Barry,
I figured out how to possibly build and use this inclinable comb manometer to measure the flatness of the of the Alfa heads.
1.(Build the manometer) Fill a 6 ft long 1/4 inch (inner diameter)plastic tube about 1/2 full with a fluid of your choice. (fluid choice is determined by how you want your meniscus to appear, viscosity, and adhesion to the tube you are using, typically use just water)
2. (Make it inclinable) bend the tube about 1/3 along it's length with the short end vertical and the long end at some incline of your choosing based on your fluid and tube surface characteristics.
3. Thoroughly clean the surface plate and the Alfa heads along the surface of contact. Lay the Alfa head on the surface plate.
4. Make a cylindrical device that will fit into the spark plug holes. This device shall have 2 holes in it with a rubber gasket that fits on it to seal it when it is screwed into the Alfa head. Attach the cylindrical device to the head. Plug all other holes in the Alfa head.
5. Connect one hole to the short end of the manometer. Connect the other hole to a device that can deliver a preset amount of air into the second hole.
6. Deliver the preset amount of air and then note the initial position of the fluid on the inline and the rate of change on the inclinable manometer.
7. The rate of change should be an indication of the air leakage from between the Alfa head and the surface plate.
8. This procedure could possibly be improved by putting a light fluid between the Alfa head and the surface plate.
Hope this helps ;-)
Bob
From: November X-Ray <n8676x@yahoo.com>
To: "GrizHFMinimill@yahoogroups.com" <GrizHFMinimill@yahoogroups.com>
Sent: Saturday, September 3, 2011 12:23 PM
Subject: Re: [GrizHFMinimill] Re: Enco free shipping code
If you get the plate to be less than five (5) lightbands of flatness, it certainly will be more than any home/hobbiest machinist will ever need!!! Getting the flat plate perfectly level is another issue.
From: Bill Williams <BWMSBLDR@PeoplePC.com>
To: GrizHFMinimill@yahoogroups.com
Sent: Saturday, September 3, 2011 1:13 PM
Subject: Re: [GrizHFMinimill] Re: Enco free shipping code
To: GrizHFMinimill@yahoogroups.com
Sent: Saturday, September 3, 2011 1:13 PM
Subject: Re: [GrizHFMinimill] Re: Enco free shipping code
Barry Young wrote:
> OK Bill, I will bite. What is an inclinable comb manometer and how is it
> used to measure flatness of a surface especially those pesky Alfa heads?
> I mean we all know what a manometer is, it is a low pressure gage using
> the difference of levels of a liquid in a tube to measure pressure
> similar to an inclinometer. The comb obviously replaces the traditional
> scale we have come to know and love on manometers, but the inclinable
> part has thrown me which I am more than certain was the point of this
> rather ostentatious post. So spill! what are you talking about, how can
> we use it in our hobby and please be sure to tell us how to build one
> from random crap lying about the ordinary amateur machinist's workshop.
> Thank you
> Barry Young
Barry, I was not trying to do as the academic expression goes:
"If you can't blind them with your Brilliance;"
"Then baffle them with your Bullshit!"
But rather I was drawing upon my experience with surface plates to find
the most outrageous example! Firstly a comb manometer is several
parallel tubes sharing a common reservoir and all in a common plane.This
last is important if you want all of the readings to be relative to each
other. A test of this commonality is to apply the same pressure to all
of them to see if you get the same results. The second test is to slope
the set of manometers so as to spread the travel along the tube for a
given rise in the fluid height. If you can get the manometer to give
good readings at a 10:1 slope then you have done well!
By routing the tubes and manifolds in the front of one sheet of
Plexiglas and then bonding another sheet to the first while caught
between two surface plates I was able to maintain the flatness of the
tubes as well as get a lot in a small space. The object of this exercise
was to measure the flow of air through a two stroke engine cylinder and
thus evaluate the porting. A long ago effort in the pursuit of a Masters
degree at a time when two stroke cycle engines were in great disfavor!
Now as you can see this has nothing to do with nervous Alfa owners
other than the the surface plate. In fact I would doubt that
any of our list members would ever need a manometer let alone a bank
of them!
Bill in Boulder
> OK Bill, I will bite. What is an inclinable comb manometer and how is it
> used to measure flatness of a surface especially those pesky Alfa heads?
> I mean we all know what a manometer is, it is a low pressure gage using
> the difference of levels of a liquid in a tube to measure pressure
> similar to an inclinometer. The comb obviously replaces the traditional
> scale we have come to know and love on manometers, but the inclinable
> part has thrown me which I am more than certain was the point of this
> rather ostentatious post. So spill! what are you talking about, how can
> we use it in our hobby and please be sure to tell us how to build one
> from random crap lying about the ordinary amateur machinist's workshop.
> Thank you
> Barry Young
Barry, I was not trying to do as the academic expression goes:
"If you can't blind them with your Brilliance;"
"Then baffle them with your Bullshit!"
But rather I was drawing upon my experience with surface plates to find
the most outrageous example! Firstly a comb manometer is several
parallel tubes sharing a common reservoir and all in a common plane.This
last is important if you want all of the readings to be relative to each
other. A test of this commonality is to apply the same pressure to all
of them to see if you get the same results. The second test is to slope
the set of manometers so as to spread the travel along the tube for a
given rise in the fluid height. If you can get the manometer to give
good readings at a 10:1 slope then you have done well!
By routing the tubes and manifolds in the front of one sheet of
Plexiglas and then bonding another sheet to the first while caught
between two surface plates I was able to maintain the flatness of the
tubes as well as get a lot in a small space. The object of this exercise
was to measure the flow of air through a two stroke engine cylinder and
thus evaluate the porting. A long ago effort in the pursuit of a Masters
degree at a time when two stroke cycle engines were in great disfavor!
Now as you can see this has nothing to do with nervous Alfa owners
other than the the surface plate. In fact I would doubt that
any of our list members would ever need a manometer let alone a bank
of them!
Bill in Boulder
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