I'm in the process of improving the educational content of my blog.  When I retired it was because the new young professors were ordered to come up with their own beginning workshop projects rather than use what I'd been updating/refining/iterating over the previous 40ish years.  What those kids came up with skipped any useful fundamentals and had the students jump into making furniture.  The outcome was a new record of evening and weekend open shop hours needed to help the students make their designs, and far less known after it all.  

Initially I just posted the project statements with a little logic behind why each project was done.  What it missed was the "live" demonstrations I always gave to show the students how each project was made. 

 

So I've just made public my first crude attempt to show the steps I taught to make a simple rabbet/dado corner joint.  https://4dfurniture.blogspot.com/2023/10/making-rabbetdado-corner-joint-using.html

 

The videos are raw off my camera as I have no video editing software.  I'd appreciate any constructive feedback, either as replies here or comments on that blog.  This corner joint is just one small step of a joinery box project. It was designed to show the students how to use many tools and processes in the fab lab, in the context of creating a small introduction project. A link to that project is at the bottom of the post linked above.

 

Thanks,

4D

Edited October 10, 20232 yr by 4DThinker

without watching your video, i find it amazing that 40 years of developed expertise was just tossed away.

 

yeah, we have new tools available now that we didn't have long ago.  but the basics of woodworking really haven't changed much.  most of it is knowing how to build a box in some form.  if you can't keep things square and do good joinery, you're just wasting time and lumber chasing what you have not mastered yet.

 

"ooohhh.....CNC!!"

 

yeah, but your cabinet has 4 different length sides....try again.

 

on the other hand, you are retired, it's not your problem anymore.

The irritating aspect is that one of the young instructors had been a student of mine.  He decided that teaching fundamentals was less interesting than jumping right into mostly making the projects for the students, which demands more time of the instructor.  Thus the extended evening and weekend hours with no consideration for the other classes that the students also take and are expected to put evening and weekend time toward. 

 

I do this to try and dump my knowledge on the web so I can finally stop worrying that I left unfinished my lifetime career.    I've seen a growing number of hits on my blog from Singapore, Turkey, India, Germany,  Norway, Sweden, etc..     

 

And yes, the CNC did change many aspects.    Yet the only thing the young kids thought they could do as an initial CNC lesson was have the students cut a groove pattern on the top of their wood top metal base table project.  The metal bases are all made from 1" x 2" thick walled metal tube, laboriously welded/ground/filled into linear shapes.  Something no manufacturer would use/do. Often fastened to the wood top with no allowance for wood expansion.  My first job out of college was for a manufacturer of metal and glass residential tables and other furniture.  We avoided welding as it had proven to be an inconsistent point of failure for past designs and too labor intensive.  Spot welding maybe, but mostly very clever mechanical connections.

4D 

you've done what you could.  if new guys want to make large mistakes, let them.  word will get around that the class takes up too much time and enrollment will fall off.  then the admins will ask "hey, why isn't anyone signing up for your class?"  rule of thumb is if there are under 15 students, the class won't be held.

 

so i hope the new guy has plan B in mind when that question arises.

I just watched one video but I thought it was an effective demonstration of the reason for the joint.

I think you have a good start. I wondered how much previous experience the student will have prior to doing a project like this. I say this because of your instructions on material movement thru the router bit and tips for tear out.

2 hours ago, 4DThinker said:

teaching fundamentals was less interesting than jumping right into mostly making the projects for the students

 

When I started my teaching career in 1970, our school had just opened and the instructional materials had been just developed. The developing company was headed by a visionary gentleman. His philosophy was to teach the same thing 3 times in three different ways. First in the classroom setting (we called it theory), second was to prove the theories with quickly done demonstrations/experimentations and finally have the students build a gradable project from discrete parts that demonstrated/proved the theory. Because everything, except the theory, was hands on the students found it interesting and fun. With few exceptions, this became my teaching strategy for every lesson.

 

Today's generation wants everything now and the young instructors don't get the importance of fundamentals. It is disheartening when one of your own students fails to make that connection. BTDT.

