It's wrong, but I can see why

Help and advice for those starting in, or converting to P4 standards. A place to share modelling as a beginner in P4.
Derek

It's wrong, but I can see why

Postby Derek » Mon Oct 05, 2015 8:01 pm

'evening.

I have finished what I thought was going to be my last practice turnout before construction started for real, but it seems that I am not naturally gifted in track building.


I would appreciate any comments on this blade tip. I think I have followed the instructions suggested by a number of well regarded modellers, but it's not quite there I don't think. Particularly with the angled filing of the inner face of the head- it goes from thin quite abruptly to full head. It runs fine, but...
WP_20151005_20_44_05_Pro-CROP.jpg
You do not have the required permissions to view the files attached to this post.

Derek

Re: It's wrong, but I can see why

Postby Derek » Mon Oct 05, 2015 8:07 pm

The common crossing looked fine at first, but somewhere I have introduced a slight bend in the wing rail. I think I know how that happened...

I made the knuckle to the figure that I found for (L)NER post grouping knuckle radius. In fact, I think I made it slightly too tight for NER practices. Does this look right (and yes I know the 2 radii don't line up perfectly- see above)

WP_20151005_20_44_16_Pro-STRAIGHTSMARKED.jpg


Any comments would be appreciated. It runs perfectly through the main road and I cannot feel even the slightest change on the knuckle/ vee nose (experimentation following the thread in 'the other place' about chamfered vee's and wheel coning and whatnot. On the turnout side there is gauge tightening as a result of the mis-aligned wing/vee as it goes through the wing. If I told you how I managed to get that bend in there you'd all die laughing.

One other thing: I calibrated my printer in Templot and for whatever reason (and I am sure it is NOTHING to do with Templot, rather more to do with my new but un-reliable HP A3 deskjet- not recommended) the calibration is out. It was fine before, but you can really see the difference when trying to follow the lines.

Derek
You do not have the required permissions to view the files attached to this post.

User avatar
grovenor-2685
Forum Team
Posts: 3918
Joined: Sun Jun 29, 2008 8:02 pm

Re: It's wrong, but I can see why

Postby grovenor-2685 » Mon Oct 05, 2015 8:19 pm

I would say you have just done the filing a little over enthusiastically, it will work but doesn't look so good.
Mainly its just practice, what size file did you use? I would suspect a rather small one, bigger is usually better. Howard's tutorial in the S4 News shows it pretty well.
To keep a nice straight cut you need to be filing largely along rather than across the rail, say 30 degrees so that you can cut the head without taking off the foot as well.

When fitting the wing rails its quite easy to get a knuckle bend a bit out, just watch for it and don't fit them till they are right, if the two knuckles are not directly opposite its a clue that something is wrong and needs correcting, your bend radius looks fine, its not something to agonise over since we don't have a spacer block in there that needs the correct radius to work. I have seen people filing a notch at the knuckle bend to achieve a sharp angle, it works but looks all wrong, extra work that actually spoils the job.
Regards
Regards
Keith
Grovenor Sidings

Derek

Re: It's wrong, but I can see why

Postby Derek » Mon Oct 05, 2015 8:30 pm

Keith,

you're a gentleman, thanks for the advice.

This is the first one I've produced since Mr Bolton's guidance at S4. You are right about the file- Howard made that point at Aylesbury and since purchasing the recommended files, the vee has been much easier to produce and I'm happy with that.

Our local preserved siding doesn't run on a Tuesday, so I will see if they will let me get up close to some blades for a look.

I know there are different methods for aligning the wings- I used a 3pt gauge to hold the vee to the straight stock rail and then another 3pt to hold the straight wing-closure rail in line and from my picture, it seems that was a success. So I think next time I will try and turn the whole thing around and put on the other wing using the same method.

Again, thanks for the advice.
Derek.

