Flywheel Off Centre!

[Alan Worland 1Participant @alanworland1]

I have been busy on my current project, a horizontal steam engine – 1 1/2 inch bore and 2 1/2 inch stroke.

Tackled the flywheel yesterday which was set up on a face plate so the actual 'casting' ran true (not the OD) All went well, it turned really well, then I turned it over clocking the now turned OD only to find the two halves of the casting were not registered together very well!

I am faced with filing the casting so the inside diameter of the spoke section runs true (not eccentric) or I have temporarily bolted it to my rotary table to true the inside diameter up with an end mill?

Not happy about either way but something needs to be done as it will not look good – and be out of balance – its a big flywheel 7 inch OD and 1 5/8 inch thick

Does the rotary table method sound my best option?

Alan

[Alan Worland 1Participant @alanworland1]

[JasonBModerator @jasonb]

You will find that with the RT method you will be taking metal off one half but there will not be enough metal on the other half or the rim. You will likely have to do both sides to average things out

Its always best to fettle castings first to take care of misalignment before turning.

Personally I'd take a bit of both sides and then set it up again and machine the casting again which means bushing teh bore and a slightly smaller OD

J

[Alan Worland 1Participant @alanworland1]

Mmmm! I hear what you are saying and it did ross my mind, but it is quite a lot out! probably best part of 0.1 in

I was proposing putting the end mill into the spoke openings to get to the 'outside inside edge' of the openings. It is not out axially just ecentrically!

I will let you know how I bugger it up further!

Alan

[Alan Worland 1Participant @alanworland1]

Well, it was 'only' .050 out (looked worse when rotating) so with it mounted on the RT and an end mill in the spoke apertures I machined material from the inside edge of the rim (in the centre where the spokes meet the rim)

Well pleased with the result and didnt take very long to correct.

In hindsight I dont think I could have set it up any different because ideally I would have liked to spread the registration error between the front face and the rear face, this wouldn't have been possible on account of only being able to look at one face at a time when set up for turning.

Anyway, alls well that ends well!

Alan

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