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finger joints by the thousands

7.2K views 21 replies 12 participants last post by  Sandhill  
#1 ·
what is the best way t cut thousands of finger joints
 
#2 ·
I think you need an industrial machine what what I see in your other post.
 
#3 · (Edited)
Other post? So did he have another post discussing this? Is he doing a production run of finger joint boxes?

So stacked "finger joint" shaper cutters (3" to 6" of stacked cutters) cutting stacked (multiple pieces of) stock clamped together, so you cut all fingers of a side on multiple pieces at a time... Commercial grade stackable finger joint shaper cutters (1-1/4" spindle) are spendy ($200 - $250 each), but you save cost in labor/time and long-term tooling costs.
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You could do the same by instead of stacked pieces, cut a finger joint profile into a block, before resawing the individual pieces apart. Sawing the pieces would be the wrinkle that would slowdown your production process. If you needed to speed that up, then a gang rip saw to rip multiple pieces at a time.

If you make jigs to clamp the blocks together (and keep them together and square) for the profile tooling, then your tooling setup can stay static (height) for the different pieces, with your jigs built to set the different offsets (height off the table)...

That is assuming your finger joint side is short enough to tool that in one pass on a shaper (3" to 6" depending on the shaper). If taller, then specialty tooling on specialty machines. If around 6".. you're looking at $800-$1000 in cutters and a 7-1/2 3 phase shaper at around $4000 to $5000. But you could many finger joints (and other profiles) cut all day, every day... in mass quantity.

Either way, you set the opposing sides as the same for where the joints start. The adjacent sides to those are just offset, so a separate tooling setup. The sides end up as the same and "interchangeable" as a piece. Pieces would then interchange between boxes. The pieces of the distinct pieces (1/2 of the pairs) are saved as setup guides to use as guides for setting your tooling on all other later pieces. Remember that a box consists of 2 pairs of opposing sides, and a bottom... sometimes 2 more pairs of opposing sides for the sides of a top... and a top.

The production process would also be affected by how the rough lumber comes to you (dimensionally)...
 
#4 · (Edited)
hi

By the thousands not that many if you have the right jig
I have one made by Porter cable that's 24" long you can do 2 boards at once so to speak..
You can use a hand router or the router table...

All you need is the template plate and screw it to wood stock..I got it from Amazon for 60.oo
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#5 ·
There was also a post by the OP in Introductions.

The finger joints are 10.5" long. I have no idea how long the boxes are.
 
#7 · (Edited)
I went back and read his first post in intro's.

"Thousands of finger joints" --and-- "going to build some boxes" are a long ways from each other.

If some boxes and 10.5" of finger joints, then like BJ said with a router and a jig like the PC jig. I have that PC jig. You aren't going to turn out thousands of boxes and stay young... But it is cost effective for turning out "some."

If a production run of boxes with sides that wide, then maybe a custom profile moulder. Or if in higher production, then a specialty industrial machine like you mentioned. Being 10.5", I'm thinking power fed, stacked grooving blades, 10 HP to drive it.

Any way it's done, it has to be cost effective for the run. Like I've said before, Sharon holds me and keeps me honest to how long it's going to be before a tool pays itself off and it's making me money, free and clear beyond that. If it's not going to make me money, then I have to justify what the other factors that are paying it's existence and space in the shop.

12 boxes that size would be 1000 fingers of a 1/4" finger joints on those sized boxes. 24 boxes to be that many in 1/2" finger joints. Maybe a budget of $100 to $300 ceiling in tooling (cutters and router cost) for that amount. Anything above that for that amount of product would not be cost effective if he is looking to make a profit. (IMHO) You can find those PC type bench mount router jigs used... That's how I got mine. If just gifts... then it is really a personal decision on what/where is that line where it' is or is not cost effective. There's one side of it which is "priceless" and the other side where you are throwing money at (what?)...Like buying a new router table with an Incra LS Ultimate system to make one box... That just wouldn't make sense, right?

If more serious, then there's a lot out there between that (jig and tool wise) and full commercial runs...
 
#10 · (Edited)
I can imagine that joining or longer in the bottom box section of a hope chest... But like you, I am now curious what he is building, how many and more general details. (Even though he said the endgrain was 10.5", things get real creative with sides over 3' long...)

EDIT-- Great video. Reminded me of a Job where one of my co-workers got in too much of a hurry and miscut a gluelam too short. (Cut the wrong beam) Had to pay for another out of his own check... Since he "paid" for it, he took the "shortened" beam home and put it up in his living room just to remind himself of that. (Ouch!!!) I didn't realise until then, that they actually finish out quite nice... LOL
 
#8 · (Edited)
Hi Mike,

Are you reading it like ' finger joints on boards 10.5" wide"?

