I grew up with the saying, ‘Bob’s your uncle’ as in ‘and there you go!” I never questioned the saying and I thought it was pretty much common knowledge.
Denyce, after explaining something to her mother said, ‘and Bob’s your uncle!” Lee, Denyce’s mother asked, “who is Bob?”
Denyce: “It is an expression you taught me when I was little. It means, ‘and there you have it!”
There was a moment or so of silence and then Lee responded, “You have an Uncle Bob”.
Denyce: “Yes, I know but that has nothing to do with the expression”.
The conversation ended soon after that with both parties quite perplexed.
A week or so later Denyce was retelling the story of Bob and how her mother didn’t know the expression. Much to our surprise the friend Denyce was telling the story too didn’t know the expression either.
So I did some research and thought I would share my findings with you just in case one day we are talking and I say, “Bob’s your uncle!” First, it is more popular in Jolly Ole’ England. 2nd, we really don’t know where it originated but every article I read, (three) points to 1887 when Robert (Bob) Gascoyne-Cecil the Prime Minister of England at the time appointed his nephew Arthur Balfour as the Minister for Ireland. Arthur had no business being the Minister for Ireland, clearly a case of nepotism. The expression was coined when Arthur referred to the Prime Minister as ‘Uncle Bob’. Clearly it is easy to get the job when ‘Bob is your uncle’.
Alas there is more. The expression is ‘Bob is your uncle, and Fanny is your aunt.”
I am far to lazy to look up the ‘Fanny is your Aunt’ I’ll leave that to you. Please let me know what you find. My only clue for you is that my grandmothers name was Fanny. But she has nothing to do with the expression.
And there you have it.
PanningForGold 
This is what I found but it’s not very much!! When I was growing up my uncles used to say that & as I had an uncle “Bob” as a kid I was confused as I knew I already had an uncle Bob so why were they telling me this!!
The long version Bob’s your uncle and Fanny’s your aunt meaning “and there you are”, or “it’s that easy!”, or “(after that) it’s done!”, or “(after that,) you have achieved what you wanted to achieve”. One variant is Bob’s your uncle and Fanny’s your granny. Other variants, of both versions, spell your as yer.
Good to know! Thanks for reading.
I first heard the expression at a magic convention when Bob Read from England finished an amazing trick. Before the day was over, everyone was going around Saying Bob’s Your Uncle. Never heard it again until Bob Swaddling showed up in New York at a convention and introduced his Bob’s Box. A coin trick. I think I still have one.
I remember Bob Read being amazingly funny. Something about a bottle production, some rolled up newspapers and a potato.
The bottle production was the best i have ever seen. Each of the few time I had sen him, maybe 3 or 4, my stomach hurt from the laughing. He was one of a kind,
Very funny but I, too, did not know the expression! Thanks , I learned something new !
Btw, I noticed a few grammar errors😩. They may typos ??
I leave the errors in for participation purposes.