Crab Comet conversion

Julian Roberts
Posts: 736
Joined: Sat Jan 09, 2010 11:33 pm

Crab Comet conversion

Postby Julian Roberts » Sat Sep 02, 2017 7:02 am

After 10 years in P4 I'm only now doing my first Comet conversion...

Having looked online I can't find much that's any help on this project. Here Mark Tatlow did the conversion many years ago and there are a helpful series of pictures though none of the completed model. On the RM Web there is this most useful photo of Dave Holt's completed model with a little about it.
blogentry-5663-0-18418700-1481197567DAVE HOLT.jpeg
Dave Holt's model (from RM web)


This thread is to occasionally ask for any comments or help.

Since raising the topic of the spacers in a previous thread I realised the kit is far too sophisticated to freelance the spacer widths, and can be built to the three 4mm gauges with parts that precisely fit around the Comet spacer widths.

Now I've got to the stage of having completed the four assemblies from which the valve gear hangs I am seeing there is an issue with the expansion link bracket and how it sits against the running board. The kit specifies these are just in contact, and this is how it is, and how it is on Dave Holt's loco. But looking at images available on Google, and the Bachmann chassis, there is a gap here, the bracket sits a bit lower, with a definite separation between the two. Perhaps related, the expansion link itself looks a bit longer to me. I'm at the stage I could make the bracket sit lower by deepening the slots in the frames. Making the link longer is possible using the spare etch perhaps.
20170831_125344 (Large).jpg

2009-05-11_123314_crab2.jpg
2009-05-11_123314_crab2.jpg (69.01 KiB) Viewed 6483 times

lms015002.jpg
lms015002.jpg (32.96 KiB) Viewed 6483 times

p82964466-3.jpg
p82964466-3.jpg (120.51 KiB) Viewed 6483 times



Looking ahead, the instructions show a link between the reverser and the valve rod bracket that I can't see on any photo, and I haven't got my head round that section yet. Mark's photo shows he has put it there - I have highlighted it below. The instructions don't include a plan view and one could be useful, though it's fairly plain sailing so far with otherwise excellent instructions and everything fitting together beautifully: hence my reluctance to depart from them...

Snip Mark Tatlow.JPG
Snip Mark Tatlow.JPG (23.94 KiB) Viewed 6484 times


Suppose I ought to get hold of a drawing really but I was hoping for a plain vanilla approach and just make the kit as it is.

User avatar
Tim V
Posts: 2230
Joined: Tue Jul 29, 2008 4:40 pm

Re: Crab Comet conversion

Postby Tim V » Sat Sep 02, 2017 10:58 am

That angle the cylinder is making to the running plate looks different to the prototype pictures. Think you need to look at a drawing before going much further.

I have built a couple of LMS design Comet models, found the motion bracket was a bit 'thin' compared with the real thing. Put a lot of metal on them - it's also an area where the model gets picked up on, so likely to get bent.
Tim V

John Palmer
Posts: 558
Joined: Fri Jul 15, 2011 11:09 pm

Re: Crab Comet conversion

Postby John Palmer » Sat Sep 02, 2017 11:35 am

The axis of the cylinder bore intersects the axis of the middle driving wheel axle - this may assist you in getting the correct cylinder alignment
Hughes mogul cylinder alignment.jpg
Hughes mogul cylinder alignment.jpg (175.16 KiB) Viewed 6431 times

Julian Roberts
Posts: 736
Joined: Sat Jan 09, 2010 11:33 pm

Re: Crab Comet conversion

Postby Julian Roberts » Sat Sep 02, 2017 1:20 pm

Thanks Tim and John - I am doing an injustice to Comet in that photo, the kit seems pretty idiot proof and the angle is not left to me! - but it is not fixed yet and I think was not properly seated. Here are some pix that I think show it as it is properly, and I think it looks correct as per your red line John. Various bits still held in place with black tack, only the valve spindle bracket and motion bracket are properly screwed down here.

20170902_130823 (Small).jpg
20170902_130823 (Small).jpg (60.65 KiB) Viewed 6414 times

20170902_132806 (Small).jpg
Slide bars held in place with tack. They prevent w/m cover being attached for now.
20170902_132806 (Small).jpg (62.62 KiB) Viewed 6414 times


Re the strength of the motion bracket, yes I agree Tim. The etch folds and gives a double thickness i.e. about 0.9mm. I hope that when the slidebars are soldered up to it and they are to the cylinders it will be strong enough. I made the whole thing, for both sides, from one piece of chunky NS on my Q1 but that was to replace a whitemetal offering. Took ages; this is a much more complex shaped item

User avatar
Mark Tatlow
Posts: 701
Joined: Tue Dec 02, 2008 11:24 pm

Re: Crab Comet conversion

Postby Mark Tatlow » Sun Sep 03, 2017 10:20 pm

Hi Julian,

Good choice of prototype!!!

