First dabble in P4

[21C141]

Having first resisted attempts of being converted to P4 at Manchester with my 14xx chassis build I finally succumbed at Worley and joined Scalefour Society.
For my first project I'm having a go at a Martin Finney LSWR wagon (diagram 1481). All was going well with the chassis being folded up and soldered (very little required) and the four sprung bearing carriers assembled. Then due to my own stupidity I've lost one of them, so now considering my options.
So I'm wondering if the chassis will still work if I made one of the axles fixed?
Any advice at this early stage would be much appreciated.

Ray.

[Tim V]

Contact Martin Finney, and ask if he could send you a spare. He can only say no.

Alternatively, try cutting out a copy of one of the others to replace the lost one.

[21C141]

Contact Martin Finney, and ask if he could send you a spare. He can only say no.

Alternatively, try cutting out a copy of one of the others to replace the lost one.

Thanks Tim for your prompt reply.
I'll give Martin Finney a ring in the morning but as these were from the main etch I'm not that hopeful, but you never know.

I did think about making a replica but not sure how to get the spring wire attached. The original has three fingers with a half etch on the outer fingers on one side and the middle finger on the other that the wire passes through.
I'll have another think about that if I draw a blank with Martin.

Ray.

[Paul Townsend]

If Martin can't help at an economic price you might consider buying a Bill Bedford designed wagon sprung etch set available in several patterns from Eileens. These are easy to assemble and work well. You get several on the etch so will have plenty for another project at a reasonable cost. You will need to assess compatibility with the Finney kit as I have not tried that.

There are other makers offering similar but more complex products that may suit better?
An LSWR expert needs to advise the most suitable.

[grovenor-2685]

You could just be lucky and find that the Bill Bedford spring hangers will work as a replacement.
Keith

[21C141]

Many thanks for the advice, but after an hour or so grovelling on the floor this morning i've found the missing wheel carrier. It wasn't on the floor at all, it had fallen in another box of bits.

I now have the wheel set assembled and there are a few tight spots in the suspension but i suspect after a bit of cleaning hopfully they should free up. Of one concern is the W irons are being sprung out by the wheels by about 0.5mm. I've checked the width of the axles at 26mm, is this normal?

Ray.

[21C141]

Having had another look at the wheel/suspension i cant help thinking something is not quite right. This is where experience is lacking.

Without the wheels the wheel carriers slide up and down nicely and they feel quite 'light' against the spring wire. When the wheels are inserted the springing becomes quite 'heavy' although fairly smooth. I cant help feeling that this is due to the W irons being sprung out as the carriers slide up towards the solebar.

Any thoughts? Looking at the assembly drawings i cant see anything amiss.

Ray.

Edit, maybe heavy springing is my imagination, i loaded one axle with about 25 grams which deflected it about 0.5mm, does this sound typical?

[grovenor-2685]

Where did you get the bearings?
Sometimes there are some which don't have a deep enough hole, its not going to be satisfactory to have the axles forcing the W irons off vertical.
Masokits etches come with a measuring device so you can sort out bearings into deep, medium and shallow, sounds like you need deeper ones.

An alternative if you use Exactoscale wheels is to shorten the axles, see http://www.norgrove.me.uk/masokit3.htm but I would check out the bearings and look for deeper ones first.
Regards
Keith

[Will L]

Having had another look at the wheel/suspension i cant help thinking something is not quite right. This is where experience is lacking.

Without the wheels the wheel carriers slide up and down nicely and they feel quite 'light' against the spring wire. When the wheels are inserted the springing becomes quite 'heavy' although fairly smooth. I cant help feeling that this is due to the W irons being sprung out as the carriers slide up towards the solebar.

Any thoughts? Looking at the assembly drawings i cant see anything amiss..

I'm afraid there are a number of variables in play around a pin point axle and bearings set which can combine so that the length over the pinpoint axle and bearings differs from space available between the W irons. For the sprung W irons to work they must be vertical and the axle/bearings a good fit. It's not clear from your description if the W irons are bowed inwards, because the axle/bearing set is to short, or bowed out, because the axle/bearing set is to long. But one way or the other this is almost certainly your problem.

It may be, in part, due to exactly where the bend formed in the W irons, or because the pinpoint axle is wrong, neither of which you can do very much about. However it is more likely to be due to variations in the dimensions of the pin point bearings. Specifically, the depth to which the bearing cup has been drilled can be particularly variable, although the depth of the flange round the end can vary too, and both can alter the effective length over the pinpoint axle and bearings. This can be a problem, as you have found, but fortunately it also allows for a solution. You need to find some bearings, either shallower or deeper than the ones you have and correct the error.

For more on this problem and the solution read to the end of this article on the CLAG website. If you don't already have spare bearings, you may need to acquire some, preferably from several manufactures, so that you more are likely to find some that err in the right direction for you.

Will

[21C141]

Hi Keith, Will

Thanks for the reply.
The pinpoint bearings came with the wagon kit. I've just spoken to Martin Finney and it's possible that this is the problem. He is going to put some new bearings in the post. Think ill get a selection for future builds.

Ray.

[Tim V]

The only bearings I can recommend as being correct over 26mm pin point axles are by Exactoscale. They also run very nicely as well.

Others, as has been pointed out, are variable.

[Andy W]

Agree with Tim, I was just about to post the very same.

