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dado fingers question

45K views 108 replies 21 participants last post by  kilocharlie 
#1 ·
Hello guys, fairly new to wood working here and I can't seem to find this question (at least explained in a style I understand) but I have a tablesaw set up with a 3/4" dado, and a incra I-box jig. After setting up the jig, I adjusted it till the fingers were snug (they started out loose) and now what seems to be the problem, how exactly do other users out there cut their fingers spacing where you can get a full finger on the top AND bottom? Is one of the full fingers part of the other board or what? I already have my wood cut out to exact measurements for the 9-5/8" deep hive bodies. I will be making medium supers later. My joints are fitting together great now, it's just the spacing on the first cut, and getting the other plank of wood to mirror the exact opposite. I know that this sounds like a pretty obvious question to most experienced hands but stumping me. Thanks for all the comments, and Merry Christmas to all
 
#59 ·
Wood moves quite a bit as the moisture content changes, as you have discovered.

All the commercial suppliers suggest you assemble boxes as soon as you get them, obviously because they are kiln dried and flat when cut, but if you let thiem sit around in humid conditions, they won't be in short order, and they can even crack as the outer parts swell faster than the inner parts. This is equally true cutting them out yourself, as the wood should have been pretty dry when you got it (unless someone stored a pallet of it outside, makes a real mess!).

Your pieces should return to close to what there were when you made them if you can dry them out a bit. Never ever put wood flat on a surface that will either enhance or restrict moisture movement, as you will get one side with higher moisture content than the other that way. Best to stand them up on one side with some space between them if you cannot maintain a fairly constant humidity.

Dirt floors are really bad in areas with lots of rain, the water migrates right in. Concrete can be a problem in the spring, when the air outside is damp and warm but the floor is cold -- tons of condensation.

Peter
 
#60 ·
Thanks abunch for your info psfred, i did have them on a metal table in the barn that was dry and flat, but just to be on the safe side, im not gonna cut my fingers till im ready to assemble them. I can cut my boards to length, BUT fingers i wont be cutting till im ready to put them together. Thanks againg for all the help
 
#61 ·
Whiskey, the reason your wood cupped is it got moist on one side when laying on the ground and not the other. So one side expanded and the other did not. try laying them back on the ground cupped side down and see if they straighten back up. IF they do assemble them and quit playing around ;)

Actually you should be able to store hive pieces unassembled. you just have to keep them save and dry.
 
#62 ·
I'll be the odd guy out and say stick to finger box joints, not rabbets nor butt joints! The finger-joint boxes are WAY stronger. Sugar pine is a good choice as it cups very little, another favorite is bald cypress as it lasts for years.

A sled (as opposed to a pushblock) is made up for finger joints. It crosses both grooves in the saw table at 90 degrees. I usually clamp 8 parts to it at a time when cutting the finger joints. There is a peg the size of a finger 3/4" over from the dado. Cut a notch, move the part over so that the notch rests on the finger to automatically space the next notch.

I find it better to make the new stagger design for the fingers at the top of the short end of the box, so that the 3/8" shelf cut into the top inside of the short end is a deep finger that extends all the way to the outside edge of the box. The top of the long side has a stepped notch to fit perpendicular to the shelf.

A glue can and a paintbrush proved too slow for gluing up a box - some glue always dried before the box was assembled. I made a dipping tray and use a good sheet metal pan under the assembly jig to control the excess. I wipe glue (Titebond III) with a squeegee first and a wet sponge second.
 
#63 ·
I find it better to make the new stagger design for the fingers at the top of the short end of the box, so that the 3/8" shelf cut into the top inside of the short end is a deep finger that extends all the way to the outside edge of the box. The top of the long side has a stepped notch to fit perpendicular to the shelf..
kilocharlie, you had me right up to there. Ha. Guess that is a matter of preference. I like the 3/8 overlap, rather than basically floating rabbet in the front and rear. Difficult, (not impossible) to nail into this 3/8 rabbet from the side. The overlap will glue, nail/stable into a full finger from the front.,

Are you saying that Titebond III dried before you got the box assembled.

cchoganjr
 
#64 ·
I'm not talking about rabbet joints. If the wood cups strongly, they fall apart. You could make mating nucs that way, they are only out a month or two, and usually in good weather. Beehives made with finger box joints and treated with linseed oil can last outside 24/7 in all weather 40+ years if re-painted every other year.

