Ronn W Posted March 23, 2016 Report Share Posted March 23, 2016 While visiting relatives last month I was admiring a slant front secretary desk and noticed amazing drawer joinery where I expected to see dovetails. I have since learned that the piece was made using Knapp Joints and that these date to the late 1800s' and that Knapp invented the machine to make them. My question is, "Does any one use these joints today?" Has anyone seen a jig that would allow these joints to be made without the Knapp machine or CNC machine? No big deal. Just curious. Quote Link to comment Share on other sites More sharing options...
Brendon_t Posted March 24, 2016 Report Share Posted March 24, 2016 I've never seen them but I'm sure if you're dedicated enough, a few hours of trial and error could yeild a set of templates for router cutting. Quote Link to comment Share on other sites More sharing options...
wdwerker Posted March 24, 2016 Report Share Posted March 24, 2016 Templates and a lot of patience. Quote Link to comment Share on other sites More sharing options...
bradpotts Posted March 24, 2016 Report Share Posted March 24, 2016 MLCS sells jigs that make them and other fancy joints like that. http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/catalog.html Quote Link to comment Share on other sites More sharing options...
Ronn W Posted March 24, 2016 Author Report Share Posted March 24, 2016 Thanks bradpotts, Expensive toy but very cool. Quote Link to comment Share on other sites More sharing options...
weithman5 Posted March 24, 2016 Report Share Posted March 24, 2016 i could see imitating it at least the one half by drilling the holes with forstner bits then a smaller diameter hole in the middle of those to put dowels. I haven't figured a good way to cut the piece that flips over those pins yet.... but i am pondering it Quote Link to comment Share on other sites More sharing options...
Ronn W Posted March 25, 2016 Author Report Share Posted March 25, 2016 Thanks for your responses. I have continued to look on line and, while I have found similar joints and jigs for similar joints, none have the scalloped look of a real Knapp Joint, where the wood between the semi circles meet in a point. See pic of antique drawer attached. Quote Link to comment Share on other sites More sharing options...
wtnhighlander Posted March 25, 2016 Report Share Posted March 25, 2016 To me, that looks like a forstner drill and dowels. The mating side would be coped to match the overlapped forster pockets, then the centers drilled and dowels glued in. The same fence / jig used to position the drawer front for the overlapping pockets could be used to allow marking the side scallops by lightly scoring with the same forstner bit. That marks center for the dowels, too. Assemble, then plane or sand out the score marks. I think it is purely decorative, though. The scallops add no real strength to the joint. Quote Link to comment Share on other sites More sharing options...
Ronn W Posted March 25, 2016 Author Report Share Posted March 25, 2016 Here is another pic that I found. The pins appear to be part of the drawer front, not separate dowels. I will try to attached a pic that show this and also a pic of the original Knapp machine. Quote Link to comment Share on other sites More sharing options...
Tpt life Posted March 25, 2016 Report Share Posted March 25, 2016 I think a shaper type cutter can cut the side by cutting from the end of the board. The forstner type bit for the face is not a bad thought. The bit would just need a hollow core for the first inch or so. Quote Link to comment Share on other sites More sharing options...
Ronn W Posted March 26, 2016 Author Report Share Posted March 26, 2016 I think I see what you are thinking but that would be a huge bit. I have seen bits that do beaded table edges but this one would have to be the depth of the drawer. I think you have identified the toughest part of duplicating this joint - the points where the curves meet on the drawer sides - very sharp interior corners. No wonder he had to invent a machine to do it. Quote Link to comment Share on other sites More sharing options...
Tpt life Posted March 26, 2016 Report Share Posted March 26, 2016 11 hours ago, Ronn W said: I think I see what you are thinking but that would be a huge bit. I have seen bits that do beaded table edges but this one would have to be the depth of the drawer. I think you have identified the toughest part of duplicating this joint - the points where the curves meet on the drawer sides - very sharp interior corners. No wonder he had to invent a machine to do it. Huge is a relationship. The spindle would be long, but the width would only need to be the spindle plus cut depth. If it turned while supported from both ends, it would resemble a lathe operation. I am just guessing what my approach might be if I need to put this into production. If the bit spun down into a table, chip out could be countered with scrificial backing. Quote Link to comment Share on other sites More sharing options...
Ronn W Posted March 27, 2016 Author Report Share Posted March 27, 2016 Aha, I see where you are going. Horizontal mounted spindle at least as long as the drawer is deep. The spindle, in addition to spinning down would have to actually move up and down by the thickness of the material (or the materail would have to raised and lower. I bet it's the latter - probably a foot pedal (this was pre-electricity). I just did a brief online search and could not find any photos or drawings or detailed description of how Knapp's machine was built. There is only one drawing of the overall machine which appears one several sites. I will look again when I have some time. If we make this tread long enough we will have it designed. Quote Link to comment Share on other sites More sharing options...
Slick218 Posted May 28, 2016 Report Share Posted May 28, 2016 Hand tools ... That's all Quote Link to comment Share on other sites More sharing options...
WillAdams Posted March 6, 2020 Report Share Posted March 6, 2020 I worked up an OpenSCAD file for making such joints --- it's on Thingiverse and should easily be findable. Wrote up the design process on the Carbide 3D Community Forums --- let me know if you have questions. Quote Link to comment Share on other sites More sharing options...
Robby W Posted March 9, 2020 Report Share Posted March 9, 2020 I believe the original machine used a bit with a hollow center, sort of like some plug cutters, to cut the drawer front. Plunge it in and you get the circular recess with the pin left in the middle. Index to the next location and repeat. The side would be a combination of a drilled holes and a cutter that left a half round shape. Not hard to do with a dedicated machine. Quote Link to comment Share on other sites More sharing options...
wtnhighlander Posted March 9, 2020 Report Share Posted March 9, 2020 2 Quote Link to comment Share on other sites More sharing options...
lewisc Posted March 11, 2020 Report Share Posted March 11, 2020 @wtnhighlander Pask Makes is one of my favourite Youtubers. He's got a great channel that's quite entertaining. 1 Quote Link to comment Share on other sites More sharing options...
Ronn W Posted March 11, 2020 Author Report Share Posted March 11, 2020 Thanks for the video. 1 Quote Link to comment Share on other sites More sharing options...
wtnhighlander Posted March 12, 2020 Report Share Posted March 12, 2020 Here's a version using Matthias Wandell's pantarouter: 2 Quote Link to comment Share on other sites More sharing options...
pkinneb Posted March 12, 2020 Report Share Posted March 12, 2020 I actually prefer the crispness of the homemade version. Thanks for sharing!! 1 Quote Link to comment Share on other sites More sharing options...
Mark J Posted March 12, 2020 Report Share Posted March 12, 2020 I thought both videos were fun to watch and neat techniques. I was interested to see Wandell throw sawdust on the glue squeeze out of the first joint he put together. I've never seen that done before. What was the purpose? 1 Quote Link to comment Share on other sites More sharing options...
wtnhighlander Posted March 12, 2020 Report Share Posted March 12, 2020 1 hour ago, Mark J said: I thought both videos were fun to watch and neat techniques. I was interested to see Wandell throw sawdust on the glue squeeze out of the first joint he put together. I've never seen that done before. What was the purpose? That's a quick way to 'clean up' the squeeze-out. Sawdust absorbs the glue, and you just rub it away. Quote Link to comment Share on other sites More sharing options...
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