That’s a hard one to answer (I’ve been trying). The kerf is very small, so unless things are suppose to fit together tightly enough that they stay by themselves, it probably won’t matter. You’d have to be measuring pretty darn carefully to notice that a board game piece or a coaster was the wrong size.
With a kerf of 0.008", (1/128") whatever you cut along the center of the lines of the design will be undersize by 0.008". To measure that small of a difference in size you’ll basically have to be using calipers (or similar/better).
On the other hand, if both parts are undersize by 8-thousandths of an inch, that’s a total of 16-thousandths, and that’s a big enough discrepancy that the parts might just fall out of each other. For a visual demonstration of this, just watch how easy it is to pull parts off the bed after they’re cut, or watch parts cut on a “pin bed” fall down from gravity.
If you cut a 10mm-wide tab along the centerline with a laser that leaves a 0.2mm kerf, it’ll come out 9.8mm wide, a 2% difference. The 10mm slot will actually be 10.2mm wide. The total difference will be about 4%.
The actual opening of my front door is 35", something 4% smaller would be 33-5/8" and would easily fit through the door (with enough room to spare for fingers).
Looking around my desk for another everyday example I spotted my Scotch tape dispenser. The inner diameter of the roll of tape is 26mm, the diameter of the rod thing on the dispenser is 25.3 - 25.5mm. 4% less than 26mm is just under 25mm. So, the fit on this tape dispenser is actually slightly tighter than that 10mm slot and tab would be.
Of course, with bigger objects, the percentage lost to kerf will be lower. A centerline cut of a 2-inch tab and a 2-inch slot in 1/2" material might be OK, I suspect.
I hope this helps (I hope it at least makes sense).
I agree with that. My gut feel, from my keyboard warrior command chair is that they would be very similar in performance. but maybe someday someone will build both and prove us wrong haha. im adding it to my GF todo list
I hope to one day have the same ease and mastery of woodworking as that guy has! What really got me were his time saving batch cuts- seeing the finger joints all get made at the same time was soooo satisfactory
Love this project, I think a version of it is going to be my first major functional design made with the glowforge. I agree with all the comments about the way his base grid was made, though- definitely plan on modifying that step!
Of all the things to make, I’ve really thought a lot about making a box joint jig. There are three major builds that compete for folks’ attentions. If I had a Glowforge now, I’d definitely make Matthias Wandel’s because of the ease of gear production.