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PostPosted: Thu Oct 19, 2006 11:03 am
by russell
Anyone ever used the hole duplictor offered by Spruce? If so how well does it work? Or any duplicator for that matter.


PostPosted: Sat Oct 28, 2006 5:34 pm
by JPXman
hey russell

can't you just lay the aluminum over the sparcaps, and use a marker to mark the hole on the inside of the new skin? then take the skin off, drill, and away you go? i had a hole duplicator and i found that it didn't quite work as perfectly as you need to make a nice tight fit around the nose ribs. just get a few holes, and then cleco it in place, and mark the rest.... something like that.

I also found the best way to put a splice on the leading edge was to rivet it on one side along the sparcaps, bottom or top, and then work the rivets up around the d-cell as you go, keeping the skin tight against the nose ribs and flat, and then when you get to the top, it is nice and flush on the other sparcap, and tight against the noseribs. I used ratchet straps around the D-cell to keep the skin tight on the noseribs.


PS: i guess i should add that i used cleco's (temporary rivets) until ALL holes were drilled, then i put the PL Premium glue on the noseribs, and cleco'd the skin back in place (to put it on quickly to let the glue get drying properly). then you can go along every 2nd hole and put in a pop rivet, take out all the cleco's and pop the rest of the rivets.

PostPosted: Mon Oct 30, 2006 3:05 am
by ozzie
if you are not getting the results from a hole duplicator you can try using a small right angle drill and backdrill the holes. i found that this worked better for me. just be carefull to not damage the spar with the chuck.

PostPosted: Mon Oct 30, 2006 8:05 am
by russell
Tyler, the problem I have with marking the holes and then drilling is that I can't seem to find the center of the mark and the holes are always off. Wrapping the skin around the D-cell and drilling through the holes in the spar sounds like the best solution. I like the idea of using the ratchet straps. Did you try to form the skin before wrapping it around the D-cell?

Ozzie, Shannon had also mentioned the use of the right angle drill and Tyler's method would require the use of one also I'm sure, so I'm watching Ebay and the like for one to show up before buying a new one locally. I could find other uses around the shop for one anyway. Thanks for the suggestion.


PostPosted: Mon Oct 30, 2006 12:48 pm
by flyalaz
Maybe something like this will help?


PostPosted: Mon Oct 30, 2006 1:35 pm
by russell
Yeah Karl, that's like the device that I found on the "Spruce" web site and was asking if anyone had tried it, but they called it a hole duplicator. So far the opinion I received wasn't favorable. Have you used one?


PostPosted: Mon Oct 30, 2006 4:17 pm
by Shannon
I purchased that hole duplicator thing you mention from Spruce. Never used it once during the entire rebuild.

PostPosted: Mon Oct 30, 2006 7:45 pm
by flyalaz
Hi Russell,

I used models like the bottom one all the time while I was working on Challenger jets.
There are many styles for front and back hole finders. The flat bar type is the most common, and is best between skins (with the pin facing down), and that block type is my version to get past obstructions and under the hole as opposed to on top of the hole.. They ALL need to be flat to the surface, otherwise any angular difference translates to moving the hole away from center. I had great success with them, but a little practice on scrap parts would be the best thing to do before working on your plane.

- Any lift between parts will change the hole location.
- Better to go under than in between (if possible)
- If unsure, drill #40 first, then pull hole as required.

Another option you can use is a long drill bit (12") and spot your holes. By pushing the bit straight, the angular change isn't that bad, then you can remove and drill straight.


PostPosted: Tue Oct 31, 2006 7:55 am
by russell
Shannon, from the photo's you sent to me of your skin overlay, the method you used worked out very nicely.

Karl, I like the block duplicator you devised and I can see just how critical being flush to the surface can be. I would liked to have had that when I was making new lower strut fittings. I had to make seven of them just to wind up with four that I was satisfied with. I'm more picky than talented which can be quite a frustrating combination!