MEM Corliss build Flywheel

[steamer]

I'm over here in the US.  I'm waiting for the OP to get back to us about the suggestions so far.
When Maryak laid that design down   He intended it to be a starting point for a new Model Engineer.   I dare say many things could be modified including the diameter of the flywheel.    In this case that person needs to decide for themselves but I'm glad to support them with that decision making process.    Bob would have wanted the forum to help

Dave

[Kim]

I just found some 7", 1/4" wall DOM tube at Speedy Metals for $26.40 per inch (on sale now for $21.12 per inch).

https://www.speedymetals.com/p-3619-7-od-x-250-wall-dom-steel-tube.aspx

Don't know if this is a reasonable price.  Certainly not what I'd call cheap, but I haven't been pricing 7" DOM tube lately.

Kim

[TerryWerm]

Hi Terry, not a wacko idea at all.  You are on the right track by suggesting a heavier rim on a smaller OD, as it’s the moment of inertia of the fly wheel, not it’s mass that is important.  Mass located at a larger radius from the axis of rotation has a greater effect than mass close to the axis.  The calculations are relatively simple and I can help with the formulae if required.

An overview of the formula and process to select the proper dimensions would be an interesting thread subject in general and would not have to be specific to any particular flywheel or engine. It would make a great reference thread! I have no idea what the formula would be, but it would be an interesting subject.

[MJM460]

Thanks Terry,

I will assume others will be thinking along similar lines and will put something together.  I will start a thread as you suggest in the next week or two.

The calculations are not hard with the right formula, and the principle of looking at moment of inertia for rotational motion compared with mass for linear motion that is important.  I will try and make it clear.

MJM460

[TerryWerm]

Thank you MJM!!  I will be looking forward to it. Gotta learn new stuff all the time!

[JasonP]

Some very helpful hints and tip, thanks guys. I didn't think of adding a standoff to my headstock, which is an option that I'll keep in the file for later.
I did try mounting the stock on my 4" rotary table, and milling the OD down, but I couldn't get it rigid enough. I persevered until I trashed my favourite 1/2" end mill 

My new solution was to phone a friend. He has a fab shop and could let me have a an offcut of 7.5" steel 1018 (I think) bar, about 3" thick. He also has an old LeBlond lathe that I can use to rough out the stock. I chucked it up in the 4 jaw, hogged it down to 6.9" and 1.5" wide, cutting a boss in one face so I can hold it on my mini-lathe. On the other side I left a 3/4 stem.
Pain in ass to do it with the big 4 jaw. My buddy has very few tools and only uses this lathe for one operation in his shop. No dial test indicators or any way to dial the 4 jaw in, so I knew this was going to be really rough. He has some carbide tooling, but the power cross feed wasn't working on his lathe and it was stuck at one speed that was too slow for carbide. The results was really rough and I'm not proud, but it got the job done.
 
I got the part on my lathe and turned the stem to 1/2". I also cleaned up the really nasty face and turned the O.D. down to 6.75" I got a really nice finish on the OD after I mounted the stem in a collet chuck. The flywheel is nicely balanced now and runs smooth in the lathe with no vibration.

I still have a lot of work to do, but the plan is to shape the flywheel on the lathe, then mill out the spokes. The final dimensions should be 6.75 x 1.375, so a bit smaller and wider than the plans, but it should work out. There will be a lot of lathe hours in this flywheel by the time it's done, and I'll probably go though a lot of carbide inserts. It's just too big to try my larger cutters, so I'll be nibbling away with 15-20 thou depth of cut with smaller tooling and lots of passes. Given the size of the flywheel, I have to reposition the QCTP to be able to get to the entire face so I can't even machine it in one pass. The joys of a mini-lathe.

MJM - Would love to see the calcs on this. I've ballparked the flywheel size and it's certainly going to have enough inertia!

Steamer - I appreciate the support. I think an awful lot of newcomers to this world will start with the 7" Chinese mini-lathe. The Corliss is pushing my 7" x 12" to the limit, but it's fun figuring it out. The s50 and 10v I built before were easy compared to this 

[Admiral_dk]

Looks a lot better after cleaning up on your own Lathe 

Per

[steamer]

Looks a lot better after cleaning up on your own Lathe 

Per

Nah    Chips are sexy! 

Keep at it Jason....it's getting there

[Admiral_dk]

I meant the Flywheel ..... anything else I missed 

[Kim]

Boy, you weren't kidding that it was rough!  But it cleaned up nicely on your mini-lathe for sure. 

Kim

[JasonP]

Finally finished turning this sucker! It was a beast on my little lathe. Final OD 6 11/16"  width 1 3/8". Smaller than I intended, but after killing a lot of carbide and blowing a controller this is what I've taken off the lathe. It runs concentric to the crankshaft, which is no mean feat when using a lathe as rigid as chocolate pudding.


Next step is to mill out the spokes. Someone had an excel spreadsheet to assist with that, I need to hunt it down.

[crueby]

Pretty sure that was Don1966 that posted the spreadsheet about spokes, search on his threads...

[JasonP]

Yep, I  found his, also Todds software. Has anyone used the software? I put numbers in and got odd results, probably because I'm not familiar with the nomenclature.

[JasonP]

In the end i used Todds software and the Excell sheet in combination to model the flywheel in Alibre, then printed those drawings and used Todds order of operations to mill it out.
Got the flywheel mounted on the rotary table, centered and securely fixtured. Then worked my way around milling it all out with 1/4" 3 flute endmill that worked well, although the surface finish is a bit rough.
The final result needs fettling with files and I'm thinking of trying to round the edges of the spokes with a rounding endmill, but it's mostly there. It should paint up nicely.

[vcutajar]

Been there and done that.
Lots of work on the flywheel but very satisfying seeing the end result.

Vince