I am not totally sure what of your questions are still "live"?

I am pretty certain that the highlighted section of the motion assembly that you have used of my work is a personal modification to hold to the motion bracket, expansion link bracket (not sure this is its correct name) and the cylinder into one assembly. You get this anyway with the slide bars in place but you are reliant on the strength of these relative slender components so I strengthened it with a bit of scrap etch. I can dig the Crab out and take another look (and picture) if this helps?

The main caution I would give you with the Comet chassis has to do with the hornguides for the front hornblocks. The cut out for this with the rebate for the spring weakens the top of the frames a fair amount. Thus, it can flex and this has the effect of altering the wheelbase unexpectedly. I felt that the way to deal with it (after suffering the problem a few times) was to laminate a plate over the top and this solved this problem.

I also put some lateral control on the pony truck, which I also thought helped a lot. Just a bit of guitar wire soldered to the pony truck slipped into a rod on the underside of the chassis.
'
Interestingly, having got the crab working fine, it has been put to a one side for a bit too long. Strangely, I had it out on someone else's layout and it was very sticky going forwards but fine working backwards. What is really odd is that getting it home and it is fine again - I can't fathom it? I am about to fit a chip to this and bring it to Scaleforum. So if you want to see my version and are coming to Scaleforum, you are welcome.
Mark Tatlow

dal-t
Posts: 615
Joined: Mon Jan 11, 2010 8:06 pm

Re: Crab Comet conversion

Postby dal-t » Mon Sep 04, 2017 7:36 am

Mark Tatlow wrote:'
Interestingly, having got the crab working fine, it has been put to a one side for a bit too long. Strangely, I had it out on someone else's layout and it was very sticky going forwards but fine working backwards. What is really odd is that getting it home and it is fine again - I can't fathom it?


Sounds like it could be pick-up problems - if your mate has weaker 'juice' or dirtier track than your own layout, and pick-up is on the margin in forward gear, it could manifest like that. I have a theory that this is why so many people find a chassis runs better in reverse than forward, if they're using simple wiper pick-ups. I cured a couple of my locos with that tendency by adopting better, sprung pick-ups from phospher-bronze wire - instantly as good forwards as backwards! Of course, if you are one of those strange split-chassis people, who saw perfectly good axles in half only to glue them back together again, that theory goes out the window (probably along with a loose half-axle) ...
David L-T

User avatar
Mark Tatlow
Posts: 701
Joined: Tue Dec 02, 2008 11:24 pm

Re: Crab Comet conversion

Postby Mark Tatlow » Mon Sep 04, 2017 8:09 am

dal-t wrote: if your mate has weaker 'juice' or dirtier track than your own layout, and pick-up is on the margin in forward gear, it could manifest like that. ...


aghh, now what i didn't say was that the sticky-ness manifested itself by an thermal overload on the controller, so pick ups weren't a problem!

The thought was that the worm might be absolutely on the edge of tight to the drive gear (it is a Highlevel Roadrunner + by the way). The effect of this was that in reverse the drive was OK but just tightened as it drove forward.

I sought to take it home and have a play and I can't replicate it at all!! I do have a cruder DC controller, so maybe I am masking the problem with this but I don't seem to get a different speed at all (I have not checked current draw yet) either. Thus, I had in mind sticking it on the test tract at Scaleforum for a couple of hours on the basis that if this is the cause then it will run in in this time.

Otherwise, if I couldn't get it to repeat the problem with DCC chip in it, I was simply going to ignore the problem!!
Mark Tatlow

Julian Roberts
Posts: 736
Joined: Sat Jan 09, 2010 11:33 pm

Re: Crab Comet conversion

Postby Julian Roberts » Mon Sep 04, 2017 8:18 am

Hi Mark

Thanks for this! Yes I thought that bit I highlighted must be for that, and I think you were following the instructions too. Unfortunately I can't come to Scaleforum though our group is coming (with two of my locos!) showing John's "Kettlewell"

Also thanks for the advice re the front hornblock, though I'm surprised.

