Thursday, 18 March 2010

More on wheels.

If only I could drop everything, which includes eating, sleeping etc.
The long awaited etches arrived today so the next month of spare time will be spent on wheels, a boring situation for most except those with a positive interest. No pictures today, but then there is little to show at present.
I have had made 15" x 48 spoke etches primarily for the Healey I am working on, but also for the MGAs and Lotus Elite which lurk in the cupboard. 18" x 60 spoke wheels are primarily for 30's Astons, but suit others like the SS100. 19" x 60 three row Alfa Romeo wheels are for a future project, whilst the etch sheets include an experimental section devoted to cross laced wheels, 14" x 60 spoke for MGBs and 15" 72 spoke for Jag, Cobra etc. Etches have been made in brass and stainless steel.
Initial work will be involved with making forming tools. There are those who simply want wire wheels, no accuracy required, but since half of the cars I have owned have been so equipped, I am used to looking at items of the correct form. Yes, slot car wheels are small, but fussy folk like me need things to be right. Thus dished spokes are essential.
The greatest worry has been the possibility of fractures of the etches when formed into the conical shape, though happily a jury rigged press tool has formed a 15" wheel without fractures, this tool being made to modify the spokes from their original flat form to an angle of about 15 degrees. A separate tool will be needed for each etch type.
Each tool consists of 3 main parts (in steel). A male and female former, together with a clamping ring to keep the outer ring flat, as its' natural tendancy is to buckle when the spokes are being stretched. The ring is held by six clamping screws, whilst the two formers are aligned by a spindle which also centralising the etch itself.
The experimental department has already been fiddled with, with a pair of 14" etches having been 'played with'. With a simple wheel, where perhaps spokes from inner and outer parts of the hub both anchor at the side of the rim, the spoke angles are typically (for the 15") 5 degres for inner and 15 degrees for outer. If the spokes actually cross, the angle will be increased, thus the MGB wheels will be at the most extreme angles used. With the cross laced wheels however, this is no great problem. I am confident that the etch from inner hub to outer rim will form OK, with the clamping ring playing its part, whilst the etch from hub outer to the centre of the rim has no outer rim and is to be threaded through the other spoke layer. It works! Unfortunately I feel it would be wise to make a former tool for this etch as well....
If time permits, a few pictures tomorrow...

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