I have dusted off the Stuart 10V castings, dug out the building book and 
found Issue 51 of MEW. Time to get started after only four years.

In MEW 51, there is an article about jigs and fixtures by Harold Hall. 
He uses the 10V as an example. In it he suggests machining the flywheel 
and bearings on a taper mandrel once the bores have been reamed. This, 
he says, allows for good accuracy and will permit both sides of the 
flywheel to be machined by simply removing it from the taper mandrel and 
turning it over.

I can't see how this works. I don't doubt that it does, I just don't 
understand and can't find any reference in my meagre library to the 
technique. It seem to me that any taper will, by definition, leave the 
flywheel tight at one end and loose at the other. I even did some sums. 
Over the 3/4" of the flywheel length, if I had a taper of 0.5 deg (1 
degree included), the casting would have one end tight and the other 
0.013" oversize. That would wobble about all day and any machining 
forces would throw it out of true.

What have I missed? Can someone explain (or point me to an explanation) 
of the business of turning accuately on a taper mandrel?

Thanks

Pete Harrison

Peter,
The answer is it's not 0.5 degrees but far less, a tapered mandrel
usually has about 10 thou per foot so on your flywheel it's about
three licks off a gnats cock.

John S.

John S wrote:
> Peter,
> The answer is it's not 0.5 degrees but far less, a tapered mandrel
> usually has about 10 thou per foot so on your flywheel it's about
> three licks off a gnats cock.
> 
> John S.

That sounds more like it. Probably more true than my topslide normally 
turns then :)

Pete

Peter Harrison  wrote:

>In MEW 51, there is an article about jigs and fixtures by Harold Hall. 
>He uses the 10V as an example. In it he suggests machining the flywheel 
>and bearings on a taper mandrel once the bores have been reamed. This, 
>he says, allows for good accuracy and will permit both sides of the 
>flywheel to be machined by simply removing it from the taper mandrel and 
>turning it over.
>
>I can't see how this works. I don't doubt that it does, I just don't 
>understand and can't find any reference in my meagre library to the 
>technique. It seem to me that any taper will, by definition, leave the 
>flywheel tight at one end and loose at the other. I even did some sums. 
>Over the 3/4" of the flywheel length, if I had a taper of 0.5 deg (1 
>degree included), the casting would have one end tight and the other 
>0.013" oversize. That would wobble about all day and any machining 
>forces would throw it out of true.
>
>What have I missed? Can someone explain (or point me to an explanation) 
>of the business of turning accuately on a taper mandrel?

http://wess.freeshell.org/Boring_new_hub.jpg
http://wess.freeshell.org/mandrill.jpg
http://wess.freeshell.org/clausing/clausingdriven640.jpg
http://wess.freeshell.org/clausing/clausingdriven2_640.JPG

http://wess.freeshell.org/clausing/Clausing.html if you want text.


First, there isn't much of a taper.  Set your tail stock over so you get a nice press fit
in that reamed bore.  Check out tables of press fits to figure just what you want to use.
0.001" per inch of diameter is my rule of thumb.

In my case, I needed to make a new hub, had to get it concentric with the old sheave, and
then needed to hold and machine the hub's od.

HTH,

Wes

On Sun, 17 Aug 2008 23:37:33 +0100, Peter Harrison
 wrote:

>John S wrote:
>> Peter,
>> The answer is it's not 0.5 degrees but far less, a tapered mandrel
>> usually has about 10 thou per foot so on your flywheel it's about
>> three licks off a gnats cock.
>> 
>> John S.
>
>That sounds more like it. Probably more true than my topslide normally 
>turns then :)
>
>Pete
Yes more like the setting of the tailstock on a big VDF lathe I used
as an apprentice. I had to machine a batch of piston rods and totally
forgot to check for parallel. One scrap "First off", I got a hell of a
bollocking ;-)
Would have made a lovely mandrel about 2" dia x 3' long.

NEVER did it again.

--

Richard

Email address is valid but remove burrs before sending!

John S  wrote:

>The answer is it's not 0.5 degrees but far less, a tapered mandrel
>usually has about 10 thou per foot so on your flywheel it's about
>three licks off a gnats cock.

Some lathes, with wear on the ways, automatically make tapered mandrels ;) .

Wes
--
"Additionally as a security officer, I carry a gun to protect 
government officials but my life isn't worth protecting at home 
in their eyes."  Dick Anthony Heller

John S wrote:
> Peter,
> The answer is it's not 0.5 degrees but far less, a tapered mandrel
> usually has about 10 thou per foot so on your flywheel it's about
> three licks off a gnats cock.

