Sarf of the river, down Nine Elms way

[Martin Shaw]

Look, I've just forked out what seems like a small countries national debt on machines tools and all the other bits so I'm going to use them on every conceivable occasion even if the job thereby takes twice as long. Filing is what clerks in offices do anyway.

Martin

 

[Brian McKenzie]

. . . . but gripping them in a chuck would be a challenge, it might just be easier to start from scratch.

Press your bearings onto the slightly tapered end of a shaft prepared in the lathe, then turn off the excess width using light cuts and a sharp tool.

 

[Martin Shaw]

Way back I put this project on hold pending delivery of the wheels, which are now here, somewhat later than the promised Telford

Now the turning is fine, the insulation insulates mostly, but as you can see the spokes whilst commendably fine for an iron casting, are somewhat rough in their finish. A bit of work with files will sort it out well enough and when painted won't be too noticeable hopefully. Of the seven insulated wheels, six of them measure a resistance in excess of 100kR, no problem there, but one driving wheel is reading 850R, which is a bit low. However when you calculate it all out the exact issue is an extra 15mA from the power supply and since the loco will only ever be DC it can be ignored. The other glaringly obvious visual casualty is the position of the crankpin, it's correctly located at a scale 9" from the axle centre, but there is an awful lot of boss. This is I suppose going to be sometimes inevitable using a generic casting, will it bother me, I don't know yet. Anyway they're going away in the box until such time, probably the new year the way things here are progressing, or not.
Regards
Ma=rtin

 

[Martin Shaw]

I thought over the weekend that I ought to invigorate this project that had become dormant for at least a year, somewhat to my shame it appears nearer two. Ah well such are plans, diversion into HiFi matters was an expensive but rewarding alternative. I opened the box on Sunday to remind myself, the inner frames for the tender no longer quite satisfy me, why I have no idea because they were fine 18 months ago, something to do with not fully thinking the plan through before production. Anyway I'm going to redo them, which since the first invocation, I have replaced the mill and it now has DRO fitted which should simplify things. I have also decided to produce new frames for the locomotive, and pending the measuring of the existing to produce a drawing I spent today ordering nickel silver flat strip from a couple of suppliers, ouch.

I'm going to live with the wheels as supplied, they are satisfactory for the overall standard of the model allbeit with some irritants, I guess when painted and whizzing round the imperfections won't annoy me too much.

I have decided the the loco should be sprung, and those very nice people at Finney7 produce Drummond axleboxes of which I cannot find any pictures, not looking hard enough I suspect, but would one of you kind folk be able to produce a pic or two for my elucidation. My pics of the job to follow tomorrow.
Regards
Martin

 

[Steph Dale]

Ah well such are plans, diversion into HiFi matters was an expensive but rewarding alternative....

I'm still there, my EMT cartridges have recently come back from a sabbatical in Switzerland.

I'm going to live with the wheels as supplied, they are satisfactory for the overall standard of the model allbeit with some irritants, I guess when painted and whizzing round the imperfections won't annoy me too much.

They'd annoy the c* out of me...

I have decided the the loco should be sprung, and those very nice people at Finney7 produce Drummond axleboxes of which I cannot find any pictures, not looking hard enough I suspect, but would one of you kind folk be able to produce a pic or two...

@PeteB of this parish has used them in his M7, which reminds me, I need to get to his message...:

Steph

 

[Martin Shaw]

Thanks Steph,

They'd annoy the c* out of me...

me too as it happens and whilst the bogie wheels can be fettled adequately and the tender wheels are hardly seen the overly large boss for the crankpin is unsightly. I might have an alternative plan for the existing coarse standard wheels to be insulated and finescaled, it will also involve another of Eastleigh's fine machines killing two birds etc.

Nuther question on axleboxes, how is the springy bit made to happen and what is the overall size of the box itself, cunning plan forming as I type this.

Martin

 

[Steph Dale]

Nuther question on axleboxes, how is the springy bit made to happen and what is the overall size of the box itself, cunning plan forming as I type this.

I normally just drill and tap a 12BA hole in the top of the hornguide and use a Slaters' spring. I must have done a pic before to show what I mean, but the best I could find with resources to hand was the first photo in this thread: Re: Steph's WR Workbench - Springside 2251

The square bearing is 8mm square (as, indeed, are most in this scale), so I'd start with a slot 9mm wide, extending at least 5mm above the axle line - maybe a touch more.

Steph

 

[Martin Shaw]

Thanks for the additional info, I'm wondering whether there is enough meat to use a 10BA screw, I don't much like anything smaller if I can avoid it, the casualty rate on 12BA taps is high. The reason for asking about bearing size is the possibility that I might want to replace it with a phosphor bronze one, I realise brass is the most common material but it really isn't the best material for a bearing of any sort, this illustrates why,


as does this



These are the bearings on a tender frame from a SECR C class, which had undoubtedly done some work, not least in carrying around a crailcrest motor, but nonetheless somewhat worn. I rebuilt it to work but it's really a candidate for new inner frames. Can you see a pattern emerging, I can.

I had intended to start dismantling the D15 this afternoon, however a look at the state of the workshop bench coupled with the temperature therein persuaded me otherwise, I have to wait in for deliveries tomorrow so perhaps the morning before it heats up.

