Sunday, 13 April 2014

Maintenance Update (felt pads, Tyseley, siphon)

Wednesday 9th
Only Bruce and myself (apart from a brief visit from Gil … up until he'd had his cuppa & biscuits!).

Roy Gamlin did call in and bring three more boxes of books for the FLA stall.  He adjourned for a necessary relief, and wasn't seen again!  He may still be stuck in the loo, for all I know!

Bruce is trying to get felt pads made to the exact size for properly lubricating the eccentrics.  Inside the "big ring" is a little hole (arrowed) which sits below a lubrication point.

In the hole should be a sort-of mesh that enables oil to spread over the top of .. a felt pad.  If the pad is too loose, the oil quickly flows past it and runs out; if it is too tight, the oil struggles to get through it (because of it being compressed); similarly, if the felt is too dense it impedes the flow …

It appears that the ideal diameter of the pad is 38mm.  Bruce has been using hole saws to cut pads (there's a row of them in the photo, of different sizes).  He has now almost a perfect fit.  He has obtained felt that is just thick enough (it must lightly rub on the bearing surface), and less dense than that which we had.  Furthermore, Bruce's logic says that a flat gauze does not allow oil to flow sideways across its surface, and hence the oil is not evenly distributed over the pad's surface.  So, using a large washer, Bruce persuaded the gauze to become concave.  Provided you fit this the right way round, it will hold the felt away from the base of the hole such that oil can spread over the surface of the felt.

Apart from painting rail chairs, I also painted Ls, Rs and Fs on the spacers for the safety valves - they need to be replaced in their correct positions.

Saturday 12th
Bruce reports:

" I was on my own for the first part of the day so I started by fettling the metal inserts for the lubrication system on the eccentric straps.

I then started cleaning some of the injector parts.

After tea break Steve arrived and we put the world to rights, we then carried on cleaning more injector parts.

Early afternoon we decided to call it a day, so Steve departed for Winchcombe and I took my homework home where I started making the spacers for the new square section safety valve springs."

Tyseley - David visited last weekend and reported
" I received the usual warm welcome and was plied with coffee (and the offer of biscuits). Bob Meanley was initially busy with another person, but I was soon taken to view progress. They have a special grinding jig for the horn guides, based on the one originally used at Swindon. This was set up through the driving axle guides and has a long bar that goes right through to ensure squareness across the frame. A similar bar is secured through the intermediate driving guides in readiness. The driving guides had been partially ground and they reported that they were not only tapered from top to bottom, but were also not square across the frames. The aim is to remove the minimum of material to ensure parallelism and squareness in all planes. When complete each axle box will be machined to suit its corresponding horn guide.

A problem will arise when grinding the right hand intermediate horn guide, in that the step will be in the way. This, along with the vacuum pump, will need to be removed. They suggested that it is reattached with fitted bolts, as it would have to be removed again should a future regrind be needed. The bolts will be fitted in stages, some being fitted while some rivets remain in place, to ensure the true position is not lost. It was interesting to note, by the presence of rivet head witness marks on the running board, that at some point the step has been moved back about an inch.

The gunmetal castings for the bearings have been obtained and six are machined with the white metal added. See the photo (of six of them) and one which shows the serrated edge, which helps to key in the white metal. They now just need to be machined to suit each individual axle journal. The remaining two are only partially machined."

Siphon van
I have had an email from Colin concerning the projected contents of the van when its overhaul is complete.  Briefly, I believe the plan is to have one half kitted out as a fruit/milk van, and the other end as a hospital van.  This covers the two intended uses of the siphon van at the date of construction.

Therefore, we are on the look-out for:
1) old-style fruit/veg boxes;
2) milk churns
3) two dummies (manikins) that can be dressed up as wounded soldiers.
4) wartime-style bed covers (khaki blanket, etc.) and mattress (palliasse)

Can anyone help in this regard, please? 


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