Darjeeling Hole sizes (to Tap or not to Tap)

[SteambuffParticipant @steambuff]

[SteambuffParticipant @steambuff]

Silly question, I have just received my water cut frames from Blackgates for the Darjeeling ‘B’ Class.

I have marked the frames out and are about to start drilling.

 

I just want to make sure that I am drilling the correct size.

 

Those marked say Dia 1/4 etc are obvious …

 

But there are some that are marked say 8BA (Does this mean I have to Tap it 8BA?) – The part that fixes to it says 8BA Clearance. (ie. Oil boxes)

 

So do I assume that everywhere it says 8BA, I drill and tap the hole for a 8BA bolt?

 

Dave

 

 

[Terry LaneParticipant @terrylane]

Yes, that’s how I would read it.

[adyParticipant @ady]

8ba is pretty small.

 

8 BA	0.086 inch	59.1 tpi	0.0169 inch	0.0657 inch	Number drill 50 1.8 mm 0.0709 inch

[SteambuffParticipant @steambuff]

Yes 8BA is pretty small, some of the parts use 10BA !!!!

 

[Terry LaneParticipant @terrylane]

It’s all relative – sometimes even 10 BA can be huge!

 

[peter ravenscroftParticipant @peterravenscroft57700]

hi steambuff

when you make the brakets for the tank check the size on both drawings (frames and tank)

wait untill you have to start tapping 12ba threads they are even smaller(con rods coupling rods etc.)

regards

peter

[SteambuffParticipant @steambuff]

Peter,

 

Thanks for that, I will check both parts on all components (Frame, Bracket and Tank) and both in ME and on Ray’s drawings.

 

I usually double or tripple check measurements … and still get it wrong.

 

Dave

 

 

 

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