Finescaling a Farish Ivatt 2-6-0

[Nig H]

Here are some pics showing progress to date.

 

This pic shows the underside of the footplate with the hole around the base of the water scoop, and the water scoop after removing the remains of its base. The scoop needs to be removed to accommodate the etched chassis.

 

 

 

This shows the drawbar after shortening the pick-up wires, and bending them inwards slightly. Below is the etched chassis. I have made a slot and a cutout in the middle spacer to fit the scoop.

 

 

Nig H

Edited January 17, 2014 by Nig H

[Nig H]

Hello,

 

Here are more pics showing some stages in assembly, and the basically finished chassis. I decided to retain some of the GF valve gear as it seemed easier to use some of the best bits such as the crosshead, lifting link and expansion link, but I'll be interested to hear what people think about the results. I'm tempted to etch the expansion link and eccentric rod.

 

The tender base and underside with etched chassis.

 

 

The Assoc frame bearings soldered inside the GF bearings.

 

Muff reduced to about 4mm length.

 

The vave gear with some etched replacement parts attached.

 

The GF chassis with a finescale wheelset inserted.

 

Three pics showing valve gear attached. It runs OK except that the R/H expansion link catches on the back of the motion bracket, so I need to move the return crank back a bit.

 

 

Nig H

[65179]

Hello,

 

Here are more pics showing some stages in assembly, and the basically finished chassis. I decided to retain some of the GF valve gear as it seemed easier to use some of the best bits such as the crosshead, lifting link and expansion link, but I'll be interested to hear what people think about the results. I'm tempted to etch the expansion link and eccentric rod.

 

Three pics showing valve gear attached. It runs OK except that the R/H expansion link catches on the back of the motion bracket, so I need to move the return crank back a bit.

 

Hi Nigel,

 

It and the WD are looking good.  If it was me I'd go ahead and do the expansion link and the eccentric rod as well, but then I like to make things hard for myself!  The replacement parts have noticeably finer fixings to adjacent bits of gear and really improve the look of what is already a rather nice model.  

 

Looking forward to having a go at this on mine!

 

Does this have the same bearing slop issues as the WD?

 

Simon 

[-missy-]

That is really useful, thank you Nigel. It looks like Farish have finally made a chassis which isnt too much of a pain to convert, fingers crossed it continues.

 

You work still amazes me, please keep on posting...

 

M

[Nig H]

Having paused for breath and looked again at the results produced, I will look at replacing the GF expansion link, eccentric rod, and radius rod, and improving the etched combination lever. I'll see if the Dapol Ivatt chasis etch bits are close enough to attempt a test replacement, then amend the artwork for the GF Ivatt. There doesn't appear to be as much slop in the bearings on the Ivatt compared with the WD.

 

Nig H

[queensquare]

Looking excellent Nigel. Do the Association frame bearings need turning down or are they a direct fit into the Farish bushes?

 

If the Farish bushes are standard across the range and if the bushes need turning (lots of 'ifs' I know) then I would suggest that bearings to fit the Farish bushes would be a really useful addition to the Association range.

 

Jerry

[-missy-]

There doesn't appear to be as much slop in the bearings on the Ivatt compared with the WD.

 

Nig H

 

Hello.

 

I wonder if that has anything to do with the wheelbase? Obviously the WD has alot more driving wheels that the Ivatt!

 

As Jerry said, if this becommes common place with Farish it will be worth the 2mmSA stocking some sort of modified bearing.

 

M.

[justin1985]

I love the solution of the Association bearing inside the GF bearing. They do look like standard parts on recent models - the J39 has very similar (presumably identical) ones, which cause the problem of being too short when used with turned down original wheelsets at 2mm b2b. I'm trying a washer arrangement with that at the moment, but if that doesn't work out this looks the perfect solution using association wheels but not needing too much chassis hacking!

[DavidLong]

I suspect that Bachmann, unlike Dapol, will stick to a standard solution where they find that it works. Anyone taken a Fairburn apart yet? The Jinty and 4F should be interesting if they use the same system as they don't have the encumbrance of outside valve gear.

 

David

[Nigelcliffe]

What is the I/D of the Farish bearing ?    It might be possible to produce wheels with a stepped axle, fat enough near the ends for the Farish bearing, and thinner in the middle for a normal muff.     (Just kicking ideas around rather than jumping down the "make a new bearing part" route ).

 

-  Nigel

[queensquare]

Not being involved with wheel production I don't know but wouldn't different size bearings be less work than different axles and presumably a modified method of assembly. Different bearings also means that wheels from stock could used.

 

Jerry

[2mm Andy]

Being able to turn down an existing wheel casting would likely be cheaper than getting new bearings produced. I suppose it depends on the diameter needed and whether there is enough meat on the current raw castings to do this. The assembly method shouldn't differ much.

 

The problem with having new bearings made is the quantity needed to get get a sensible unit price, even from friendly CNC machinists.

 

Andy

[Nigelcliffe]

Being able to turn down an existing wheel casting would likely be cheaper than getting new bearings produced. I suppose it depends on the diameter needed and whether there is enough meat on the current raw castings to do this. The assembly method shouldn't differ much.

 

The problem with having new bearings made is the quantity needed to get get a sensible unit price, even from friendly CNC machinists.

 

Andy

 

Correct, hence my question. 

  

I know a fair bit about our current wheel production methods, and am working on ways to improve loco wheels. 

 

 

- Nigel

[queensquare]

Being able to turn down an existing wheel casting would likely be cheaper than getting new bearings produced. I suppose it depends on the diameter needed and whether there is enough meat on the current raw castings to do this. The assembly method shouldn't differ much.

 

The problem with having new bearings made is the quantity needed to get get a sensible unit price, even from friendly CNC machinists.