That would make some sense...

I was reading it the way it said "10.5" long".......LOL ( the way I read it)....
 
#9 ·
Ahhh...penny drops.

I agree with bobj3.
 
#13 · (Edited)
For making precise box joints to join the corners of a box the I-Box jig does an excellent job and you can use it either a router table or a table saw and cut multiple pieces at a time.

Finger joints are usually used to join boards end to end for making longer boards out of short pieces. They are best made in volume on a shaper and typically used for paint grade work where the joints will not be seen.

The I-box jig is fairly new on the market and is far better than the other box joint jigs
because it is easily adjustable to produce perfect fitting joints of any size of 1/8 to 1"
per increment with usually only one test cut needed after it has been set up. The I-box jig lets you adjust for tightness of fit to as little as a few thousandths using only an adjustment knob on the jig. You can make home made box joints and box joint jigs many ways and for much less money, but you will likely spend hours and many test cuts before you get the jig adjusted correctly. After using my I-Box jig the first time all of my home made box joint jigs became firewood. If you truly have thousands of box joints to cut a CNC router would be best

Charley
 
#14 ·
Do a Google search for "finger joints for bee hive" there are a lot of videos on that. Maybe that is what you are building? I stumbled on to one a while back and was amazed. I never thought about how they did all those finger joints on hives until then. Those guys just warm up with thousands, I think, before they really get going.
 
#15 ·
Hei Looking at your drawing, fingerjoints are usally used at the end grain of the wood and not on the lenght. Why do you want to use fingerjoints ?? when there is so many more ways ? What is the use of the boxes ?

Regards Leif
 
#16 ·
Leif makes a good point. You are severing the grain at every notch which will make the fingers very weak and prone to snapping off. Perhaps a lock miter joint instead?
 
#17 ·
Leif and Charles--

I don't get it(?) Are you two assuming that because his sketchup drawing has the shading on his grain going vertically, instead of horizontally... that that's how he plans to orient his grain?

Other than that diagram, where that shady pattern is a idiosyncrasy of provided generic shading patterns in sketchup... He has 3 posts so far and I don't see anywhere in those 3 posts where someone would pick up that someone wastrying to cut box joints in crossgrain instead of endgrain. Did I miss something? Maybe I did?
 
#18 ·
Leif and Charles--

I don't get it(?) Are you two assuming that because his sketchup drawing has the shading on his grain going vertically, instead of horizontally... that that's how he plans to orient his grain?
?
Yes, that and the fact that 90% of the time or more the long dimension is the one that is chosen to run with the grain. It's usually based on economics and supply. The wider you go the more expensive the wood gets and the harder it is to come by. That doesn't mean that Leif and I aren't wrong, but Leif's point is certainly worth pointing out.
 
#19 · (Edited)
Attached are some Sketchup drawings of the box joint jig I've found to work especially well. The first shows the construction of the jig and the second shows how boards are loaded ready for routing. This is NOT my design ... I found it on you tube (and for the life of me, cannot find it again. I'll keep looking!).

The boards are clamped to the center strut (for lack of a better word) and a flush-trim bit routes the joints by following the protruding fingers. I can route 3 or 4 boxes at once (opposing sides of the boxes are grouped together on each side of the strut of the jig). I place 2 pieces of paper between all of the protruding fingers to make the joint fit just right.

It's very important for the center strut to be square in all three dimensions -- otherwise the boxes won't fit right and will be out of square. The fingers also have to extend 90 degrees from the face of the strut. I laminated two lengths of 2x10 for my strut.

This can easily be built to accommodate what ever length you need. The fingers can be different sizes too.
 

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#21 · (Edited)
Craig,

a box joint is supposed to make a strong joint, not weaken the structure.
It was mentioned already - if you really want the box joints on the long side of the board, severing the grain, you end up with a much weaker joint than just simple butt-gluing on long grain.
Been there, done it - and learned from it.

I see multiple possibilities for your box:
* either turn the boards grain orientation, so that the fingers are cut into the end grain - for the butt joint for the end piece, that would even be strengthened
* Or use different joints on all the edges - rather than a weakening finger joint in long grain, use other joints, like for example a miter joint. Or use some decorative finger joint corner beams, where you rabbet the sides and bottom into - in a way of a frame and panel structure.

Just keep in mind, glue bonds on long grain to long grain are the strongest, and "fancy" connections of boards in end grain are most stable - so use the appropriate orientation of boards - or placement of techniques to get strongest results.

Martin
 
#22 ·
Thousands???????



I'd have to pay someone else to do it, LOL All kidding aside safety is a big concern when doing repetitive tasks so be careful.