Among the students taking the program, most have entered with an interest in Interior Architecture/Design and no prior woodworking or metal work or shop experience.  If we get anyone that comes in with prior experience they usually become TAs or leader in the class who help the other students.  I usually keep an eye on those kids though as the confidence of a 20 year old about his/her own capabilities is often hiding limited skills and sometimes dangerous habits related to the used of dangerous tools.   Still much for them to learn.   When the shop space for the class got remodeled into a much larger/expansive space it meant watching all the students was impossible.  The TAs were there to help students who had wandered away from their instructor or didn't want to bother him/her if they were talking to/helping another student.   I'd have students who would show up with something done wrong. They had no experience and between them and the TA that helped them the solution they came up with was the best they could do. Many "let me show you how to do that correctly" opportunities arose.

4D

43 minutes ago, 4DThinker said:

most have entered with an interest

Virtually all my students fit into this category. My largest class was 27, smallest around 18. The classes always included 3 grade levels (high school soph, juniors and seniors) which meant 3 different subject levels at the same time. Students were with me 5.5 hours a day. There were 2 separate groups of students who attended. In the early days the groups rotated every 3 weeks (half a marking period) in later years it was changed to rotating half way thru the school year.

 

 

Wood shop and metal shop were classes offered when I was in junior high school.   Took them both.  High school offered a woodworking class but I opted for drafting courses instead. Grandfather had been an Architect and I thought that might be a career path I could take.  Found my engineer genes handed down from my father's side preferred furniture design as a quicker route to a finished product.   It strikes me that all those classes were in basement/back of the building/away from other classrooms spaces, seemingly demoted as less important perhaps.   In any case I clearly benefited from all those courses.  A previous department head, impressed with my ability to help students with angled and compound angled joinery in their projects was sure I was using calculus to figure it out.  The truth was actually my drafting skills learned in high school.   Something it is clear current students are not taught.   3D CAD modelling has replaced it, but misses the problem solving/auxiliary plane projection techniques to find needed information that mechanical drafting taught me.   I draft within my excellent CNC software (Aspire from Vectric.com) and then can use the vectors derived to make the toolpaths needed. 

 

The post about rabbet dado joints has so far been hit a surprising number of times.  I know there must be similar info on YouTube already so that surprises me.   

4D

3 hours ago, 4DThinker said:

It strikes me that all those classes were in basement/back of the building/away from other classrooms spaces, seemingly demoted as less important perhaps.

Ahh, yes, the vocational courses. Segregate those who could never make it to college and were only slightly above the cutoff for the "slow learners" classes. My high school experience exactly. Took the 3 year Building Construction vocational course that was located in the "shop wing" of the school. Best thing I ever did. And, just to prove all the academia wrong, I became the first vocational student in the school district, to become a member of the NHS. Talk about the elephant in the room! 

 

I truly believe those experiences of feeling inferior, because of the courses I took, was the most important factor in my career as a Vocational Instructor. Trying to make a difference in the stigma of vocational students/courses.

Just as a point of reference, in Jr. High (as well as probably before but not so obvious perhaps), the ~100 students in my class were separated into 4 groups.  Rather than name them something less obvious like red, blue, or tigers, lions, etc. they were 7-1, 7-2, 7-3, and 7-4.  More or less on intelligence levels.  Once we got to high school, it was nearly the same, the top level being "college prep" on down.  We had industrial arts (shop) in Jr. High for all the boys.  That is where my woodworking got sparked.  We did wood, metal, plastic, and leather work.   The girls had home ec.  (my older sister ended up with a graduate degree in home ec. education)  Once we got to high school, those classes ended for the top level.  The girls had a track for typing, shorthand, and basic bookkeeping. The lower boys' level was known as "the shop guys."   From what I could tell, they mostly worked on automotive stuff.  I lived in "The steel valley" so most of those guys ended up working at a steel mill, a factory that made automotive electrical components, or at the Chevy assembly plant that opened a few years earlier.  (They are all now mostly closed, starting in the 1980s).  I have always said that when I grew up, the four choices for women in a career were school teacher, nurse, secretary, or housewife.  My wife, following the trend and her two older sisters was a teacher and later transferring to be a CPA.   I am glad my girls had more options.  They got degrees in industrial engineering, speech and language pathology, and school psychology.

