Model Engine Maker

Help! => Mistakes, muckups, and dangerous behaviour => Topic started by: Jo on November 12, 2018, 09:04:55 AM

Title: Boo Boo Bin
Post by: Jo on November 12, 2018, 09:04:55 AM
I thought that it might be useful to start a Boo Boo Bin thread where we can all show that we are mortal and make mistakes. So it is only fair I thought I would start with a couple of my features that didn't make it into the final engine  :embarassed:


How many of you remember my numerous attempts at making the crankshafts for my Stuart Triples  ::)

Not so spectacular (or scary when they failed ) But the second photo shows undersized collets, heads where I got the measurements wrong, rotary valves were I put the pin in the wrong position. A bent con rod and piston where I forgot to take it out when I thought the crankshaft was stuck in a crank case and tapped it with a mallet :facepalm:

And my famous Stentor piston with the baffle 90 degrees out. :ShakeHead:


Is anyone else brave enough to be honest  ;)

Jo
Title: Re: Boo Boo Bin
Post by: Ye-Ole Steam Dude on November 12, 2018, 09:57:29 AM
Hello Jo,

You are very, very brave and honest. I wish that I could contribute some photos to this thread...... :mischief:. Don't get me wrong, I have made my share of Boo Boos, it's just I do not take any photos and do not want to be reminded  :lolb:

Have a great day,
Thomas
Title: Re: Boo Boo Bin
Post by: gerritv on November 12, 2018, 12:08:07 PM
This one from March 2017 when I was building my Eureka Relieving device. I took the description from ME seriously and carved this from solid. A lot of cutting/swarf resulted, one of my first serious jobs on this lathe. Everything seemed fine except that I got one of the eccentrics offside :-(
The part looks great on my wife's desk as a paper weight!

(I made the replacement in 3 parts, a lot less cutting and lower risk of things going wrong.)
Title: Re: Boo Boo Bin
Post by: Gas_mantle on November 12, 2018, 02:18:03 PM
I guess a lot of us have at some point made one of these bent conrods.  ::)

In my case a deep cut caused it to ride over the tool, one for the boo boo bin  :Lol:

(https://farm5.staticflickr.com/4831/44028092220_7a8e60a78a_c.jpg) (https://flic.kr/p/2a5BtUh)

(https://farm2.staticflickr.com/1913/31973735218_250cff31ae_c.jpg) (https://flic.kr/p/QHpKwS)
Title: Re: Boo Boo Bin
Post by: gerritv on November 12, 2018, 02:51:49 PM
A bent con rod and piston where I forgot to take it out when I thought the crankshaft was stuck in a crank case and tapped it with a mallet :facepalm:

Jo
If that con-rod bend is from your tapping I would hate to be around when you seriously whack something with a hammer :-)

Gerrit
Title: Re: Boo Boo Bin
Post by: zeeprogrammer on November 12, 2018, 02:57:30 PM
If I post all my boo-boos...we'd be out of server space.

But here's my latest...

Two cylinder blocks that got slung out of the vise.
One cylinder block with the cylinder in the wrong place.
One con-rod with too much taken off one end.

Title: Re: Boo Boo Bin
Post by: Jim Nic on November 12, 2018, 03:25:04 PM
Peter, you're right.

I also have other "trial pieces", too numerous to mention, that end up being flung in the scrap bin usually without pausing to take a picture.  I do sometimes publicise my errors but generally they are a result of my own stupidity and I feel that others would not learn anything from seeing the results of that.

The picture below shows a mandrel with a centre machined on the end and 2 holes for the rod fixing bolts to fit into and transmit the drive.  The other bit is the reprofiled rod after the thought that "This is going well. I'll take a deeper cut." crossed my mind.

Jim

Title: Re: Boo Boo Bin
Post by: Gas_mantle on November 12, 2018, 03:58:19 PM

 "This is going well. I'll take a deeper cut."
Jim

Jim, that short sentence must account for half of all machining errors. The other fatal one is 'This is taking too long, I can save time by doing it this other way'  ;)
Title: Re: Boo Boo Bin
Post by: zeeprogrammer on November 12, 2018, 04:10:13 PM

 "This is going well. I'll take a deeper cut."
Jim

Jim, that short sentence must account for half of all machining errors. The other fatal one is 'This is taking too long, I can save time by doing it this other way'  ;)

Most of my boo-boos occur after thoughts like "Is that right?", "What's that sound?", "Something seems off.", "Huh?",...and I ignore myself.
I still haven't accepted the fact that my inner me is smarter than me.

