H

Haackeye

Member
As a newbie without prior parts fabrication experience, I would appreciate some photos and text showing a raw piece of stock marked with layout lines and an explanation of the techniques used to layout and prepare the part for cutting, drilling, etc. Some simple parts like Rudi's close proximity riveting tool and a few more complicated parts called out in the RV-12 plans would be truly helpful for me and perhaps for others.

Even better would be videos (similar in concept to the rib fluting tutorial posted by Alan Gilmore) but showing how to layout the part on raw stock, make the initial cuts using the appropriate power tool, drilling any holes, (with explanation of any alignment jigs used) and then filing, sanding and finishing the part.

This may be elementary or simplistic to those who are comfortable with shop techniques but I took academic classes in school and do not have the benefit of learning shop techniques while in school.

Thanks!

Larre Haack
"Haackeye"
 
Parts Fabrication for Newbies

Hi Larre,

Yours is a good posting as it reminds us to look carefully at the drawings
before we commit the design to metal. The rule of measure twice; cut once
is a good one.

Here are some general things to keep in mind:

If you can't see or fully understand what is being required in the drawing, STOP.
It probably won't get any better by applying tools to the problem. Go back to
the pictorial drawing and review the assembly as a whole.

Pick out the important datums (data?) in the drawing. These are the essential
locations or sizes that are fixed. They usually fit to other parts in a particular way (some parts are made twice, but in right hand and left hand versions,
ie, mirror images of one another). Measure from the datum out to other points.

Leave hefty margins in your cutting to avoid costly errors. Haack (couldn't resist) saw or band saw for roughing out and then use a coarse
grade abrasive on a sanding disc or belt to fine tune your shape.
Files of all shapes and cut give good results without the 'WOW, that
happened rather fast' factor. The Scotchbrite wheel leaves an acceptably
fine surface for finishing and installation.

Van's designs incorporate accepted edge margins and rivet pitches, etc.
It would be sensible to review these rules in the Standard Aircraft
Handbook, FAA AC 43:13, MIL-R-Spec 47196 (see Van's web links), etc.

Do not use pencils or scribes to lay out on aluminum. The 'Sharpie' brand
of permanent marker is an accepted layout tool. Use their 'ultra fine' tip model. Avery Tools offers an edge marking gauge that uses the sharpie pens.
Use this for parallel lines, marking margins, etc.

A small engineer's square is very handy in locating right angles. These
can be found in adjustable versions.

Finally, it may be useful, in the early stages, to make test pieces out of
hardware store Al to get your technique and confidence up to speed.
Just make sure these are marked 'not for aircraft use'.

All the best for good building.

Sam
 
Is this a general curiosity or do you have one of the RV-12 kits already? If the request is for general information you can most likely find some videos on youtube (not necessarily aviation related).

If you have one of the kits in hand perhaps you can get a local EAA member to stop by and help out. I would consider coming up there if you have one of the kits as I'd like to see one with my own eyes :)
 
Thanks for the responses so far

I appreciate all the advice offered by Sam.

Jetrep - I do not yet have an RV-12 kit, but I do have a complete set of plans for both the tail group (can't remember how to spell that french word at the moment) and the fuselage.

In addition to the plans I also ordered some angle stock and some AEX Tie Down stock from Van's to practice fabricating the A-1207 Actuation Brackets and the A-1208 Pivot brackets called out on Page 18-02 in the Wings plans. I made a copy of that page when I visited the factory in October.

I plan to practice fabricating some practice parts on the complete plans sets for the empennage and fuselage too to validate my ability to fabricate parts before commiting to the kits. I think I can assemble parts, but am not confident of fabrication until I prove to myself that I can do it successfully.
 
Haackeye said:
In addition to the plans I also ordered some angle stock and some AEX Tie Down stock from Van's to practice fabricating the A-1207 Actuation Brackets and the A-1208 Pivot brackets called out on Page 18-02 in the Wings plans. I made a copy of that page when I visited the factory in October.

I plan to practice fabricating some practice parts on the complete plans sets for the empennage and fuselage too to validate my ability to fabricate parts before commiting to the kits. I think I can assemble parts, but am not confident of fabrication until I prove to myself that I can do it successfully.
Click to expand...

If you successfully fabricate these two different parts and the tie down anchor brackets, you will have completed just about all of the parts you would be required to fabricate for an RV-12
 
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