Torquay Manor 5 Gauge Axle boxes

[Roy BirchParticipant @roybirch29994]

Hello All

I am trying to make the axleboxes for my Torquay Manor, I am making them as the picture above with the exception that I am using Needle roller bearings for the axle, the problem is that the outside diameter of the bearings is 1 inch and not .750 as the drawing for a split box indicates. This means that the metal left after machining the bore for the bearings and the slots for the coil spring hangers is only 1/32 on the inside of the slots,  Is this enough? if not what are the suggestions to get around this still using my needle bearings and a solid axle box?

 

Kind Regards

Roy

[Dave WoottonParticipant @davewootton]

Hi Roy

You may be better off posting this question on the Model Engineer Proboards forum, it is much more locomotive based than this one, many active loco builders on their with a wealth of experience.

I can’t really help much with your question as I’ve never used needle rollers on axleboxes, the big problem I believe would be keeping ash and grit out. The only time I have seen them used the builders have used cannon axleboxes for that reason. I have two high mileage locomotives ( with plain bearings) and on both the trailing axleboxes have worn excessively due to being directly below the ashpan, and the ash and oil had formed a very effective grinding paste. On one of them I’ve just converted the rear axle to cannon boxes.

On John Baguley’s excellent website there is his build log of Helen Longish which has a description of some experiments he carried out on the needle roller axles for his locomotive. Hoping the above may be of some use.

Dave

[JasonBModerator @jasonb]

Not a loco man and image is too small to see the detail or sizes but 1/32″ does not sound like much. Probably wants a rethink making the space between the horns wider and then you can fit a wider axle box that will have more metal around the bearing.

[Brian Baker 2Participant @brianbaker2]

Greetings Roy, the Torquay Manor design makes a fine model which you will be pleased with.  I would not use needle rollers, which need to run on a hardened axle, having found they break up due to grit & dirt getting in, which mixed with stray lubricating oil which always seems to be about under a loco, make excellent grinding paste.  I would, and do, use plain cast iron axleboxes, or split if you really want to use them, but with a cannon axlebox to try to keep out the muck.

Good luck with your Manor

Regards

Brian B

[duncan webster 1Participant @duncanwebster1]

For light loads you don’t need hardened axles, but you do need to keep the muck out. Have you looked at drawn cup outer races?

[Howard SnowdenParticipant @howardsnowden92695]

Hello Roy. I used needle roller bearings on my 71/4″ 9F. I was fortunate in obtaining needle roller bearings with inner hardened races. I personally would not use needle roller bearings unless they run on hardened inner races. To use roller bearings, i did have to re-design the horn block guides, opening them slightly to provide more material on the inner sides of the axle box, which is the issue you have. I also fitted made cannon box sleeves so the axles runs in a sealed tube filled with grease and fitted oil seals on the outer sides of the axle boxes to ensure dirt does not enter. So to use needle roller or other similar rolling bearings you do need to give a lot of thought to the issues early on. I hope this helps. Good luck. Howard

[duncan webster 1Participant @duncanwebster1]

See this https://modeleng.proboards.com/thread/2248/needle-roller-bearing-axleboxes

rreal experience of needle rollers on unhardened axles. I seem to remember Peter Rich being an advocate, but memory might be wrong

[Roy BirchParticipant @roybirch29994]

Duncan

Many thanks for the link, it did address what I am trying to do as the person had the same issue, my problem is easily solved by just not using needle bearings, a bit by explanation is that the loco was a part build that I got from another Model Engineer which belonged to his friend who had passed away, the loco was intended to be made with working leaf springs, the axlebox for this has the spring hanger lobes on top of the axle box so a needle bearing fits in easily which was the way I got the loco, the axle boxes were too loose so I am making new ones and just assumed that I could reuse the bearings as they were new, at this time it was also suggested to me that it would be far quicker to do coil springs so I went down that path, ground up the cast iron to the plans and then decided to draw an axle box out and that is how I noticed the problem, the problem does not exist if I just use plain cast iron bored boxes or use the bearings and just go for working leaf springs.

Does anyone have any suggestions regarding working springs opposed to coil springs? I do have a 4ft square sheet of the correct Tufnol and the frames are mostly drilled for the working spring hangers.

Also there has been mention of ash and oil forming a grinding paste which could cause wear in the needle bearings but would this not also be the case with plain bores for the axle boxes?

Kind Regards

Roy

[duncan webster 1Participant @duncanwebster1]

You’re going to have to explain why changing from leaf springs to coil changes the bearing arrangement. Leaf springs give a less ‘bouncy’ suspension as they have inherent damping.

[Roy BirchParticipant @roybirch29994]

Hello Duncan

If I go with Needle bearings on leaf springs the axle box for these have the hangers on the bottom of the box, If I go with coil springs then the rod that holds the coil spring is fixed inside the axle box and has to have slots cut into the axle box for fixing according to the plan.

In measurement terms the coil spring axle box is as follows

The box measures 1.562 from top to bottom ex the spring rods

the centre of the bore is .906″ from the bottom

the bore is .750″ for a plain bore but the needle bearings are 1.000″

the slots that hold coil spring hanger are .375″ deep from the bottom

This means that the increased size of the bore to account for the needle bearings comes close to the bottom of the slots for the coil spring hangers

The math is .906″ – half the bore which is now .500 this leaves .406″ the slots for the coil spring hangers is .375″ which when subtracted form .406″ leaves only .031″ of metal around the needle bearing case

The leaf spring axle box is 1.406″ from top to bottom

the bore for the needle bearings is 1.000″

the centre line for the bore is .750″ but this axle box has no slots milled as the hangers are at the bottom.

This time the math is .750″ – .500″ which is half the needle bearing od comes to .250″ leaving about 8 times more steel to support the bearing.

If you read the above this is what I was really asking which is can .031 of steel around a needle bearing support this on a 5 gauge loco, if not then the answer will be to go back to plain bores as that will leave me steel of about .281″ around the axle as the plain bores are only .750″ and not 1.000″ for the needle bearings.

 

Kind Regards

Roy

[duncan webster 1Participant @duncanwebster1]

The suspension pins on Emma Victoria are just screwed into tapped holes in the bottom of the box. You need to have plenty of clearance around the horn keeps to allow box to tilt, but if you waist the pins it is achievable. This would sort your problem I think. 2 BA would be plenty big enough

[Author]

Posts