Author Topic: Large Flywheels  (Read 3832 times)

Online Jo

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Large Flywheels
« on: August 24, 2021, 02:07:10 PM »
One of our casting sets was short of a flywheel and Graham offered to get one cast for me. When it finally arrived I could only describe the parcel and its contents as a "heavy lump".

Quote
Hi Jo.
Yes a heavy lump indeed….
It was the final addition that made Vincent’s engine run smoothly. The pattern was made from a Vee belt pulley with three rings of flat bar rolled and welded to form the rim. If you can find a spare half hour perhaps you’d machine it and let me know if it’s sound?

Its not going to take half an hour to turn up  :hellno: It took 1/2 hour to file off the flashing from the inner edge of the rim in between three spokes so I could try to see if it could be held on a three jaw chuck. I decided no it could not be held safely on the three jaw chuck. So this is how I machined it on the faceplate.....

This flywheel is not massive, only rather heavy  :paranoia: One side of the flywheel was better than the other so I have clamped that "good face" against the faceplate and roughly centred the flywheel by eye using the edge of the tool as a reference. Its within about 3mm of centre.

I started with the obligatory chicken stick making sure it stayed put against the faceplate, selected slow speed and turned Big C on  :paranoia:



Slowly hand feeding the cross slide, listening to the chink, chick as the tool cut the nasty uneven lumps off. Another 2 cuts and:



As you can see I have a flat surface but it is not yet smooth and it will do for now, that extra cut that needs to come off is going to save me a potential problem shortly  ;)

You can see how big the faceplate is relative to the cross slide position and how I have had to angle the tool post to enable the tool to cut the surface:



Time now to test my muscles by turning it round ready for the main part of the turning ::)

Jo

« Last Edit: August 24, 2021, 02:10:50 PM by Jo »
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Online Vixen

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Re: Large Flywheels
« Reply #1 on: August 24, 2021, 02:46:25 PM »
Hello Jo,

That looks to be a big heavy lump of iron. Whats it's weight and diameter? It's appears to be about at the diameter limit for your lathe, so I hope it stays safely in place on the faceplate. 

What does the cryptic message on the tailstock refer to?

Stay safe

Mike
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Offline propforward

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Re: Large Flywheels
« Reply #2 on: August 24, 2021, 02:46:48 PM »
That is a big lump of metal. Impressive!
Stuart

Forging ahead regardless.

Online Alyn Foundry

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Re: Large Flywheels
« Reply #3 on: August 24, 2021, 03:44:48 PM »
Hi Jo.

Good to see the flywheel on the lathe.

I’ve definitely got one “ waster “ here. We just discovered that they’d run one into the rim and “ risered “ the hub. This has left a very porous looking ingate. Only time and machining will tell.

I have my fingers crossed for phase two.

Here’s one I prepared earlier, much earlier…. :)

Cheers Graham.

Online Jo

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Re: Large Flywheels
« Reply #4 on: August 24, 2021, 04:53:45 PM »
Mike: The post-it on the tailstock is to remind me that the DRO X-axis read head had been skipping - I think I have fixed it but to be aware of it.


I think they risered the hub on this one and then broke it off  :facepalm:


Before I put the flywheel back up I thought I would capture a quick picture of the edge:



While it looks horrible the wider edge seems to be on only one side so I will be cutting on the smaller diameter side.

I had to use the uneven centre where the riser had been broken off while remounting the flywheel, not easy as it was all over the place:



So first job was to face that off and centre drill:



Now to position the tool to cut the rim... First off set the top slide so I can get round the back:



Zero the DRO while the tool is touching the faceplate as I don't want to cut into that  :hellno:  Then check, yes as suspected  :ShakeHead:



I cannot use the chuck guard as it hits the tool post and of course that means it needs to be up and..



then it blocks the Z axis readout  :Doh: Now that I am aware of those time to check the available movement of the tool, first to the outside facing edge:



And check that there is sufficient space to move in without hitting the tailstock:



With tailstock support we can now finally we can face the outside of the rim.



The outside of the rim will have to wait until tomorrow, I have some important watering and cross stitching to do  ::)

Jo
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Offline maury

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Re: Large Flywheels
« Reply #5 on: August 24, 2021, 05:59:56 PM »
I used to machine large flywheels, and I was using a foundry that made parts for the oil field industry here in Texas. Needless to say a lot of them came back quite rough.
I found using a light hammer and chisel worked well for removing the flashing.
Good luck on your flywheel.

maury
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Offline gbritnell

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Re: Large Flywheels
« Reply #6 on: August 24, 2021, 08:26:16 PM »
Well at least the iron looks clean!
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Offline Roger B

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Re: Large Flywheels
« Reply #7 on: August 24, 2021, 08:28:03 PM »
That's quite a piece, way beyond my capabilities. I am stretched by an RCM 125mm flying wheel  ::)
Best regards

