Here is a list of all the postings Dusty has made in our forums. Click on a thread name to jump to the thread.
|Thread: darjeeling locomotive|
I am sorry if my reply confused you. What you must remember is that this Loco is scaled at roughly 1 3/4" to the foot. The wheel standards you are quoting apply to locomotives that are scaled at 3/4" to the foot. My current Loco is a 3 1/2 N.G. Loco. My wheel back to back dimension is 3 5/32", the flange is 1/8" wide, simple maths show that this gives a dimension of 3 13/32. A whole 3/32" narrower than the nominal 3 1/2" gauge track. I did not say as designed this loco would not run on 3 1/2" track, but there is a real danger that it would have a propensity to de-rail. I think that when I get round to building I will reduce the width of the flange to 1/8" this would in someway overcome the potential problem I have highlighted, without the need to completely redesign the axles. I dont know how Ray has got on with his loco, a lot depends on the accuracy of the gauging of his track.
re Dave Harris's post
Wheel standards do not apply to narrow gauge loco's. You must read the back to back dimension in conjunction with the flange dimension. Flange dimensions on narrow gauge loco's are far more substantial than main line loco's. If Martin Evans standard were to be applied to this loco the wheels would run on the flanges if run on a standard 3 1/2 gauge track. This would give an inside flange dimension of 3 19/32" patently 3/32" wider than the track. Hope this explains your query Dave. (yes I know I am not the Editor)
I have looked at the axle drawing and am of the opinion that the wheel back to back dimension is wrong. These are my reasons; The axle is 3 and 3/16ths for the back to back dimension added to this is the width of the flange x 2 =5/16 added to the previous 3 3/16 = 3 1/2".
this is far to tight for a normal track let alone one where the gauge may be a little tight. The effect of this would be to cause the wheels to climb the track thereby derailing the loco this would be very evident on curves. The dimension should be, in my humble opinion no more the 3 1/8 for the back to back dimension.
It would also improve running if the wheels were coned by about 2 degrees, this would help centralise the loco on the track. I am ready to be shot down in flames.
Hi to all who are building this Loco.
Just a reminder to those of you who are using 3mm plate for the frames to compensate for the slight difference in thickness from 1/8" plate. If you make the front beams and the angle which joins front and rear frames together 15thou wider and also the axleboxes 7thou narrower where they fit through the frames, you could save a lot of heartache later remembering to make compensation in valve gear components, fly cranks, cylinder bolting faces etc etc etc. No, I have not started building yet, another project to finish first, Then I will start. You may not think that such a small difference can affect the loco, I can assure you it can, having built a narrow gauge o/s frame loco I speak from experience. From what I have seen it appears that leaving the rear frames as the are will not matter, allwats remembering to adjust the joing braket fabrication.
|Thread: The use of adjustable reamers|
I fear I am or about to be a prophet of doom. Be very careful of the grade of phos you use for these bearings if you intend to ream them. Drawn Phosphor Bronze is an absolute B****** to machine it has a tendency to grab drills and reamers. Try to get something like colphos or perhaps a leaded bronze. These will, I feel sure suit your application. They are much friendlier to machine.
Adjustable reamers are a repair tool, I would not advocate their use for sizing a hole to a specific size. It is better that a hole is bored to size. In use the reamer is adjusted (by means of the collars at either end of the reamer) to just and I do mean just scrapes metal from the hole. The reamer can then be adjusted by slacking of the collar at the end nearest the square by say 1/16th of a turn and the tightening the collar at the other end. repeat until the hole has been cleaned up or has reached size. Do not be tempted to take a larger cut as adjustable reamers have a tendency to dig in, this if it happens leaves a hole nicely out of round. Do not attempt to ream a hole that is out of round to start with. It is far better to run a drill through the hole to make it round before you start.
Hope this helps. Dusty
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