My inner me needs to be more assertive.

Title: Re: Boo Boo Bin
Post by: Roger B on November 12, 2018, 06:32:51 PM
This cylinder head went in the bin, along with the first 8 pistons for my 3cc vertical engine  :toilet_claw:
Title: Re: Boo Boo Bin
Post by: crueby on November 12, 2018, 06:42:51 PM
Most of my bigger boo boos got hidden in the bilge of rc boats as ballast (and I have a bunch of boats!) or cut down for smaller parts.
Title: Re: Boo Boo Bin
Post by: Vixen on November 12, 2018, 08:54:01 PM
What happens when you type in a G00 Rapid Move command instead of a G01 controlled feed rate move?

(http://lister-engine.com/coppermine/albums/userpics/10013/DSCF5231.JPG)
Title: Re: Boo Boo Bin
Post by: crueby on November 12, 2018, 09:08:41 PM
What happens when you type in a G00 Rapid Move command instead of a G01 controlled feed rate move?

(http://lister-engine.com/coppermine/albums/userpics/10013/DSCF5231.JPG)
Looks like the make-a-spring command!
Title: Re: Boo Boo Bin
Post by: b.lindsey on November 12, 2018, 10:58:55 PM
When I was making the flywheels for the Tiny hit and miss engine which required 6 spokes, I miscalculated the RT rotation. It's 60 degrees, not 72 for six spokes... :facepalm2:. If anyone needs a partial 5 spoke though let me know  ;)

Bill
Title: Re: Boo Boo Bin
Post by: crueby on November 13, 2018, 12:21:38 AM
Bill, in that state it looks like a logo for the Poo Poo company!   :Lol:
Title: Re: Boo Boo Bin
Post by: b.lindsey on November 13, 2018, 12:27:10 AM
Minus a few "o"s once I realized what I was doing :paranoia:

Bill
Title: Re: Boo Boo Bin
Post by: Zephyrin on November 13, 2018, 07:21:00 AM
A wrongly sided camshaft doesnt look like a booboo as long as you are not trying to fit it in the  engine...

Title: Re: Boo Boo Bin
Post by: gerritv on November 13, 2018, 01:33:14 PM
When you are too focused on where you are cutting to notice where you are also cutting:
Title: Re: Boo Boo Bin
Post by: Mcgyver on November 13, 2018, 05:06:13 PM
my numerous attempts at making the crankshafts for my Stuart Triples  ::)


yeah, those Stuart built up cranks are a nightmare.  Save some time and toss them directly into the scrap bin.  I too made a pretzel, but redeemed myself from the solid

(https://i.imgur.com/RYBACz5.jpg)

(https://i.imgur.com/JCVK1XN.jpg)

Title: Re: Boo Boo Bin
Post by: crueby on November 13, 2018, 05:10:33 PM
Ouch!  And not even the right shape for a 'wobbler' engine!   :Lol: The replacement one came out great!
Title: Re: Boo Boo Bin
Post by: Jo on November 18, 2018, 04:22:41 PM
To make us all feel a bit better Eric let me photograph his attempts at Elf crankshafts to show you.

These are not only small and fiddly but the first batch he machined with the wrong throw  :facepalm:

Jo
Title: Re: Boo Boo Bin
Post by: Twizseven on November 24, 2018, 08:32:33 PM
Recently managed to obtain a Lenz LPA 1S Boring and Facing head.  It has a 40Int arbor and my colleague is making a MT3 arbor for it to suit my Chester Super Lux.  I had the nice simple job of making one of the limit plates as one was missing. Copy dimensions and shape from existing one no problem.  Spot the problem in the photo below.

I copied the existing Right hand one perfectly, unfortunately I did not turn it over to machine the guide.  So I have two lovely right hand plates.  Started again and marked up opposite hand and spent another couple of hours.

Just had to take the final couple of thou off the guide and the motor on the mill failed.  Bit of filing and it fits.  The correct one fitted on the left in the photo and the right hand spare the on the box.

Problem is I now need to find out whats gone wrong with the motor.  It just hums when press starter button.  Gave no indication of issues it had been running 5 minutes earlier.  Although had the machine about 10 years I doubt if it has been used more that 20 or 30 hours in that time.

Colin
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