Worst Saturday I've had in long time

[RmvBfrFlght]

I'm a little confused on how 4 to 7 tenths is tighter than 2.9 thous . What a shame if the connecting rod caused the engine to grenade. Well I guess it's a shame no matter what the cause.

It is tenths of a thou.

0.0029 versus 0.0004 - 0.0007

RemoveBeforeFlight

 

[TurboBob]

i had a stroker years ago, and the shoulders of the rods were relieved. I don't recall if it was to clear the bore or the camshaft.

what is the heat treat process like for rods like this?

Bob

 

[A2000RICH]

4 to 7 tenths is .0004 to .0007 (tenths of thousands) 2.9 thou is .0029 (thousands)

 

[Ttype6]

.4" is four tenths of an inch
.0004" is 4 ten thousandths of an inch.
.0029" is 29 ten thousandths of an inch.

 

[750H.P.V6]

.4" is four tenths of an inch
.0004" is 4 ten thousandths of an inch.
.0029 is 29 ten thousandths of an inch.

True however it's is common for machinists and engine builders to abbreviate ten thousandths as "tenths".

Neal

 

[Rafs-T-Type]

Makes sense. Thanks.

 

[Ttype6]

True however it's is common for machinists and engine builders to abbreviate ten thousandths as "tenths".

Neal

So, .4" is four tenths of an inch and .0004" is four tenths of an inch. I don't see how that could create any confusion.
I wonder why we ever used to referred to one as tenths and the other as ten thousandths.
If I tell my machinist I want two tenths clearance,how does he determine the amount of clearance I want?

 

[750H.P.V6]

I figure your machinist would be able to figure out the appropriate clearance. .2 inches is not far off from a quarter inch (.250"). We're measuring engine clearances not doing carpentry. In your example you're missing a zero .4 or .0004 would both be considered 4 tenths depending on who you're talking to. Don't believe me ask a machinist?

Neal

 

[Ttype6]

.4 or .0004 would both be considered 4 tenths depending on who you're talking to. Don't believe me ask a machinist?

Neal

If we have two or five zeros we can't call it tenths?
Is there a math book that you could recommend that would explain this?

 

[750H.P.V6]

Where are we going with this conversation? As I already stated that it's standard in the machine shop / engine building industry to abreviate any measurement in ten thousandth's of an inch as "tenths".

Taking this a step further .2 would be 2 tenth's of an inch, .02 would be 2 hundredth's of an inch, .002 would be 2 thousandth's of an inch and last but not least .0002 would be 2 ten thousandth's of an inch which in the trade is referred to as 2 "tenths".

If you were to specify a clearance of 4 tenth's no competent machinist is going to think you mean just over 3/8th inch. If this isn't clear enough I don't know what to tell you.

Neal

 

[earlbrown]

4 to 7 tenths was the little end. 2.9 thou was the big end.


It's also odd the rod got pulled apart. A turbo engine is nicer to rods in that respect since the piston inertia gets dampened a little at TDC exhaust.

 

[turbobitt]

Where are we going with this conversation? As I already stated that it's standard in the machine shop / engine building industry to abreviate any measurement in ten thousandth's of an inch as "tenths".

Taking this a step further .2 would be 2 tenth's of an inch, .02 would be 2 hundredth's of an inch, .002 would be 2 thousandth's of an inch and last but not least .0002 would be 2 ten thousandth's of an inch which in the trade is referred to as 2 "tenths".

If you were to specify a clearance of 4 tenth's no competent machinist is going to think you mean just over 3/8th inch. If this isn't clear enough I don't know what to tell you.

Neal

I agree and just about every machinist would refer to .400 as four hundred thousandth and not .4 tenths. It's just the way there precision brain works.

 

[Ttype6]

I agree and just about every machinist would refer to .400 as four hundred thousandth

.400" is four hundred thousandths of an inch.

 

[turbobitt]

.400" is four hundred thousandths of an inch.

Now your getting the picture

 

[Ttype6]

Now your getting the picture

Wow,I was the first person in this thread to correctly state what each digit is called as we move to the right of the decimal point. All I did was correctly point this out because someone else was confused by the incorrect terminology that was being used. Some how,you think I'm the one person who doesn't understand. Maybe you're confusing what I've written with some other thread.

 

[750H.P.V6]

You win.

Neal

 

[Ttype6]

You win.

Neal

I'm simply correct. If you want to call a banana an orange,you're free to do so. Please be warned that you'll be creating a lot of confusion when you do this.
Because A2000RICH stated that he liked to shoot for 4 to 7 tenths pin to piston clearance and found it to be 2.9 thousandths and also stated that 2.9 thousandths was looser than the 4 to 7 tenths that he would like to see,Rafs-T-Type was confused.
A2000Rich then went on to say that 2.9 thousandths (29 ten thousandths) was looser than than 4 to 7 tenths. It's not. If we state the dimensions correctly,29 ten thousandths of an inch is looser than either 4 ten thousandths of an inch or 7 ten thousandths of an inch. Because A2000RICH called a banana an orange Rafs-T-type was appropriately confused. I was not.

 

[87-WE2]

Now I'm confused. Is the piston the banana or the orange? Guess it doesn't matter - either way his fruit salad is toast. Mr. Clark set the record straight. Back on topic.

If the rod is suspect, I wouldn't send it back to Eagle I don't think. To get them to do an analysis would be like getting the fox to watch the henhouse. I'm associated with about 10-12 metallurgical failure analyses a year and the steel manufacturer NEVER conducts the analysis. The subject piece is sent to an independent lab for analysis (usually paid for by the owner of the failed piece), and the manufacturer is allowed to witness or monitor the procedures. The results are then presented to the owner, and he shares the conclusions with the manufacturer only if he wishes to.

Just my experience.

 

[richardv6]

Wow. I am glad that's all figured out.

 

[Mike E]

Wow,I was the first person in this thread to correctly state what each digit is called as we move to the right of the decimal point. All I did was correctly point this out because someone else was confused by the incorrect terminology that was being used. Some how,you think I'm the one person who doesn't understand. Maybe you're confusing what I've written with some other thread.

You're in the heart of machine shop country. Please go to all the machine shops and tell the seasoned old machinist they are doing it all wrong and tell them how to do it correctly. And have a friend tape the interaction for us.

It may not be technically correct to call .0001 a tenth, but it is the way it is. Whether you like it or not. It's slang, becuase saying ten thousandths over and over and over all day long gets tiring.