Roger

Offline RReid

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Re: Large Flywheels
« Reply #8 on: August 24, 2021, 08:36:43 PM »
Quote
That's quite a piece, way beyond my capabilities. I am stretched by an RCM 125mm flying wheel
I agree with Roger. I once turned a 27" diameter part on a 28" (or 14" by UK reckoning) lathe. Now I have to use the same technique to turn a 3" diameter flywheel!
Regards,
Ron

Online Jo

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Re: Large Flywheels
« Reply #9 on: August 25, 2021, 07:17:37 AM »
I've machined a fair bit of Cast Iron and what ever type they made this out of it is making everything go black (including the white t-shirt I was wearing yesterday  :facepalm:)

+1 for the chisel to remove flashing but you need to make sure it doesn't break into the bit you want to keep. I resorted to cutting down the stuff between the spokes with a hacksaw there was so much of it  ::)

That's quite a piece, way beyond my capabilities. I am stretched by an RCM 125mm flying wheel  ::)

Its the flying bit that I always get concerned about  :paranoia:


Hope to get the outer rim outside face done later.  :) 

Jo
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Offline jadge

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Re: Large Flywheels
« Reply #10 on: August 25, 2021, 11:01:16 AM »
Hmm, not sure I'd want to stand in the way of a flywheel with only two clamps.  :o

Here's how I held my flywheels for machining:



The two diametrically opposed posts bolted to the faceplate locate the flywheel in the plane of the faceplate and also provide the drive, ie, the drive doesn't rely on friction between faceplate and casting. The clamps simply prevent the flywheel from falling off the faceplate and are only nipped up. The flywheel is held off the faceplate so the OD can be machined at the same setting as the front face and bore. For scale the faceplate is 18" diameter and the flywheel a bit under 17" diameter before machining.

Andrew

Online Jo

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Re: Large Flywheels
« Reply #11 on: August 25, 2021, 11:58:20 AM »
Hmm, not sure I'd want to stand in the way of a flywheel with only two clamps.  :o


It is being held on by a pair of Unbrako Tee bolts which have a tensile strength of 180 Ksi (Kilopounds per square inch pressure)  plus the tailstock as backup = it is not going anywhere. And of course the faceplate has 8 slots and only 2 line up on a 6 spoke flywheel in a position you can get a clamping plate on :disappointed:

I have the larger faceplate as well, thankfully this one fits on the diddy faceplate so I don't have to take out the gap  ;)


2mm off so far and you can see just how far the two sides of the flywheel were out: one side is showing half machined and the other nothing  :-\

Jo


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Online Vixen

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Re: Large Flywheels
« Reply #12 on: August 25, 2021, 12:07:16 PM »

2mm off so far and you can see just how far the two sides of the flywheel were out: one side is showing half machined and the other nothing  :-\

Jo

Hello Jo

Did you centre the flywheel casting on the hub centre? or on the inside of the flywheel rim?

Just asking.

Mike
It is the journey that matters, not the destination

Oh! sod the journey, lets hit the bar and pool instead.

Online Alyn Foundry

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Re: Large Flywheels
« Reply #13 on: August 25, 2021, 12:15:55 PM »
Good morning Jo.

May I provide a minor correction about your casting?

Yours was run directly on the hub. This means that the “ sprue “ effectively became  the riser after the pour.

In your opening post you presented my email reply to you after delivery where I explained about the patterns origins. This is what is termed an “ odd side “ in foundry parlance. This means that to be able to make a casting the moulder has to dig down to find the split line. Because I wanted 4 flywheels they made an odd side box so that the digging down to the split was reduced to a minimum. The pattern, by my standards today is absolutely awful, a foundrymans nightmare. No draft on the rim which makes the “ pull “ very difficult to do without damaging the fragile edges of the sand. Because an odd side box is used there’s always a major chance of “ flashing “ occurring on the spokes etc.

Every foundry that I’ve used over the years was instructed not to “ fettle “ the castings other than to remove heavy flashing and runners. This ensured that the recipient wouldn’t complain about any missing detail on their casting. This policy led to minimal returns other than the odd, unseen flaw.

The Iron…. Well, I’m impressed. Reminiscent of the grade that Rhuddlan did all those years ago. I’ve had a tussle with a hub on a smaller flywheel recently. A really “ chilled “ spot caused some choice words but some quality Carbide won the battle.

Here’s a photo of one of theirs but made from a split pattern, the difference is astonishing. Apart from a quick tickle with my Powerfile under the rim in three places for chucking, zero fettling was required.

Cheers Graham.

« Last Edit: August 25, 2021, 03:23:55 PM by Alyn Foundry »

Online Alyn Foundry

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Re: Large Flywheels
« Reply #14 on: August 25, 2021, 12:26:13 PM »

Hello Jo

Did you centre the flywheel casting on the hub centre? or on the inside of the flywheel rim?

Just asking.

Mike

Hi Mike.

Obviously not Jo but my method is to get the inner rim looking as true as possible to the eye when it’s rotating.
There’s very little that can be done in this area, machining wise. The hub is then trued up along with the outer rim and hopefully the whole assembly looks good when it’s done.

Cheers Graham.
« Last Edit: August 25, 2021, 04:15:20 PM by Alyn Foundry »