Author Topic: Turning a Crankshaft  (Read 10496 times)

Offline Jo

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Turning a Crankshaft
« on: February 15, 2017, 01:32:36 PM »
I thought you may like to see this series of photos capturing turning a crankshaft from solid. The drawing says make it up but they say it is better from solid so, start by taking a billet of steel and using a suitable hacksaw cut off a length that allows for facing up:

1, Find a suitable sized Vee block, and mount it square to the table.

2, Mount billet on a Vee block, clamp in place and face the end.

3, Not forgetting to cut a couple of flats for driving off

4, Drill for crankshaft centres.

5, Turn round and do the other end.

6, Off to the Lathe And avoiding the driving flats mount in a three jaw and tail stock centre.

7, Not forgetting that coolant may come in handy on these little jobs.

8, One roughed out crank.

More to follow  :naughty:

Jo


« Last Edit: February 15, 2017, 01:57:48 PM by Jo »
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Offline Jasonb

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Re: Turning a Crankshaft
« Reply #1 on: February 15, 2017, 02:05:15 PM »
What a Whopper. Almost looks big enough for a BB1 :thinking: EDIT then again that is not your workshop!

How did you get the second set of holes in the same orientation as the first?

J
« Last Edit: February 15, 2017, 02:09:02 PM by Jasonb »

Offline Jo

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Re: Turning a Crankshaft
« Reply #2 on: February 15, 2017, 02:29:11 PM »
How did you get the second set of holes in the same orientation as the first?

You don't think that is going anywhere if you take the clamp off and turn it round while still resting on the vee block do you  :lolb:

Jo
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Offline Jasonb

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Re: Turning a Crankshaft
« Reply #3 on: February 15, 2017, 02:36:46 PM »
But that was not how it was done, the drive flat is at the top in the photo where the second end is being machined so it has been turned end for and and rotated. :ShakeHead:

And besides how would you get at the cap screws holding the vee bar to the table without removeing the crankshaft blank :hellno:

Maybe you need to phone a friend ;)
« Last Edit: February 15, 2017, 02:41:29 PM by Jasonb »

Offline Jo

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Re: Turning a Crankshaft
« Reply #4 on: February 15, 2017, 03:06:14 PM »
I knew there was hours of fun to be had watching a crankshaft being turned  :popcorn:

Jo
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Offline Dave Otto

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Re: Turning a Crankshaft
« Reply #5 on: February 16, 2017, 12:57:21 AM »
Looks like I'm going to have to go shopping for a mill with a horizontal spindle.  :lolb:
Nice write up Jo.


Dave

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Re: Turning a Crankshaft
« Reply #6 on: February 16, 2017, 01:18:28 AM »
Following along and paying attention.  :)

Offline Gas_mantle

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Re: Turning a Crankshaft
« Reply #7 on: February 16, 2017, 07:40:43 AM »
What engine is it for ?

Offline Jo

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Re: Turning a Crankshaft
« Reply #8 on: February 16, 2017, 07:43:52 AM »
What engine is it for ?

A Reeves Commander.

I was offered the casting set but on the grounds I could not lift the bed plate on its own I turned it down   :-\

Jo
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Offline Gas_mantle

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Re: Turning a Crankshaft
« Reply #9 on: February 16, 2017, 09:12:01 AM »
What engine is it for ?

A Reeves Commander.


That sure is a monster size engine - it will take a big meths burner to get it running  ;)

Offline Dave Otto

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Re: Turning a Crankshaft
« Reply #10 on: February 17, 2017, 01:05:07 AM »
What engine is it for ?

A Reeves Commander.

I was offered the casting set but on the grounds I could not lift the bed plate on its own I turned it down   :-\

Jo

You are making a crankshaft for an engine you don't have castings for??

Offline zeeprogrammer

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Re: Turning a Crankshaft
« Reply #11 on: February 17, 2017, 02:09:27 AM »
What engine is it for ?

A Reeves Commander.

I was offered the casting set but on the grounds I could not lift the bed plate on its own I turned it down   :-\

Jo

You are making a crankshaft for an engine you don't have castings for??

Add the word 'yet' to your last sentence Dave and we might have an idea of her plans.  ;D
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Offline Jasonb

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Re: Turning a Crankshaft
« Reply #12 on: February 17, 2017, 07:40:06 AM »
You are making a crankshaft for an engine you don't have castings for??

Dave, you must have missed my comment that it was not Jo's workshop.

Muddled Engineer is making the crankshaft

Will he have it finished for tomorrow Jo?

Offline Jo

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Re: Turning a Crankshaft
« Reply #13 on: February 17, 2017, 08:05:34 AM »
No I am not making it. Yes it is Eric's set of castings.

Any set of castings I show the slightest interest in he suddenly gets a new lease of interest in ::) but often as not after a few days he sells them  :-[

No it will not be finished for tomorrow as he spent yesterday buying another machine tool. He may mill the crank pin gaps today but discovered the dividing head has a 50int not the 40 he originally thought it had...

Jo
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Offline Jasonb

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Re: Turning a Crankshaft
« Reply #14 on: February 17, 2017, 08:18:51 AM »
Seeing the HP and LP marked on the crankshaft does it have different throws or journal diameters for each?

I'm sure he must have a 50-40 reducer stashed somewhere

Offline Jo

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Re: Turning a Crankshaft
« Reply #15 on: February 17, 2017, 08:37:10 AM »
Seeing the HP and LP marked on the crankshaft does it have different throws or journal diameters for each?

