To scrap or not to scrap?

[dicej32]

I'm building an Upshur farm engine. Due to my initial problems with drilling holes accurately in my drill press (separate thread) my front plate has a bored hole which ended up .028" off center to the left as measured between the inside of the bore and the side of the plate on both sides.

As seen by the photo, its barely noticeable to the naked eye and being a part that took a few hours to make with some hand filing done I'm skeptical of starting over. The cylinder holding stud holes haven't been drilled yet so they'll just be moved over by the .028". Any comments, ideas? Do i scrap it?

Thanks,

Jenaro

 

[Lew Hartswick]

Just take 028 off the right side and it'll be centered.
...lew...

 

[rake60]

Lew's solution is a PERFECT answer!

No one will ever know but you.
I don't know things work in you home shop, but in my own
the QC inspector in one hell of an easy guy to please.

If it can be fixed, salvaged or hidden, it was never wrong in the first place...

Rick

 

[deere_x475guy]

Lew's solution is a PERFECT answer!

No one will ever know but you.
I don't know things work in you home shop, but in my own
the QC inspector in one hell of an easy guy to please.

If it can be fixed, salvaged or hidden, it was never wrong in the first place...

Rick

Take a look at this cylinder, see the red circle...yeppers..it doesn't belong there. I did that as a last operation....after I had way more hours in it than I want to admit :. I about crapped when I realized my error. I walked way and thought about it for awhile and realized where it's at I could just screw a plug in it. ;D ;D. Never scrap if you can work around it. So far I have been able to work around most of them..)...

Bottom line, don't scrape it....the others have already given you a great work around...

Bob

 

[Philjoe5]

I'm fairly new to model engine building (less than 2 years) so I guess I approach each new engine I build as a learning experience. If I make a mistake, but the part is salvageable, I press forward. The one instance where I might not do this is when several other parts have to be changed to accomodate the out of spec part. I just know I'd forget to make the necessary changes, then things get too complicated for me. If the completed engine runs I soon forget about the fact that I might have made the piston 0.010" too short or whatever. If the engine doesn't run I know where to start looking to make new parts. Even if the engine runs, I may make the whole engine again, just because it's so much fun to seem them run. I usually don't make the same mistakes twice ;D

Cheers,
Phil

 

[Bogstandard]

Jenaro,

Look at the signature at the bottom of my post.
If you are happy with it as it is, and it won't affect the running of the engine, stuff it and carry on.

If it can be fixed, it was never wrong in the first place.

It will be your engine, learn from your mistakes and carry on.

I make mistakes all the time, my recycle box is full of bits that couldn't be 'fixed'. If you don't make mistakes, how are you going to learn how to improvise when the time really comes.
If there is a person on here who has never made a mistake, then I would expect him to have a paddle in deep water without sinking.


John

 

[dicej32]

Looks like I'll be taking off the .028 from the right side. Thanks for all the suggestions. I'm learning quickly that it's real easy to make crooked stuff. Certainly a learning curve there.

 

[te_gui]

I have heard it said the difference between a "good" machinist and a "great" machinist was the ability to overcome and adapt to mistakes and have a successful outcome in the end. Since this whole process is for most of us a huge learning experience, the process of working thru a mistake is a great exercise in thinking beyond the box, and can lead to some exciting discoveries. I am my own worst critic for most of my projects so as long as I can live with it, who really cares about the rest of the world.

 

[DickDastardly40]

Good advice above!

Are the two smaller holes as shown drilled in relation to the bore or the sides and will whatever fastening that goes through those holes impinge on the cylinder as it is potentially 0.028" closer to one hole than the other?

The best thing about building anything from scratch is if you get to a stage where you can't resurrect a mistake you don't have to buy/source an elusive casting.

The downside I suppose is that you'll probably have more time in the part when it becomes scrap, but then again as mentioned by BS scrap for this engine is potential material for the next, so it's all good!