The new stagger-stepped pattern can be seen in Dadant's or Mann Lake's catalog. The stagger step on the top finger makes the 3/8" shelf less likely to warp apart from the long side of the box, and you can staple right through it 90 degrees to the shelf and into the end grain of the long side. It is a far superior design.

Painting glue with a brush on 4 faces of 30 finger joints takes too long. Just dip the ends, 1/2 assemble, and wipe the excess off back into the tray, then fit it over the squaring jig and clamp and staple. (Wash the glue off the squaring jig.)

An air-powered staple gun sure gets the job done better than nails. You can set the depth of better guns so that the crown of the staple is buried and your belt sander won't rip a belt on one.
 
#65 ·
Here is my new sled, made from trimmings from cutting a dinning table down to a coffee table.
http://i1141.photobucket.com/albums/n599/6minz/DSCF4217.jpg
I cut the long sides, 4 at time (I do not final rip to width until done so I chalk the reference edge). http://i1141.photobucket.com/albums/n599/6minz/DSCF4218.jpg
After all of the long sides are cut I leave them clamped and reverse them to the first notch. http://i1141.photobucket.com/albums/n599/6minz/DSCF4219.jpg
The short sides then ride right along the blade, making the first finger so that the frame rest will not be seen from the outside. A perfect mated fit. (shown with 3 short ends for clarity) http://i1141.photobucket.com/albums/n599/6minz/DSCF4220.jpg
I remove the long ends and finish the sides.
After the first cut remove the long sides and finish cutting the short ends.
Yeah my shop is a mess and I did use rebar tie wire to put the propane heater on top of the band saw table!
 
#66 ·
kilocharlie... I am not talking about rabbet joints either.

I am at a disadvantage here I suppose, I don't have a new Dadant, or Mann Lake catalog. I will try to pull up a photo from Mann Lake, or Dadant of the joint you are talking about. If it is a superior joint, I am all for it. I would like to see it. I did not think that this design was as strong as the traditional overlap of the front rabbet (frame rest) onto the end of the side boards, because the rabbet (frame rest) could warp away from the end of the side of the box, and you would be nailing/stapling into the end of a 3/8 rabbet (the frame rest).

Is this the type joint you are talking about. I made these nucs last year when we were talking about the new joint that Kelly Bee either made or was considering making.

Wood Plywood Hardwood Wood stain Lumber


Wood Plywood Box


cchoganjr
 
#67 ·
I found that I only need to put glue on the short sides. Each finger and across the face, is fast enough that the glue does not set up on me and all fingers have glue. I drill and counter sink the holes on every other finger (kid job) before glue up. Clamp, square and shoot two screws (2 1/2”) into each long end only (since they are screws I only need to do the long sides, they will not pull out). It was great with kid help but when he is gone I do not always get a nice square end so I am building a Harry posted except with clamps.
 
#69 ·
Cleo, how do you do the first wide finger/ joint. I know it has to be simple but I am missing it (I am also missing why but you have explained it to me so many time it will not help) LOL
 
#70 · (Edited)
minz To tell you the truth, I can't remember how I did it. There was a thread last year about this new joint, someone explained it to me, and I went out in the shop and made the nuc pictured above. Turned out, that wasn't how the joint was being made. Where I had the width of 2 fingers without a valley on the side piece, what they were talking about just had one finger on the long side that the end fit inside.

I am in Georgia this week, when I get back to Ky on Sat. I will look at the nuc again, perhaps I can tell you then.

The only reason I made it was because someone suggested this would be a better joint. I didn't think so, after I made it. As you can see the top nail is a #4, and it is nailed into the 3/8 rabbet, (frame rest). I don't think it would be as strong as the 3/8 overlap on the end.

I remembered how I did it. Just start at the bottom cutting my box joints rather than starting at the top. Make a second valley cut at the top on the end pieces.

cchoganjr
 
#71 ·
Brushy Mountain leaves the finger on the top of the ends and cuts the recess on the long board to fit and has you nail through the 3/8"part. Seems to work fine, but it's a hassle when you are not using a gang saw that cuts the whole board at once. Home jigs that let you cut one dado at a time will require two setups and remembering to cut that first one properly.

