by Bill Gaylord » Mon Nov 21, 2016 3:31 pm
On the 500 series and small 900 series, I've had some of the best die-cutting I've come across with them. Had a 500 series Hellcat, where the die-cut parts were like laser cut. They were that good. I try to remember that at the time, die-setting was a real art performed by old-time craftsmen. Many builders would have been less accurate cutting by hand, which is why they gravitated toward die-cut kits, versus cutting by hand with a print wood kit. Guillow's again had what I've seen to be pretty accurate parts, compared with a few other manufacturers. I've seen comments such as "parts not matching plans". When you take a 1mm thick line from a drawing, and then transfer it to die-cutting, it's easy to have a +/- 1mm tolerance from perfection, even if the center of the hand drawn lines were CAD perfect, which they weren't. I'm working on a hand drawn design now, where I had to pad one former about 1.5mm in one area, and deck another about 1mm tops. That small bit of difference would have made the difference between a perfect smooth curved fuselage, and obvious bows in the transition. I tried to correct my original templates to reflect the change, but I could imagine if they were transferred to die-cutting, it would be easy to end up with the same scenario I had, where 1mm here or there of adjustment was needed.
My only issue with the older kits was unmatched and heavy wood. When you get a kit where one sheet of fuse formers are contest wood, and the other are oak, then that presents a problem. At least match them, so I can either remove a lot of wood and still benefit from the strength of heavy wood, or give me light matched sheets so I can laminate stringer reinforcements across the weak cross-grain areas and be efficient about it. Same goes for oak main spars, where you can't afford to add 15 grams of weight for main spars and leading edges. I've also had kits with one spar rotted carrot soft, and the other hard as oak. I still end up replacing those parts on the newer kits, as I can usually find or cut lighter and better matched spars from my own stock.