:38 pm

I am one of those who posts on my own workbench, watches other things but does not often comment. I have been watching your progress on this and have to say the result is simply stunning. I suspect that boiler failure would have finished some people off (me!) but I really do like the way you resolved it and kept at it. It gives people like me encouragement. Despite modelling the GWR, the Stanier locos are very firm favourites of mine.

Do you have any other Brassmasters locos in line?

Regards,

Craig Warton

Dave Holt
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Re: Brassmasters Blk5 45232

Postby Dave Holt » Sun May 03, 2020 7:49 pm

Hi Craig.
Thanks for the kind comments.
I've got another Black 5, a Rebuilt Scot and a Fowler 4F in the pile, along with loads of other stuff, of course.
I'll try and get on with the tender (fully welded type) for this loco, but who knows what after that?
Dave.

Dave Holt
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Re: Brassmasters Blk5 45232

Postby Dave Holt » Tue May 05, 2020 7:20 pm

Some progress has been made with the tender, despite a slight setback caused by my clumsiness.
I had read through the instructions, studied the diagrams and several drawings in the Wild Swan profile series before starting. My gut feeling is that the chassis is more complicated than the loco!
Anyway, I started with the functional outer frames. These provide for CSB suspension, although it's a slightly odd arrangement with two support points between the wheel-sets rather than the more conventions single support. Still, I trust someone has worked it such that it works OK. The design intends the use of pinpoint axles and bearings but I wanted some side-play on the centre axle so decided to use Exactoscale parallel type. This requires the 1 mm axle ends to be sleeved to take the 2 mm bore Gibson wheels. By pure chance, I quickly found some 2 mm x 1 mm brass tube - just the job.
The set-back occurred whilst I was filing off the etch cusp on the frames. I'd run a scrawker(?) along the etched fold line to make it easier to form the 90 degree bends and must have overdone it, because the etch separated at the front and, eventually, with further handling, the whole drag box area broke away completely. Subsequently, the drag box was folded up and then soldered into the frames, after bending the rear end, with the aid of bluetak and some blocks of wood. Phew, that was close.
Here is the frame assembly, with the CSB wires and bearing carriers, ready to receive the wheel-sets.
BM_Blk5_45284_120.JPG

Dave.

davebradwell
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Re: Brassmasters Blk5 45232

Postby davebradwell » Tue May 05, 2020 9:44 pm

Dave, just had a message from Chris Pendlenton who has concerns about the Brassmasters tender chassis and asked me to bring it to your attention. He built the very similar design for their Ivatt 2-6-0 and found that with the shallow engagement, the axleboxes tended to fall out of their hornguides if there was any sideplay, allowing the axles to skew. Have you previous experience of this type?

DaveB

Dave Holt
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Re: Brassmasters Blk5 45232

Postby Dave Holt » Wed May 06, 2020 9:02 am

Funny you should say that Dave. After posting the photo, I realised that the centre axle side play could allow the bearing holders to disengage so I've fitted some retaining clips to those holders. I'm not intending any perceptible side play in the front and rear axles, so they should be retained in their guides OK.
Thanks to Chris and you for raising the issue.
Dave.

Dave Holt
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Re: Brassmasters Blk5 45232

Postby Dave Holt » Fri May 08, 2020 9:29 am

Best laid plans.....
Following the timely warning posted by Dave Bradwell and a rather unsatisfactory trial fit of the rear wheel-set, I've fitted retaining clips to all the axle bearing carriers to hold them in their guides. I utilised parts of the spare brake pull rods, which have half etched strip so that it gives a bit of clearance to the bearing carrier but still restrains it. Not the neatest work, but it won't be visible on the finished model.
BM_Blk5_45284_121.JPG

The sleeved Exactoscale axle/Gibson wheel combination hasn't worked out, so plan B is in progress - new wheels and custom machined axles from 2 mm rod with 1 mm reduced ends. I think the problem arose because the brass tube I used for the sleeves was very slightly over 2 mm diameter and was such a tight press fit in the wheels that problems with assembly and resulting wheel wobble, and adjustment of the back-to-back, resulted.
Dave.

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PeteT
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Re: Brassmasters Blk5 45232

Postby PeteT » Fri May 08, 2020 10:03 am

Thanks for sharing this issue, and solutions Dave/Dave/Chris. I'm about to answer my own question here - but will air it regardless - this issue is greater with parrallel axles, as pinpoints - by use of the cones - should push the carriers into the slot and so the issue will be less likely to bite? That said (and hence answering it myself) the clips are a neat little solution which don't look time consuming to produce, so it looks like a sensible addition whichever axles and bearings are being used.

I see that parrallel bearings allow more scope for a bit of side play on the middle axle without introducing slop - but I've worked around this for pinpoints using the 1mm exactoscale axle with 2mm wheelsets on a 2mm/1mm tube method. (I'm not claiming this is my idea, but I've implemented it successfully).

