Some Modelling 'How To' tips



 
  1. .....................Motorising a Peco Point
     
  2. .....................Laying Peco Third Rail
     
  3. .....................Modelling 4mm Scale Conductor Rail
     
  4. .....................Make a Screw Link Coupling
     
  5. .....................Glazing RTR injection moulded coach bodies
     

SR Target


 


 
 
 
 
 
 
 

Motorising a Peco Point

For the non-electrically minded

Peco Points have a centering spring feature in the design which increases the force needed to change the point. To impart the increased force it is necessary to include a Capacitor Discharge Unit (CDU) in the circuit which discharges a high output pulse to the solenoid. This should be wired as the sketch below. The diagram shows the operating switch as an Atlas Nº56, but obviously can be any type. It is necesary to use a dedicated controller for your 16v AC supply if you are going to use a common return for each point. A CDU can handle up to six points operating simultaneously. Use heavier wire than normal as high currents are involved.

Peco Point Wiring


 
Return to top

Making a Screw Link Coupling

Practical experience from Keith Meredith

I can make one in about 15 mins (not the hook) it's a bit fiddly but I'm afraid it's the nature of the thing.

First of all I will not insult your intelligence by describing how to make a hook, suffice it to say a couple of drills, a needle file, a strip of 15 thou brass and a little time will do.

But now the tricky bit the coupling itself, I have listed the things you need

  1. 0.33mm brass wire
  2. some thin electrical wire (which you will strip, you only need the sleeve)
  3. a sewing pin (small head)
  4. super glue gel

THE LINKS (2off)

Cut a piece of brass wire to 15mm long (use a sharp knife to cut the wire, I`ve found it doesn`t flatten the ends) next fold the first 3mm of each end to 90 degrees so it looks like three sides of a rectangle. Place the shaft of a 1.5mm drill in the centre of the wire with the ends pointing up and gently fold them up to form the link. Hopefully the ends will overlap, make sure the sides of the link are parallel and with your knife cut the ends of the link centrally so that they butt together. I have found when making small items it is better to keep them as big as you can for as long as you can. Cut a piece of sleeving to the width of the link and insert the cut end of the link into each end of the sleeving. In doing this try not to disfigure your nice new links.

THE SCREW

Cut a piece of sleeving about 20mm long, it doesn`t really matter how long. Position your sewing pin centrally and at 90 degrees to the sleeve wall then push your pin straight through the side and out the other so that the head of the pin touches the sleeve, now cut the pin to about 5mm measured from the top of the head and slide the pin back so the cut now touches the sleeve wall. Cut the sleeving to about 5mm each side of the pin and insert a small length of brass wire each side after touching the end of the wire in some super glue to hold against the pin. Now when the glue is set cut to the correct length 2 to 3mm each of the pin to form the screw.

ASSEMBLY

Lay the two prepared links flat so that the straight bars face each other, dip the ends of the screw in Super Glue, hold the pin head vertically and sandwich between the links, hold till set. Gently open up one link and insert into hook (make sure the T bar hangs down when coupled), close link and spray matt black.

THE RESULT

I hope this all helps I have tried to keep it simple. I have made one and it hauled 20 wagons without any problems. It is not to the finest of scales but that's not what I'm after, it looks suprisingly good and it's not too fiddly.
 
Return to top


An approach to glazing RTR injection moulded coach bodies

Practical experience from John Arkell

Many Coach bodies are moulded so thick that it is not possible to accurately represent the flush glazing of the coach without compromising the appearance of the windows with over thick moulded plastic inserts.

The following method will allow glazing these coaches with microscope cover slips, which are real glass. The instructions will show how to machine a rebate to accept the glazing, how to cut the glazing, how to shape if necessary and finally how to glue in the glazing.

The first step is to machine the rebate that will accept the glazing. The rebate is machined around the window on the inside of the coach but the milling is done from the outside. You will need the following:

Dental burr with a "T" shaped head that will cut sideways. I used one with a 3/32" shank in the collet chuck of my flexible drive shaft Badger bench top drill, but a Dremel or equivalent will do.

