WW1 Thornycroft restoration

You are going to want one of these for machining the inner radius:

https://picasaweb.google.com/lh/photo/lorjlRbUi9B2VQy0Cd0KcNMTjNZETYmyPJy0liipFm0?feat=directlink

(already used for the same job on Jez)

The alternative, of course, is a big lathe and a fixture on a faceplate, but the horizontal borer is a much simpler setup as you have 3 degrees of freedom rather than just the one.

Unfortunately Andy that link seems to produce all 283 photos that you have on Picasa. I didn't see one that showed what I think you intended :cry:. sorry !

David

You are going to want one of these for machining the inner radius:

https://picasaweb.google.com/lh/photo/lorjlRbUi9B2VQy0Cd0KcNMTjNZETYmyPJy0liipFm0?feat=directlink

(already used for the same job on Jez)

Unfortunately, I don't have ready access to a borer but my friend Adrian does have this large lathe. I must go and speak nicely with him........

Steve

Mug restoration.

Thanks Arjan. I will remember that for next time. The bits are landfill somewhere by now......

Steve

Unfortunately, I don't have ready access to a borer but my friend Adrian does have this large lathe. I must go and speak nicely with him........

You are more than welcome to use ours, the only problem is that it is in Yorkshire, and you aren't.

Thanks Andy. You are very kind. It is always good to have another string to the bow!

Steve :-)

Too many distractions at the Devon end have slowed progress up down there but all six shackle pins for the back springs have now reached the same stage. All that has to be done now is to machine spanner flats, drill cross holes for lubrication and holes for feathers and split pins.

Too many distractions at the Devon end have slowed progress up down there but all six shackle pins for the back springs have now reached the same stage. All that has to be done now is to machine spanner flats, drill cross holes for lubrication and holes for feathers and split pins.

would you not case harden these then?...

They are machined out of EN8 - we used the same material on our previous restorations and did not case-harden any of them. As Steve has commented - they are essentially consumable items and we do not see ourselves wearing them out "in any case" (boom-boom!)

Tony

We were fortunate to be able to salvage two king pins when stripping down our various front axles.

However, both were a bit worn, particularly at the bottom end. As we need to replace the bushes in the stub axles anyway, we felt that it was worth trying to salvage the pins. Steve put a file across one and found that they were not very hard so he decided to skim the bearing surfaces. They didn’t have centres so he started by screwing 1/4”BSP plugs into the ends and then setting them up in the fixed steady to drill them. He arranged that the steady ran on the part of the pin which had been in the axle end and was therefore unworn.

In the last picture, it is very hard to see but Steve has used a trick to improve the accuracy of the centre. He has arranged that the cutting edges of the slocumb drill are arranged horizontally and has then steadied them by holding some rod in the toolpost and gently pushing the side of the drill to stop it wandering. You can’t see it very well because the rod he has used is the reverse end of a boring bar and is black. It does however, work very well indeed as long as you treat the drill very gently.

He set the pin between the new centres and skimmed the bearing surface.

He then reversed it and did the opposite end, skimming only the bearing surface.

Whilst doing all of this, he found why the bottom end was worn so much more than the top. The grease hole did not go right through the pin so only the top was lubricated! To remedy this, he set the pin up once again and drilled through from both ends using a long-series drill. As you can see, he stretched the capacity of the poor old Myford once again! That done, the grease grooves were re-dressed using the Dremel grinder and the pins were finally complete and ready to fit back in the axle.

Nice work as usual chaps, and thanks for the steadying trick, I had that same drill wandering problem the other day..:thumbsup:

He then reversed it and did the opposite end, skimming only the bearing surface.

 

Whilst doing all of this, he found why the bottom end was worn so much more than the top. The grease hole did not go right through the pin so only the top was lubricated! To remedy this, he set the pin up once again and drilled through from both ends using a long-series drill. As you can see, he stretched the capacity of the poor old Myford once again! That done, the grease grooves were re-dressed using the Dremel grinder and the pins were finally complete and ready to fit back in the axle.

i suppose an alternative (on a lathe with a bigger headstock bore) would have been to use a roller box....

True. A bigger lathe would have made life a lot easier. However, the joy of this game is 'This is the equipment I have got. How am I going to do it?'. There is great satisfaction in overcoming these challenges!

Steve

That is one half, the other half is keeping the other half happy

would there be a career in making parts for people?

It would take time before i hit your level, but i can set the bar higher as i go.

The Shackle Pins for the rear springs have now been completed and the springs can now be hung. The final jobs done on them were machining spanner flats, drilling the cross holes for lubrication, for feathers and for split pins.

A trial fit of the completed shackle pin in the bracket in the chassis.

Steve has just finished off the front wheels by clearing out the greaser holes and then honing the bores. The bearing surfaces had been satisfactorily re-machined on Adrian’s big lathe but the surface finish was a bit rough so Steve decided to hone them using a hone in his pistol drill.

. This is a very slow process so after twenty minutes whilst the bore was a lot better, it was still not a glass smooth finish. However, it was an improvement and Steve deemed this to be satisfactory. He then re-cut the grease grooves using the Dremel grinder. The wheels are now ready for the tyres to be fitted and final painting to be carried out.

I'm intrigued by the wheel bearing arrangement; I would have expected the bronze bush to be a press fit in the wheel and to be free to turn on the stub axle, however the presence of a grease groove in the wheel suggests that the opposite is true.

Is this the case, or will the bush be free to turn on the stub axle as well?

Superb work as ever; I am always looking forward to the next instalment!

The honing tools sometimes leave quite rough surface. Put folded fine sandpaper around the honing tool, wrap it in sandpaper cylinder. Folded, with sand-side inside and outside, to make sure that the honing tool will not rotate inside the sandpaper cylinder, but will rotate together with it. Pour diesel for lubrication and do that sandpaper-honing. The result will be very good surface, much better that just the ordinary honing. Same can be done on the engine cylinders, when the honing leaves quite rough surface.

The bronze bushes are fully floating in the wheel and on the axle, both front and rear. This was part of the subvention scheme specification so that they would be interchangeable between manufacturers. The Dennis is actually running on at least one Thornycroft bush as it had least wear!

Thanks for the tip, Ted. I will keep that one in mind.

Steve

Here is an alternative home made tool for getting a fine polish on a bore, it can also be used as a glaze buster in cylinders.

I find it works well using 120g emery with paraffin for the final polish.

John

Another good tip. Thanks John!

Steve

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Here is an alternative home made tool for getting a fine polish on a bore, it can also be used as a glaze buster in cylinders.

 

I find it works well using 120g emery with paraffin for the final polish.

 

John

That's what I use for deglazing hydraulic cylinders in work!! Bigger the cylinder diameter the longer the paper in the slot. For deep tubes I use a length of 10mm steel tube in the drill Chuck and a slot in the other end.

Works a treat!!

No changing stones etc, just swap for different grades of paper from rough to smooth, running up and down the bore to create a cross hatch pattern!!