 

Andy

 

That makes sense, see told I didn't know what I was on about

 

cheers Jerry

[justin1985]

What is the I/D of the Farish bearing ?    It might be possible to produce wheels with a stepped axle, fat enough near the ends for the Farish bearing, and thinner in the middle for a normal muff.     (Just kicking ideas around rather than jumping down the "make a new bearing part" route ).

 

-  Nigel

 

Presuming its the same as the J39, its 2.9mm, or rather the axle is, so probably fractionally more (I don't have it to hand right now). 

 

I'd be very surprised if this would work, as the Farish frames and therefore bearing locations are so narrow. The bearings are certainly much closer together than a conventional 2mm chassis side frames are, so the wheels would need a good few mm of shoulder to work - surely making them not compatible with normal chassis construction. 

 

I think actually having a shouldered bearing fitted from the outside, that also that adds about 0.5mm on each side to the outside of the bearing would be desirable to cut down the excessive sideplay that results on the J39 with wheels to 2mm standard back to back.

 

Justin

[2mm Andy]

Correct, hence my question. 

  

I know a fair bit about our current wheel production methods, and am working on ways to improve loco wheels. 

 

 

- Nigel

 

Sorry, I should have made it clearer that my reply was aimed at Jerry's question. 

 

Andy

[-missy-]

It might be possible to produce wheels with a stepped axle, fat enough near the ends for the Farish bearing, and thinner in the middle for a normal muff.     (Just kicking ideas around rather than jumping down the "make a new bearing part" route ).

 

-  Nigel

 

Hi.

 

The only problem I can see with that is the 2mmSA might potentially end up with a large range of wheels to suit each locomotive type instead of a single 'one size fits all' bearing.

 

M

[Wyvern]

Hi Nigel,

 

This certainly looks like a very promising route for an easier finescale conversion.   With regards to your bearings, have you turned off the bearing flange in order to recess the association bearing?  

 

Guy

[Izzy]

Do I take it that the mention of bearing slop infers that the bearings are a loose fit in the chassis slots rather than that the Farish wheels are a loose fit in the bearings? 

 

Izzy

[Nig H]

Hi Nigel,

 

This certainly looks like a very promising route for an easier finescale conversion.   With regards to your bearings, have you turned off the bearing flange in order to recess the association bearing?  

 

Guy

Hello Guy (and others),

 

I measured the Farish axles at the bearings location as 2.9mm. I soldered the Assoc bearings onto a length of 1.5mm rod, put that in my lathe, then turned the outer flanges down until a GF bearing just slid over all of them. It doesn't take long to do.

 

 

Do I take it that the mention of bearing slop infers that the bearings are a loose fit in the chassis slots rather than that the Farish wheels are a loose fit in the bearings? 

 

Izzy

I don't know about Farish wheels in their bearings, but I was referring to GF bearings being a loose fit in the GF chassis slots.

 

 

Regards,

 

Nig H

[Nig H]

Here are some pics with the revised valve gear assembled on the left hand side.

 

 

 

 

I'll try to thin down  the combination lever a bit, but its getting to the limits possible with etching while retaining some strength, and having to be bent out then down to clear the slide bars and crosshead.

 

I think its worth mentioning that there is a fair bit of fiddly work involved in finescaling this and the WD chassis, especially the valve gear. You also need to handle the loco and tender bodies carefully and try not to bash anything. I intend to provide details of all the work involved as part of the instructions for the kits.

 

Nig H

[DavidLong]

That looks excellent, Nigel. I'll look forward to seeing it 'in the metal' at one of the Thursday meetings!  It'll be just down to me as to how much of a b******s I can make of it  I think that I'll deal with the 0-4-2T first to get some false confidence up!

 

David

[queensquare]

Here are some pics with the revised valve gear assembled on the left hand side.

 

Ivatt chassis #9.jpg

 

Ivatt chassis #10.jpg

 

Ivatt chassis #8.jpg

 

I'll try to thin down  the combination lever a bit, but its getting to the limits possible with etching while retaining some strength, and having to be bent out then down to clear the slide bars and crosshead.

 

I think its worth mentioning that there is a fair bit of fiddly work involved in finescaling this and the WD chassis, especially the valve gear. You also need to handle the loco and tender bodies carefully and try not to bash anything. I intend to provide details of all the work involved as part of the instructions for the kits.

 

Nig H

 

Thats a massive improvement Nigel.

 

Those motors really do look nice. One of Bachmann's senior reps lives just up the road from me and I've tried tapping him up for spares but no joy yet :-(

 

Jerry

[Donw]

Being able to turn down an existing wheel casting would likely be cheaper than getting new bearings produced. I suppose it depends on the diameter needed and whether there is enough meat on the current raw castings to do this. The assembly method shouldn't differ much.

 

The problem with having new bearings made is the quantity needed to get get a sensible unit price, even from friendly CNC machinists.

 

Andy

I am not sure I follow this new bearings would be one item to stock whereas special wheels sets in different sizes would be more of a problem. I do understand the quantity/price issue.

Don

[2mm Andy]

I am not sure I follow this new bearings would be one item to stock whereas special wheels sets in different sizes would be more of a problem. I do understand the quantity/price issue.

Don

 

The thought was that if the existing wheel castings can be machined to match the farish bearings then there would be no new products required, merely a different way of assembling existing components. Yes, it would be more shop stock, but from components already in store (and most likely already paid for). The downside would be that it would probably put more pressure on our volunteers who assemble and quality check the current range of loco wheels.

 

My personal view is that replacement bearings would be the neatest way to go. It just relies on Bachmann/Farish sticking with this chassis design for their new models - not a certainty by any means!

 

Andy

Edited January 31, 2014 by 2mm Andy