Wheel-setting kit built three cylinder locomotives?

[Nova]

so far from looking online all the quartering jigs and self setting driving wheels (IE Romford self quartering wheels) are made to suite 2 and 4 cylinder locos with a 90 degree crank interval.

this is all well and good for the numerous two cylinder locos that populated the LNER network and indeed the rest of Great Britain, but not so good for setting three cylinder locos, a problem also present in just about every RTR model of a three cylinder loco available

I'm wondering and asking if there are any available jigs or "self setting" wheelsets that will allow cranks to be set at 120 degree intervals.


if not then I can always resort to somehow making my own quartering jig...but that's to be covered in a whole other thread a long way down the line (pun fully intended )

[Phil]

Shouldn't that be a "thirding jig" for 120 degree angles?

[Nova]

Shouldn't that be a "thirding jig" for 120 degree angles?

yes, but I don't think "thirding" is an actual word

[Dave S]

a problem also present in just about every RTR model of a three cylinder loco available

You say it's a problem, whereas I say 120 degrees cranks are an over complication. You can't actually see both sides of the motion at the same time anyway.

Sometimes you have to ask why Romfords and straight quartering is popular.

[Hatfield Shed]

With wheelsets that are a push fit on a round axle, a simple jig like the old Hamblings item only needs a second crankpin locating hole drilling one side to enable the wheels to be located consistently 'thirded'.

Shouldn't that be a "thirding jig" for 120 degree angles?

yes, but I don't think "thirding" is an actual word

Oh but it is, the source of the 'Ridings' of Yorkshire.

[JASd17]

Why does the name Rob Ormiston-Chant come to mind?

John

[billbedford]

a problem also present in just about every RTR model of a three cylinder loco available

You say it's a problem, whereas I say 120 degrees cranks are an over complication. You can't actually see both sides of the motion at the same time anyway.

Sometimes you have to ask why Romfords and straight quartering is popular.

Can't be anything to do with the costs of extra tooling and axles for a minority interest product, can it?

[Pebbles]

There appears to me to be a number of theoretical issues being raised; this being one of them. The Romford wheel, as has been highlighted, is for most individuals the most convenient.

[Hatfield Shed]

Sometimes you have to ask why Romfords and straight quartering is popular.

Can't be anything to do with the costs of extra tooling and axles for a minority interest product, can it?

The extra tooling for RTR press fit on round axle ends is trivial: but quartering is the most tolerant setting if the coupling rods are expected to function in transmitting the drive from the powered wheel to the other coupled wheels. Current OO RTR is made mechanically 'slack', and the assembly will not work if the coupled axles are altered to 'thirded'. A reliable result requires a careful kit build, and don't expect it to run on set track radii either if three or more axles are coupled.

While it is true that the three cylinder drive is in a minority in UK practise, It is a significant minority in that it is the most common multicylinder form and found on many of the most popular locos in model form: most of Doncaster's wide firebox output, ditto Bulleid's, and LMS express passenger 4-6-0 designs.

[Blink Bonny]

Ay up!

It can be done. I had a Mainline Scot that I altered to correct crank settings. Then I ran it double headed with a Mainline rebuilt Patriot and there appeared to be no difference.

I learned from this that sometimes true accuracy can be sacrificed with no real loss of realism. Now, if you are planning to model working conjugated valve gear then correctly set cranks are a must. Gibson wheels or similar present no difficulties but my experience is not to bother.

[Nova]

Ay up!

It can be done. I had a Mainline Scot that I altered to correct crank settings. Then I ran it double headed with a Mainline rebuilt Patriot and there appeared to be no difference.

I learned from this that sometimes true accuracy can be sacrificed with no real loss of realism. Now, if you are planning to model working conjugated valve gear then correctly set cranks are a must. Gibson wheels or similar present no difficulties but my experience is not to bother.

wanting to set the cranks to the right setting is simply a case of "because I can/want to". it's like the problem with the oxford rail cattle wagons having one side wrong (?), you wouldn't see that it's incorrect just from looking at the correct side, but once you know it becomes a little niggle in the mind. for now I can put up with it until I have a layout and workbench on the way to being built, but once I have the tools to correct the matter, I will.

there's also the issue of DCC sound (which I plan to have), when a loco with quartered wheels has the sound of a 3 cylinder loco the exhaust beats never truly match up

[Blink Bonny]

Ay up, Nova!

You hit the nail on the head as to why I did it. To see what happens! It's like compensated chassis. I built a Jinty (Romfords) with a compensated chassis and a Johnson Half Cab with a rigid chassis and P4 profile Gibson wheels*. Despite using code 100 track I found the half cab was by far the better runner. Result? More trials, with Bulleids and 0-4-4Ts. Same thing the rigid chassis run better.

This may be due to my building, I dunno. But I now just build rigid. But I had to try!

*. The wheels had been packed with. OO/EM axles and the profile only became clear when compared to standard wheels.

[billbedford]

If you build frames with one fixed axle that axle will aways follow every dip and lump in the rails. The answer is to fix none of the axle -- or all of them.

[Atlantic 3279]

That's true of course, although the extent to which the loco (or other compensated vehicle with single fixed axle) lurches about on the track depends on how smooth or lumpy your track is and how well the crossing gaps match the wheel profiles. Lay the track properly on the right kind of surface and the behaviour of the stock will be better. Also, the general running qualities of a compensated loco do depend on how carefully it has been built in the first place. When I've built compensated, I've always checked everything, stage by stage as far as possible, not going on to a "next step" that locks the previous result permanently into the characteristics of the vehicle until I'm fully satisfied that things are as they should be.

I'm not sure that single-fixed-axle compensated vehicles will ever be well-at-home on code 100 track with its wide crossing gaps, especially if there code 100 has been adopted to accommodate the all too frequent wide variety of wheel profiles and wheel settings in use.

[Nova]

I'm not sure that single-fixed-axle compensated vehicles will ever be well-at-home on code 100 track with its wide crossing gaps, especially if there code 100 has been adopted to accommodate the all too frequent wide variety of wheel profiles and wheel settings in use.

My test of track laying will be to see if my Heljan garratt, which I've had no problems with so far unlike other people besides maybe derailing on awkward track joints which can be put down more to its sheer size and weight more than any production faults, will make it around a full circuit without jumping the rails on an uneven joint

and I'll be going with code 75, I was going to use code 100...then I saw Peco's lovely bullhead track