User avatar
grovenor-2685
Forum Team
Posts: 3918
Joined: Sun Jun 29, 2008 8:02 pm

Re: It's wrong, but I can see why

Postby grovenor-2685 » Mon Oct 05, 2015 8:49 pm

I used a 3pt gauge to hold the vee to the straight stock rail and then another 3pt to hold the straight wing-closure rail in line and from my picture, it seems that was a success. So I think next time I will try and turn the whole thing around and put on the other wing using the same method.

indeed, always easiest to do the straight one first, I assume you used a crossing flangeway gauge as well. Once the first one is in it helps doing the second as you can line up the knuckle bends to match. just be a bit wary of the 3 pt gauges for small radius turnouts, no 6 and below or curved points where you need to allow for gauge widening.
That bit is covered here http://www.norgrove.me.uk/points-2.html
Regards
Regards
Keith
Grovenor Sidings

Derek

Re: It's wrong, but I can see why

Postby Derek » Mon Oct 05, 2015 9:03 pm

Thanks Keith.

Yes, I used the S4 thin metal gauge for setting the first flangeway and the one from the S4 stores marked as DD Wheelwrights for the second one.

Because I have gone for quite gentle knuckles, there's nothing to 'push' against the DDW gauge. There's nothing to stop me turning the crossing around and using the same stock rail to hold the vee and the second wing steady (or use a piece of rail on a flat surface as all I need to do is hold the two parts in line).

Further changes I am going to make:
1. Buy a stronger soldering iron. A quick in- melt- out rather than trying to hold it all together for so long.
2. When bending the knuckles, bending around the correct radius and then flattening it out to the right angle isn't giving me the true curve- especially if I do them individually. I think the knuckle is a bend once and throw it away if it isn't right. A nice home made jig should be possible for this I think.

Gauge widening: at what point should I start that (I am building B6's for the shed area first)? Immediately after the stock gauge?

Derek

nigelcliffe
Posts: 747
Joined: Mon Jul 21, 2008 8:31 am

Re: It's wrong, but I can see why

Postby nigelcliffe » Mon Oct 05, 2015 9:35 pm

Derek,
just to add, I find the sledge gauge, described in the 2mm Scale Association's book on Track to be very useful for checking crossing areas. Whilst the book has an obvious 2mm bias, its sufficiently wide ranging to be interesting to other scales. Some of the home-made tools and gauges are particularly useful.

- Nigel

John Fitton

Re: It's wrong, but I can see why

Postby John Fitton » Tue Oct 06, 2015 12:17 pm

Regarding Keith's comment about the spacer block between the knuckles, is this a standard size or does it vary with crossing type (A, B, C etc)? If there is a degree of similarity I wonder why no one has thought about lost wax castings.

John Fitton

Derek

Re: It's wrong, but I can see why

Postby Derek » Tue Oct 06, 2015 12:39 pm

Hello Nigel
I couldn't find any reference to it on the internet, but I have a friend who is into 2mm stuff so I will ask him. Thanks.


Hello John
Wouldn't it need to be different? The radius for (L)NER varies by APPROX 5.5 mm radius for every 1:X and I believe 4 mm for every 1:X on GWR, so only a small difference really. Whether it is noticeable or not probably depends upon the margin of error in constructing the knuckle. Also, the knuckle surely is set by the vee ratio- 1:5....1:10 etc rather than the switch size ABC etc.

I had visions when I started this of drilling through the rail and putting decorative bolts on the knuckle, check and flangeway and all the various blocks- not forgetting the bolt/screw just in front of the vee nose. For now I will just settle for getting the basics right.

Derek

User avatar
grovenor-2685
Forum Team
Posts: 3918
Joined: Sun Jun 29, 2008 8:02 pm

Re: It's wrong, but I can see why

Postby grovenor-2685 » Tue Oct 06, 2015 7:53 pm

Spacer blocks in this area will be different for every crossing angle, IMHO model ones would just be a nuisance, somethings are not worthwhile in our scale.
I think the neck blocks, bottom left on this sheet refer. http://www.norgrove.me.uk/GWRtracknotes/R4401.pdf
You can see one on here Image and see that it matches the crossing angle.
Regards
Regards
Keith
Grovenor Sidings

Derek

Re: It's wrong, but I can see why

Postby Derek » Wed Oct 07, 2015 12:52 am

That knuckle looks quite a sharp angle. Is that an optical illusion, something common to tandems or is it just 'that's the way this one was made'?


Return to “Starting in P4”

Who is online

Users browsing this forum: ClaudeBot, SemrushBot and 0 guests