Spike's folding table - Catching a Toad

[richard carr]

Peter

Where are the holes for the brakes, I can't see them.

Looks good otherwise.

Richard

 

[Dog Star]

Never mind the "whols" Richard - where are the brakes!!!! Classic early diesel problem, no braking power when pushed by 1000 tons of minerals.

Being serious for a minute - there needs to be a fair bit more of hacking to "retrieve" and to include various bits of moulding from the JLTRT bogies for example:-

* the headstocks of the bogies;
* the spring detail;
* the fixing points for the brake gear and bogie side frames.

Getting the two bogies fitted to the underframe is a major achievement considering that the ABC motor bogie design, as provided, was difficult to fit to the underframe. I understand that the majority of JLTRT diesels have a bolt to attach a bogie to the underframe - the head of the bolt fits into a recess in the bogie bolster and then into a screwed insert in the underframe (or maybe a nut on top of the underframe). The Class 37 has a bolt moulded into the underframe and hence there is a nut underneath the bogie bolster. There is just about 20 thou clearance between the underside of the bolster and the cardan shaft so the recess had to be deepened and an appropriate nut thinned to the point where the nut no longer fouls the cardan shaft. To get this to work means running a die down the existing screw thread, fitting the bolster with the nut and then removing the excess threaded portion.

At the moment the nuts are retained by virtue of having cut a "tight" thread - eventually we shall need to make some circular, tapped, collars with a couple of holes in the visible face... plus a pin spanner to tighten the retainer.

And then we have to sort out how to attach / remove the bogies with the body in place... at the moment the bogie bolster is fixed to the underframe and then the bogie frame is attached to the bogie bolster plate. The screws which attach the bogie to the bolster are likely to be not accessible when the body is in place... and the body has to be in place before the bogies are attached as the bogies are likely to obscure the front body screws. Catch 22 comes to mind here.

Graham on behalf of Peter

 

[richard carr]

Very true Graham, did you manage to get to Bristol today ? Unfortunately we have had about 5 inches of snow so I decided not to risk it and fitted the windscreen wipers to the Deltic

Richard

 

[alcazar]

And did they help with the snow? LOL..........I had to ask as they seemed relevant to your snow problem.

Fascinating thread.
Would it be possible to REMOVE the captive bolt, solder a nut to the bogie transverse plate, relieve the footplate for the nut and pass a screw right through with a suitable washer?

Those ABC motor bogies are just beautiful to look at. Does anyone know if they can be used easily with JLTRT's Western? Or the Peak?

 

[lancer1027]

Hi Alcazar,

Yes i think ABC specifically do one for a western . Ian ( D1054 ) is the man to ask as i think he has fitted several to westerns.

Rob

 

[alcazar]

Thanks. A Western is still on my wish list, but I'm waiting to see if Dapol do one first.....

 

[Dog Star]

Would it be possible to REMOVE the captive bolt, solder a nut to the bogie transverse plate, relieve the footplate for the nut and pass a screw right through with a suitable washer?

We could have drilled a pilot hole through the bolt and then enlarged the hole to remove the bolt. We could then have fitted a 4mm brass threaded insert and used a bolt from below the bolster plate. We chose not to take that course of action for any of these reasons:-

1/ without knowing what was hidden in the casting, might have made a big mistake.
2/ prior experience of removing bolts / studs from blind holes has been restricted to 1" BSW studs in boiler mountings where a gas torch and a nose-pick chisel work wonders.
3/ the place where the drill would come through is in the open space of the cab and hence visible.
4/ the thread inserts to hand are for 3.5mm.

Still, if something goes wrong here maybe we can try Plan B.

 

[Dog Star]

Following the comments above about the fuel tank, here is a link to the picture mentioned in the posts.


regards, Graham

 

[john lewsey]

Any more news on this 37

 

[Spike]

I have decided to reclaim the 37 from Dog Star's thread.

Progress has been made on the bogies, and I now have one resin side frame attached to the ABC motor bogie, whilst allowing the side frame to be removed should I need to once the model is complete.



This has been achieved by soldering L shaped brackets to the side of the ABC bogie where the small lugs on the resin frames would locate. The brackets have been drilled and tapped 10 BA to allow for screws to be run up from underneath.