Been looking through YouTube videos for rabbet/dado joinery.   Almost all have latched onto the 1/4-1/4/-1/4 method done with a table saw and a dado blade setup to 1/4" wide for 1/2" thick material.   I found that when there is only 1/4" of material left on the dado side that the 1/4" left from the the slot to the edge often breaks off.  More likely when done in plywood sides.  When I do them using a router table I prefer either a 3/16" bit or a 1/8" bit for the dado side, leaving as much as possible from there to the end of the board.  The tongue left that slips into the dado is still continuous grain from the joining board and still plenty strong if only 1/8" thick.  I've got a couple boxes around made with 1/8" used and neither have been glued up yet.  They slipped together nicely but stay together so well that I have put them in use before gluing them up.  Glue wouldn't hurt, but the clean-up of squeeze out would certainly add more work to the effort.

4D

Reading over my previous post my mind popped into the idea of...  rather that a simple straight dado, how about essentially a stepped joint interlock?   

 

Fingers still strong with the continuous grain of the side board. Stuttered slots rather than a straight through slot would keep the material between the slots and the end of the board well connected. Less damage to the dado side.  Admittedly harder to make unless a CNC is used.  Essentially a hidden finger joint that looks like the simple rabbet/dado joint.  The radius ends of the slots wouldn't show, and could be minimized a little if using a 1/16" bit to pocket out 3/16" wide slots. 

 

 

Such are the musings of a retire furniture design educator.

4D

Added another corner joint lesson to my blog.  This time the splined miter joint.  

 

Not a great deal of application for it, but it was added to the joinery box project as an opportunity to use the table saw tipped to 45 degrees with a miter gauge.   Had a co-worker who went into production mode to design and build drafting desks for the college.  1x2 metal pipe frames with 1/2" thick baltic birch drawers and trays that could be attached left or right, inside or outside the frame.  The drawers, boxes they slid into, and tray were all joined using this spline joint.  Never failed for the 20 odd years they were in use.

 

Have a look and let me know if I missed anything important.  Text and photos only.  No videos. 

https://4dfurniture.blogspot.com/2023/10/splined-miter-simple-corner-joint-that.html

Thanks!

4D

i use that one quite a bit.  helps with glue up, no shifting.

 

box i made for my wife's and later my remains.

i like the way the nested corner splines came out.  cherry and wenge.

17 hours ago, DAB said:

i like the way the nested corner splines came out.  cherry and wenge.

I agree. Little details like that are what make a design stand out and prolong discussion/appreciation about it.  Although not needed for such a simple box they also add considerable strength to the corner.

4D

I regularly to what I call "keys" as opposed to splines on mitered corner boxes.  I originally just had a jig that ran next to the rip fence.  Later I got fancy and made one that rides in the miter slot and I just move the box in the jig instead of the jig.  I shortly thereafter made one for the router table that does a dovetail key.  I've used it once but need to pay more attention to flush cutting the excess.

 

A couple of a few I can see from where I'm sitting in the living room.

 

  

The main advantage of the splines is that it makes it easy to glue up the mitered box. 

Dovetail and simple slice keys as shown expect the box to already be glued up.  

At some point in my past, using my CNC, I made a miter sample with build in interlocking keys.  Same cut on both sides of the corner.  Of course it required my adjustable angle clamping fixture to clamp the boards at 45 degrees.  Not  sure what happened to that sample but am sure I never made is for a students project.  Much easier to just cut a spline slot and slip in a spline.   

Third of 4 corner joints lessons added to my blog.  This one not as difficult or fancy but was intended to teach the student about the drill press and bit options.etc.   The simple Rabbet.  No. not about rabbits which seem to like my front yard. 

 

https://4dfurniture.blogspot.com/2023/10/rabbet-joint-with-lesson-on-using.html

Screws with plug to cover them.  I would have added a few more video buts didn't realize the little camera I used was in 4K mode. Files ended up too big for Google. 

Love to have you look it over and tell me if I missed anything or the info was confusing.

 

4D