Class 22 Diesel (next project)

[Ron LadenParticipant @ronladen17547]

Thanks Dave and Ian, I must admit I favour the idea of using a suitable washer/spacer and since my post I have found some PTFE ones which are 0.5mm thick 16mm ID – 28mm OD which is just about the exact size of the face of the olilite shoulder. I think with PTFE which is pretty tough and very low friction they should do the job well and keep things simple.

Ron

[Jeff DaymanParticipant @jeffdayman43397]

Hi Ron,

+1 on Ian SC's suggestion to use two hard shim washers for your application. Personally I would just use two greased steel ones. Reason for not using a plastic one in the stack is that anything soft in there will pick up dust and hold it, lapping away continuously at the harder parts. With occasional use as in your locomotive it may never be an issue but with prolonged use I've seen plastic bushings wear steel shafts 3 mm on dia and plastic washers wear solid steel bushings away by 6 mm. 10 cent plastic parts still looked great – multi hundred dollar steel parts were scrap!

Just food for thought. Good luck!

Edited By Jeff Dayman on 11/06/2019 16:57:06

[Ron LadenParticipant @ronladen17547]

Posted by Jeff Dayman on 11/06/2019 16:56:32:

Hi Ron,

+1 on Ian SC's suggestion to use two hard shim washers for your application. Personally I would just use two greased steel ones. Reason for not using a plastic one in the stack is that anything soft in there will pick up dust and hold it, lapping away continuously at the harder parts. With occasional use as in your locomotive it may never be an issue but with prolonged use I've seen plastic bushings wear steel shafts 3 mm on dia and plastic washers wear solid steel bushings away by 6 mm. 10 cent plastic parts still looked great – multi hundred dollar steel parts were scrap!

Just food for thought. Good luck!

Edited By Jeff Dayman on 11/06/2019 16:57:06

Thats interesting Jeff but why two greased steel shim washers and not just one between the pulley and the oilite bearing..?

Ron

[Jeff DaymanParticipant @jeffdayman43397]

Hi Ron, Why two greased steel shims? just based on experience and some basic tribology theory.

If you had one shim between a rotating pulley hub and a stationary Oilite bushing, in theory if there is side pressure on the shim the shim will rub on the Oilite or the pulley or both, a high wear situation.

If there are two greased shims, in theory one shim may stall on the Oilite or rotate slowly, the other shim may stall on the pulley or rotate slowly, but the main relative rotation will occur between the two greased shims. The grease separates the shims and minimizes the wear and the shims being hard and relatively flat and smooth steel will have low friction coefficient to begin with. This usually will result in low or no wear on pulley or Oilite. It's not a tragedy if after many hours you have to replace the shims for 50 cents or a dollar. You have saved many tens of dollars replacing shims rather than a chewed up pulley and Oilite bush.

Again for occasional use the above theory may not matter much but just offering food for thought based on working on a LOT of machinery over the years, seeing what works best.

All ready to be shot down in flames now by the usual armchair experts!

[Ron LadenParticipant @ronladen17547]

Posted by Jeff Dayman on 12/06/2019 00:00:37:

Hi Ron, Why two greased steel shims? just based on experience and some basic tribology theory.

If you had one shim between a rotating pulley hub and a stationary Oilite bushing, in theory if there is side pressure on the shim the shim will rub on the Oilite or the pulley or both, a high wear situation.

If there are two greased shims, in theory one shim may stall on the Oilite or rotate slowly, the other shim may stall on the pulley or rotate slowly, but the main relative rotation will occur between the two greased shims. The grease separates the shims and minimizes the wear and the shims being hard and relatively flat and smooth steel will have low friction coefficient to begin with. This usually will result in low or no wear on pulley or Oilite. It's not a tragedy if after many hours you have to replace the shims for 50 cents or a dollar. You have saved many tens of dollars replacing shims rather than a chewed up pulley and Oilite bush.

Again for occasional use the above theory may not matter much but just offering food for thought based on working on a LOT of machinery over the years, seeing what works best.

All ready to be shot down in flames now by the usual armchair experts!

Thanks Jeff, that makes sense.

Ron

[Howard LewisParticipant @howardlewis46836]

Have you any shim stock from which you could punch / cut the washers?

And to use Graphite, or MoS2 grease rather than plain Calcium or Lithium grease, to minimise friction?

Howard

[Dave Smith 14Participant @davesmith14]

Ron

On the various grills have you considered getting them either laser cut or etched in either steel or nickel silver. They could be made from two laminated layers one with the grill vents the second and overlay to form the surround.

