ptulmer

My Feedback: (5)

to measure the cylinders? It says "high precision", but doesn't it indicate by thousandths?

http://cgi.ebay.com/_W0QQitemZ330172...QQcmdZViewItem

fizzwater2

My Feedback: (61)

Perhaps this is a newer version of the same thing?

http://www.etamic.com/pages_e/Produi...Pneutamic.htm#

Looks like the one in the auction measures in microns, probably .0001 meters (1 micrometer).

If it works.

gcb

Hmmm, yes...a micrometer(mi-crom-e-ter) measures micrometers(mi-cro-me-ters, or microns).

I suppose the same folks who changed that, call the planet Your-Uh-Nus.

George

ptulmer

My Feedback: (5)

Hmmm, that's about .00004. Not too shabby for $62 plus actual shipping. I wouldn't know how to use it, but it's interesting. That is pretty close to what Cox used to make the TD .01. Unless I'm reading it wrong, Cox used 25 millionths and that would measure to 40 millionths. I wish it were in standard measurements. I try to stay away from metric as it's very confusing...

George, I always assumed it was a micro-meter. (or really small meter)

vicman

My Feedback: (10)

Patrick,
To answer your question would they use this type of gage, Yes. I can't tell if it's metric or not. All the air gages I have used in the past were with a bar scale, those look pretty old. They could very easily be in 10 millionth incraments. You will need to have the mandrel and bushing for the size hole you are wanting to check. Not all that easy to make without an OD grinder. I used to make my own in emergencies otherwise I ordered them from the oem. Also not all that efficient for low quantity unless needing to hold that tight a tolerance, and then you would need a controlled environment for thermal compensation.
For our application we can get plenty close with deltronic pins too. These would be used when finish honeing or more likely lapping operations.

gkamysz

My Feedback: (19)

The only part missing in that auction is the actual gauge tooling. What you see is the readout. I don't think Cox used anything like this. I would imagine they used a well made set of guages. Once the grinding machine was setup it could run a lot of parts to the same dimensions. The grinding equipment they used was well known for it's accuracy and repeatability, especially when the temperature was properly controlled.

Ahhh, Vicman beat me to it.

vicman

My Feedback: (10)

Sorry Greg,

You saw the same thing I did. Like everything the tooling is where the true cost it.

Considering the engines where in their heyday during the 60s I would think that airgaging would've been the most effecient and accurate way to check production parts. In my experience we would set up for as low as 50 pc especially when the hole was long and blind. We usually would jig grind and then lap for the finish and lived in the 10 millionth world. Crazy days man. Do a little work on the part let it cool while we worked on another. Just holding them too long made checking a bear.

fizzwater2

My Feedback: (61)

Another question for you guys -

I would like to have a dial depth indicator with a base on it, for doing things like measuring the stroke of an engine, measuring clearance at TDC, etc. I have a depth measuring foot for my dial calipers, but it's somewhat awkward with the 6" caliper hanging up there, makes it tough to hold the base down properly.

Anything I should be looking for, without breaking the bank? I found a Fowler indicator for ~35 bucks at MSC Industrial, and the base for another 19 at the same place. I don't think I'll need something that gets used every day, but I need to be able to fairly quickly measure stroke for inspecting Q500 engines at a race, make sure no one has stuffed a .46 crank in a .40 case, etc.

Thanks,

ptulmer

My Feedback: (5)

Fizzwater, it sounds like a magnetic base might work for you. Harbor Freight sells them about as cheap as you could want. They are heavy enough to work without a metal surface. You could make something tall enough to check the engines while they are on the airplane with a little work.
Enco has sets that are cheaper than MSC asks just for the base!

http://www.use-enco.com/CGI/INLMK3?PMK0NO=857247

ptulmer

My Feedback: (5)

Well, Vic, this brings up another point of confusion for me. How did they bore the cylinders? Was it ground and what would that look like? I've never seen equipment that worked at that small a scale. Cox was the first to use air gaging on model engines, but it wasn't ever clear whether that was just on the .01's or if it went all the way up the line with those kinds of tolerances. At one time, I thought the .049s were put together by trying parts for fit. Surely you wouldn't need to do that with 25 millionths of an inch tolerance!?

fizzwater2

My Feedback: (61)

Magnetic probably isn't going to do me any good - the liners & cases of the engines are aluminum and brass..