Meanwhile I'm going off piste and making a glorified separate valve spindle (bit of wire). Here is my Walschaerts Weekend try out with bits of wire holding things in place. This shows the front hornblock area too.
20170903_111927.jpg

User avatar
Tim V
Posts: 2230
Joined: Tue Jul 29, 2008 4:40 pm

Re: Crab Comet conversion

Postby Tim V » Mon Sep 04, 2017 3:25 pm

To Mark, try running it on a battery (not rechargeable ones), the pure DC will find tight spots easily.
Tim V

User avatar
PeteT
Posts: 224
Joined: Tue Jan 11, 2011 9:53 pm

Re: Crab Comet conversion

Postby PeteT » Mon Sep 04, 2017 4:56 pm

Hi Julian,

I can't add a lot of use, but am following with interest as I've got one lined up to be done once the round tuit has arrived & a few other projects have been completed...

One of the wild swan LMS locomotive profile books (no 2) covers the crabs & will no doubt have some drawings to help. If nobody in your area group has one you could scrounge, give me a shout...

Cheers,

User avatar
PeteT
Posts: 224
Joined: Tue Jan 11, 2011 9:53 pm

Re: Crab Comet conversion

Postby PeteT » Mon Sep 04, 2017 6:11 pm

To add to that, I've just had a browse & there are indeed lots of useful valvegear drawings & photos. There is also a drawing of the pony truck, which has 6' 7.75" from pivot point to axle centreline.

Cheers,

Julian Roberts
Posts: 736
Joined: Sat Jan 09, 2010 11:33 pm

Re: Crab Comet conversion

Postby Julian Roberts » Tue Sep 05, 2017 6:45 am

Pete
Ooh yes please! is my first reaction...however just to say I have the book for the Compound and find I can't "read" the real working drawings that are in there. The simple type of outlines in e.g. the Railway Modeller over the years are at my level of understanding. Photos, yes, they are very useful. Just thinking I have to go to Sheffield in three weeks with a spare day so I could get to the East Lancs, nothing like taking photos for oneself.

Thanks so much for this thought Pete. I'll PM with my email.

Julian Roberts
Posts: 736
Joined: Sat Jan 09, 2010 11:33 pm

Re: Crab Comet conversion

Postby Julian Roberts » Tue Sep 05, 2017 7:55 am

John Palmer wrote:The axis of the cylinder bore intersects the axis of the middle driving wheel axle - this may assist you in getting the correct cylinder alignment


Does the same apply to the axis of the valve spindle to its crosshead and the pivot of the expansion link?

Having made pretty well from scratch Walschaerts for another loco in 009 I am surmising that any tiny alteration won't make much difference to getting the valve gear to work adequately. To do it really properly involves forked joints etc, a level up from this I think, as in kits by Dave Bradwell and others. The combination lever bends "in the way" above the slide bars in photos but whether it's long enough to do that I don't know, don't think the instructions mention it. Here's another test; also visible is the expansion link bracket slot - the line shows the design level
Attachments
2017-09-04 21.54.04 (Small).jpg
2017-09-04 21.54.04 (Small).jpg (54.3 KiB) Viewed 6020 times

User avatar
Will L
Posts: 1643
Joined: Sun Jul 20, 2008 3:54 pm

Re: Crab Comet conversion

Postby Will L » Tue Sep 05, 2017 7:02 pm

Julian Roberts wrote:Does the same apply to the axis of the valve spindle to its crosshead and the pivot of the expansion link?


No.


Sorry that was rather Bill like. There is no equivalence here. The Combination lever is pivoted on the end of the valve spindel but it is more accurate to say it more hangs off it than aligns to it. The leavers which drive this pivot point are be designed so it is driven back and forth as required by the valve events, but it is the attachment to the valve spindle that ensure it does it in the same plane as the valve spindle. Therefore the geometry of all the bits after that obviously relates to, but aren't governed by, the plane the valve spindle moves in.

Edited to qualify a bit further

Julian Roberts
Posts: 736
Joined: Sat Jan 09, 2010 11:33 pm

Re: Crab Comet conversion

Postby Julian Roberts » Sat Sep 16, 2017 10:02 am

Thanks Will. I'll come back to that topic.

Mark mentioned earlier the frames needed strengthening above the front wheels. I have taken his advice but for the rear wheels, as the frame flexes a tiny amount if built as per instructions. A piece of spacer fixed on as below doesn't foul anything including a Lo Loader gearbox attached to the rear wheels, and gives the rigidity needed. I'm not attaching gearbox to the middle wheels as I want the below footplate level to be visible as the boiler curves inwards, not a cut out as per the usual modelling cliché and as per the Bachmann model (and the Comet instructions). I think there's enough room in the firebox for a 1024 with the shaft cut off and no flywheel. Certainly a 1020 has ample room.

