Stock duplicating. Have you done it? Advice and insight.

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D.Pagenkopf

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In the last year I have created a stock duplicator. Over the last two months I've been working away at it and improving parts as challenges come up.

There always seems to be something that happens in the process and I have a custom piece of maple firewood...

The set up is basic. A rigid gantry that slides back and forth on linear bearings. The router and stylus move up and down on a pair of parallel square tubing arms. The router and stylus move left and right on a linear bearing and an angle iron support.

The rotating assembly is chain driven. I only turn in one direction. The unit is locked by half moon clamps with 1/2" bolts.

The master stock is clamped by a custom clamp setup to try and prevent movement.

The most recent additions to the unit are the linear bearings to the gantry unit, the custom clamp and a new Bosch router.

I'm copying a Winchester 94 stock right now. I custom cut a wooden support piece and hot glue it into the action.

My basic protocol is start by measuring distance between stylus and router. Check bit depth on my straight edge. Clamp master. Cut the action inletting. Change bits, check bits depth. Cut shaped butt. Every time the stock is adjusted it is clamped in place.

Will post pictures later today.
 
D.Pagenkopf said:
In the last year I have created a stock duplicator. Over the last two months I've been working away at it and improving parts as challenges come up.

There always seems to be something that happens in the process and I have a custom piece of maple firewood...

The set up is basic. A rigid gantry that slides back and forth on linear bearings. The router and stylus move up and down on a pair of parallel square tubing arms. The router and stylus move left and right on a linear bearing and an angle iron support.

The rotating assembly is chain driven. I only turn in one direction. The unit is locked by half moon clamps with 1/2" bolts.

The master stock is clamped by a custom clamp setup to try and prevent movement.

The most recent additions to the unit are the linear bearings to the gantry unit, the custom clamp and a new Bosch router.

I'm copying a Winchester 94 stock right now. I custom cut a wooden support piece and hot glue it into the action.

My basic protocol is start by measuring distance between stylus and router. Check bit depth on my straight edge. Clamp master. Cut the action inletting. Change bits, check bits depth. Cut shaped butt. Every time the stock is adjusted it is clamped in place.

Will post pictures later today.
Click to expand...
I’d love to see your pictures, because I’m also building a rotary carving duplicator for manual use.
 
I have two duplicate carvers now one home made , the other professional. Looking forward to your pictures. Best advice now would be to invest in dust collection system and good quality dust mask. Then practice lots on soft wood first .
 
One interesting concept that I noted while I was sort of designing this thing in my mind, was a mention somewhere to use an oversized tip on the stylus for rough dimensioning. That makes a fair bit of sense to me.
 
Eagerly awaiting your pics, congrats!

Also planning on making a duplicator albeit of limited size, something using a laminate trimmer as the cutting tool and skateboard-wheels running on steel pipes for movement.

 
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As an old school tool maker I spent a couple years running duplicating machines cutting mould cavity. These were the days when CNC machines were a new concept for a tool shop. Wood of course is much more forgiving than tool steel as far as depth of cut and cutter paths. We used to start off leaving .250"/side with .200" depth of cut when we were roughing, so the stylus was .5" bigger than the cutter. For finishing (before CNC machines) we would finish at .005/side after heat treat.
Once CNC machines became common on the shop floor the duplicators would still start off with +.250" per side and finish leaving .060" per side and let the CNC machines take care of the finish work.
 
mooncoon2 said:
why did you use a round nose cutter as opposed to a square nose ?

cheers mooncoon
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Sorry, I wasn't saying that's my setup, it's just the most deluxe pantograph copier I have seen.

The answer to your question though is that the profile of the cutter has to be the same size as the tip on the follower if the cutter is to exactly follow it. Sometimes the sides are used for example.
 
Sorry to thread-jack, but if anyone here starts duplicating stocks as a service, I would be very interested. As have probably hundreds of other people as I searched this subject on this forum - it's kinda hard to find people doing stockmaking right now, pretty much all the reputable builders I've talked to are either retiring or booked up.

I have a SxS shotgun and blanks I need duplicated and a weird Mauser 71 sporter project that I need to copy inletting for.
 
There have been stocks advertised having been carved on a multi-axis machine (Don Allen). Most pantograph carving machines have three axis movement. Longitudinal, left/right, up/down. This machine added another. The heads could tip forward and back to enable more carving detail. Apparently one of these machines can produce 95% stocks.
I have used a North Star carving machine. North Star was the industrial standard for many years. The one to which I had access was 12 spindle - up to twelve cutters, with a center stylus position over the pattern. It had six motors, each driving two cutters using flat belts. I never tried more than six blanks at a time. Dangerous machine. Very loud, lots of exposed high speed belts and cutters. Could sure generate a large pile of chips in short order. It was also old and not all that precise. Fairly high scrap rate. Eventually gave up and sent the master pattern to Fajen, who produced the needed stocks. Simply more efficient to out source the stocks.
Incidentally, vibration can be a problem. Not so much with a short stock, but certainly with a long muzzleloader full stock.
I wonder how Jim Kibler machines his long stocks using a CNC machining center. This is one aspect of his operation about which he does not post videos.
 
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