bertiedog

Just to save time till any books arrive, does anybody know from their copy what the wheel diameter of the drivers were?

It's sort of vital to be able to use the existing wheels or get castings on order Asap.

Exact spoke count does not really matter.

Also the overall length? and possibly the boiler diameter as well.

It's not a commercial build, just a build for a friend, and saving some time is important on this project.

Stephen

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It appears via the reference kindly supplied, by Kevin, that Amazon have dealers with stock, so problem is basically solved. The build is to use up wheels, motor and gearbox from an 060, but the wheels are the same size, and I happen to love open cab tank locos.

The 4 mm versions all had a pivoted chassis, it rocked to provide compensation and force the weight to be distributed to the drivers evenly. They sailed along over rough track without a murmur, and should do in 7 mm just as well.

The motor can remain hidden and the boiler stuffed with lead to give it a bit of grunt.

 many thanks,

 Stephen.

It apparently appears in this book.

 

http://www.slightlybetterbooks.com/jnmaskelyne.html

Thanks for the reference, the drawing did look like the work of J. N. Maskelyne. now to trace the book or find which edition of the MRN it was published in.......anybody got any ideas?

Stephen.

A request for building a Dean No34/35 044 in 7mm has landed on the bench, and I can't find any net references to drawings or outlines. 

I am pretty sure it was covered in the Model Railway News in the late 1960's or early 1970's as I built several commercially in 4mm scale to what appeared to be a photocopy of an MRN style drawing.

I don't have an MRN collection to refer to, but are drawings in some other GWR reference book.

​Any help greatly appreciated ,

Stephen

Finally my Unimat needs an overhaul, replacing the bed rods etc to get rid of play, but also making new toolpost and making a thread chasing attachment, that is like the original had. but better tool holding. The lathe remains unmodified and can cut any TPI Imperial thread, metric threads or BA or any other pitch possible within the capacity of the machine.

The master thread fits the rear hole of the headstock, and diameter does not matter. the follow tip or thread form, made from a segment of a matching nut arranged to run on the sample thread.

This thread follower is coupled to a bar running along the whole bed at the back, and has a movable arm that has the cutting tool on it, resting for support on the tool support on the cross slide.

As the follower forces the tool to move, the tool tip is adjusted to cut the work. At the end of the thread the whole arm is lifted to disengage the follower and tool, which is then returned to the start and the process repeated till the thread is correct fit in a test nut, or measured. Threads can be external or internal or L/hand, it just copies the pitch of the follower. The quality of the threads made this way is unsurpassed.

The Unimat is perfect for this form of cutting threads, but similar ways could be adopted for other small lathes. 

The lathe already has extra low speeds as per Rex Tingey's book. but needs a powered fine feed developed for it, based on a shaft under the whole bed, with a stepper motor to power it timed from the main drive with an optical coupling.

It should require no major alterations to the basic design, just gears to couple the shaft to the manual bed feed screw.

I will do notes on these mods on a new posting Asap.

Stephen.

Couple of points, flywheels on axles do not work, they would as suggested have to be geared up, and it is wasted duplication of a drive, keep it simple....

The chance of gear stripping on a flywheel system is zero in practical terms, stripped gears occur for other reasons. When a loco hits the buffers under power from the flywheel it will simply break traction between the track and wheels, by far the weak point in the transmission.

The break traction and slip will protect the gears unless very fine pitch, poorly mounted or miss aligned in a major way..

The more complex the drive, the more to go wrong and there is little space to spare in OO drives.

Magnetic and clutches are best confined to O gauge or above, where space can be found more easily.

However some larger diesels in 00 would lend themselves to more experimental drives.

As said, shunting or any loco, benefits from a flywheel ....that is not trying to be technical but 50 years experience of building locos with them fitted.. If you want technical details of flywheels and gyros I can give you the fullest details, but this is not needed to improve a motor in a model loco.

Stephen.