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Mike Garwood
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Re: Brassmasters Blk5 45232

Postby Mike Garwood » Fri May 08, 2020 12:32 pm

Pete
I think you have one of my trial etches for a BR STD tender that demonstates that same point. I have been thinking of using the High Level spacer saver bearings and re-designing the chassis.

Sorry to hi-jack

Mike

BR tender OS spring v2.dwg
BR tender
(116.81 KiB) Downloaded 44 times

davebradwell
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Re: Brassmasters Blk5 45232

Postby davebradwell » Fri May 08, 2020 1:01 pm

If you make the slot in the frames 2mm wide then that will guide the bearing perfectly. You just need a plate that goes round the bearing flange to connect it to the spring. Why. have all the extra guides and setting up? I believe LMS and BR tenders had very close frame spacing and this gets them closer than any other off the shelf solution provided you use plain flanged brgs.

To achieve side-play on the centre axle, there is also Mark Tatlow's scheme for 6 wheel coaches where he uses a 1mm Exactoscale pin-point axle with the wheels mounted on a piece of 2mm tube that can slide on it. Fine if you can get an accurately sized bit of tube, it would seem! Certainly the issue of sideplay is more important with 8 wheel tenders.

DaveB

Dave Holt
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Re: Brassmasters Blk5 45232

Postby Dave Holt » Thu May 14, 2020 9:26 pm

Not that much modelling due to domestic duties, but some progress on the tender chassis.
Whilst waiting for the replacement wheels and axle material, I have done some work on the water scoop arrangements. The instructions have this done after the inner frames are fixed to the outer and the wheel-sets in place. However, I felt it would give much easier access to the linkage if it were done before joining the inner and outer frames. I've had to leave the vertical link to the actual scoop as a temporary joint to allow the rear cross member to be slide/wiggled into place on final assembly. Apart from this, I can't see that my sequence has created any problems.
I must say, it's been a war of attrition so far. I'm not sure how Jim S-W got on, and his build is a more recent kit, but I've had to make several modifications to the kit parts to get it all to fit and be in the right positions. The biggest issue was with the cast scoop pipe which sticks down too far, has a locating pip which is about half the diameter on the hole in the spacer and it's too far forward. As a result, it's been on and off at least three times to allow modification and re-positioning. In the end, I cut 1.5 mm off the height and moved it back the same amount, in order to get the "pivot" ears in the right position relative to the back edge of the rear cross member.
This latter would not seat down properly because the front edge was catching on part of the operating linkage. Close examination of the GA drawing revealed that the prototype had a pocket cut out of the front edge to clear the mechanism, so a similar arrangement was added to the kit item.
Here is the modified scoop pipe. In the end, I didn't fit the sleeve to the mounting peg as it prevented the pipe moving back far enough.
BM_Blk5_45284_122.JPG

Here is the rear cross member with the clearance notch in the front edge.
BM_Blk5_45284_123.JPG

The elongated locating hole for the scoop pipe. In the end, the pipe mounting pip is hard up to the back of the modified hole in order to get the bottom of the pipe in the right place.
BM_Blk5_45284_124.JPG

The scoop pipe fixed in its new position, showing the relationship to the cross member.
BM_Blk5_45284_125.JPG

A shot with the lower end of the scoop attached to the pipe and the linkage temporarily connected up. The final attachment has to be done after the cross member is fixed in place.
BM_Blk5_45284_126.JPG

Next job is to make and fit the bracing struts to the scoop pipe. Although there are two locating slots etched in the frame spacer, oddly, there is no mention of there rather visible items in the kit instructions or assembly diagrams.
Dave.

Dave Holt
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Re: Brassmasters Blk5 45232

Postby Dave Holt » Fri May 15, 2020 8:55 pm

Scoop bracing struts fitted, along with the scoop operating rod/cranks and representations of the train vacuum pipe and steam heat pipe, both of which are visible through the tender frame cut-outs.
BM_Blk5_45284_127.JPG

BM_Blk5_45284_128.JPG

After taking the photos, I noticed that one of the bearing carriers had become slightly displaced due to handling. These carriers will be better held in place once the axles are in and will be protected from handling issues by the axlebox castings.
Dave.

Dave Holt
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Re: Brassmasters Blk5 45232

Postby Dave Holt » Sun May 17, 2020 10:42 pm

A trial fit of the rear frame cross beam has been undertaken. My original plan to slide it in under the scoop didn't go to plan as I had inadvertently soldered the top joint of the vertical scoop link so that it couldn't be swung out of the way. The only recourse was to cut a slot in the centre of the rear edge of the cross member. As the missing bit is right in the centre and very close to the scoop, hopefully, it won't be too obvious on the finished model.
BM_Blk5_45284_129.JPG

Dave,


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