What I do is cut the dado in the top of the sides, cutting the rabbet off. I then run a 1 1/2" finish brad at about a 45 degree angle into the top finger, or just leave it un-nailed. I don't think there is much difference in strength and they are easier to cut. Since you shouldn't be prying on the top of the rabbet anyway, you get a nice solid 3/4" side all the way down.

Peter
 
#81 ·
Home jigs that let you cut one dado at a time will require two setups and remembering to cut that first one properly.
psfred..I don't understand the two setups you reference. Could you elaborate.

When I get to the end cut I simply lower my dado blade 4 turns,( that is how many turns it takes to cut off 3/8 inch from the top finger of the long boards on my Craftsman saw) shove sled forward, flip board, slide sled forward, raise dado 4 turns and cut remainder of the box joints. Only additional setup is the time it takes to turn blade down 4 turns and then back up 4 turns.

It is a pain trying to discuss something when all we can do is describe., To bad we don't have interactive video so we could hold up a piece, or run a piece across the saw to show what we are talking about.

Anyway, thanks guys. I learn something new every day. Please don't ever take anything I say as being confrontational, I am just trying to understand. And, if there is a better way of doing it, count me in. I appreciate learning how others do it, and I like sharing what I have learned over the years with others.

How is it that I can reread something I have just typed 10 times for grammar, spelling, and typing, then hit reply, only to read my post and find 5 more errors. Good thing we have edit available. Even then I miss some.

cchoganjr
 
#72 ·
psfred.... I'm with you, there probably isn't much difference in strength, but, I make mine the way they have been made for years with the front and rear pieces,(ones with the rabbet, frame rest), overlapping the top side finger by 3/8 inch,the width of the front and rear rabbet.

I cut the front and rear boards first. Then I cut the top finger (on each of the 2 side boards) 3/8 less by lowering the saw blade 4 turns, then turn back up 4 turns to cut the other fingers full length. Works for me.

cchoganjr
 
#73 ·
Minz - Nice sled! Thanks for the photos!

Peter and Cleo - Close, but the new arrangement leaves the "wide finger" on the top of the short end out to full 16 1/4" width with the frame hanger rabbet in it. The notch in the top of the long end is staggered to mate up to the rabbet and full-depth rabbet below (it is a double-wide finger). The advantage is that the fastener goes through the 3/8" x 5/8" narrow lip part (cross-section) of the rabbet at 90 degrees to the grain and into the end grain of the long side, and allows for a lot more glue area in that spot, changing it from the weakest joint in the hive body to a very strong one, and not sending a fastener into the end grain of the narrow 3/8" x 5/8" lip.

Sorry, I tried an ASCII pic, but the editor omits all the spaces, destroying the image.

Also, yes, it is another setup for a single dado with a sled. A gang or form cutter that does all the fingers at once can have the stagger step built into it. Stack them and cut 'em all at once. :)
 
#76 · (Edited)
Sorry, I tried an ASCII pic, but the editor omits all the spaces, destroying the image.
You can fix the spacing problem by making the ASCII pic in a fixed pitch font, such as "Courier New" used in the example below, and use the BBCode [CODE]xx[/CODE] to bracket the ASCII pic:

Code:
[RIGHT][FONT=courier new]ABCDEFGHIJK
BCDEFGHIJK
CDEFGHIJK
DEFGHIJK
[/FONT][FONT=courier new]DEFGHIJK
[/FONT][FONT=courier new]DEFGHIJK[/FONT][FONT=courier new]
DEF  IJK
DEF  IJK
EFGHIJK[/FONT][/RIGHT]
Also, I used the "Align Right" button to make things align up. You may need to go to the "Advanced" menu to find the "Align" buttons. More info on BBCode functions can be found by clicking on the "BBCode is on" link at the very bottom of this page.