Regards
Peter

 

[Spike]

Further progress today. Completed all side frames and could not resist putting the bogies back under the body. Still have to adjust the height of the side frames with some packing washers.

Peter

 

[The Penguin Of Doom]

I've not seen a drive system like that before.

It looks very good. Looking forward to the loco build too.

Cheers.

Sean.

 

[OzzyO]

Still have to adjust the height of the side frames with some packing washers.
Peter

Looks more like you have to drop the body hight down not pack it up. Or are you going to pack the bogie side frames up using washers (how as the frames are mounted to the bottom of some L brackets?). To get this and keep the axle centres in line with the axle boxes.


Check the buffer hight from the top of the rails, but don't use another bit of stock unless you do know that the buffer hight is correct.

The other thing could be that the ABC bogie mounting beam is to high or low (god forbid that ABC may have got it wrong).

OzzyO.

 

[Dog Star]

Looks more like you have to drop the body height down not pack it up.

To establish a reference point for the conversion of the inner frame from JLTRT resin to ABC brass we assembled a bogie from the resin inner and outer frames, placed the wheeled bogie on plate glass and then measured the height of the top of a side frame above a glass plate. We then did the same thing for a bogie assembled with the ABC motor bogie and the resin outer frames. The difference between the two measurements indicated that we need to drop the outer frames by circa 0.5mm. Your photo suggests that the measurements and, additionally, the height of the buffers above rails need to be checked.

What shall be helpful, if anyone knows, is the height of the bogie frame above rails for a prototype fabricated bogie.

 

[Dog Star]

I've not seen a drive system like that before.

From ABC Gears.

ABC offers two motor gearbox products for motorising diesel kits. There is a motor / gearbox with a Delrin chain to power a second axle... and there is a motor bogie which uses a cardan shaft to connect the outer axles of a bogie. Whilst the motor bogie option is not cheap that product does come with Slater's wheels so the purchase price needs to be seen in the light of £42 being for the wheels. If requested, the motor bogie can be supplied with the wheels re-profiled for S7

 

[richard carr]

Peter/Graham

Although there is no disputing Ozzy's photo the practical reality is that you need a bit of a gap or the bogie will catch on the body and cause a derailment. For good running it is essential that the body only rests on the central pivot. All my 37s have too big a gap compared to the prototype but that's a necessary modelling compromise.

Richard

 

[Cliff Williams]

The 24 and 25 are the same, you have to pack them slightly or they have no lateral movement and derail at the slightest thing.
That is a big job you have there altering it all to fit! I use the Delrin chain and ABC motor and gearbox, I can bang it together in no time, saves a lot of re-engineering and works well.

 

[Spike]

Progress over the last few days has been the setting of the bogie side frames to their correct height to align the axle boxes with the centre of the wheel. The resin springs on the just like the real thing bogie moulding were transferred over to the abc bogies.



Here is the rear beam cut and shut from the original to fit with the side frames which have have been moved outwards to fit scale seven.



Here is the front beam which is made from brass as the resin one included in the photo was not going to work with the abc frame as I could not reduce the thickness enough so a brass replacement has been made.



Peter

 

[Dog Star]

Thanks to @Pugsley and @SimonT for the idea of splitting the end beams and re-joining with a rod through the middle. The frames are set 2mm further apart - 1mm per side - to provide clearance for the centre wheelset when negotiating the B6 turnouts on Scrufts Junction. The rear end beam could be thinned sufficiently so as to provide a sliding fit for the rear of the ABC bogie frame (which is a flat surface). The front of the ABC bogie frame carries a support for the front end of the moving gearbox and hence the front resin beam could not be thinned enough without becoming too weak (even with a rod from end to end). The replacement brass beam is an "U" section made from 12 thou fret and with a 0.9mm brass dowel rod at each end to provide for location into the side beams.

Next step is to manufacture some brackets to support the brake block hangers (as per the rear beam). Initial thought is to try to buy some brass "U" section or rectangular tube and cut slices. Anyone have any other suggestions?

 

[OzzyO]

This will be a lot more work, but could you cut the front end beam where the rib runs down and just add the brass section as the thinner bit between the two ends?

OzzyO.