A length of brass tube with an internal diameter slightly larger than the shank of the burr but which will slide down over the burr. K & S 3/32 ID

Cut the tube so that, with the burr pushed fully home in the chuck, when the tube is slid over the burr and comes against the chuck the burr protrudes from the tube. The amount it sticks out will govern the depth of the rebate to be milled. The end of the tube should be buffed to remove any rough edges, as this will be in contact with the painted surface of your coach. In use the burr rotates and the tube is stopped from rotating by holding a finger against it.

Diagram

The width of the rebate that will be cut is dependant on the difference in the diameter of the cutting head and the diameter of the waisted shank immediately below the head. Lightly oil between the burr and the tube so that the tube does not wear at the chuck end.

I recommend that you try on a scrap body shell. Using the brass tube as a depth stop this allows a constant depth of rebate to be milled. Work slowly so that the burr will not overheat and melt the plastic. Clean frequently to keep the burr free cutting.

In the corners of all windows the edge of the rebate will be a quarter circle of a radius slightly larger than that of the opening. The Glass will be cut rectangular and the radii will have to be ground off the corners using a diamond-coated burr or diamond coated needle files.

If the body shell side is too thick and you end up milling a slot rather than a rebate then take off the inner side of the slot from the inside with a sharp craft knife. It is usually quite thin.

The Cover slips come in several standard sizes 18mm x18mm and 22mm x 22mm and are obtainable from good photographic shops that sell microscopes and accessories. The brand name I have always used is Chance-Propper. They are sold in boxes of 100. Do not buy the circular ones as there is too much wasted.

When working with glass it is advisable to wear eye protection and a mask if using Diamond coated burrs to machine the corners of the panes.

Measure the height and width of the rebate in the window openings and make a list of the various different sized openings and how many of each size are required for your coach

On a sheet of plain paper mark out using a ruler and set square the exact size of the window openings in pencil. Jot down the quantity next to each rectangle.

To cut the cover slips you will need a Diamond Gramophone stylus that can be held in a pin chuck. This could cause some amusement at your local record shop as you look through all the styli to find a suitable one. You will also need a short steel rule. And a cutting mat.

Line the cover slip up with two sides of the rectangle drawn on the paper and work out the most economical cutting pattern for your windows. Lay the steel rule over the glass so that it is lined up with the third side of the square. Take the diamond and scribe the glass against the rule. Take the rule off the glass. Lay the rule on the cutting mat and slide the glass over the rule so that the glass is half on half off the rule with the scribe line at the edge of the rule. Use one finger to hold the glass down on the rule and with the other hand lightly tap the glass hanging over the edge of the rule. It should snap cleanly along the line scored by the diamond. Turn through ninety degrees and repeat the process until you have the correct size panes. Accuracy will come with a little practice. You do not need to score the glass with a heavy hand. You will need to rotate the diamond in the pin chuck until you discover its best cutting angle.

Offer the rectangle to the coach body and note how much of the corners will have to be ground off using either a diamond coated burr in the drill or diamond coated needle files.

When you are satisfied that the pane fits the rebate it can then be glued in place using a Cyano-acrylate adhesive. Try to obtain one that has non-fogging properties. I can recommend "Roket Odourless Cyano Glue" from Deluxe Materials. They also sell a set of Micro Tips and Tube that can be added to the standard 20g bottle. The tube is a very fine polythene tube to allow the glue to be exactly placed without the need to get the standard bottle and nozzle inside the coach.

Once the glue has set the glass can be cleaned using a cotton bud dipped in methylated spirits. The final touch is to apply any smoking or non-smoking transfers to the window.

Sticking a piece of Scotch Magic tape on the inside of the window can easily do frosted windows.

 
Example  
 
  Example

This page was last updated 20 June 2003

SR Target

Valid CSS!    Valid HTML 4.01!