Regards
Martin

 

[Steph Dale]

...the casualty rate on 12BA taps is high.

Hmm, my set of carbon steel ones are about 20 years old. You're supposed to lubricate them with cutting grease and back them off by half a turn every turn. I put them in a pin vice rather than use a tap wrench as it gives better feel if they're starting to stick. They can be made to last forever!

...brass is the most common material but it really isn't the best material for a bearing of any sort...

True to an extent. You could use whitemetal liners in them though - just like the real thing! Again - decent lubricant is really the order of the day; something synthetic and PTFE-loaded perhaps? Phosphor-bronze is really overkill for our sorts of applications and loads, I think. At least you didn't suggest ball races

Steph

 

[Martin Shaw]

Steph
Thanks for that. A couple of short stories, 419 did a tour of English heritage railways in the spring, not wholly satisfactorily it has to be said. Heating big ends essentially, when it was built the Caley used a yellow brass for the brasses, which must have worked since neither the LMS or BR sought fit to change them. Unfortunately these were stolen during the last overhaul and our engineer decide to use gunmetal replacements. It has since been discovered and now rectified that there was about 4 thou ovality in the journals and given the harder nature of the gunmetal the highspots were sufficient to break down the oil film and heat the brasses. They are being machined for whitemetal inserts.

I was driving No1 three weeks ago when it decided that its 70 year old LH big end "brass" brass would give up, subsequently found to have an axial crack that has the appearance of being quite old, probably came with the engine 50 years ago from the NCB. Pattern made and new ones cast, at god knows what cost.

I might have a loco in the collection with ball races, it seems like a lot of work for not too great a gain.

I took the bull by the horns and cleared up the workshop, stuff ready for start of play tomorrow.

I have also discovered something interesting about wheels, to be revealed.

Martin

 

[adrian]

and back them off by half a turn every turn. I put them in a pin vice rather than use a tap wrench as it gives better feel if they're starting to stick. They can be made to last forever!

That's brave backing off every turn. I barely run half a turn if that before backing off to remove the chip. Although I'd agree with using the pin vice for better feel.

 

[Yorkshire Dave]

.... and my neighbour uses M4 and M6 taps in a pillar drill ! - with tapping fluid/oil.

 

[Steph Dale]

.... and my neighbour uses M4 and M6 taps in a pillar drill ! - with tapping fluid/oil.

I've met your neighbour and it doesn't surprise me!

Steph

 

[adrian]

and my neighbour uses M4 and M6 taps in a pillar drill ! - with tapping fluid/oil.

When I was working for my Dad I used to make old school frame spacers using 3/16" hex brass in the lathe. They were tapped under power with a 6BA tap in the tailstock. Mind you it was a Myford ML7 Tri-lever which gave fantastic control over the power feed.

 

[simond]

We’ve got a whopping great CNC miller at work. It positively terrifies me to watch it tapping - the smallest we use is M3 - as once the program is proven, it goes at it quite ferociously...

Steph will recall I had a little “oops” with it a year or so ago.

Atb
Simon

 

[paulc]

.... and my neighbour uses M4 and M6 taps in a pillar drill ! - with tapping fluid/oil.

He probably uses spiral taps , much better for power work .
Cheers Paul

 

[Martin Shaw]

I have tapped M6 on the mill, it has a setting that limits the speed and ups the torque, as well as instant reverse, but I think 12BA would be pushing it.

Regards
Martin

 

[Martin Shaw]

I'm sorry Steph, a further question, the Drummond hornblocks are I presume correct for your T9 and L11 kits, but are they generic to all Drummond locos. I would suppose so but I'm thinking ahead for once and I'm going to need something for this in due course. I have no knowledge of it's origins although I understand it's quite old, and possibly scratchbuilt. I'm strongly resisting the urge to take it apart, far too many projects in bits as it is.

Regards
Martin

 

[Martin Shaw]

The postman came today and delivered all the usual c***, a bill, and some very well packed nickel silver strips suitable for frames and the like. I can no longer prevaricate this job into indecision, so a start was made.
The chassis is held into the body by this screw that also retained the bogie,

and a tab soldered to the underside of the cab floor that pokes through the rear stretcher of the frames.

The frames drops at the front and pulls forward to release it.


There is nothing particularly unusual about the bogie, it might be a kit etching but could equally be not so, it will need replacing. The coupling rods are reusable if in need of a clean up, but the crankpins are currently 6BA csk brass screws into the rear of the drivers and they are considerably undersized for the holes they fit into.



Removing the wheels, axles and motor left the bare frames, pretty they are not.



They look distinctly odd, the position of the bearings for the driving wheels makes no sense until I realised that the frame top doesn't meet the underside of the footplate. They look as though they were etched but I can find no identifying marks on the frames or the inside of the body to confirm this, nor whether it's a kit or not, I'm tending towards not. Frankly it's not worth spending any effort on as I suspected so a new one is the order of the day, but I think some drawings and possibly a plastikard mock up before metal is cut, some thinking to do here.

Regards
Martin

 

[Steph Dale]

Martin,

Can you PM me a phone number and time to call over the weekend - I may well be able to help you out here...

Steph