Dave

[Ron LadenParticipant @ronladen17547]

Posted by Howard Lewis on 12/06/2019 16:28:52:

Have you any shim stock from which you could punch / cut the washers?

And to use Graphite, or MoS2 grease rather than plain Calcium or Lithium grease, to minimise friction?

Howard

Hi Howard,

No I dont have any shim stock and to be honest I am still considering the PTFE shim washers, PTFE is very very low friction and I am just wondering if they will do the job without wearing the alu pulley or the oilite bearing. However from what Jeff explained would PTFE make the situation worse, I dont know.

Ron

[Ron LadenParticipant @ronladen17547]

Posted by Dave Smith 14 on 12/06/2019 17:54:58:

Ron

On the various grills have you considered getting them either laser cut or etched in either steel or nickel silver. They could be made from two laminated layers one with the grill vents the second and overlay to form the surround.

Dave

Dave,

Yes I have considered laser cutting for all the various grill panels, I am very fortunate in having a friend who can get laser cutting done for me FOC so it would seem the obvious way to go.

Ron

[Paul KempParticipant @paulkemp46892]

Ron,

Personally I think you are over thinking the situation between pulley and bearing. Firstly the relative rotational speeds are pretty low as are the loadings. If the shaft is to be a soft (say mild steel) material then using hardened washers is likely to have them cut a groove in the shaft over time! Oilite is a bearing material and no reason to suppose that in this 'thrust' application it will be any less efficient than in the normal radial condition. Many thrust bearings are plain bronze with oil lubrication, oilite is a similar but 'self lubricating' material. Your PTFE washer is probably the kindest solution to shaft, bearing and pulley if you really want to control the axial location of the assembly. Lastly I doubt the loco will travel the distance of London to Edinburgh so whatever you do is unlikely to wear catastrophically.

is the TE on the back burner now?

Paul.

[Ron LadenParticipant @ronladen17547]

Posted by Paul Kemp on 12/06/2019 21:34:26:

Ron,

Personally I think you are over thinking the situation between pulley and bearing. Firstly the relative rotational speeds are pretty low as are the loadings. If the shaft is to be a soft (say mild steel) material then using hardened washers is likely to have them cut a groove in the shaft over time! Oilite is a bearing material and no reason to suppose that in this 'thrust' application it will be any less efficient than in the normal radial condition. Many thrust bearings are plain bronze with oil lubrication, oilite is a similar but 'self lubricating' material. Your PTFE washer is probably the kindest solution to shaft, bearing and pulley if you really want to control the axial location of the assembly. Lastly I doubt the loco will travel the distance of London to Edinburgh so whatever you do is unlikely to wear catastrophically.

is the TE on the back burner now?

Paul.

Thanks Paul, that was my thinking, the loco wont be doing any marathons and the thrust loading wont be heavy so I thought the PTFE option worth a try.

The TE is on the back burner but not forgotten, in fact I spent some time yesterday evening looking at more motor options. I keep going back to an outrunner brushless as a possibility, if used with li-po packs the batteries could be housed within the engine, still giving it some thought.

Ron

[Nick Clarke 3Participant @nickclarke3]

Ron I know you have described your traction engine, but the idea just crossed my mind – why not make it a showman's and have the motor as the dynamo – doing things in reverse so to speak. OK I know it is not prototype practise to move running the dynamo, but the engine look could be made good?

Just a thought – I'll go back to sleep now

Edited By Nick Clarke 3 on 13/06/2019 12:18:08

[Ron LadenParticipant @ronladen17547]

Posted by Nick Clarke 3 on 13/06/2019 12:17:57:

Ron I know you have described your traction engine, but the idea just crossed my mind – why not make it a showman's and have the motor as the dynamo – doing things in reverse so to speak. OK I know it is not prototype practise to move running the dynamo, but the engine look could be made good?

Just a thought – I'll go back to sleep now

Edited By Nick Clarke 3 on 13/06/2019 12:18:08

Hi Nick

That has in fact crossed my mind, whichever way I go the engine drive will sort of be working in reverse i.e. motor driving a geared wheel, the wheel driving gears back to the crank and the crank driving back to the piston. Driving the flywheel/crank from a top front mounted motor (dynamo) I would think quite feasible. What put me off the idea when first I looked at it was the belt drive but now having some experience of poly V belts and pulleys I dont think that an issue.

Thanks for the idea, I will give it some more thought.

