Copper RingDavid

Thought I had better do some notes to keep you appraised of progress and given the easiest way is with pictures I have done it as a web page.

on the left is an attempt at doing the outer ring in the copper wire you supplied. It may not be obvious from this picture but it is anything but round.

This was formed by folding it around a laser cut former but the basic problem is that the metal is too soft so it tends to form a series of flats between the curved sections.

It would probably be fine for a static model but as this is to revolve any eccentricitiy or mishape would stand out a mile.

The copper is also too soft to use in any mechanised bending tools I have access to.

I have a set of bending rolls as shown in the picture on the left and I also have some 2mm dia brass rod so I have tried to make the rings using this tool.

Its design lacks a key feature and probably wasn't designed with doing full circles in mind.

To roll a full circle you have to actually bend about 1 1/4 full circles as the rolls can't do anything with the last 20mm at each end as the end comes off the third roller at this point. The trouble with then doing 1 1/4 turns is that as the circle closes the free end of the rod needs somewhere to go that doesn't distort the bend. Usually this would be the nect larger groove but there is only one on these rolls and its not big enough to provide clearance so you get some distortion

For the larger of the rings this isnt such a great issue and slightly over rolling it allows it to spring around another bit of laser cut jig and to then be cut with a piercing saw.

The inner ring is more of a problem as its down on the minimum the rolls will do so it can't over roll so this one ends up sprung in and there is a bit of distortion as flats at the join of the ring.

The outer ring is a decent circle

and the join is quite fine
  2 rings

The two rings have assembled into the jig and in this form look OK.

The next job is to make the spokes and again I will use the brass rod as its a lot easier to file the have round recesses in the end to mate with the rings.

You didn't specify any detail beyond some diameters for the centre so here is what I plan on doing......

1. the specified boss diameter is the outer edge of the cut out at the middle of the jig

2. I will turn a boss, think top hat shape, that has a section at this diameter and another section at the diameter of the middle MDF circle with the lots of little holes in it.

3. This will provide a flange that the spokes can solder too.

4. If I can set my mill up to do it I may keep all the boss at the full 22mm dia but mill in slots on the quadrants for the spokes to sit in.

5. The boss will be drilled for an axle as specified.
  I hope to get the spokes done this afternoon but the boss may take a little longer as to meet your deadling this job has queue jumped several others and its getting done between coats of paint on one job and coats of weathering on another job but it is going to run into a bottle neck at the lathe as its set up to do yet another job which must be finished before I can undo the set up.

need more hours in the day, days in the week etc
  Complete Ring

Thanks for your e-mail. The centre will be 22mm as the spokes are now cut for that.

The joins need a bit of cleaning up with emery but I won't do that until they're solidly attached to the boss to give them support.

There is a very slight out of true vertically which I think can be corrected once the attached to the boss.
test Wheel1
  Broad Gauge Meat Van
  The following are a few photos of the latest version of the Broad Gauge Meat Van which I have assembled at home this weekend.

The result is that there are a few small tweaks to make on Monday morning before cutting one out to send to you - or if you are happy with what you see here I could do all four.

I have springs for the passenger cars cut and still have to do the Mylar axlebox things for both wagons.

There are a couple of questions below I would be grateful for your answer to before I go on. I'll highlight them in red.
This view shows a body made up but unpainted and I made a bit of a discovery with the Mylar. Previously i would have supplied it with the self adhesive backing on which holds it very firmly but is forever truying to stick in the wrong place as you try to locate it.

As this was only a trial I didnt want to waste the double sided tape as its expensive so on this one I put the Mylar in place and then flooded it with Butanone.

Not only did it stick it in place, it allowed some fiddle time to move bits into place and was all in all a lot less stressful than the tape version.

Question 1 - do you want tape or will you use solvent?
  Meat Van

By this picture I had given it a waft of primer to make the details show but this view prompts another question.

I have put cutouts in the floor to clear the wheels. Their size is a guess and they don't go right to the edge of the floor to be flush with the sides.

There are two reasons for this. 1, I didnt think of it at the time and 2, there are tabs on the edge of the floor which locate in the sides which couldn't be there if the slot went to the edge. Once its all glued up and rigid its the work of moments to take them to the edge with a file.

Question 2 - do the wheel slots need to be larger?

This is the other side of the primered body. There is nothing like a close up photo to show up that you glued one of the trim pieces on crookedly!