2017-09-10 15.55.47 (Small).jpg
2017-09-10 15.55.47 (Small).jpg (111.41 KiB) Viewed 5754 times

Julian Roberts
Posts: 736
Joined: Sat Jan 09, 2010 11:33 pm

Re: Crab Comet conversion

Postby Julian Roberts » Mon Sep 25, 2017 7:19 am

Weekend of rail journeys, not unfortunately to Scaleforum, gave me time to write the following

I missed out above that the major effort was in getting the proper mating of chassis and Bachmann body. This is because I did not find the instructions very clear on how to get the front correct where the Comet frames have to be severely pruned to fit the Bachmann body. The rear fits the body in a self evident manner. I had thought I might cut off the cosmetic front of the Bachmann chassis frames but this is made of very tough mazac  type material.  

In the end I found that arranging it so that the frames meet each other not thus....
2017-08-28 13.43.32 (Small).jpg
2017-08-28 13.43.32 (Small).jpg (38.76 KiB) Viewed 5537 times

but thus:
2017-08-29 13.10.27 (Small).jpg
2017-08-29 13.10.27 (Small).jpg (45.79 KiB) Viewed 5537 times


...gives a good level mating of the chassis top and body along the bottom level of the boiler, as well as obviously looking more logical, though the cylinder will cover this join. It was however necessary to file the slot in the plastic for the valve spindle crosshead assembly a little deeper (which at a later stage proved to be of interest).

However this did make the ride height different.

Before cutting the chassis from the fret I had marked the centre line of the axle holes given by the provided rigid suspension, surmising this should in theory give the correct ride height. The sprung hornblock bearings would be half a mm below the top of their movement to get the same ride height.

2017-08-22 11.06.22 (Small).jpg
Rigid axle centre line marked
2017-08-22 11.06.22 (Small).jpg (77.14 KiB) Viewed 5537 times


Unconventionally I fix three wheels to their axles having arranged the quartering jig thus
2017-09-07 23.09.31 (Small).jpg
Plastic less thick than wheel tread evo stik-ed to GW jig, bears against tread, not flange
2017-09-07 23.09.31 (Small).jpg (113.05 KiB) Viewed 5537 times

.... to be able to locate these wheels without an axle hole when it is time to mount the other wheel.

By mounting these single wheels in the frames thus...
2017-08-28 16.29.59 (Small).jpg
2017-08-28 16.29.59 (Small).jpg (66.34 KiB) Viewed 5537 times

it is possible to establish exactly what will happen by trying various thicknesses of wire above the hornblock bearings.
2017-08-31 22.51.13 (Small).jpg
1mm rod tacked in
2017-08-31 22.51.13 (Small).jpg (53.7 KiB) Viewed 5537 times

I found that to get the buffers to meet my stock correctly this half mm needed to be increased to 1mm.
As I want to make the loco as heavy as possible, and the tender hanging on the back to give extra weight, I don't want the springs to "bottom out" to give a ride height too low.

Here is a hornblock I modified with rod about 1mm diameter. This will act as a coil spring retainer as well as limiting the upward travel.
2017-08-23 22.14.44 (Small).jpg
2017-08-23 22.14.44 (Small).jpg (59.18 KiB) Viewed 5537 times

20170913_212415 (Small).jpg
20170913_212415 (Small).jpg (93.91 KiB) Viewed 5537 times

All 6 now have 1mm upward travel restrictors. Easily filed shorter if it turns out I've got this wrong. The centre axle doesn't need upward travel to be restricted so the chassis frame spring retainers are shortened by the same 1mm.
Downward travel is restricted by the cosmetic springs when they are fixed on, so can easily be modified to give 1mm travel.
20170909_110456 (Small).jpg
20170909_110456 (Small).jpg (61.93 KiB) Viewed 5537 times

The springs as designed give no force beyond this level
20170909_110610 (Small).jpg
20170909_110610 (Small).jpg (64.6 KiB) Viewed 5537 times

but a 12BA nut will do the trick. (Here the spring is stretched to see what happens, that will be unnecessary!)
20170909_114013 (Small).jpg
20170909_114013 (Small).jpg (64.35 KiB) Viewed 5537 times

User avatar
Mark Tatlow
Posts: 701
Joined: Tue Dec 02, 2008 11:24 pm

Re: Crab Comet conversion

Postby Mark Tatlow » Mon Sep 25, 2017 7:55 pm

Hi Julian,

Seeing your notes is prompting a few of the Comet chassis' foibles to come back. I do not recall having to cut back the front of the frames. I also soldered a plate as an extension of this to rest on the underside of where the footplate projects beyond the smokebox.

