Five Cylinder Radial With Ohc

[BRIAN]

Hi Ken.
I ordered the blank thick,because I was worried about holding it and thought that I may have to drill into it.,we will see.
When I have it on the face plate it will be reduced to 16mm thick then it will form part of the jig to machine the case. After that it will be reduced to 10mm. and the seating's for the crank bearing also the bearings and pockets for the intermediate gears, On the inside it will be relived to reduce weight.
It also allows the crank to be fitted.
You can get an idea of it's importance on this ghosted drawing,
This may take a while.
Brian.

 

[BRIAN]

Next stage.
The blank is now bored to take the 12mm spigot that I have on both 2 and 3 morse tapers so I can center on the lathe and on my rotary table.



Moving on to the lathe the blank is mounted onto the spigot by a draw bolt keeping it hard up to the face plate no need for any other retainers
it was faced and reduced so it will now fit in my 4 jaw chuck for the next part of the work.




Brian.

 

[wrmiller]

I came up with the idea of a mt taper blank bored to take a .5" (12mm?) insert with differing diameters on the other end of the insert to center round work on my little 6" rotary table. Glad to see someone already beat me to it!

 

[BRIAN]

Hi Bill
I have built up a selection of different spigots over time , for me the most important part is the thread in the centre to take a draw bar
it's saved my bacon on more than one occasion.
Brian.

 

[rwm]

Is a spigot the same as a mandrel?
R

 

[BRIAN]

Thank you for querying the use of the word spigot as against mandrel for a method of location.
I had to think back as to it's origins , It was certainly a word my father would have used for short peg or location, also a cork or bung.
My wife being Scottish uses the word for a tap.
So it was back to the dictionary to see it's real meaning and it turns out all of these are correct. so you are probably right that mandrel
would be the more correct word. Dad would probably have said, yes you are using the spigot as a mandrel, but as he passed away a long time ago and I am 76
I think it's just a ancient memory,
Thanks for the trip down memory lane. Brian.

 

[BRIAN]

Now having centred the work in the 4 jaw I am able to reduce the diameter to fit the crankcase jig .
This jig is the size of all the registers on the casing and fits both male and female registers. see post #10.
all work will now be done on this jig





Brian.

 

[BRIAN]

The blank is now reduced to it's final thickness and fitted on the jig and centred on the mill.
The ten holes that take the screws that fix the bulkhead in the case are drilled, also the five holes for the screws that hold the bulkhead to the jig when the case is finished these holes will be the lube feed to the countershaft bearings.







Brian.

 

[BRIAN]

Now we move on to the case. 5" is to large for my chucks so a simmiler job to the bulkhead , attach it to the rotary table with a draw bolt and carefully mill the top flat.


Then mill out a slot so it will fit onto the 80mm four jaw. the slot must be deeper than the jaws so I have clearance when I bore from the other side.



Mount the blank on the four jaw holding outwards.




Then true up ready to do the important bit..It's awkward to get around the outside so I used a boring bar upside down and run the lathe in reverse.



All trimmed up ready to go.



Slowly slowly Brian.

 

[BRIAN]

OK now for the first of the serious stuff. firstly the end has to be bored out 8mm deep to receive 10mm thick blank and a 70mm diameter hole

When I get the screws I will fix the Bulkhead in place This will leave a 2mm register protruding.



This then fits the jig that will allow me to to do all the remaining work on the crank case.



When the case is finished the bulkhead will be reworked to fit further into the casing and support the rear main bearing and the five accessory shaft bearings

you can see its position in this drawing.




I cannot progress further until the screws arrive, but as this was to be my winters work I have only just ordered them so it may be a while.


Brian.