Al

 

[Bernd]

Well since we are showing our little "engineering changes" on our projects. :big: :big:
I'll include mine. I've come to the conclusion I must be dyslexic. : I'm building the wobbler from Elmer's engine. The frame has a hole in it with a counter bore to hold the spring which holds the piston to the frame. I drilled the hole but forgot to turn over the piece to counterbore the hole. I was about to make new frames (I'm building two at once) when it came to me to just build a mirror image of the wobbler.

Now I guess I'll have to call them the reverse wobbler. :big: :big:

Bernd

 

[wareagle]

I'm building an Upshur farm engine. Due to my initial problems with drilling holes accurately in my drill press (separate thread) my front plate has a bored hole which ended up .028" off center to the left as measured between the inside of the bore and the side of the plate on both sides.

....... Any comments, ideas? Do i scrap it?

Thanks,

Jenaro

Okay, rules of thumb in the shop:
1) In regards to the outcome of a part in the home shop environment, everything turns out perfect. Remember, this is for FUN, and odds are it is not a part for NASA.
2) If it is wrong, won't fit, backward, or ______ when you are done and unsalvagable, then it was a procedural test piece. If anyone argues, refer to rule number one.
3) If it is salvagable, refer to rule number one.

Jenaro, your particular piece was machined that way, not out of error, but for "measurment" and "fixturing" purposes.

 

[Brass_Machine]

Okay, rules of thumb in the shop:
1) In regards to the outcome of a part in the home shop environment, everything turns out perfect. Remember, this is for FUN, and odds are it is not a part for NASA.
2) If it is wrong, won't fit, backward, or ______ when you are done and unsalvagable, then it was a procedural test piece. If anyone argues, refer to rule number one.
3) If it is salvagable, refer to rule number one.

Jenaro, your particular piece was machined that way, not out of error, but for "measurment" and "fixturing" purposes.

Heya Wareagle... you forgot one. If it is a cool looking part and it doesn't fit or whatever... it is now MACHINIST ART :big:

Eric

 

[Tin Falcon]

I have said before but it bears repeating. The home Shop is like a college engineering lab no mistakes not scrap but lots of learning experiences!!!
It is only a bad experience if someone is heart or serious damage to th machines occur.
Tin

 

[compound driver 2]

Hi
making mistakes is not a problem, not learning from them is a mistake.
Make the part again and see if you can improve on it. That would be my
way about it.
Mind you that all said and done engines like this should work with 5 or 10 thou
error with out much problem. Like the guy said these are not destined for NASA
or a power plant. So just enjoy the build and watch the scrap pile grow.

Cheers kevin

 

[Tin Falcon]

another thing that can be doneis think outside the box. Forinstance you tap the wrong side of the cylinder block on a McCabe runner engine you in theory could just make a mirrior image of the engine assuming the base is not yet made. I am not saying I actualy did this LOL
Tin

 

[shred]

.. and when your "practice" pieces get too small to adapt, put them in the 'to be cast into something else' bin... who cares if you aren't set up to cast iron yet

Seriously my problem usually is compounding a mistake rather than stopping right there to think about it. Ways to salvage the original error always occur to me after I've messed it up unrecoverably with hasty attempts to fix the first one..

 

[PolskiFran]

Depending on the the amount of "shoulder" on the cyl. sleeve, it may be possible to locate the plate in the correct position and rebore to "clean up" the original bore. Then make the corresponding part , cyl. sleeve, to match the dimension in the plate.

Some people have a "humble box". I have a "humble pile".

Frank

 

[rake60]

I'm not very organized in my stock storage.
Just steel, brass and aluminium bits tossed into
boxes on the floor.
It looks very much like this.

Isn't it odd that many pieces of that stock very
closely resemble engine parts?

Rick

 

[Bogstandard]

Rick,
I will bet you that with what you have there, dozens of engines can be made without buying any more materials. Imagination is what is called for when looking at bits like that, visualising what is in there trying to get out.
If you can do that, you are in the same league as Michelangelo Buonarroti, it was purported that he could look at a piece of marble and visualise the statue within.
Shame he couldn't make little engines.

John

 

[Philjoe5]

John,
Do you mean something like this? :big:

Cheers,
Phil