Thanks also correcting my error that the problem with the frame flexing was to the rear driver not the front.

I think if I were doing this again I would fit CSBs to it, rather than rely on the individual springs. The use of the spigots to locate the springs is essential (as is a bag of spare springs!). They go off to orbit and I eventually soldered the base of mine onto the top of the hornblock.

Anyway, I had a successful test run of my crab - here is a video of its efforts.


https://www.youtube.com/watch?v=N0air8r-gWI


I had not put any weight in it, so to get a full load on I plonked loads of lead on - hence the rather odd appearance!
Mark Tatlow

Julian Roberts
Posts: 736
Joined: Sat Jan 09, 2010 11:33 pm

Re: Crab Comet conversion

Postby Julian Roberts » Tue Sep 26, 2017 7:26 am

Hi Mark - nice video! Thanks. Yes, I did not want to contradict you (and wasn't it about 8 years ago you were doing this?!) but you had provided a useful hint regarding the bendy frame. Here is a pic of the step where I have made the Comet chassis fit the Bachmann body. Edit - visible on extreme right. Will try to find pic to make a bit clearer what I mean.
2017-09-09 11.36.04 (Small).jpg
2017-09-09 11.36.04 (Small).jpg (126.5 KiB) Viewed 5417 times

here's a better shot showing the step I filed
2017-08-29 10.58.30 (Small).jpg
2017-08-29 10.58.30 (Small).jpg (48.5 KiB) Viewed 5345 times

It fits just inside the Bachmann front framing (visible in one of the pics in the previous post), a little had to be thinned off the mazak frame insides to get it to sit between them. If it was made with P4 spacers it wouldn't fit here; the Bachmann framing is thick and about 17mm outside width so that's more or less correct I would suppose...
Here's the small amount of filing needed on the Bachmann body to take the frame (made with EM spacers)
2017-08-28 20.17.53 (Small) (Small).jpg
2017-08-28 20.17.53 (Small) (Small).jpg (30.76 KiB) Viewed 5345 times


Really I'm just aiming to do a blow by blow account but reduced from every blind alley and mistake, and raise the occasional question.
Valve gear on hold as I have to get the centre wheels paired up and mounted before I can go any further with that, so that has meant getting the couplings rods done, matched John Brighton style to the hornblocks not vice versa.
20170925_170828 (Small).jpg

User avatar
Will L
Posts: 1643
Joined: Sun Jul 20, 2008 3:54 pm

Re: Crab Comet conversion

Postby Will L » Tue Sep 26, 2017 7:46 pm

Mark Tatlow wrote:I think if I were doing this again I would fit CSBs to it, rather than rely on the individual springs.


I'd say that was fair comment. Avoiding the degree of "faf" Julian was going through with individual springs, not to mention getting a predictable/easily adjusted ride height, was precisely why I was happy with compensated chassis, until CSB came along.

Julian Roberts
Posts: 736
Joined: Sat Jan 09, 2010 11:33 pm

Re: Crab Comet conversion

Postby Julian Roberts » Wed Sep 27, 2017 7:13 am

Hi Will!

My intention was a quick and easy build following the instructions. Then I toyed with the idea of compensation as I know I get good results that way. But that involves too much thinking it all out in advance which I find I can't visualise. And here was a well designed kit, everything thought out, and I thought it was time I tried this style of suspension, which is a feature of some great kits from Brassmasters that I have in my retirement drawer. When I get CSBs as part of a kit I want to make I'll do it!

One thing I wonder is whether is whether to use a 1020 with a flywheel, or a 1024 without one. There may be room for these alternatives. Does a flywheel give more benefit than the extra size of motor? What I'm after is starting and stopping that look like the real thing, with that sense of inertia and massive weight. But I'm not sure I see a difference here with a flywheel - I have one loco where there wasn't room for one, and it behaves just as well in giving that starting and stopping as the others. It is getting the motor moving off at its slowest speed that is the issue, and I wonder if the flywheel actually hinders that, while it certainly smooths the running once in motion, and maintains the exact speed even on tiny power losses where track is less clean.

