How to machine a flywheel ?

[Brian JohnParticipant @brianjohn93961]

Correct positioning on the face plate.

[Brian JohnParticipant @brianjohn93961]

Does anybody have any photos of (3 inch to 7 inch) flywheels corrrectly held in place on the lathe prior to machining ? From what I have read, a flywheel cannot be held in a 3 jaw chuck so it has to be bolted to a face plate. I would like to see how this is done.

[Thor 🇳🇴Participant @thor]

Hi Brian,

I don't know if you have read this description (from Steves workshop), may be it can be of help.

Thor

Edited By Thor on 19/05/2014 07:20:13

[JasonBModerator @jasonb]

I have done several using 3-jaw and 4-jaw chucks as well as faceplate. Of the three the 3-jaw would be the least suitable as you can't easily adjust the rim true

A lot depends on the size of the flywheel in relation to the chucks/faceplates/lathe available, number of spokes and how true the inner edge of the rim is to start with. Do you have a particular flywheel in mind and can you remind us of the size of your equipment.

J

[Brian JohnParticipant @brianjohn93961]

I have a Sieg C2 7 X 12 lathe. I have ordered one of each of these flywheels and pulleys :

**LINK**

Well, I have ordered most of them ; some in brass, bronze, aluminium and cast iron.

Edited By Brian John on 19/05/2014 09:54:51

[Jon GibbsParticipant @jongibbs59756]

Have you seen this video from Tubalcain2 (MrPete222)?

**LINK**

Jon

[GaryMParticipant @garym]

Hi Brian,

An alternative approach here **LINK** for a small flywheel from Harold Hall's very helpful website. I used this method for the Stuart S50

Gary

[RICHARD GREEN 2Participant @richardgreen2]

Here are a few pictures of machining the flywheel for my 6" Burrell, the flywheel is 25 1/2" diameter on a 27" faceplate, the keyway was cut on an 8" slotter.

Richard.

[JasonBModerator @jasonb]

Where possible I prefer to hold the flywheel by the inside of the rim using the 4-jaw as there is not the problem of keeping bits of packing in place or distorting teh flywheel by clamping onto unsupported spokes. This is not always possible if your chuck is not big enough or the number of spokes gets in the way, 5 spoke flywheel ssuffer with this and really need a faceplate.

This shows the sequence that I used to machine a 10.2" flywheel, although bigger than yours its the same principal just a smaller chuck and smaller flywheel.

These are a couple of shots of a 9" 5 spoke that had to be done on a faceplate, the MDF packing supports the spokes so the clamps don't bend them and also allows the tool to cut past the outside of the rim without running into the faceplate

These 9" ones had a long central boss so that wa scleaned up first then used to hold the flywheel by to do the rest with a bit of tailstock support for good measure.

J

[Roderick JenkinsParticipant @roderickjenkins93242]

This was how I did my Wyvern flywheels:

File off all the flash and and any lumps on the faces of the rim.

 

Most flywheels are cast with a split pattern so registration between the 2 halves may not be perfect. Choose a side to be the "outside" i.e. the side that the engine will be mostly viewed from. Mount this side out on the faceplate with 3 sacrificial pads (ally in this case). Try to get the inside of the rim running as true as possible. Take a cut across the face of the rim and the circumference.

Now reverse the flywheel and centre on the faceplate using a DTI on the rim circumference

The sacrificial pads allow you to take a cut across the whole of the rim circumference

The video shows a mis-registration problem. The "good" side of the rim was fine but you can see the eccentricity on the reverse side. Not too bad for the Wyvern since this has twin flywheels so both of them can be mounted with the good side on the outside – less easy to hide on a single flywheel steam engine.

Hope this helps,

Rod

 

Edited By Roderick Jenkins on 19/05/2014 19:42:15

[Brian JohnParticipant @brianjohn93961]

What about drilling a hole through the hub and holding the flywheel using a mandrel ? Has anybody tried this ?

[Neil WyattModerator @neilwyatt]

Me!

Works fine for small flywheels, up to about 3 1/2", also a way of helping ensure the outer diameter is wobble-free. Not sure it's the best way for the heavy mob. About the ONLY way to finish pulleys of 1 1/2" or less in diameter.

Has the advantage you can machine all three 'sides' of the rim at one setting (unless it's recessed).

Neil

[JasonBModerator @jasonb]

Disadvantage is that you can't really clock the cast rim to see if your drilled (preferably reamed also) hole goes in in the right place to get the unmachined inner rim running true.

As Neil says the leverage on a larger flywheel can make it hard for the mandrel to keep a grip

J

[Neil WyattModerator @neilwyatt]

Should clarify, I use a 4-jaw to turn and ream/bore the boss, then mount on a mandrel to finish the rim.

Neil

[JasonBModerator @jasonb]

I got the impression that Brian was asking about it as the initial way to hold the flywheel for all turning rather than the fairly common method to finish the back.

You can always use an expanding mandrel to hold the flywheel while you turn the pully mounted to the flywheel so its all running true

Edited By JasonB on 13/06/2014 20:38:09

[Boiler BriParticipant @boilerbri]

By Ek lads your getting competitive with this one.

Boiler

[Brian JohnParticipant @brianjohn93961]

Is a dial gauge essential to all this ?

[Brian JohnParticipant @brianjohn93961]

Should the inside of the flywheel be machined or just leave that alone ? I usually clean up the inside of the flywheel and spokes with a hand file and then polish off with a wire brush in the rotary tool.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Brian John on 14/06/2014 04:47:52:

Is a dial gauge essential to all this ?

.

Essential: No

Convenient: Yes

[JasonBModerator @jasonb]

I would say your eye should be better than a DTI in this case. Running the DTI on a cast surface you will never get it to Zero. Its usually easier to have a lathe tool or bit of bar in the toolpost that just clears the inner face so as you turn the part round by hand you can see where the flywheel is moving, aim to get as small a change in the gap as possible. DTI is best when you reverse the flywheel to do the other side

Does depend a bit on the design of the flywheel, some you can just machine the outer face and two edges others need a bit of a cleanup behind the rim and to the sides of the outer web.

J

[Michael GilliganParticipant @michaelgilligan61133]

Brian,

Jason's description is [predictably] excellent.

I would just add that a pack of "Rizla+ Blue" cigarette papers would be a wise investment.

• Lick & Stick a piece of this paper onto a surface, and you can easily get the tool positioned to within about a thou'
• Position several around a surface, and it's a simple job to get it running true.

MichaelG.

[Brian JohnParticipant @brianjohn93961]

Who sells 1/4 inch mandrels in the UK ? There are a few companies selling them in the US but their postage rates are exorbitant.

[roy entwistleParticipant @royentwistle24699]

Brian You've got a lathe and you're asking who sells mandrels       Why ?

Roy

Edited By roy entwistle on 18/06/2014 15:55:38

[JasonBModerator @jasonb]

ARC do them but its an ideal little job making your own that will get you used to using the lathe and far cheaper too.

J

[Ian S CParticipant @iansc]

We made our own at school metal work so we could machine the gear blank for the hand bench grinder we were making. Ian S C

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