Small End Bushes.txt
I copy my operation sheet for your general interest 
Small End 
Phosphor Bronze from EMAM is 27 OD x 12 bore as A4358 
rough to 21mm od x 67 lg x 19/32 drill bore but watch that rough bore is true. 
This blank makes two bushes. Hold in 21mm collet to produce first bush, hold on 
first bush to make second bush, then part off, face and chamfer. 
check internal bore as this is always marginal on boring 
Nom bore in rod 0.8125" 
Hone out to give 85% clean up 
Turn bronze bush blank +0.0015 / 0.0020" OD 
Bronze bush rough bore 0.593" = 19/32" drill 
Length = Rod width + 1.4mm 
Chamfer ends + bores 
Turn lead Rod bore - 0.0005" x 1.5mm 
Push in rod 
Mill cutout + ( side oil reliefs for racing) 
Drill + Tap 2BA for security screw (Racing) 
Loctite in 2BA brass cheese head screw flush to inside of bush blank (Racing) 
Bore to 0.6245" dia on jig to correct centre distance 
Internal oil grooves on racing engines by hand.(Racing) 
Hone to loose SF on gudgeon pin 0.6262 / 0.6265" dia 
Cut off brass screw (Racing) 
I do realise that my methods are perhaps more "particular" than normal, but I 
have made many machines for car factories and note the tolerances specified. The
reliability of Japanese products is, to a large extent, a result of accuracy of 
manufacture. 
I am not looking for work and if you do not have the facilities, perhaps a local
engineering shop or good model engineer can help. 
Whatever you do, I do urge you to be sure that you have accuracy within two thou
in parallel and twist. I aim for one thou. 
I would strongly recommend that you do not resort to the trick of putting in the
hole and then bending and twisting the rod till it seems to have alignment. The 
rod usually "Unwinds" in service and reverts to its unstressed attitude. A rod 
that has been running will have settled into its natural attitude and will not 
move again in normal use. It therefore follows that the hole should be put in 
correctly first time. 
An engine with rods in good alignment will give a good service life. 
Alfred Scott knew exactly what he was talking about when he chose the logo "Made
to limit gauge" Of all the components in this deceptively simple engine, the rod
little end to big end alignment is by far the most crucial. 
Kindest Regards and Happy Christmas 
Roger Moss
_________________
Rebuilding and upgrading of Scott and Silk power and transmission units. New 
enhanced replica Scott engines. Special manufacture Scott technical info at our 
website 
Moss Engineering 
			
		 
	
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