Flywheel Fabrication

I need to make a 6 spoke flywheel from the solid for a small hot air engine. In the back of my mine I seem to remember an article(s ) in one of the magazines on using a rotary table on the mill to carve out the spokes. I have gone through all the indexes I have but nothing jumps out at me. Rather than re-invent the wheel (pun intended ) does anyone know where the article(s ) might be?

I have MEs from '79 and EIM from day one plus "Live Steam" and "Modeltec" from the '70s and '80s.
Thanks.
John

I fabricated one from a slice of thick wall tube and round bar spokes. I can post a photo if it helps.

Like Duncan, a disc of plate and rod spokes. or roll/bend rod for the rim. Noel.

I made mine the 'naughty' way since I didn't have a rotary table at the time. The blank mounted on a temporary axle and MD and using the pitch circle tool on the DRO I made a series of primary holes for the hub end of the spokes and the rim ends. The rim was then chain drilled before the naughty bit of using an endmill to cut between the drill holes and hand turning the blank to clean up the rim. I did go slowly and with a safety stop for each section.

There are a number of pics in my Sterling bas folder which should help show how to do the same much more safely on a rotary table.

pgk

This is a flywheel which I made on a rotary table. (Dimensions are for this flywheel only).

A CAD drawing made first to determine the geometry of where to position the work on the mill.

1. Turn a solid flywheel from round bar and make mounting plate for milling on RT.

2. Center the RT under the mill spindle and zero the DRO, Clamp centre of mounting plate with centre of RT.

3. Clamp flywheel (FW) to mounting plate and move X-axis (21mm). Mill curved slot (35 degrees)

4. Rotate FW for cutting next slot. Use pin for positioning. Repeat for remaining slots.

5. Move table to 0,0 position. Align Datum 2 with centre of RT.

6. Move table to position of Datum 2 (15,8) and mill slot.

7. Repeat for Datum 2.

There are a few tables/calculators on the net where you punch in a few sizes, tool dia etc and it gives you the positions for initially drilling out the internal corners and then the angles depending on if you want parallel or tapered spokes. I'll have a look for one a bit later

Thanks from me also for taking the trouble to post that, Paul - very useful.

John, David Kerzel also gave words and music for a straight-spoked wheel for his H/M engine published on Florida AME website;

FloridaAME - David Kerzel's Hit Miss Engine

I include it here because such a useful thread title will bring others here in the future, I'm sure.

Marv's flywheel program is on his site flywheel zip

Another on MEM forum, you will need to be registered to get the attached files

Edited By JasonB on 10/05/2023 07:34:17

Thanks everyone for your replies. Rather than fabricate it, I have a spare brass casting for a depressed centre disk flywheel that I cast for another project that I want to use, but I want to make it a 6 spoke style rather than disk, hence my query.

Jason your link to the one on MEM looks like it will do what I want, but Marv's programme won't run, gives an error msg."written for a 16 bit system, won't run on a 64 bit system".

Paul, yours looks like it will be good if I decide to do curved spokes.

Still don't know if my recollection of an article in one of the mags.is real or if I am dreaming!

Thanks again, this has given me enough to work with.

John

I ran the flywheel program in Dosbox. It produced a text file with a .out extension. Here is a sample from it.

The rotary table settings (deg) for the inner holes are:
30.000
90.000
150.000
210.000
270.000
330.000

The rotary table settings (deg) for the outer holes are:
7.000
53.000
67.000
113.000
127.000
173.000
187.000
233.000
247.000
293.000
307.000
353.000

Martin C

Martin does this HTLM version work out the same as the dropbox version?

Based on FLYWHEEL.zip at Marv Klotz's
link

Lofty

Edited By Lofty on 11/05/2023 22:02:03

The default numbers I put into the zip version were the same as the default numbers in the HTML version. So I imagine it is basically the same underlying program. Try using the HTML defaults and see if you get the same results.

Martin C

Just noticed that further down on the HTML version it says it is based on the flywheel.c program that is in the zip file.

Edited By Martin Connelly on 11/05/2023 23:22:21

Martin, looks like the dos .c version is better than the HTML version, only getting 6 results for outer bolt holes where should be 12,

input:

6
0.440
1,367
0.1875
0.1875
0.125
7

Rotary table settings (° for the inner holes
30.00
90.00
150.00
210.00
270.00
330.00
Rotary table settings (° for the outer holes
5.25
54.75
104.26
153.77
203.27
252.78
302.28
351.79

Nearest Integral Angle Solution

Rotary table settings (° for the inner holes
30.00
90.00
150.00
210.00
270.00
330.00

Rotary table settings (° for the outer holes
5.00
55.00
105.00
155.00
205.00
255.00
305.00
355.00

thanks

Lofty

As John found the one that is on MEM does the job without having to try and get it to run and also has a lot of detail on putting the numbers into practice Can be accessed here

I just ran Llofty's link to Marv's HTML version using the parameters for my 6 spoke flywheel. Like Lofty I find it gives an incorrect number and angular position for the outer row of holes. It gives 10 vice the 12 it should be. After looking at the results I can see where the error is. My flywheel has the angle from the spoke centre line to the centre of the first hole as 11 degrees. If the centre line of a spoke is made the 0 degree datum then this gives the first hole at 11 degrees, the second at 11 + 38 (49 degrees ) ( since 11+38+11=60, the angle between spokes ), then the third hole should be 11+38+11+11=71 degrees with each succeeding hole being +38, +22, +38 etc. to give 12 holes.
The output of Marv's HTML program however gives the holes at 11, 49, 87, 125, etc. The first two holes are correct but the remaining are arrived at by just adding the 38 degrees between holes ignoring the every other 22 degree spacing between holes either side of a spoke.

From Martin's results with the Zip version it looks like it give the correct output for the outer holes ie. 7, 7+46=53 +14 (2 x 7 )=67 +46=113 +14=127 etc. for 12 holes. So there appears to be a problem with the HTML version. Are there any other errors in it's calculations I wonder ???

John

Hello

I made 2 curved spoke flywheels from cast iron slices. I have the details somewhere. Is this what you want ?

regards

Steve

Thank you very much for this.

Edited By DiogenesII on 13/05/2023 07:54:40