Kitmaster, (Rosebud) were a very odd company, the expansion into railway based products seems to have been a whim of the owner, and done without reference to costs. I think (no reference) they had a grant or Goverment development money provided on the move to the new factory at Roands. I knew one of the mould makers who later retired back to Kent where the company started. He said the speed of the work startled him, no way was proper costing done, and the money began to run out . At the end of the mould making they were working on Lner A4 and Flying Scotsman as well as TT products.

Sales had been buoyed up by sales through Woolworths but after a big start they soon reached saturation level, and the profits never appeared.

In the average model shop, Kitmaster in the unusual cardboard boxes where expensive compared to bagged Airfix etc. Only imported US made kits cost more. Our local well stocked model shop found them slow sellers.

The retail cost was high, Airfix worked as volumes were huge and price popular level. The lack of Chinese production of railway themed kits seem to indicate that there is no mass market to provide sales, even with low wages and cheap production costs.

Dapol manage by slowly extracting the life out of the old moulds, even the coaches have returned. Damaged moulds have vanished, mainly from rust acquired in storage whilst the company was in bankruptcy, before Airfix bought the machines and moulds, stored in the open under tarpaulins!

So although Dapol and others have tried injection moulded Locos, the high costs make it near impossible.

3D printing is the only answer, but current standards are just too crude, look at any Airfix moulding from the 50's, it far superior in every way., but 3D is getting better all the rime..

Stephen

The problem is the cost of moulds, compared to potential sales, too costly a risk, unless support by a large company with diverse other products.

3d printing may eventually be the answer when the detail and finish rival a moulded plastic item.

Kitmaster managed the moulds as they had other activities, and expanded in a rush, not accounting for the costs that bankrupted them.

Airfix survived as a producer because of a huge range, but then the costs of Uk production got to high.

So the future depends on the 3d process improving or CNC mould cutting being combined with 3d.

It may be a few years though before really fine crisp detailed models can be produced.

The best intermediate solution is a basic 3d carcass. with added etched metal details and fine mouldings attached to the basic body

Stephen.

It smooths out the starting jerk, and the overun to halt, shunting engines are high gear ratio, speed slow, so need aid to run over the frogs, and dirty track with the addition of motor smoothness whilst running

Shunting engines are closely observed in operation, and need the predictable performance to cover the coupling operation. DCC can do with a decent mechanism standard.

With RTR the fact it has a flywheel fitted does not g/tee that it will function better than  on a flywheel free one., DCC will never cure a bad design of either type.

Stephen

It  all depends on the design,, the hollowing should be equidistant from each end  and  leaves a sleeve over the shaft as big as the thickness of the  flywheel. Some commercial designs are just shoddy.

This is all about getting the best smooth performance  out of a small shunting  loco. not an engineering thesis on Flywheels..

It's not the shafts that wear, it is the sintered bronze motor bearings that wear oval that is the cause for concern. They are initially soft, but work harden in use and surprisingly large wear can happen  in running in, aggravated by any strain from the flywheel forces.

Although small, the forces are proportional, and still can cause wear that is preventable.

Straight forward engineering science, I have no particular references to quote, but the effects taught in college and university studies. Above all is practical experience  on working will full size flywheels on both Steam engines and  Electric motors.

The heavier the flywheel the better, but with a high mass then gravity forces the weight down on the shaft bearings more as the mass increases.. The lightening by hollowing reduces the wear, it also lowers the flywheel effect, but the max diameter mass is doing most of the work, the loss is proportionally small when hollowed out.

Stephen.

The point about a solid flywheel is it has greater mass and the out of balance forces plus gravity, tend to hammer the bearings.

Hollowing out the flywheel reduces  the overall mass  and leaves the effective flywheel effect, but with less wear on the motor bearings.

With ball raced motors use solid flywheels....

Stephen

Peco Code 70 US standard gauge?.... nothing on the Peco site etc, are you sure it is not the code 70 narrow gauge track that they already supply.. Code 70 or smaller code iis near impossible to buy in the UK, so If Peco enter the market it would be very welcome.