They are different spacing's from the end of the shaft and the drawing shows the HP leads the LP by 90 degrees... ::)

Jo
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Offline Jasonb

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Re: Turning a Crankshaft
« Reply #16 on: February 17, 2017, 10:17:44 AM »
Metric sizes on a Stuart drawing, whatever next :ShakeHead:

Offline Jo

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Re: Turning a Crankshaft
« Reply #17 on: February 17, 2017, 10:20:05 AM »
Metric sizes on a Stuart drawing, whatever next :ShakeHead:

 :headscratch: That's a Reeves product/drawing designed by David P.

Stuarts do a smaller engine = 6A

Jo
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Offline Alan Haisley

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Re: Turning a Crankshaft
« Reply #18 on: February 17, 2017, 07:32:18 PM »
About how much did that billet weigh? It seems a monster.

Offline Jo

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Re: Turning a Crankshaft
« Reply #19 on: February 17, 2017, 08:09:54 PM »
About how much did that billet weigh? It seems a monster.

I was told 60Kgs.

Jo
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Offline Jasonb

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Re: Turning a Crankshaft
« Reply #20 on: February 17, 2017, 08:17:57 PM »
That sounds a bit much, assuming it started out as 4" bar then it would need to be just over 3ft long to weigh 60kg :thinking:

60lbs would be nearer the mark

Offline steamer

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Re: Turning a Crankshaft
« Reply #21 on: February 17, 2017, 09:03:42 PM »
Slippery slope Jo!     Steam launches are optimized to consume vast quantities of money!!!

"Thar be dragons!!!!!!"


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Offline Dave Otto

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Re: Turning a Crankshaft
« Reply #22 on: February 17, 2017, 10:30:04 PM »
You are making a crankshaft for an engine you don't have castings for??

Dave, you must have missed my comment that it was not Jo's workshop.

Muddled Engineer is making the crankshaft

Will he have it finished for tomorrow Jo?

Yes I did miss it; sorry about that.

Dave

Offline steamer

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Re: Turning a Crankshaft
« Reply #23 on: February 17, 2017, 10:34:09 PM »
THAR BE DRAGONS!!!!!
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline Jo

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Re: Turning a Crankshaft
« Reply #24 on: February 18, 2017, 01:14:06 AM »
That sounds a bit much, assuming it started out as 4" bar then it would need to be just over 3ft long to weigh 60kg :thinking:

60lbs would be nearer the mark

It started at 4 1/2" or 120mm dia, 750mm long. - Cubify calculates it out at 61.23Kg or 66.68Kg.

Jo
« Last Edit: February 18, 2017, 01:20:43 AM by Jo »
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Offline Gas_mantle

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Re: Turning a Crankshaft
« Reply #25 on: February 18, 2017, 01:45:29 AM »
I'd be curious to know what the finished item weighs, there must be 30-40kg of swarf to make to yet :o

Offline Jasonb

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Re: Turning a Crankshaft
« Reply #26 on: February 18, 2017, 07:57:39 AM »
That sounds a bit much, assuming it started out as 4" bar then it would need to be just over 3ft long to weigh 60kg :thinking:

60lbs would be nearer the mark

It started at 4 1/2" or 120mm dia, 750mm long. - Cubify calculates it out at 61.23Kg or 66.68Kg.

Jo

I was going by the fact the ctr holes are more than half way to the edge to get my 4" dia

At 750mm long that would make Eric's mill table about 2ft front to back as there is only 4-6" hanging off the front :headscratch:

I'd say 450mm long max. You should know that some chaps like to exagerate the length of things :LittleDevil:
« Last Edit: February 18, 2017, 08:32:20 AM by Jasonb »

Offline derekwarner

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Re: Turning a Crankshaft
« Reply #27 on: February 18, 2017, 08:14:08 AM »
Folks......the weight calculation  :happyreader: for the crankshaft is just the individual cranks+journals totals = mass & is simple

However from an engineering/metallurgical point, it would be interesting to understand the Grade of the steel billet.........

Derek
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Offline Jasonb

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Re: Turning a Crankshaft
« Reply #28 on: February 19, 2017, 07:47:52 AM »
Having seen the crankshaft in the flesh yesterday I can confirm that it is indeed only 400-450mm long.

And the 60kg weight quoted included the rest of the bar that the billet was cut from :lolb:

The full set of castings for this engine were last seen being loaded into the boot (trunk) of Jo's car, your guess is as good as mine what happened to them after that :LittleDevil:

Offline Jo

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Re: Turning a Crankshaft
« Reply #29 on: February 19, 2017, 07:59:57 AM »
The full set of castings for this engine were last seen being loaded into the boot (trunk) of Jo's car, your guess is as good as mine what happened to them after that :LittleDevil:

 :thinking: Maybe I should start a thread about making a vertical engine.

Jo
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Offline Jasonb

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Re: Turning a Crankshaft
« Reply #30 on: February 19, 2017, 10:07:09 AM »
The full set of castings for this engine were last seen being loaded into the boot (trunk) of Jo's car, your guess is as good as mine what happened to them after that :LittleDevil:

 :thinking: Maybe I should start a thread about making a vertical engine.

Jo

What have you cut it in half to make it a bit lighter? ;)

 

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