finally time to experiment with Shaper Origin - dovetails

[Rob Young]

Been a while since I've had a block of time to play with my Shaper Origin. Things and other projects just kept taking priority.

Most of what I've used the Shaper Origin for in the little free time I've had is cutting templates plus a little inlay work. But its been on my mind for a while to see if I can use the SO to do a through dovetail. While this may not seem like a big deal, the tail being cut by the dovetail bit is an undercut. On the usual jigs, this isn't a problem. But because the SO is a handheld CNC and if you stray too far off the path it can't correct and so will automatically retract the bit. And that is gonna cause problems...

Anyway, a little bit of CAD to plan the paths (there are a few pre-made files that can be edited so that helps get things started) and I have two SVG files that represent the required paths for pins and tails. Cut up some aspen I had laying around and I've got all my test pieces. 

Interesting thing about doing it this way is there shouldn't be the usual steps a jig has where you need to fiddle with the template or bit depth to get the fit right. The SO doesn't have this issue. So long as you have reasonably accurate measurements of the stock and bit sizes you can have paths the have built in a few thousands extra gap for glue.

And dang if it didn't work! Need to update my CAD file with about 0.5mm more board thickness so the pins/tails are proud. As designed I ended up with a flush or slightly recessed fit. Bit more work to flush that way. But fit right off the machine. Part of that is aspen is soft enough to squish just a bit when forcing the joint together the first time.


Now to go ahead and cut up the rest of the joints and then make a groove for a bottom. The SO is really good at stopped dado/groove work if you don't mind the rounded end.

   

   

[Rob Young]

Followup with all four sides done, a bottom installed and a bit of cleanup done.

As mentioned, I didn't do my CAD quite right so instead of having slightly proud pins and tails, they were just a smidge below the surface. So took a bit of extra planing and followup sanding to level everything. But it all worked out.

Sides are aspen from big box store (keep a little bit around for prototyping because it is cheap and already well prepped four sides). Bottom is some 1/8" masonite. Glued up with liquid hide glue because that was the bottle closest to me when it was time for glue. And a quick hit of Zinser blonde shellac followed by a quick wax with Johnson's Paste Wax and a gray scrubbie pad. 

   

   

   

Overall it works pretty well. Probably slower than using a fixed jig. Maybe a bit faster than hand cutting but I'm also out of practice. Certainly an interesting way to do these joints. Going to fiddle with the CAD and try and do some variable size joints.

[Dumb_Polack]

Followup with all four sides done, a bottom installed and a bit of cleanup done.

As mentioned, I didn't do my CAD quite right so instead of having slightly proud pins and tails, they were just a smidge below the surface. So took a bit of extra planing and followup sanding to level everything. But it all worked out.

Sides are aspen from big box store (keep a little bit around for prototyping because it is cheap and already well prepped four sides). Bottom is some 1/8" masonite. Glued up with liquid hide glue because that was the bottle closest to me when it was time for glue. And a quick hit of Zinser blonde shellac followed by a quick wax with Johnson's Paste Wax and a gray scrubbie pad. 






Overall it works pretty well. Probably slower than using a fixed jig. Maybe a bit faster than hand cutting but I'm also out of practice. Certainly an interesting way to do these joints. Going to fiddle with the CAD and try and do some variable size joints.

I dunno...letting the 'puter cut your DTs sounds like cheatin', no???

I have the PC jig....yes I realize they're not hand cut DTs, but it does involve some skill on my part.

[Alan S]

They look good to me!

As far as "cheating" goes, it looks like fun, so it met that goal while making the joint. Sounds like a win.

Figuring out how to do it on the SO was trickier than following jig directions, and what you physically did was almost identical to using a jig (moved the router by hand, and let fine precision be guided by the device.)

[Rob Young]

I dunno...letting the 'puter cut your DTs sounds like cheatin', no???

I have the PC jig....yes I realize they're not hand cut DTs, but it does involve some skill on my part.

Cheat, smeat, the wood don't care.


I can cut them by hand and like to do so. But I'd use a jig for say a kitchen worth of drawers. 

And it is pretty much just us on the forum that both KNOW and CARE about the difference anyway.


The biggest difference, to me, between this method and the PC (or Leigh or whatever) jig is that I don't have the calibration step where you need to fine tune the bit depth, collar concentricity (Leigh Jig) or front/back shift of the template. After you get a jig dialed in it just works. Same here.

What I do get is the sort of near infinite adjustability that the moveable pins on the Leigh Jigs and old PC Omni jig provide without the need to find yet another place to store jig parts. With this same tool setup I can also do M&T, box joints, sliding (tapered and not) DT joints, grooves/dados (stopped and through), template routing (without the templates), inlays, etc. Limitations exist as with all router based cuts in that I'm limited by the sizes of bits available. But for fine work like inside corners on inlays, I've got bits down to 0.8mm (more or less 1/32") diameter and can get them smaller if need be. 

Probably the slickest trick I've done is cut the mortises for Soss hinges. Since the tool can also be used to probe the exact material size for placing grids, it can drop the necessary paths for Soss hinges dead on the right offset. Then you cut and if you need to bump out the mortise another 0.002" to fit the hinge, no problem. Can't shrink the mortise of course but you can cut a plug, glue in and then re-cut smaller.

[Rob Young]

Figuring out how to do it on the SO was trickier than following jig directions, and what you physically did was almost identical to using a jig (moved the router by hand, and let fine precision be guided by the device.)

Exactly. Once you have the CAD file generated, the step in a "regular" jig where you need to calibrate depth of cut, bushing position/size (Leigh Jigs) and template setback are eliminated. It does (as do jigs) assume well milled and stable material to make this work right.

Should add that the CAD files are parametric so pretty easy to re-configure for different # pins/tails, material size, etc. without much effort on my part. And its already in a CAD system (Autodesk Fusion360) I use at work so no learning curve. YMMV.