Stephen

There should be no wheels for OO that have 2mm flanges, most are smaller, but the Chinese vary the exact dimension, and some brands do not have the same wheel standards across the range, even Hornby do this on budget legacy models.

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Stephen.

Will Peco bullhead accept NEM-wheels too?

It´s not only RP25 wheels?

The Bullhead Peco point is only intolerant  to very old model wheels, the correct 14.5 mm back to back work on these. They will work with Romford, Hamblings, Jackson or equivalents in UK practice and most modern Hornby or continental NEM standards a long as the flange height is not excessive. As long as current NEM standards are observed they will run OK, but the back to back often varies on Chinese production, and must always be checked.

Also a lot of current RTR makers are claiming RP-25 standard when they are not. They use the max tolerances to make them, and then add in alterations like tapering the flange excessively. Few have the root radius between tyre and flange correct.

Stephen

Flywheels are always beneficial, if properly fitted and as large as practical. They overcome magnetic cogging of the poles of a motor, and with coreless motors add to the momentum considerably.

Theres no need to test or prove it, the use dates back 80 years and encompasses both hobbyist  and professional productions.

The gear ratio does not have a dramatic effect, witness the Hobbytown diesel designs that can coast several inches at slow speed and feet at higher scale speeds.

The momentum overcomes pickups troubles, and generally the loco will run quieter with a flywheel.

The big but is the bearings must be substantial, and nothing must be out of balance.

Stephen

I hope this is simple and plain, out of the box the unifrog is a dead frog point, with no frog switching like an electrofrog.

The blades and stock rails are bonded and do not switch the frog like an electrofrog.

So you must switch the frog to regain a live frog, via a point motor or manual switch.

If you provide no switching then they are a dead frog type.

 So two choices dead or alive.......but the live option now requires a switch.

It is not complicated, just a small change.

Stephen

After an enforced couple of weeks in hospital, I am intrigued to find there are still ongoing comments about the Unifrog. It is only a small change, but to maintain live frog operation frog switching must be done, thats all.

It is dead frog out of the box and fitted without switching, and suits DCC with or without switching.

As usual Peco have been very accurate but sparse with instructions, especially online, where their website is comprehensive, but disorganised, as they still live in the era where suppliers charged for catalogues, and depend to a great extent on the RM for publicity,

This is not good enough, and full dedicated notes should be online now, they must pull their socks up on this.

Stephen

Tootally Thomas are the Uk importer, he may sill have supplies from the first batch.

The Unimat simply could not handle cut offs that big, but parting can nearly be eliminated in most model engineering, by sawing and refacing. It is just a different approach to the work. Parting is a factory production method to save time.

The Unimat can be easily uprated to stiffer bed rods, see the books by Rex Tingey etc.

Excellent lathe all round, but not as tough as some.

Stephen

I posted way back in the early days of this thread about him taking out a subscription to Model Railway News before the war. I presume his English was good enough to be able to order it and to read it.

Bernard

Yes, he spoke reasonable English, as I had this from one of the interrogating officers, who though retired in the 1970's worked part time as our accountant. Generally  he insisted at the trial on German Translators so there could be no confusion.And, yes Joseph Goebbels was another train enthusiast with a large toy train layout at his Berlin residence.

STEPHEN.

Göring had a favourite restaurant in Munich, owed by a Jewish family, who found he `protected` them from the actions suffered by others purely because he liked the food. If queried as to his status the owner referred the Gestapo etc to Göring, whose mention ensured release,.....complete double standards by Göring,

For those with out a lathe , saw out the middle section, leaving the  base and top, and find some plastic rod or tube of a slightly larger diameter, and drill into the base and top and through  the new middle if solid, and assemble with epoxy with the hole containing a support wire.

The chimney appears in modern photos to have a slight taper, straight in older shots.

One other item to make are the distinct lubricators on the front foot plate in polished brass, and fit lamps and brackets for them.

Stephen