How good is "good enough"?

Homebuilt Aircraft & Kit Plane Forum

Help Support Homebuilt Aircraft & Kit Plane Forum:

Kurt Ayres

Member
Joined
Oct 12, 2019
Messages
12
I'm beginning my second (scratch) build. The first had very little sheet metal work, while this one is all metal. So, as my thread title asks, how good is good enough on the parts I make? I know that they will never be as pretty factory-made ones, but how much "wave" in the flanges or little dents from the forming hammer, for example, is okay?
 

Twodeaddogs

Well-Known Member
HBA Supporter
Joined
Jan 18, 2009
Messages
1,200
Location
Dunlavin, County Wicklow,Ireland
Very minor errors won't matter but you should always strive for best finish. No need to be insanely perfect because it will head wrecking. I know of one guy who kept rejecting parts he had made because the line of rivet holes weren't laser straight. You could have built another aircraft from the stuff he was putting aside. Strive for airworthiness before perfection.
 

TFF

Well-Known Member
Joined
Apr 28, 2010
Messages
15,839
Location
Memphis, TN
It’s your opinion of airworthy.

Is it going to hold together? That is the first judgment call. Will it fit? Second call. Are you proud of it with what you had to work with? Not everyone has the same tool access or skill, but you need to be happy with it. Will you stick your kid in it? Nothing more important than that.

A lot has to do when the learning curve. Sometimes a part has to become a practice piece so you know how to do the official better.
 

wsimpso1

Super Moderator
Staff member
Log Member
Joined
Oct 18, 2003
Messages
8,476
Location
Saline Michigan
I know of one guy who kept rejecting parts he had made because the line of rivet holes weren't laser straight.
It sounds like he needs to investigate better tools and techniques. Proper use of layout tools, a sharp center punch, sharp drills, and a drill guide can make for straight lines of equally space rivets.

I have seen too many folks who are not laying out parts with precision, not center punching or not punching on the lines, using dull drills and crooked to the surface, and then being upset with their results. Good work results from good tools applied with good technique.
 

proppastie

Well-Known Member
Log Member
Joined
Feb 19, 2012
Messages
5,336
Location
NJ
ex wife could not hold a screwdriver square to the screw.....so drill square, hold the rivet gun and bucking bar square 1-1.5 diameter sticking out before you buck a rivet is easier than 2D.....if you screw one up often it is easier to add another rather than bugger up drilling the bad one out. ......have fun
 

Dan Thomas

Well-Known Member
Joined
Sep 17, 2008
Messages
6,373
You can save money and time if you take some metal and practice forming it, drilling it, and riveting it. Make your learning-curve mistakes on stuff that won't become part of the airplane, and then you'll make the flying stuff so much better once you have the hang of it. Don't be so impatient that the first rivet you buck is on your shiny new project. It doesn't work, and that mess will be there forever for everyone to see.

Your first training flight is not a solo flight. There are reasons for that. Perfection, or even acceptable performance, is not achievable at the first go.
 

gtae07

Well-Known Member
Joined
Dec 13, 2012
Messages
2,193
Location
Savannah, Georgia
Make your learning-curve mistakes on stuff that won't become part of the airplane,
Practice kits (like the Van's toolbox, or their old aileron practice kit) are great. Non flight critical yet still something that looks "real" and maybe even useful, so it keeps your attention better. I've found I work harder and pay better attention if I'm working on something interesting rather than boring practice coupons.
 

Twodeaddogs

Well-Known Member
HBA Supporter
Joined
Jan 18, 2009
Messages
1,200
Location
Dunlavin, County Wicklow,Ireland
I had to demonstrate riveting techniques and practises to a group of builders and the method that best captured their interest was to hang a sheet of commercial aluminium on a frame and get them to practise riveting in a straight line. When set up in teams, they actually git quite competitive and made great efforts to beat the other guys. When they had made their lines, we then bashed them with an axe and made them carry out repairs in the approved fashion.
 
Top