[SEL] remetaling brass bearings LONG

[Cam grundy]

Hi Russ, You done well Mate, a very good job. Cam.
----- Original Message ----- 
From: "Russell Gilbert" <russell at ncable.com.au>
To: "SEL" <sel at lists.stationary-engine.com>
Sent: Wednesday, June 13, 2007 9:50 AM
Subject: [SEL] remetaling brass bearings LONG


> Howdy folks; some time back I posed the question of just simply 
> building up the brass bearings for my graham with white metal (like 
> building up with solder) instead of making whole new brass bearings. 
> These are quite large bearings and would be quite expensive to 
> reproduce in brass/bronze. With very little ware really it seemed 
> like an option to just fill/coat the bearings with about a 1 to 2mm 
> thickness if white metal and machine them to the correct thickness 
> and replace etc. Well this has now been done and I have to say I'm 
> very pleased with the results.   ......................................
> ......................... HOWEVER!
> 
> There is no such thing as simple!  from the start. On the firing 
> stroke of the engine one could see a "jump" (if you like) in the 
> crank and flywheel on the side shaft side of the engine when running. 
> This made me check the bearings out to find that on the side shaft 
> side, one could quite easily stick a credit card into the gap found 
> between the top eage of the bottom bearing and crank shaft.  When I 
> removed the bearing cap and top bearing from the opposite side all 
> looked pretty good.  So time to remove the bearings. When cleaned up 
> I could see where a distinctive ware mark in the troublesome bearing 
> (bottom half) had been made. So this area was to get a little more 
> white metal than the rest. The other 3 bearing peices looked pretty 
> good so off to dads place for the big white metal soldering job to be 
> done. I left the bearing with dad as I had to work etc. Anyway dad 
> called to let me know the job went pretty good. He had a little bit 
> of mucking about to get the white metal to stick to the brass; a 
> little more heat and soldering flux got it done. The soldering iron 
> hot and some extra heat to the bearing and all looked like it was 
> going well. A nice looking coating of white metal had gone on the 
> bearings apart from one which had a slight crusty apearence to it 
> which we think is from getting just a little too hot.
> this link is to show a pic of what they now looked like :
> http://home-and-garden.webshots.com/photo/2621978930036399874BmBbHr
> 
> Well being more than happy at this point I took my bearings around to 
> a mates place for machining. We fixed the bearings together with hose 
> clamps and placed into the lathe and used a michrometer to get them 
> centred best we could. All going well so started to machine 
> them.  This was pretty easy; however it was a bit of a shock really 
> to see that there was simply just not enough white metal in there to 
> machine out.
> This link you can see clean white metal and plenty of pitting where 
> it is shallow:
> http://home-and-garden.webshots.com/photo/2530864950036399874qhfQqN
> 
> This next link shows the first bearing (side shaft side) after 
> machining. The top section come up pretty well but the bottom half is 
> in need of the soldering doctor once again.
> http://home-and-garden.webshots.com/photo/2556790590036399874vdJrao
> 
> Well to the next side; it was not until know that I had even pick up 
> the fact that when these two bits were placed together they were not 
> anywhere near close to being round! There didn't seem to be any cause 
> for alarm before removing them so I never studdied them before all 
> this work started. Well I recon this was the main cause for the ware 
> in the other side.  Two problems! Firstly at some stage the top shell 
> has had a huge amount of machining done to the sides of the bearing 
> to help bring it down tighter onto the crank shaft! Why would this be 
> needed? Well theres the second problem, you can see in the pics that 
> the bottom of the bottom bearing is worn somewhere in the tune of 
> 3mm. I can tell you now that the coating of white metal dad placed 
> onto these two shells was going to go know where near close enough to 
> fill these holes!
> This pic shows the gap needing to be filled again; the cliper shows 
> the difference in wall thickness from the bottom of the crankshaft 
> bearing to the bottom of the other side!
> http://home-and-garden.webshots.com/photo/2052053360036399874eRzuDB
> In that pic you can also see that the top white metal is not to bad 
> but the bottom was hardly touched during machining
> 
> this next pic shows the shims thickness (4mm) need to get the outside 
> of the bearing round again. You can visually see the difference in 
> wall thickness from the top to the bottom of the bearing.
> http://home-and-garden.webshots.com/photo/2773022770036399874vEZdXM
> 
> So back to dads for the second filling. This was now much harder to 
> do than the first time because of the amount of metal/thickness 
> needed. We had trouble keeping the white metal that we built up 
> enough to stay put as we moved alone to put more in. It would be fair 
> to say that IF! .... at the start I had picked up that the amount of 
> metal need to fill this bearing  was going to be as needed; I would 
> have tried my hand at pouring it in after setting it up with a wooden 
> shaft etc through the middle. Anyway this was not done. We had to go 
> onto using the oxy to concertrate our heat onto a smaller area 
> allowing more control to a smaller working area. No soldering iron 
> but just the stick of white metal melting and poking it into place.
> 
> All looked well so back to gregs place for another machining. Very 
> pleasing result this time around. The bearings do have some minor 
> pitting hear and there but overall very neat. (the pitting will hold 
> oil anyway right  :-o ) The engine is now back together and ready for 
> the Junction Rally in a few weeks time. It runs much smoother now, No 
> jumping of the shaft and know knocking because of this problem 
> also.   So there you go; ............. We learn't something here I 
> recon. Would I do the same thing again? Most deffinately! The result 
> is great. Advice; check the bearing out properly for ware before 
> making the decission to build up or poor the white metal.
> cheers, Russell
> 
> 
> 
> 
> 
> Russell Gilbert
> Sunny Sunraysia
> russell at ncable.com.au
> http://community.webshots.com/user/russellsrelics
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