Something like this is what I'm looking for - and I think your enco lead was a good one, I found an SPI dial indicator 0-1" on sale for 15 bucks, and their base is 18.50..

http://www.jettengineering.com/about/build.jpg

Thanks to Jett Engineering for the picture...

ptulmer

My Feedback: (5)

Geez, man. How dense can I get. I've seen one of those bases for a dial caliper, but didn't consider it for this application. My less than vivid imagination was picturing one of the depth calipers with a granite base, but using the heavy magnetic base that I use to indicate for my four-jaw chuck.
Enco has terrific prices compared to MSC and their catalog is small enough to read in privacy (if you get my drift) without hurting your knees. When the MSC catalog came in I told my wife not to use it to kill roaches, it might pull her back out. That thing must weigh twenty pounds!

fizzwater2

My Feedback: (61)

Ah, the old reading room... I think they should all be equipped with a magazine rack.

I have a copy of the MSC catalog here at work, haven't wanted to spare the effort to lug that thing down the stairs and take it home! Mostly I just look online at their catalog websites.

Thanks for the reminder about Enco, you are correct - their dial indicator with depth base adds up to about 33.45, quite a bit less than the one I was looking at over at MSC. Might just have to break down and order one.

vicman

My Feedback: (10)

FW, you can use any 1" travel indicator and a block of aluminium or steel with a hole reamed for the stem and a set screw to hold it in place. You can set the indicator for a given depth with some blocks to give you a range of what you think things should be.
Are you doing your inspections with the head on or off? With this type of base you could most likely do your check thru the plug hole.

Patrick, I am not sure what Cox used for doing the holes. If I were to do it back then I would've used swiss or Davenport screw machines and honed to finish. Sunnen machines are very accurate for this type of operation.

BobHH

My Feedback: (18)

Vicman, wa that a Phillips head screw or a standard head screw machine!!

Bob Harris

Taildragger726

Wow Vicman,, when I grow up,,, I wanna be just like you !

vicman

My Feedback: (10)

It's a thankless world I live in.[sm=tired.gif]

fizzwater2

My Feedback: (61)

Through the plug hole I'd probably have to opt for a 2" travel gauge. My Jett supersport is about .825 from the top of the sleeve at BDC, by the time I added the head & fins to that, it would be over 1". Typically this is measured with the head off, to the top of the sleeve.

Head on is an interesting concept, though - one could even turn an ABC engine through it's squeaky spot near TDC and get a reading, without worrying about the sleeve lifting up.

Darrol Cady (www.darrolcady.com) sells a nice setup for measuring clearances, etc, but it's more than I want to spend..

http://www.darrolcady.com/Accessorie...linertool.html

The whole purpose of the .2" shim is to allow measuring TDC without the pinch at the top you get in an ABC engine. Neat idea, but more work than necessary for checking engine stroke at a contest to determine legality of an engine.

ptulmer

My Feedback: (5)

Dang Vic, you sound just like my wife![sm=kiss.gif] (you look kind of like her, too... could it be?!)

vicman

My Feedback: (10)

Hey Patrick,
You want any more topless pics of your wife?[sm=bananahead.gif]



FW, If you use a bar that is from .25-.375 and a small set screw you can let the neck of the indicator go below and right next to the plug surface and get your .8 + travel.

skaliwag

My Feedback: (1)

Wow ... That's an expensive Chinese digital caliper... $75.. I have one exactly the same. $20 from Harbor... $15 when they are on sale.

fizzwater2

My Feedback: (61)

guess the extra 55 bucks is for the depth base and the 0.2" ring that fits around the sleeve on a racing .40 engine..

There is something to be said for convenience, too - if I had to invent or make a sleeve like that, it would end up costing me more than the 55 bucks extra. I think the "through the plug hole" method has some merit.. might have to investigate that one.

DICKEYBIRD

CDCO has some great prices on machining related stuff. http://www.cdcotools.com/index.php Seems to be the same Chinese goodies that the others are selling but considerably cheaper. Look under "Measuring Tools" & see if something they have will help you. I measure stroke with a homemade depth gage, then measure it with a caliper.

Enco prices aren't quite as good but has their free shipping codes every month on orders over $50.00. Be careful, machining stuff will latch onto you and attack like Kudzu! Ask me how I know.

DeviousDave

I've worked in shops that work to tolerances that high on ground inside diameters. We used Air Gages to check them.

fizzwater2

My Feedback: (61)

I ended up ordering an Enco brand dial indicator, with a kit full of accessory points for it, and the 18.50 base. Total with shipping was only about 36 bucks, should do what I need. Thanks for the inputs, guys!