[21C141]

Where did you get the bearings?

Masokits etches come with a measuring device so you can sort out bearings into deep, medium and shallow, sounds like you need deeper ones.

Keith

I've had a look at the Masokits pdf's but its not clear which one has the measuring device, sounds like this could be useful. Can you advise which etch is needed and where to get it from.
Thanks.
Ray

[grovenor-2685]

The measuring device comes with his sprung w-irons, pic shows one example, the small fret has 4 washers that are to be used to adjust the position of the bearings in the carrier, the border of the small fret has the measuring triangles labelled 1,2 and 3.
Masokit purchase info is on his website. http://www.scalefour.org/masokits/index.html

W-iron.png

Keith
PS Email me your address and I can post you one.

[Ian Everett]

I must have spent some 40% of my modelling time searching for small objects on the floor below my bench.

The best five minutes of time spent was to stick Velcro pads to each corner of an old apron and two corresponding squares to the underside of my bench. When I model I put on the apron and stick its corners to the bench so then most small flying objects land on my apron, not on the floor.

Good luck with the P4 modelling.

Ian

[iak]

Masokit purchase info is on his website. http://www.scalefour.org/masokits/index.html

W-iron.png

Keith

Last years prices are still up, is a new one coming frae Mr Masokits?

[21C141]

I decided to modify the existing pinpoint bearings with a modified drill to make each one about 0.2mm deeper. If it all went wrong I have some new bearings on the way. This seems to be quite successful and i now have a free running sprung compensated chassis.

chassis.JPG

I now need to buy some guages, set the B2B and build some track to test it on.
I've just read the thread 'What Back to Backs are you using'. At least three different measurements and talk of EM profile wheels.
All a bit confusing for a beginner.
Can somebody advise me on the correct set(s) of gauges I need to set the B2B and build some pointwork, and where to get them from.

Ray.

[Tim V]

Given several different modellers, you'll get several different answers

If you look in the standards, the BtoB is 17.67 - 17.87mm. The higher end makes the stock "stiffer" on the track and particularly around corners - meaning larger radii the wider the BtoB.

The crucial thing to note is to have one gauge and use that one only. Don't be tempted to have two - as that will lead to confusion. Pro-tem, you can use a vernier till you get one.

I can also recommend without hesitation (repetition or deviation) the Tony Sissons gravity gauge.

[andrew jukes]

Sorry, Tim, but that's not quite right.

The P4 standards stipulate a B-to-B in the range 17.67mm - 17.75mm.
The Society's recommendation is to work at the upper end of the range and I believe Scalefour Stores gauges are 17.75mm.
Bernard Weller always insisted the correct P4 standard to be 17.67mm and 'old Exactoscale' gauges were this size.
P4 gauges sold by Exactoscale since 2004 have been 17.75mm

Exact scaling of the prototype gives 17.87mm and Ray Hammond supplied gauges to this dimension when suggesting what are now often known as S4 standards.
These standards require some tightening of point and crossing clearances compared with 'proper' P4.
A fair number of modellers work to the tighter standards but some of them use a B-to-B of 17.82mm (rather like under-gauge track, over-gauge B-to-B wheelsets are bad news and 17.82mm reduces the risk of this).
Exactoscale supply S4 gauges measuring 17.87mm and have (to special order) supplied gauges measuring 17.82mm.

It's unclear at this stage which B-to-B gauges will be available from C&L.

On radii, wider B-to-Bs make gauge widening more important. If an extra 0.2mm on B-to-B is offset by an extra 0.2mm gauge widening on tight curves, then there would be no difference in the minimum radius allowable.

Hope that's clearer

Regards

Andrew Jukes

[Tim V]

Sorry, Andrew is right

Just measured my Studiolith BtoB, 17.69mm

[Philip Hall]

I prefer the lower end of the range, and my two gauges are 17.69 like Tim's. All are very old indeed; one came from the EMGS, and the other was a Society gauge that I had machined down a touch to 17.7 and which my vernier now tells me is 17.69! This means that a wheelset with an ever so slight wobble will not give trouble, and normally gauge widened curves are possible down to 3 ft or maybe a bit less. If you have larger radii this is not so important, but I still prefer that little bit extra play between the railheads.

Philip

[21C141]

The only B2B gauge I can find on the Scalefour shop is
290 Brook Smith wheel back-to-back gauge, boxed £5.20

No indication as to what measurement this is.

Ray.

[Armchair Modeller]

Alan Gibson does them

http://www.alangibsonworkshop.com/

see page 9 of his catalogue - 17.7mm

[Terry Bendall]

The only B2B gauge I can find on the Scalefour shop is 290 Brook Smith wheel back-to-back gauge, boxed £5.20

Unfortunately from time to time the Stores does have difficulty in getting the various gauges from the manufacturers. The committee has recently identified a new supplier who will hopefully be able to maintain a more regular supply.

Terry Bendall

[21C141]

Thanks for the information on gauges. I needed to order some wheels from Alan Gibson Workshop so added the B2B and track gauges as well as he had all of them in stock.
(Arrived next day- excellent service)

Next on the list is to look at couplings. I like the simplicity and functionality of Kadee's on my 00 stock but they do look a bit clunky, will investigate the Alan Jackson couplings as the wagon already has a mounting for these.

Ray.