Note :  This is a consenting gnat, obviously.

-- 
Boo

Boo wrote:
> John S wrote:
>> Peter,
>> The answer is it's not 0.5 degrees but far less, a tapered mandrel
>> usually has about 10 thou per foot so on your flywheel it's about
>> three licks off a gnats cock.
> 
> Note :  This is a consenting gnat, obviously.
> 
I think he said "off" not "of" :)

On Aug 17, 11:26 pm, Peter Harrison 
wrote:
> I have dusted off the Stuart 10V castings, dug out the building book and
> found Issue 51 of MEW. Time to get started after only four years.
>
> In MEW 51, there is an article about jigs and fixtures by Harold Hall.
> He uses the 10V as an example. In it he suggests machining the flywheel
> and bearings on a taper mandrel once the bores have been reamed. This,
> he says, allows for good accuracy and will permit both sides of the
> flywheel to be machined by simply removing it from the taper mandrel and
> turning it over.
>
> I can't see how this works. I don't doubt that it does, I just don't
> understand and can't find any reference in my meagre library to the
> technique. It seem to me that any taper will, by definition, leave the
> flywheel tight at one end and loose at the other. I even did some sums.
> Over the 3/4" of the flywheel length, if I had a taper of 0.5 deg (1
> degree included), the casting would have one end tight and the other
> 0.013" oversize. That would wobble about all day and any machining
> forces would throw it out of true.
>
> What have I missed? Can someone explain (or point me to an explanation)
> of the business of turning accuately on a taper mandrel?
>
> Thanks
>
> Pete Harrison

If you are not too confident of turning the taper, just turn the end
of the bar to fit in the reamed hole and then bring the rest down to a
thou over and reach for the file and emery cloth to finish off, we'll
forgive you.
Peter

wrote in message 
news:2c998587-8fca-4a92-aa8c-9d3ab64e2c8f@a1g2000hsb.googlegroups.com...
On Aug 17, 11:26 pm, Peter Harrison 
wrote:
> I have dusted off the Stuart 10V castings, dug out the building book and
> found Issue 51 of MEW. Time to get started after only four years.
>
> In MEW 51, there is an article about jigs and fixtures by Harold Hall.
> He uses the 10V as an example. In it he suggests machining the flywheel
> and bearings on a taper mandrel once the bores have been reamed. This,
> he says, allows for good accuracy and will permit both sides of the
> flywheel to be machined by simply removing it from the taper mandrel and
> turning it over.
>
> I can't see how this works. I don't doubt that it does, I just don't
> understand and can't find any reference in my meagre library to the
> technique. It seem to me that any taper will, by definition, leave the
> flywheel tight at one end and loose at the other. I even did some sums.
> Over the 3/4" of the flywheel length, if I had a taper of 0.5 deg (1
> degree included), the casting would have one end tight and the other
> 0.013" oversize. That would wobble about all day and any machining
> forces would throw it out of true.
>
> What have I missed? Can someone explain (or point me to an explanation)
> of the business of turning accuately on a taper mandrel?
>
> Thanks
>
> Pete Harrison

If you are not too confident of turning the taper, just turn the end
of the bar to fit in the reamed hole and then bring the rest down to a
thou over and reach for the file and emery cloth to finish off, we'll
forgive you.
Peter

I'm building a 10V at the moment.  I've not done the flywheel yet but I 
finished off the ends of the bearings and the top of the column using taper 
mounting.  Just created the taper with a few seconds with a file on a 
parallel mandrel turned a thou or so over and it worked fine.

For the flywheel I'm more inclined to use a threaded mandrel.

petercolman45@hotmail.com wrote:
> On Aug 17, 11:26 pm, Peter Harrison 
> wrote:
>> I have dusted off the Stuart 10V castings, dug out the building book and
>> found Issue 51 of MEW. Time to get started after only four years.
>>
>> In MEW 51, there is an article about jigs and fixtures by Harold Hall.
>> He uses the 10V as an example. In it he suggests machining the flywheel
>> and bearings on a taper mandrel once the bores have been reamed. This,
>> he says, allows for good accuracy and will permit both sides of the
>> flywheel to be machined by simply removing it from the taper mandrel and
>> turning it over.
>>
>> I can't see how this works. I don't doubt that it does, I just don't
>> understand and can't find any reference in my meagre library to the
>> technique. It seem to me that any taper will, by definition, leave the
>> flywheel tight at one end and loose at the other. I even did some sums.
>> Over the 3/4" of the flywheel length, if I had a taper of 0.5 deg (1
>> degree included), the casting would have one end tight and the other
>> 0.013" oversize. That would wobble about all day and any machining
>> forces would throw it out of true.
>>
>> What have I missed? Can someone explain (or point me to an explanation)
>> of the business of turning accuately on a taper mandrel?
>>
>> Thanks
>>
>> Pete Harrison
> 
> If you are not too confident of turning the taper, just turn the end
> of the bar to fit in the reamed hole and then bring the rest down to a
> thou over and reach for the file and emery cloth to finish off, we'll
> forgive you.
> Peter

