Another drafting question...rocking engine...

[zeeprogrammer]

Attached is the drawing of the cylinder for the rocking engine with some notations from me. [Tried to attach drawing...but many of you know this engine.]

There's some dimensions I don't understand.

A number of people have made this engine but I don't recall anyone commenting on the dimensioning.

Calculate overall length of bottom drawing...

Bottom right drawing shows 0.4 for cylinder depth.
Upper right drawing shows 0.55 for cylinder depth plus the end that has the 10-32.
Difference is 0.15.
Add that to bottom drawing of .87 and you get 1.02.

Calculate overall length of upper drawing...

Bottom right drawing shows .87. Subtract .4 and the bit that gets milled out is .37.
Add that to the .55 of the upper right drawing and you get 0.92.

Where's that 0.1?

I'm thinking that what's important is the distance from the crankshaft hole to the cylinder and the depth of the cylinder.

What is reference?

Why is the .87 in parentheses?

This may be simple to experienced people...but it's a little frustrating to me. 0.1 seems an awful big difference. Or did I do something wrong?

Thanks.

And don't get any funny ideas. This doesn't mean I'm building the rocking engine. ;D

 

[CrewCab]

Bottom right drawing shows .87. Subtract .4 and the bit that gets milled out is .37. .47
Add that to the .55 of the upper right drawing and you get .92 1.02.

 

[Maryak]

Zee,

That's what happens when it's not to base 16. ;D

Best Regards
Bob

 

[mklotz]

I think I understand now where a lot of these "measuring errors" are coming from.

 

[Brian Rupnow]

On engineering drawings, if a dimension is shown in parenthesis, that means is is a "reference dimension", and that it is put there for your convenience. These dimensions are a "resultant", that is to say, if you have made the parts correctly based on OTHER dimensions, the dimension in parenthesis is what will "result" from doing so.---HOWEVER--You should not use this dimension to make your part from.

 

[zeeprogrammer]

Aw good grief. I did this three times!!! I can show you. It's on three drawings.

I have two options...

1) Take the high road. Fess up to being a dummy and wasting everyone's time.
2) Take the low road. This was a test. You all passed.

There's a weak 3rd option...life is a bit confusing lately...wife home after a year overseas...daughter 1 having our 1st grandchild...daughter 2 leaving today for college...

Aw who am I kidding? Stupid. Sorry. It's option 1.

Bob...that's why I should've done it in base 16. I'm more used to that.
Marv...I'd be good if the DIs were in hex.

Brian....thank you thank you! Some real help there.

Is there a 'nyah' smiley for these other guys? :big:

Geesh this is embarrassing. Thanks all. Hope you enjoy.

 

[Kermit]

Geesh this is embarrassing. Thanks all. Hope you enjoy.

You, dear friend, are proving yourself to be just like the rest of us.

Pants on one leg at a time or something like that, eh?
Kermit

 

[zeeprogrammer]

Pants on one leg at a time or something like that, eh?

Pants? Oh...right...gosh durn it...where are they?

Thanks Kermit. I appreciate it. I just hate wasting other people's time...it's worse than having mine wasted (which is rare on this forum).

 

[CrewCab]

This was a test. You all passed.

;D Cheers


CC

 

[vlmarshall]

This was a test. You all passed.
Thanks all. Hope you enjoy.

Wooohooo, what'd I win? ;D

 

[zeeprogrammer]

It's in the mail Vernon.
Same prize for all the other winners. Just pick it up at Vernon's.

 

[vlmarshall]

Same prize for all the other winners. Just pick it up at Vernon's.

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