The noise of a high revving motor doesn't worry me in the least as I make locos for exhibition use where there is far too much noise to notice a motor whine. I use either 90 or 120:1 gearing to give me a roughly 30mph (less with shunters) all out max speed on all my locos. (Chris Gibbon's previously 80 or 108:1 gearboxes are to those ratios now, a redesign means there is room for a grubscrew)

Here is a pic of making rods John Brighton style just in case that was not self evident
20170926_213518 (Small).jpg
The front one will go behind!

20170926_214049 (Small).jpg
Right way round now!

User avatar
Will L
Posts: 1643
Joined: Sun Jul 20, 2008 3:54 pm

Re: Crab Comet conversion

Postby Will L » Wed Sep 27, 2017 8:16 am

Julian Roberts wrote:One thing I wonder is whether is whether to use a 1020 with a flywheel, or a 1024 without one. There may be room for these alternatives. Does a flywheel give more benefit than the extra size of motor? What I'm after is starting and stopping that look like the real thing, with that sense of inertia and massive weight. But I'm not sure I see a difference here with a flywheel - I have one loco where there wasn't room for one, and it behaves just as well in giving that starting and stopping as the others. It is getting the motor moving off at its slowest speed that is the issue, and I wonder if the flywheel actually hinders that, while it certainly smooths the running once in motion, and maintains the exact speed even on tiny power losses where track is less clean.


Hi Julian

There is a great divide out there between those who believe in flywheels, and those who think that they aren't spinning fast enough to make any difference when you realy need them. That is to achieve smooth starting and stopping. I'm a non believer I'm afraid. I'd rather rely on suspension so all the wheels are on the track, efficient pickups on at least 6 wheels and a good controller. DCC user can have it easy with stay alive capacitors, but a well built flywheel free loco can creep reliably in DC .

Also I am confident that a 1024 is a much better motor than the 1020 and I'd always chose it over its shorter brethren if I had the chance

Philip Hall
Posts: 1257
Joined: Mon Aug 10, 2009 7:49 pm

Re: Crab Comet conversion

Postby Philip Hall » Wed Sep 27, 2017 8:52 am

Hi Julian,

I'm a flywheel believer! Although only when it's easy to put one in; I don't treat it as an absolute essential. I have always thought that a flywheel actually does very little in the momentum department (unless we're talking really big and heavy) more that it will help to keep the motor spinning when there is a momentary current interruption. However, these days I am finding that plenty of pickup (for example, on a 2-6-2T I am adding pickups to the pony trucks) is just as good, and DCC users will have the stay alive gadgets to help them.

I think the most important thing is the power of the motor and its slow running capability.

Philip

Julian Roberts
Posts: 736
Joined: Sat Jan 09, 2010 11:33 pm

Re: Crab Comet conversion

Postby Julian Roberts » Thu Sep 28, 2017 9:41 am

Thanks Will and Philip - don't know why yesterday I didn't mention my last complete loco is the High Level Barclay Tank and with Chris' input I altered the design motor 1426 (as far as I recall) to a 1420 so that there was room for a flywheel, and changed the gearing from 80 to 108 - and I'm very happy with the outcome. But 6 pickups do their job properly.

I wonder Will if the reason your preference for the 1024 over the 1020 can be perceived from the EMGS data sheets that give torque etc, or whether your preference is for less definable reasons. You have persuaded me so far to go for the 1024...having bought two spare 1020's recently! - though I managed to get the 1024 advertised here yesterday!

David Knight
Posts: 625
Joined: Sun Jul 20, 2008 6:02 pm

Re: Crab Comet conversion

Postby David Knight » Thu Sep 28, 2017 1:41 pm

Going back to the suspension for a moment, are there suitable CSB carriers for the Brassmasters hornblocks or do conventional hornblocks have to be used? I ask because I have a Crab frame lurking in my “eventually” pile.

Cheers,

David

User avatar
PeteT
Posts: 224
Joined: Tue Jan 11, 2011 9:53 pm

Re: Crab Comet conversion

Postby PeteT » Thu Sep 28, 2017 1:54 pm

David Knight wrote:Going back to the suspension for a moment, are there suitable CSB carriers for the Brassmasters hornblocks or do conventional hornblocks have to be used? I ask because I have a Crab frame lurking in my “eventually” pile.

Cheers,

David


Well yes! I designed some, which are available from Rumney Models. These include a tail from the bottom to allow the springs to be attached to it. They are covered on my workbench thread.

For completeness Jeremy has also done some which are available via the Scalefour stores, and I think are covered on his steam railmotor topic.


Return to “Steam Locomotives”

Who is online

Users browsing this forum: No registered users and 3 guests