EDIT:I saw that I had improperly terminated the CODE parameter. Once that error is fixed, it works much better, as shown above. Now no need to substitute periods for spaces. :lookout:
 
#74 ·
This joint is a royal pain to cut on a dado set on a table saw if you are making a lot of boxes, since you have to make several cuts that require a different setup for each one. Commerical boxes are cut on gang saws (all the fingers are cut by separate blades on a mandrel at the same time, one pass per board, both sides), but I have to cut them one dado at a time. It's quite enough hassle to cut that many dados already, I don't want to have to do two complete setups. This is complicated by the current use of 5/8" deep rabbets rather than 7/8" rabbets, which DOES increase the strength of the remainder -- it's shorter and stiffer, hence less likely to get broken off, but unless you want to cut MORE dadoes, the top finger isn't the full depth of the rabbet any more.

This is the standard joint from Brushy Mountain and the old Kelley boxes, but I don't see any real advantage. Looks nice, certainly seals well, but I don't think it's all that much stronger. Kelley now uses the same joint I do -- the rabbet is the dado on the end pieces, all the dados on the sides are the same. Easier to manage during production, I suspect.

The strength in a box joint is not in the nails or glue, it's in the fact that you have substantial interlock between the boards. The main place that boxes get damaged, other than joint failures due to water intrusion and rot, is when someone sticks a hive tool in between the boxes and pries up on the frame rest rabbet. Doesn't take may events like this to damage it, it's not very strong, and it doesn't matter which way it's nailed up, prying on it will dent it.

If it wasn't such a pain, I'd use the joint you describe just because it looks better and is more likely to seal, but I don't think there is enough gain in strength to bother. The bees take care of any water leaks and will more or less completely fill any crack between the boards with a pretty decent glue.

Note that if you drive a nail at a 45 degree angle, you won't be putting it in the narrow part, it will be in the wide part. I wouldn't drive ANY nail into a 3/8" x 5/8" part, it will split if the nail is big enough to do anything besides look pretty.

Peter
 
#75 ·
Peter - I agree, it is a PITA to cut on a single dado setup. Since it is an end finger, just leave the top part long and dado the full-depth notch, and index to the spacing peg and keep on cutting dados. Cut the top stagger notch in the long side later on the band saw or router table. Much easier and cleaner. The advantage shows up several years down the road when the weather curls the narrow lip out away from the box long after the glue has failed (old design). The new stagger joint should hold up a dozen years longer, as it has 75% more gluing area and room for 2 fasteners. It is WAAAAYYY more betterer.

Double down on the "don't kick the hive tool into the narrow lip" sentiment! That's kind of like, "Try not to stab the hive full of AHB's with the forklift". Hee Hee Hee.
 
#80 ·
Cut the top stagger notch in the long side later on the band saw or router table.
kilocharlie....Why wouldn't you just build a fence pattern that fits in the miter groove,(eliminating measuring each time, just drop in miter groove and clamp to table), then crank your same dado on your table saw that cuts your box joints up to 3/8 inch, stand the end pieces perpendicular to your table and run againstpattern to cut that 3/8 inch off, flip your board and do the same on the other end. If you cut multiples at a time, leave them clamped and cut this 3/8 inch off multiples at a time. This would eliminate band saw or router stated above.

cchoganjr
 
#77 · (Edited)
Cleo - I just saw the image on your post #66. It is the opposite finger cadence - the short end has an extra-wide finger (2 fingers wide, or 1.5") with the rabbet at the top, not a notch. The long side has a staggered notch to fit the rabbet in the short end.

In your pic, the short end of the box has a notch at the top and the finger is on the long end. "Opposite finger cadence" is the best phrase I can think of. Again, it is a PITA to make on the table saw. If I was cutting the new design on a table saw with a single dado gang, I would leave the part that matches up to the rabbet long and cut the rest of the dado notches as normal, then go back and cut the top (half-) step on the router table. The strength difference will show up 10 years down the road...it will still be very strong (especially if you dip it in Linseed oil) instead of curling outward or splitting end grain away from the nail (if any) as per the old design. The new stagger-notch design weathers much better, and is considerably stronger in the first place. It is completely worth the extra step, even more so when treated with linseed oil, dried properly, and a paint job maintained regularly.

Minz - My sled is only slightly different - I made the base wide and added support triangles for the upright, a hand protector box over where the dado comes out, and a pair of coat hangar rod handles.

