I am so very sorry Sylvan for not having gotten back to your question that you asked me about gunstocks. I got wrapped up in some things around the house and I forgot to get back to the thread. I need to start putting "sticky note" reminders on the monitor!
I had bought a duplicator that a buddy had gotten for himself but didn't have enough public demand for his carvings to justify keeping the thing. I liked it for its ease of use for some things, but it had some design flaws so I ended up building a small CNC mill with a vacuum clamp that I ran off a laptop. A client of mine designs servo motors so I had a bit of a head start in that area and I wrote the drive software that would accept dumps from AutoCAD...unfortunately, it has its own limitations for doing gunstocks so I designed a different machine and built it using a 3HP Hitachi router as the drive motor/cutter....I still have that one in my storage unit.
One of the problems with all of the duplicators units that I have seen, including my own, was that most require the BUTT end of the stock that is going to be duplicated to be attached to a rotating fixture (like a little synchronized wheel). The wood that is to be the new stock is attached to the other synchronized wheel...yes, the two wheels are synced together and rotate in tandem. Where the PROBLEM lies is that at the FRONT of the gun stock that is the template pattern has to be attached to a spindle or some rotating fixture. The ones that I have seen and used require that the front "spindle" be attached to the template stock inside of the inletting...when duplicating the stock, the locator pin can't get past that front spindle on the template stock's inletting to complete the "tracing" of the pattern. That leaves an incomplete area in the new stock that has to be resolved manually.
I had designed a set of blueprints to make a new duplicator, but I didn't bother building it as I quit doing gunsmithing work as people were just too stressful and it just wasn't worth it anymore so building a new one would have been a waste of money (would have cost about $3K to build).
I looked at the machine that you provided a link for. It looks interesting and honestly, you CAN build quality instruments/tools without spending a lot of money and get great results...years ago, I but very high-end electric guitars with a duplicator that I built for under $200...but they didn't have to rotate 360 degrees like a gunstock has to when being duplicated (per the machines that I have seen and used).
I am not trying to put a damper on your flames of enthusiasm...the price of the plans looks to be very reasonable and the materials should be pretty cheap.
Here is the best advice that I can give to you...before you clamp a $300 walnut or fancy maple blank in the machine (if you build it), test the quality of what you can produce by using a "workable" wood like Poplar...heck, you can go to Home Depot and get dimensional Poplar for about $30-40 and laminate it together to have a "stock blank" that is 40+" long x 2 5/8 - 2 3/4" thick to test on! That way you can get the feel of the machine and get to know what it can do and how it does it and work out any bugs that you may discover while refining your technique!
I still have one of my duplicators in my storage unit, but the thought of getting it out and hauling it back to my shop at home kills me...laugh.
Anyway, I HAVE built some that worked great...they were machined aluminum
and steel, but never let somebody tell ya that you have to spend a TON of cash on one...just really give some thought to the process and test test test BEFORE you start on an expensive piece of wood.
If you need help...just give a whistle. Is the email address that you have in your profile here at Dianawerks Collective a good address? If I can contact you via email or phone, I'll help all that I can.
-Curtis