Ron

[Ron LadenParticipant @ronladen17547]

Started machining the belt pulleys ready for fitting to the wheels, they need the boss removing, the width reduced to 10mm from 13mm and the bore increased from 8mm to 16mm. I turned up a stepped mandrel to centre the pulley to the wheel, the axle seat for the wheel is 1/2" dia and the main axle diameter where the pulley sits is 5/8" (16mm). I put a small hole in the centre of the mandrel which with a pair of dividers made scribing a PCD for the screw holes dead easy. The mandrel will also come in handy when I screw and fix the pulley to the wheel keeping all centered and aligned ready for fitting to the axle.

Edited By Ron Laden on 16/06/2019 16:06:36

[Ron LadenParticipant @ronladen17547]

There are a good number of Bo Bo British diesel locos and the class 22 is one of them and that is what I set out to build, but I am considering playing my "change my mind card" .

I came across a couple of older Pullman locos which have a bit more interest in the detail and shape of the body and not so often modelled as far as I know but then I found the one below.

Its a class 20 but surely a "showmans engine" in the world of diesel locomotives, not decided but seriously tempted.

[Ron LadenParticipant @ronladen17547]

The 4 axles/wheels are complete with drive pulleys fitted, the pulley wheels are not fixed to the axles yet as I have to slide on the motor mounting plates before fixing.

[Ron LadenParticipant @ronladen17547]

Well the wife is not too impressed with the shiny red class 20 loco. Upon seeing the picture of it she said "oh no its far too ornate, looks like something from a fairground, way over the top" I said, I know thats what I like about it. She said, "stick with the baby warship"

So there you go, thats what the wife thinks of it ….

 

Edited By Ron Laden on 20/06/2019 17:17:35

[Ron LadenParticipant @ronladen17547]

The 8 axle boxes are all machined apart from fitting the axle bearings but I am awaiting a 13mm drill for that job.

Put in the spring mounting holes this morning, drilled the bulk out and then finished with an endmill to leave a square seat for the spring. I must get around to making Jasons vice stop but a quick setup of an angle plate with a low level clamp added did the job.

Edited By Ron Laden on 26/06/2019 08:14:38

[Ron LadenParticipant @ronladen17547]

Sorry double post.

Edited By Ron Laden on 26/06/2019 08:11:20

[Ron LadenParticipant @ronladen17547]

The 1/8" slitting saw arrived, I was looking for a 3mm to fit my R8 / 22mm arbor but struggled to find one. Jason suggested that if I could get away with a 1/8" then ARC had them in stock though the mount hole was 1" and would need to knock up a stepped bush which I did.

The saw is for slotting the axle box spring mounts (8 off) so I set them up this morning using the 4 jaw mounted on the RT. I thought it the best way to hold them with the blade running through between the jaws it worked fine, took no time to do all eight.

Thanks Jason, I would probably still be searching for a 3mm saw at the right price.

[Ron LadenParticipant @ronladen17547]

The basic axlebox and spring mounts are done, they will need 25mm long springs which at their rating gives 3mm compression when all 8 boxes are loaded and a further 6mm of travel when running. I went with those dimensions/figures on the 0-4-0 and it works fine. The bearings are shouldered oilites, 10mm long which matches the length of the stub axles and conveniently leaves a recess for bearing caps which I will turn from aluminium.

[Jeff DaymanParticipant @jeffdayman43397]

Looking good Ron!

[Ron LadenParticipant @ronladen17547]

Thanks Jeff.

Just out of interest or for anyone looking for heavier type compression springs for axle boxes and the like I,ve put up a picture showing what I go with. I use die springs, always buy them from China via Ebay, they are good quality and there is a huge range of sizes. They are cheap as chips always come with free postage and they are usually delivered within 7 days or less.

I dont know if Chinese manufacturers/suppliers always use the same colour code for the different strengths but I,ve had the same colour springs from different suppliers and they were identical. For my use I have rated them as Blue=Medium, Red=Med/Heavy. Green=Heavy and Brown=V. Heavy.

I will probably go with red on the class 22 based on the 0-4-0 working well with 4 red springs and a AUW of 25kgs. The 22 should weigh around 50 kgs but with 8 springs.

 

Edited By Ron Laden on 20/07/2019 09:25:11

Edited By Ron Laden on 20/07/2019 09:26:38

[Thomas StauboParticipant @thomasstaubo12021]

Nice work!

What is the dimensions of the springs you are using?

[Ron LadenParticipant @ronladen17547]

Posted by Thomas Staubo on 20/07/2019 20:55:44:

Nice work!

What is the dimensions of the springs you are using?

8mm diameter x 25mm long.

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