Also, make a squaring jig - a strong box or block just slightly smaller (1/32") than the inside dimension of your box. Cover it with brown plastic mailing tape so the glue doesn't stick, and wash it off with the wet sponge after you sponge off the hive body. Clamping with bar clamps is quick and easy, get 8 staples into the box corners so it holds square, and shove the jig out. You can clamp as strategically as necessary as you complete stapling, checking with your framing square. You staple the box to the jig less often this way. Doing this and building the boxes over-tall, then trimming them flat and square to final height makes them stack pretty evenly. You are only ever off about 1/16" out of square across an entire run of boxes and using the same jig, from run to run as well.

Steve A - Are you talking about a hidden dowel joint? I guarantee fingers + glue + 1.75" long x 1/2" crown staples are stronger after the weather has had at them a few years, but I like how you question everything.

Another good joint is a lockmiter joint made at 90 degrees, as it has no end grain exposed and LOTS of glue area. Staple or nail it all you want, even biscuit it. Faster to make, and probably the best joint out there, but you have to have a planer to control the thickness so both parts are the same thickness and really slam that board down on the shaper table (and the 90 degree part against the upright angle plate) with finger boards. Unless you are going to set up for high accuracy, it's probably very frustrating for the average guy in the home shop.
 
#78 · (Edited)
Big thank you, Graham!

I have a buddy here now so will make an ASCII pic soon.

Ok pray for me...

\...............\
.\...............\
..\...............\
...\...............\<--Long Side (19 7/8" finished)
....\...............\
.....\...............\
......\________\_____________________________________________________________________________
.......l\....3/8" wide x 5/8" deep narrow lip on top of short end (16 1/4") of hive body due to rabbet for hanging frames
.......l..\______________________________________________________________________________________
....l\.l...l
....l.\l...l<--NOTICE STAGGERED NOTCH in long side!
....l......l......O<--nail
....l......l..Double-wide finger (3/4" x 1.5" with 3/8" x 5/8" rabbet on inside)
....\.....l
.....\....l
......\...l......O <--nail
....l\..\.l
....l.\..\l_________
....l..\..l................l
....l...\.l................l
....\...\l_________l..First finger from long side
......\..l
.......\.l
.........l__________
.........l.................l

I hope this helps.
 
#79 ·
kilocharlie...Thanks.. I think I have the concept. I am in Georgia until Saturday, but when I get back to Ky. I am going to look at this, build a nuc and take pictures to see if I understand it.

If I understand this concept it is the same concept used for years, except it has a double finger on 16 1/4 board with 3/8 rabbet in it and the front frame rest rabbet overlaps the first finger of the long side of the box.( which has a reduced finger)

I can't debate,(notice debate, not argue) the merits of the new/vrs old concept, but since I have never had a problem with the old way,(several thousands of boxes) I think I will stay with the old way, at least for the time being. This is not to say that I am set in my ways in my older years, I am ALWAYS open to new and better ways to do things, and I sincerely appreciate people discussing and advancing better ways to make equipment and keep bees.

kilocharlie..I just saw your more recent post. I will reread it and get back later. Still in Georgia so can't do anything until I get back to Ky.

cchoganjr
 
#82 ·
KC- I fixed the CODE NOCODE issues and put it into a fixed-pitch font, but I'm not sure exactly how the pic should look.
Code:
\...............\
.\...............\
..\...............\
...\...............\<--Long Side (19 7/8" finished)
....\...............\
.....\...............\
......\________\__________________________________ ___________________________________________
.......l\....3/8" wide x 5/8" deep narrow lip on top of short end (16 1/4") of hive body due to rabbet for hanging frames
.......l..\_______________________________________ _______________________________________________
....l\.l...l
....l.\l...l<--NOTICE STAGGERED NOTCH in long side!
....l......l......O<--nail
....l......l..Double-wide finger (3/4" x 1.5" with 3/8" x 5/8" rabbet on inside)
....\.....l
.....\....l
......\...l......O <--nail
....l\..\.l
....l.\..\l_________
....l..\..l................l
....l...\.l................l
....\...\l_________l..First finger from long side
......\..l
.......\.l
.........l__________
.........l.................l
 
#83 · (Edited)
Graham - Big thanks! I should have tried the right justify trick. The only problem with my ASCII pic is that some of the lines (namely the 3/8" narrow lip due to the frame hanger rabbet underlines) are too long and wrapped around. It came up right on my screen, but the host isn't quite WYSIWYG.

