Magnetic Hole Finder

[Kyle Boatright]

I'm looking for a tool I used (and lost, apparently) back when I was bulding my kit.

It was a piece of transparent green film, about the size and thickness of a credit card. To use it, you taped or glued a magnet to the inside of a structure and then moved the green film over the outside of the structure. When you got the film over the magnet, you could see the image of the magnet. Once you saw the magnet, you had external confirmation of the location of the flange (or whatever) you were trying to hit with your drill.

Does anyone know where I can purchase another one, since mine is long gone?

[Snowflake]

That sounds pretty cool. Was it accurate enough that you could use a donut-shaped magnet, and then drill down through the center of it without risk of damaging the magnet?

[az_gila]

...this one...

http://www.flyboyaccessories.com/sto...roducts_id=273

...and I have an older one that has a hanging wire that will point to a magnet placed on the inside of the work. The magnet has a #40 pin in it - can't find a reference to that style though.

[Kyle Boatright]

Originally Posted by Snowflake

That sounds pretty cool. Was it accurate enough that you could use a donut-shaped magnet, and then drill down through the center of it without risk of damaging the magnet?

It was very accurate. What I did was use rubber cement or low adhesion masking tape to hold the magnets in place. The adhesive would give way and the magnet would be pushed out of the way when the drill penetrated.

So, yes, a dougnut shaped magnet would have worked. But little round magnets are easy to find at craft shops, so that's what I used. Even if I nicked one, no problem.

[Rick6a]

For locating holes, an alternative to magnets that also delivers dead accuracy is to use transfer punches:

http://www.vansairforce.com/communit...ad.php?t=11999

I've used them many, many times in repair work where they really come into their own. Aside from that, before matched hole construction became the norm, I used transfer punches to locate all the pilot holes underneath (optional removable) flooring. Even after matched hole became the norm, I located the side skirts to the RV-8 canopy using transfer punches. It made very quick and accurate work out of a potentially tedius job. Something to consider.

[Ironflight]

I was recently sent one of these "Magkits" by a forum member to try - apparently, with all these prepunched kits, the need to find blind holes is greatly reduced from way back when men were men and.....

I was told that the fellow who produced the "Magkits" doesn't do it anymore (mine was a leftover) because of low demand.

Haven't had a chance to use it for real yet, but it sure is neat to see the magnet through the little viewer.

Rick, do you know where us mere mortals who DIDN'T work in an aircraft factory can get those transfer punches? I have always admired them when you post pictures....

Paul

[flytoboat]

Originally Posted by Ironflight

Rick, do you know where us mere mortals who DIDN'T work in an aircraft factory can get those transfer punches? I have always admired them when you post pictures....

Paul

I'm not Rick, but as a "mere mortal", I got mine at Harbor Freight. Search for item number "3577".
http://www.harborfreight.com/cpi/cta...temnumber=3577

[SvingenB]

I had to replace my skins on the HS of my -4 (no prepunched holes), and found the strap duplicators too large and clumsy to be useful because they would interfere with the jig. I made a small handy one from a SS ruler, an m6 bolt and a rivet.

http://rv-4-svingenb.blogspot.com/20...plicators.html

[Rick6a]

Originally Posted by Ironflight

Rick, do you know where us mere mortals who DIDN'T work in an aircraft factory can get those transfer punches? I have always admired them when you post pictures....Paul

Paul,

Virtually any mere mortal can purchase the little bits of hardened steel from Brown Tool:

http://www.browntool.com/Default.asp...,ProductNumber

Even Avery has a limited selection:

http://www.averytools.com/p-1057-hol...sfer-pins.aspx

[nucleus]

http://www.amazon.com/gp/product/B00...ss_T15_product

I like the kind that screw in for when you already have nutplates and need to make holes that line up above. Brown tool sell these also I believe.