OK. I get it now. This evening turned a couple of inches of stock down 
to about 0.004 over size. Then turned the last inch to a snug fit in the 
flywheel. Next, with the topslide set to about 0.5 deg. I left the 
crosslide alone and used the topslide to turn the inner inch of the 
mandren to get the taper.

The flywheel is a good tight fir with no wobble and it can be reversed 
to machine both sides. I now have it machined on all (relevant) surfaces 
and it runs beautifully true. Mounting the flywheel like this does allow 
it to 'ring' a bit giving some fine chatter patterns. However, theu look 
quite pretty so I will leave them there for a bit.

Thanks for all your help.

I'l be back.

Pete Harrison

Peter Harrison wrote:
> petercolman45@hotmail.com wrote:
>> On Aug 17, 11:26 pm, Peter Harrison 
>> wrote:
>>> I have dusted off the Stuart 10V castings, dug out the building book and
>>> found Issue 51 of MEW. Time to get started after only four years.
>>>
>>> In MEW 51, there is an article about jigs and fixtures by Harold Hall.
>>> He uses the 10V as an example. In it he suggests machining the flywheel
>>> and bearings on a taper mandrel once the bores have been reamed. This,
>>> he says, allows for good accuracy and will permit both sides of the
>>> flywheel to be machined by simply removing it from the taper mandrel and
>>> turning it over.
>>>
>>> I can't see how this works. I don't doubt that it does, I just don't
>>> understand and can't find any reference in my meagre library to the
>>> technique. It seem to me that any taper will, by definition, leave the
>>> flywheel tight at one end and loose at the other. I even did some sums.
>>> Over the 3/4" of the flywheel length, if I had a taper of 0.5 deg (1
>>> degree included), the casting would have one end tight and the other
>>> 0.013" oversize. That would wobble about all day and any machining
>>> forces would throw it out of true.
>>>
>>> What have I missed? Can someone explain (or point me to an explanation)
>>> of the business of turning accuately on a taper mandrel?
>>>
>>> Thanks
>>>
>>> Pete Harrison
>>
>> If you are not too confident of turning the taper, just turn the end
>> of the bar to fit in the reamed hole and then bring the rest down to a
>> thou over and reach for the file and emery cloth to finish off, we'll
>> forgive you.
>> Peter
> 
> OK. I get it now. This evening turned a couple of inches of stock down 
> to about 0.004 over size. Then turned the last inch to a snug fit in the 
> flywheel. Next, with the topslide set to about 0.5 deg. I left the 
> crosslide alone and used the topslide to turn the inner inch of the 
> mandren to get the taper.
> 
> The flywheel is a good tight fir with no wobble and it can be reversed 
> to machine both sides. I now have it machined on all (relevant) surfaces 
> and it runs beautifully true. Mounting the flywheel like this does allow 
> it to 'ring' a bit giving some fine chatter patterns. However, theu look 
> quite pretty so I will leave them there for a bit.
> 
> Thanks for all your help.
> 
> I'l be back.
> 
> Pete Harrison
Pete, Were you using the tailstock to support the mandrel? Should 
reduce/remove the chatter if everything else on the lathe is in fair shape.

Bob

Bob Minchin wrote:
> Peter Harrison wrote:

>> The flywheel is a good tight fir with no wobble and it can be reversed 
>> to machine both sides. I now have it machined on all (relevant) 
>> surfaces and it runs beautifully true. Mounting the flywheel like this 
>> does allow it to 'ring' a bit giving some fine chatter patterns. 
>> However, theu look quite pretty so I will leave them there for a bit.
>>
>> Thanks for all your help.
>>
>> I'l be back.
>>
>> Pete Harrison
> Pete, Were you using the tailstock to support the mandrel? Should 
> reduce/remove the chatter if everything else on the lathe is in fair shape.
> 
> Bob

Hah!

Only thought of that after I finished! Then again, reading my post, I 
was actually machining a small christmas tree.

Pete