Your's is closer - the only miss is there are too many periods in the first finger on the long side (down below the 2nd "O <--nail"). The lower case "l" should line up with the inside edge of the long side, where it diagonals down above. All in all, a fantastic effort. Cheers!

Cleo - My digital camera is dead right now, so if you have a Brushy Mountain Bee Farm 2012 catalog, look carefully at page 8 in the bottom left corner under the title "Select Woodenware" all 3 boxes are made with this joint, and the medium super shows the top finger the best because the end grain appears a little bit darker, so you can see the staggered notch. From your response, I think you get it now.

Dadant and Sons' 2012 catalog shows on page 12 a stagger but NOT the double-wide finger on the top 16.25" end that gives the huge advantage (more gluing area and 2 fasteners). Mann Lake shows the same mistake on page 13 of it's 2013 catalog, so check out the Brushy Mountain pic. Photocopy it and blow it up to full size. Right now, the one in the Brushy Mountain picture is the best way to make standard Langstroth hives and really is worth the small extra effort. BTW, I admire your mental tenacity! You really want to get this...no one can stop a guy like that. Bravo!

One more easy modification to the method you seem to be using now is to put a plate the right thickness (3/8") below the stack of parts in the sled while dado cutting the "short notch" (just for that one funny cut), then remove the plate, index the stack of parts to your next full-depth cut (immediately adjacent to the shallow cut in this case), and continue dado cutting the other fingers as normal. This should be a little bit easier, and it eliminates the need to crank the dado down 4 turns (not easy to repeat accurately). Good luck, and safe journey. - Casey
 
#84 · (Edited)
Has anyone built a gang dado on a shaft? I'm wondering how much deflection due to side loading (cutting force - worst case scenario) and how much safety factor to design into my bearing / shaft combination (figure 10" long shaft supported at both ends)?

I'm expecting a 1" shaft will do for deeps, with a cast iron flanged, semi-sealed ball bearing with a 4-bolt pattern (about 4.5" square on centers) will do the job, but I'm making the prototype out of 1 1/8" plywood - quick and dirty first, aluminum plate welded later!

My design has 100 workpieces stacked sideways in the big sled, and a gang of cutters on two vertical shafts to cut the whole shebang in one pass. I'm thinking a top frame truss to tie it all together will reduce deflection and hence force-variation will be minimized. Anyone using V-belts? Multi-groove belts? Cog belts? I'd love to hear from anyone who has run some numbers, drawn, or actually built one.
 
#85 · (Edited)
kilo.. I haven't built one, but, I have seen them, and there is a good example on uTube. I am trying to find it. I think his shaft is about 1 inch, shaft supported by pillow block bearings, and belt driven. He cuts one at a time, but, it is fast, it is a device where you simply drop the wood into a holder, then using a long handle you push the wood forward and it cuts all cuts at one pass. Perhaps 5 seconds each piece.

I can't remember the uTube video, hopefully, someone will, it is something like cheezer or something like that.

I found it... "Behive finger joints" by Justin Cheesman I hope this will link you to it. http://www.youtube.com/watch?v=y9Sti5hf0Uc His video shows the 3/8 indention on the long side of the bee box.

cchoganjr
 
#86 ·
Thanks, kilocharlie.... I don't have a Brushy Mountain, but, I will see if I can download it. I buy very few bee supplies, mostly frames and foundation. Everything else I make, and if I do need something, Kelly Bee Co. is only 35 minutes from me. For me, the woodworking is almost as much fun as the bees, and it gives me something to do in the Winter.

Yes, I used the 3/8 piece under the stock, but for me it was just as fast to lower 4 turns, cut the two, and crank back up 4 turns, as it was to pick up the spacer, place it on the sled, cut the two pieces and remove the spacer and hang back on the wall with other patterns.

cchoganjr
 
#87 ·
The gang cutter you describe is probably exactly what's use for production, the only difference would be a mechanism for continuous feeding maybe.

Plan on a 5 horse motor at a minimum, you're gonna need some power to cut that many at once. My saw bogs on a 13/16 cut, let alone eight, with a two horse motor.

Obviously the profile cuts are easy on the gang saw, you just set up whatever you want and have at it.

Peter
 
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